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2016 Vol. 15 No. 12 Previous Issue    Next Issue

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Review
Crop Genetics · Breeding · Germplasm Resources
Physiology·Biochemistry·Cultivation·Tillage
Plant Protection
Animal Science · Veterinary Science
Soil & Fertilization﹒Irrigation﹒Plant Nutrition﹒ Agro-Ecology & Environment
Food Science
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The causes and impacts for heat stress in spring maize during grain filling in the North China Plain - A review TAO Zhi-qiang, CHEN Yuan-quan, LI Chao, ZOU Juan-xiu, YAN Peng, YUAN Shu-fen, WU Xia, SUI Peng 2016, 15(12): 2677-2687.  DOI: 10.1016/S2095-3119(16)61409-0 Abstract ( )   PDF in ScienceDirect   High-temperature stress (HTS) at the grain-filling stage in spring maize (Zea mays L.) is the main obstacle to increasing productivity in the North China Plain (NCP). To solve this problem, the physiological mechanisms of HTS, and its causes and impacts, must be understood. The HTS threshold of the duration and rate in grain filling, photosynthetic characteristics (e.g., the thermal stability of thylakoid membrane, chlorophyll and electron transfer, photosynthetic carbon assimilation), water status (e.g., leaf water potential, turgor and leaf relative water content) and signal transduction in maize are reviewed. The HTS threshold for spring maize is highly desirable to be appraised to prevent damages by unfavorable temperatures during grain filling in this region. HTS has negative impacts on maize photosynthesis by damaging the stability of the thylakoid membrane structure and degrading chlorophyll, which reduces light energy absorption, transfer and photosynthetic carbon assimilation. In addition, photosynthesis can be deleteriously affected due to inhibited root growth under HTS in which plants decrease their water-absorbing capacity, leaf water potential, turgor, leaf relative water content, and stomatal conductance. Inhibited photosynthesis decrease the supply of photosynthates to the grain, leading to falling of kernel weight and even grain yield. However, maize does not respond passively to HTS. The plant transduces the abscisic acid (ABA) signal to express heat shock proteins (HSPs), which are molecular chaperones that participate in protein refolding and degradation caused by HTS. HSPs stabilize target protein configurations and indirectly improve thylakoid membrane structure stability, light energy absorption and passing, electron transport, and fixed carbon assimilation, leading to improved photosynthesis. ABA also induces stomatal closure to maintain a good water status for photosynthesis. Based on understanding of such mechanisms, strategies for alleviating HTS at the grain-filling stage in spring maize are summarized. Eight strategies have the potential to improve the ability of spring maize to avoid or tolerate HTS in this study, e.g., adjusting sowing date to avoid HTS, breeding heat-tolerance varieties, and tillage methods, optimizing irrigation, heat acclimation, regulating chemicals, nutritional management, and planting geometric design to tolerate HTS. Based on the single technology breakthrough, a comprehensive integrated technical system is needed to improve heat tolerance and increase the spring maize yield in the NCP.

Crop Genetics · Breeding · Germplasm Resources

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Genetic dissection of the developmental behavior of plant height in rice under different water supply conditions WANG Jiang-xu, SUN Jian, LI Cheng-xin, LIU Hua-long, WANG Jing-guo, ZHAO Hong-wei, ZOU De-tang 2016, 15(12): 2688-2702.  DOI: 10.1016/S2095-3119(16)61427-2 Abstract ( )   PDF in ScienceDirect       Plant height (PH) is one of the most important agronomic traits of rice, as it directly affects the lodging resistance and the high yield potential. Meanwhile, PH is often constrained by water supply over the entire growth period. In this study, a recombinant inbred line (RIL) derived from Xiaobaijingzi and Kongyu 131 strains grown under drought stress and with normal irrigation over 2 yr (2013 and 2014), respectively (regarded as four environments), was used to dissect the genetic basis of PH by developmental dynamics QTL analysis combined with QTL×environment interactions. QTLs with net effects excluding the accumulated effects were detected to explore the relationship between gene×gene interactions and gene×environment interactions in specific growth period. A total of 26 additive QTLs (A-QTLs) and 37 epistatic QTLs (E-QTLs) associated with PH were detected by unconditional and conditional mapping over seven growth periods. qPH-2-3, qPH-4-3, qPH-6-1, qPH-7-1, and qPH-12-5 could be detected by both unconditional and conditional analyses. qPH-4-3 and qPH-7-5 were detected in four stages (periods) to be sequentially expressed QTLs controlling PH continuous variation. QTLs with additive effects (A-QTLs) were mostly expressed in the period S3|S2 (the time interval from stages 2 to 3), and QTL×environment interactions performed actively in the first three stages (periods) which could be an important developmental period for rice to undergo external morphogenesis during drought stress. Several QTLs showed high adaptability for drought stress and many QTLs were closely related to the environments such as qPH-3-5, qPH-2-2 and qPH-6-1. 72.5% of the QTLs with a and aa effects detected by conditional analysis were under drought stress, and the PVE of QTLs detected by conditional analysis under drought stress were also much higher than that under normal irrigation. We infer that environments would influence the detection results and sequential expression of genes was highly influenced by environments as well. Many QTLs (qPH-1-2, qPH-3-5, qPH-4-1, qPH-2-3) coincident with previously identified drought resistance genes. The result of this study is helpful to elucidating the genetic mechanism and regulatory network underlying the development of PH in rice and providing references to marker assisted selection.

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Linkage map construction and QTL mapping for cold tolerance in Oryza rufipogon Griff. at early seedling stage LUO Xiang-dong, ZHAO Jun, DAI Liang-fang, ZHANG Fan-tao, ZHOU Yi, WAN Yong, XIE Jian-kun 2016, 15(12): 2703-2711.  DOI: 10.1016/S2095-3119(16)61465-X Abstract ( )   PDF in ScienceDirect       Cold stress is one of the major restraints for rice production. Cold tolerance is controlled by complex genetic factor. In this study, a backcross inbred lines (BILs) population derived from an inter-specific cross (Oryza sativa L.×O. rufipogon Griff.) was used for genetic linkage map construction and quantitative trait locus (QTL) mapping. A linkage map consisting of 153 markers was constructed, spanning 1 596.8 cM with an average distance of 11.32 cM between the adjacent markers. Phenotypic evaluation of the parents and BILs under (6±1)°C cold stress revealed that the ability of cold tolerance in BILs at early seedling obeyed a skewed normal and continuous distribution. Fifteen QTLs on chromosomes 6, 7, 8, 11, and 12 were identified using survival percent (SP) and non death percent (NDP) as indicators of cold tolerance, which could explain 5.99 to 40.07% of the phenotypic variance, of which the LOD values ranged from 3.04 to 11.32. Four QTLs on chromosomes 3, 5 and 7 were detected using leaf conductivity (LC) and root conductivity (RC) as indicators of cold tolerance, ranging from 19.54 to 33.53% for the phenotypic variance explained and 2.54 to 6.12 for the LOD values. These results suggested that there might be multi major QTLs in O. rufipogon and some useful genes for cold tolerance have been transferred into cultivated rice, which would be helpful for cloning and utilizing the cold tolerance-responsive genes from wild rice.

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Molecular identification of ω-secalin gene expression activity in a wheat 1B/1R translocation cultivar CHAI Jian-fang, ZHANG Cui-mian, MA Xiu-ying, WANG Hai-bo 2016, 15(12): 2712-2718.  DOI: 10.1016/S2095-3119(15)61290-4 Abstract ( )   PDF in ScienceDirect       ω-Secalin was an important factor influencing processing quality of wheat 1BL/1RS translocations. On the basis of four ω-secalin gene sequences cloned from Lankao 906 (a wheat cultivar with 1BL/1RS translocation) with putative transcription activity, a pair of primers with suitable restriction endonucleases added at their 5´ ends were designed to amplify the mature protein-coding regions of the four genes. After digestion with restriction endonucleases, the amplified products were ligated into the prokaryotic expression vector pET30a(+). The prokaryotically expressed recombinant proteins and gliadin isolated from the Lankao 906 seed were analyzed on the same acid polyacrylamide gel electrophoresis. All four prokaryotically expressed secalin bands had corresponding seed-expressed gliadin bands. The four corresponding gliadin bands were confirmed to be the expression products of the four ω-secalin genes by liquid chromatography tandem mass spectrometry (LC-MS/MS). This conclusion was further confirmed because the four ω-secalin bands could be detected in all 14 wheat 1BL/1RS translocation cultivars used in the study, although there was some interference for the detection of one ω-secalin band from nearby wheat gliadin bands. The sequence information of ω-secalin genes with expression activity will be helpful for improving the processing quality of wheat with 1BL/1RS translocations by using RNA interference method to silence the expression of the ω-secalin genes.

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Mapping of the heading date gene HdAey2280 in Aegilops tauschii LIU Guo-xiang, ZHANG Li-chao, XIA Chuan, JIA Ji-zeng, ZHANG Jun-cheng, ZHANG Qiang, DONG Chun-hao, KONG Xiu-ying, LIU Xu 2016, 15(12): 2719-2725.  DOI: 10.1016/S2095-3119(15)61291-6 Abstract ( )   PDF in ScienceDirect       An optimum heading date is essential for sustainable crop productivity and ensuring high yields. In the present study, F2:3 populations were generated by crossing an early-heading accession, Y2280, with a late-heading accession, Y2282. The heading dates of the F2 and F3 populations were investigated in a field study. Using publicly available simple sequence repeat (SSR) markers, the early heading date gene HdAey2280 was mapped onto Aegilops tauschii chromosome 7DS between the flanking markers wmc438 and barc126 at distances of 15 and 9.1 cM, respectively. Further analysis indicated that HdAey2280 is a novel heading date gene. New SSR markers were developed based on the Ae. tauschii draft genome sequence, resulting in four new markers that were linked to the heading date gene HdAey2280. The closest distance of these markers was 1.9 cM away from the gene. The results collected in this study will serve as a framework for map-based cloning and marker-assisted selection in wheat breeding programs in the future.

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Heterotic loci identified for plant height and ear height using two CSSLs test populations in maize WANG Hong-qiu, ZHANG Xiang-ge, YANG Hui-li, CHEN Yong-qiang, YUAN Liang, LI Wei-hua, LIU Zong-hua, TANG Ji-hua, KANG Ding-ming 2016, 15(12): 2726-2735.  DOI: 10.1016/S2095-3119(16)61376-X Abstract ( )   PDF in ScienceDirect        Heterosis is an important biological phenomenon, and it has been used to increase grain yield, quality and resistance to abiotic and biotic stresses in many crops. However, the genetic mechanism of heterosis remains unclear up to now. In this study, a set of 184 chromosome segment substitution lines (CSSLs) population, which derived from two inbred lines lx9801 (the recurrent parent) and Chang 72 (the donor parent), were used as basal material to construct two test populations with the inbred lines Zheng 58 and Xun 9058. The two test populations were evaluated in two locations over two years, and the heterotic loci for plant height and ear height were identified by comparing the performance of each test hybrid with the corresponding CK at P<0.05 significant level using one-way ANOVA analysis and Duncan’s multiple comparisons. There were 24 and 29 different heterotic loci (HL) identified for plant height and ear height in the two populations at two locations over two years. Three HL (hlPH4a, hlPH7c, hlPH1b) for plant height and three (hlEH1d, hlEH6b, hlEH1b) for ear height were identified in the CSSLs×Zheng 58 and CSSLs×Xun 9058 populations as contributing highly to heterosis performance of plant height and ear height across four environments. Among the 29 HL identified for ear height, 12 HL (41.4%) shared the same chromosomal region associated with the HL (50.0%) identified for plant height in the same test population and environment.

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DNA methylation patterns of banana leaves in response to Fusarium oxysporum f. sp. cubense tropical race 4 LUO Jing-yao, PAN Xiao-lei, PENG Tie-cheng, CHEN Yun-yun, ZHAO Hui, MU Lei, PENG Yun, HE Rui, TANG Hua 2016, 15(12): 2736-2744.  DOI: 10.1016/S2095-3119(16)61495-8 Abstract ( )   PDF in ScienceDirect       Fusarium wilt of banana, which is caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), is a serious soil-borne fungal disease. Now, the epigenetic molecular pathogenic basis is elusive. In this study, with methylation-sensitive amplification polymorphism (MSAP) technique, DNA methylation was compared between the leaves inoculated with Foc TR4 and the mock-inoculated leaves at different pathogenic stages. With 25 pairs of primers, 1 144 and 1 255 fragments were amplified from the infected and mock-inoculated leaves, respectively. DNA methylation was both changed and the average methylated CCGG sequences were 34.81 and 29.26% for the infected and the mock-inoculated leaves. And DNA hypermethylation and hypomethylation were induced by pathogen infection during all pathogenic stages. Further, 69 polymorphic fragments were sequenced and 29 of them showed sequence similarity to genes with known functions. And RT-PCR results of four genes indicated that their expression patterns were consistent with their methylation patterns. Our results suggest that DNA methylation plays important roles in pathogenic response to Foc TR4 for banana.

Physiology·Biochemistry·Cultivation·Tillage

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Foliar application of sodium hydrosulfide (NaHS), a hydrogen sulfide (H2S) donor, can protect seedlings against heat stress in wheat (Triticum aestivum L.) YANG Min, QIN Bao-ping, MA Xue-li, WANG Ping, LI Mei-ling, CHEN Lu-lu, CHEN Lei-tai, SUN Aiqing, WANG Zhen-lin, YIN Yan-ping 2016, 15(12): 2745-2758.  DOI: 10.1016/S2095-3119(16)61358-8 Abstract ( )   PDF in ScienceDirect       Temperature extremes represent an important limiting factor to plant growth and productivity. Low concentration of hydrogen sulfide (H2S) has been proven to function in physiological responses to various stresses. The present study evaluated the effect of foliar application of wheat seedlings with a H2S donor, sodium hydrosulfide (NaHS), on the response to acute heat stress. The results showed that pretreatment with NaHS could promote heat tolerance of wheat seedlings in a dose-dependent manner. Again, it was verified that H2S, rather than other sulfur-containing components or sodion derived from NaHS solution, should contribute to the positive role in promoting wheat seedlings against heat stress. To further study antioxidant mechanisms of NaHS-induced heat tolerance, superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6) and ascorbate peroxidase (APX, EC 1.11.1.11) activities, and H2S, hydrogen peroxide (H2O2), malonaldehyde (MDA), and soluble sugar contents in wheat seedlings were determined. The results showed that, under heat stress, the activities of SOD, CAT, and APX, H2S, H2O2, MDA, and soluble sugar contents in NaHS-pretreated seedlings and its control all increased. Meanwhile, NaHS-pretreated seedlings showed higher antioxidant enzymes activities and gene expression levels as well as the H2S and soluble sugar levels, and lower H2O2, MDA contents induced by heat stress. While little effect was detected in antioxidant enzymes activities and soluble substances contents in pretreated wheat seedlings compared with its control under normal culture conditions (data not shown). All of our results suggested that exogenous NaHS could alleviate oxidative damage and improve heat tolerance by regulating the antioxidant system in wheat seedlings under heat stress.

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Effect of polyamine on seed germination of wheat under drought stress is related to changes in hormones and carbohydrates LIU Yang, XU Hong, WEN Xiao-xia, LIAO Yun-cheng 2016, 15(12): 2759-2774.  DOI: 10.1016/S2095-3119(16)61366-7 Abstract ( )   PDF in ScienceDirect       Drought is a multifaceted stress condition that inhibits crop growth. Seed germination is one of the critical and sensitive stages of plants, and its process is inhibited or even entirely prevented by drought. Polyamines (PAs) are closely associated with plant resistance to drought stress and seed germination. However, little is known about the effect of PA on the seed germination of wheat under drought stress. This study investigated the involvement of PAs in regulating wheat seed germination under drought stress. Six wheat genotypes differing in drought resistance were used, and endogenous PA levels were measured during seed germination under different water treatments. In addition, external PA was used for seed soaking and the variation of hormones, total soluble sugar and starch were measured during the seed germination under different water treatments. These results indicated that the free spermidine (Spd) accumulation in seeds during the seed germination period favored wheat seed germination under drought stress; however, the free putrescine (Put) accumulation in seeds during the seed germination period may work against wheat seed germination under drought stress. In addition, seed soaking in Spd and spermine (Spm) significantly relieved the inhibition of seed germination by drought stress; however, soaking seeds in Put had no significant effect on seed germination under drought. External Spd and Spm significantly increased the endogenous indole-3-acetic acid (IAA), zeatin (Z)+zeatin riboside (ZR), abscisic acid (ABA), and gibberellins (GA) contents in seeds and accelerated the seed starch degradation and increased the concentration of soluble sugars in seeds during seed germination. This may promote wheat seed germination under drought stress. In conclusion, free Spd and Put are key factors for regulating wheat seed germination under drought stress and the effects of Spd and Put on seed germination under drought notably related to hormones and starch metabolism.

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Increased sink capacity enhances C and N assimilation under drought and elevated CO2 conditions in maize ZONG Yu-zheng, SHANGGUAN Zhou-ping 2016, 15(12): 2775-2785.  DOI: 10.1016/S2095-3119(16)61428-4 Abstract ( )   PDF in ScienceDirect       The maintenance of rapid growth under conditions of CO2 enrichment is directly related to the capacity of new leaves to use or store the additional assimilated carbon (C) and nitrogen (N). Under drought conditions, however, less is known about C and N transport in C4 plants and the contributions of these processes to new foliar growth. We measured the patterns of C and N accumulation in maize (Zea mays L.) seedlings using 13C and 15N as tracers in CO2 climate chambers (380 or 750 µmol mol–1) under a mild drought stress induced with 10% PEG-6000. The drought stress under ambient conditions decreased the biomass production of the maize plants; however, this effect was reduced under elevated CO2. Compared with the water-stressed maize plants under atmospheric CO2, the treatment that combined elevated CO2 with water stress increased the accumulation of biomass, partitioned more C and N to new leaves as well as enhanced the carbon resource in ageing leaves and the carbon pool in new leaves. However, the C counterflow capability of the roots decreased. The elevated CO2 increased the time needed for newly acquired N to be present in the roots and increased the proportion of new N in the leaves. The maize plants supported the development of new leaves at elevated CO2 by altering the transport and remobilization of C and N. Under drought conditions, the increased activity of new leaves in relation to the storage of C and N sustained the enhanced growth of these plants under elevated CO2.

Plant Protection

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MAP kinase gene STK1 is required for hyphal, conidial, and appressorial development, toxin biosynthesis, pathogenicity, and hypertonic stress response in the plant pathogenic fungus Setosphaeria turcica LI Po, GONG Xiao-dong, JIA Hui, FAN Yong-shan, ZHANG Yun-feng, CAO Zhi-yan, HAO Zhi-min, HAN Jian-min, GU Shou-qin, DONG Jin-gao 2016, 15(12): 2786-2794.  DOI: 10.1016/S2095-3119(16)61472-7 Abstract ( )   PDF in ScienceDirect   The mitogen-activated protein kinase (MAPK), a key signal transduction component in the MAPK cascade pathway, regulates a variety of physiological activities in eukaryotes.  However, little is known of the role MAPK plays in phytopathogenic fungi.  In this research, we cloned the MAPK gene STK1 from the northern corn leaf blight pathogen Setosphaeria turcica and found that the gene shared high homology with the high osmolality glycerol (HOG) MAPK gene HOG1 of Saccharomyces cerevisiae.  In addition, gene knockout technology was employed to investigate the function of STK1.  Gene knockout mutants (KOs) were found to have altered hyphae morphology and no conidiogenesis, though they did show similar radial growth rate compared to the wild-type strain (WT).  Furthermore, microscope observations indicated that STK1 KOs did not form normal appressoria at 48 h post-inoculation on a hydrophobic surface.  STK1 KOs had reduced virulence, a significantly altered Helminthosporium turcicum (HT)-toxin composition, and diminished pathogenicity on the leaves of susceptible inbred corn OH43.  Mycelium morphology appeared to be significantly swollen and the radial growth rates of STK1 KOs declined in comparison with WT under high osmotic stress.  These results suggested that STK1 affects the hyphae development, conidiogenesis, and pathogenicity of S. turcica by regulating appressorium development and HT-toxin biosynthesis.  Moreover, the gene appears to be involved in the hypertonic stress response in S. turcica.

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Antimicrobial, herbicidal and antifeedant activities of mansonone E from the heartwoods of Mansonia gagei Drumm. Rachsawan Mongkol, Warinthorn Chavasiri 2016, 15(12): 2795-2802.  DOI: 10.1016/S2095-3119(16)61444-2 Abstract ( )   PDF in ScienceDirect       In vitro biological activities including anti-phytopathogenic fungi, antibacterial, antifeedant and herbicidal activities of the extracts from the heartwoods of Mansonia gagei Drumm. were evaluated. The dichloromethane (DCM) extract displayed antifungal activity against four plant pathogenic fungi (Alternaria porri, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora parasitica) higher than the methanolic (MeOH) extract. The separation of the DCM extract using bioassay guided antifungal activity against P. parasitica led to the isolation of mansorins A, B, and C, mansonones C, E, G and H. Among isolated compounds, mansonone E displayed the highest antifungal activity against P. parasitica, followed by mansonone C, mansorin B and mansonone G. This potent compound revealed the same minimum inhibitory concentrations (MIC) of 31 µg mL–1 against C. gloeosporioides and P. parasitica, and minimum fungicidal concentration (MFC) of 31 and 125 µg mL–1, respectively. Moreover, mansonone E exhibited highly significant antibacterial activity against both Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc) with MIC and minimum bactericidal concentration (MBC) as 7.8 and >500 µg mL–1, respectively. This compound furthermore could inhibit the feed of Spodoptera litura with 45.9% antifeedant and significantly herbicidal activity reduced the shoot and root growth of Brassica chinensis, Oryza sativa, Mimosa pigra and Echinochlooa crus-galli. Mansonone E has potential as a new natural pesticide for agricultural plant pathogen management.

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Field resistance to spinosad in western flower thrips Frankliniella occidentalis (Thysanoptera: Thripidae) LI Dong-gang, SHANG Xiao-yong, Stuart Reitz, Ralf Nauen, LEI Zhong-ren, Si Hyeock Lee, GAO Yu-lin 2016, 15(12): 2803-2808.  DOI: 10.1016/S2095-3119(16)61478-8 Abstract ( )   PDF in ScienceDirect       The western flower thrips, Frankliniella occidentalis, is one of the most destructive sucking pests of vegetables, fruits and ornamental crops in China. Spinosad is one of the most commonly used insecticides to manage thrips. To assess the incidence of spinosad resistance in F. occidentalis field populations in eastern China, survival rates for 24 different populations were compared with those of a susceptible laboratory strain. All populations showed significantly higher resistance to spinosad compared with the control as determined by comparing median lethal concentrations. Two populations from Shouguang and Liaocheng in Shandong Province were classified as having moderate and high levels of resistance to spinosad with a mean resistance ratio of 17.0 and 89.2, respectively. Our research indicates a widespread reduction in spinosad efficacy for controlling F. occidentalis field populations, and that resistance management strategies should be implemented as soon as practicable, to reduce the potential of progressive resistance development and loss of efficacy.

Animal Science · Veterinary Science

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Effects of back fat, growth rate, and age at first mating on Yorkshire and Landrace sow longevity in China HU Bin, MO De-lin, WANG Xiao-ying, LIU Xiao-hong, CHEN Yao-sheng 2016, 15(12): 2809-2818.  DOI: 10.1016/S2095-3119(16)61381-3 Abstract ( )   PDF in ScienceDirect   In the present study, genetic parameters for longevity and genetic correlations with back fat (BF), average daily gain (ADG), and first mating age (FMA) were estimated from 19 300 Yorkshire and 18 378 Landrace sows from 12 farms derived from one breeding system. General linear models (GLM) were employed to estimate genetic correlations with heritability (h2). Longevity was defined by six different parameters (i.e., traits) and heritability ranged from h2=0.13 to 0.16 (P<0.05) in both swine breeds. Genetic correlations between different longevity definitions were positive and high (r=0.79 to 0.99; P<0.05). BF exhibited low positive genetic correlations (r=0.12 to 0.15; P<0.05) with longevity traits identified in both pig breeds which were dependent on trait definition, whereas ADG and FMA showed weak negative genetic correlations with longevity traits. The influence of BF, ADG, and FMA on longevity traits was examined by dividing the production and reproductive traits into several numerical groups; the influence of each longevity trait was subsequently analyzed among the different groups. The results indicated BF was the best trait to improve longevity among BF, ADG, and FMA, which showed positive effects for almost all longevity traits. For Yorkshire sows, gilts with over 18 mm BF were most desirable; Landrace with 10.6–13 mm BF were suitable for longevity. ADG was not favorable for gilt selection, because the correlation between growth rate and longevity very low. For FMA, our results indicated gilts mating before 230 days exhibited a longer life span. Therefore, we suggest farmers should select for thicker back fat and mate at an earlier age to improve sow longevity.

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Expression analysis, single nucleotide polymorphisms within SIRT4 and SIRT7 genes and their association with body size and meat quality traits in Qinchuan cattle GUI Lin-sheng, XIN Xiao-ling, WANG Jia-li, HONG Jie-yun, ZAN Lin-sen 2016, 15(12): 2819-2826.  DOI: 10.1016/S2095-3119(16)61419-3 Abstract ( )   PDF in ScienceDirect       Silent information regulator 2 (Sir2) proteins, or sirtuins, are nicotine adenine dinucleotide (NAD)-dependent deacetylases that connect metabolism with longevity in lower organisms. In mammals, there are seven Sir2 homologs, namely, silent information regulators (SIRT1–7). SIRT4 and SIRT7 genes play a crucial role in regulating lipid metabolism, cellular growth and metabolism. This suggests that they are potential candidate genes for affecting body size and meat quality traits in animals. Hence, this study aimed to detect genetic variations of both SIRT4 and SIRT7 bovine genes in Qinchuan cattle, and to evaluate the effect of these variations on economically important body size and meat quality traits. Expression analysis using quantitative real-time PCR (qPCR) indicated that SIRT4 and SIRT7 were broadly expressed in all thirteen studied tissues. The expression of SIRT4 was higher in liver, muscle, and in subcutaneous fat tissue. In the case of SIRT7, the expression was higher in lung, abomasum, and subcutaneous fat. Using DNA sequencing, a total of three single nucleotide polymorphisms (SNPs) were identified within SIRT4 and SIRT7 genes in 468 Qinchuan cattle. These included one novel SNP within 3´ untranslated regions (UTR) of SIRT4 (SNP1: g.13915A>G) and two novel synonymous substitutions in SIRT7 (SNP2: g.3587C>T and SNP3: g.3793T>C). Statistical analyses indicated that all three SNPs could significantly influence some body size and meat quality traits in Qinchuan cattle. These novel findings will provide a background for application of bovine SIRT4 and SIRT7 genes in the selection program of Chinese cattle.

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Impacts of the unsaturation degree of long-chain fatty acids on the volatile fatty acid profiles of rumen microbial fermentation in goats in vitro GAO Jian, WANG Meng-zhi, JING Yu-jia, SUN Xue-zhao, WU Tian-yi, SHI Liang-feng 2016, 15(12): 2827-2833.  DOI: 10.1016/S2095-3119(16)61418-1 Abstract ( )   PDF in ScienceDirect       This study investigated the impacts of the degree of unsaturation (unsaturity) of long-chain fatty acids on volatile fatty acid (VFA) profiles of rumen fermentation in vitro. Six types of long-chain fatty acids, including stearic acid (C18:0, control group), oleic acid (C18:1, n-9), linoleic acid (C18:2, n-6), α-linolenic acid (C18:3, n-3), arachidonic acid (C20:4, n-6) and eicosapentaenoic acid (C20:5, n-3), were tested. Rumen fluid from three goats fitted with ruminal fistulae was used as inoculum and the inclusion rate of long-chain fatty acid was at 3% (w/w) of substrate. Samples were taken for VFA analysis at 0, 3, 6, 9, 12, 18 and 24 h of incubation, respectively. The analysis showed that there were significant differences in the total VFA among treatments, sampling time points, and treatment×time point interactions (P<0.01). α-Linolenic acid had the highest total VFA (P<0.01) among different long-chain fatty acids tested. The molar proportion of acetate in total VFA significantly differed among treatments (P<0.01) and sampling time points (P<0.01), but not treatment×time point interactions (P>0.05). In contrast, the molar proportion of propionate did not differ among treatments during the whole incubation (P>0.05). However, for butyrate molar proportions, significant differences were found not only among sampling time points but also among treatments and treatment×time point interactions (P<0.01), with eicosapentaenoic acid having the highest value (P<0.01). Additionally, no statistically significant differences were found in the acetate to propionate ratios among treatments groups (P>0.05), even the treatments stearic acid and α-linolenic acid were numerically higher than the others. The inclusion of 3% long-chain unsaturated fatty acids differing in the degree of unsaturation brought out a significant quadratic regression relation between the total VFA concentration and the double bond number of fatty acid. In conclusion, the α-linolenic acid with 3 double bonds appeared better for improving rumen microbial fermentation and the total VFA concentration.

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Effect of lactic acid bacteria inoculants on alfalfa (Medicago sativa L.) silage quality: assessment of degradation (in situ) and gas production (in vitro) LIU Ce, LAI Yu-jiao, LU Xiao-nan, GUO Ping-ting, LUO Hai-ling 2016, 15(12): 2834-2841.  DOI: 10.1016/S2095-3119(16)61424-7 Abstract ( )   PDF in ScienceDirect       Alfalfa (Medicago sativa) is difficult to ensile successfully because of the low content of moisture and water-soluble carbohydrates (WSC) in fresh alfalfa and the high buffering capacity in fresh alfalfa. Here, we conducted a study to evaluate the effects of three lactic acid bacteria (LAB) inoculants (Lactobacillus casei, Lactobacillus plantarum, and Pediococcus pentosaceus) on silage quality, in situ ruminal degradability, and in vitro fermentation of alfalfa silage. The first cut of alfalfa was wilted, chopped, and randomly divided into four groups: the control (CON) and control mixed with three separate LAB inoculants (106 cfu g–1). Simmental steers with a body weight of (452±18) kg and with installed rumen fistulas were prepared for in situ degradation and for in vitro gas production. LAB inoculants had a lower (P<0.05) content of butyric acid than the CON group. Among them, the L. casei inoculated silage had a higher (P<0.05) content of water-soluble carbohydrate (WSC) and a lower (P<0.05) NH3-H content. The effective degradation (ED) of crude protein in LAB inoculation decreased (P<0.05), while the ED of acid detergent fiber increased (P<0.05) in situ fermentation. The alfalfa silage with LAB inoculants produced more carbon dioxide (P<0.05). The NH3-H content of mixed incubation fluid in L. casei inoculated silage was lower (P<0.05) compared with other groups. Therefore, this study showed that LAB inoculants could improve both ensiling quality and degradation. In particular, the L. casei inoculations exhibited better performance by limiting proteolysis during ensiling.

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Genetic characterization of antimicrobial resistance in Staphylococcus aureus isolated from bovine mastitis cases in Northwest China YANG Feng, WANG Qi, WANG Xu-rong, WANG Ling, LI Xin-pu, LUO Jin-yin, ZHANG Shi-dong, LI Hong-sheng 2016, 15(12): 2842-2847.  DOI: 10.1016/S2095-3119(16)61368-0 Abstract ( )   PDF in ScienceDirect       Staphylococcus aureus is the most common etiological pathogen of bovine mastitis. The resistant strains make the disease difficult to cure. The aim of this study was to characterize the genetic nature of the antimicrobial resistance in S. aureus cultured from bovine mastitis in Northwest China in 2014. A total of 44 S. aureus were isolated for antimicrobial resistance and resistance-related genes. Antimicrobial resistance was determined by disc diffusion and the corresponding resistance genes were detected by PCR. Phenotype indicated that S. aureus isolates were resistant to penicillin (84.09%), erythromycin (20.45%), tetracycline (15.91%), gentamicin (9.09%), tobramycin (6.82%), kanamycin (6.82%) and methicillin (2.27%). 9.09% of the S. aureus isolates were classified as multidrug resistant. In addition, genotypes showed that the isolates were resistant to rifampicin (100%, rpoB), penicillin (95.45%, blaZ), tetracycline (22.73%, tetK, tetM, alone or in combination), erythromycin (22.73%, ermB or ermC), gentamicin/tobramycin/kanamycin (2.27%, aacA-aphD), methicillin (2.27%, mecA) and vancomycin (2.27%, vanA). Resistance to tetracycline was attributed to the genes tetK and tetM (r=0.558, P<0.001). This study noted high-level geno- and phenotypic antimicrobial resistance in S. aureus isolates from bovine mastitis cases in Northwest China.

Soil & Fertilization﹒Irrigation﹒Plant Nutrition﹒ Agro-Ecology & Environment

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Soil shear properties as influenced by straw content: An evaluation of field-collected and laboratory-remolded soils FANG Hui-min, ZHANG Qing-yi, JI Chang-ying, GUO Jun 2016, 15(12): 2848-2854.  DOI: 10.1016/S2095-3119(15)61327-2 Abstract ( )   PDF in ScienceDirect       Following a rice or wheat harvest, a large amount of crop residue (straw) is retained in fields. The straw is often incorporated into the soil in order to increase the soil organic carbon storage and to reduce soil erosion. However, it has become apparent that the incorporated straw can significantly alter soil shear properties, which can dramatically affect energy inputs for tilling and other soil management practices. In this study, laboratory-remolded wheat straw-soil samples were compared with field-collected straw-soil samples; we found high correlations for the cohesion (R2=0.9084) and internal friction angle (R2=0.9548) properties of the samples. Shear tests on rice and wheat straw with different moisture content levels clearly demonstrated the relatively higher shear strength of wheat straw compared to rice straw. The cohesion of remolded rice and wheat straw-soil samples exhibited an increasing linear trend with an increase in densities, whereas the internal friction angle data for these samples exhibited a quadratic trend. Overlapping the cohesion curves revealed that the wheat straw-soil and rice straw-soil samples had the same cohesion at a straw density of 0.63%. Similar results were obtained when the internal fraction angle curves overlapped; the resultant point of intersection was observed at a straw density of 0.46%. As a whole, the remolded sample methodology was found suitable to simulate the shear properties of soils sampled directly from fields.

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Shifts in soil bacterial communities induced by the controlled-release fertilizer coatings PAN Pan, JIANG Hui-min, ZHANG Jian-feng, YANG Jun-cheng, LI Shu-shan, LIU Lian, ZHANG Shuiqin, LEI Mei 2016, 15(12): 2855-2864.  DOI: 10.1016/S2095-3119(15)61309-0 Abstract ( )   PDF in ScienceDirect       Coated controlled-release fertilizers (CRFs) have been widely applied in agriculture due to their increased efficiency. However, the widespread and a lot of coated CRFs application may leave undesired coating residues in the soil due to their slow degradation. Limited information is available on the effects of substantial residual coatings on the soil bacterial community. By adding 0, 5, 10, 20, and 50 times quantities of residual coating from conventional application amount of resin and water-soluble coated CRFs, we studied the responses of soil properties and bacterial community composition to these two residual coatings in black soil. The results showed that the resin and water-soluble coatings did not essentially alter the properties of black soil or cause dramatic changes to bacterial diversity within the test concentration range. The residual resin and water-soluble coatings also did not distinctly alter the relative abundance of the top ten bacteria at phylum level. Heatmap results suggested that the treatments were basically clustered into two groups by concentration rather than types of coating material. Pearson correlation analysis showed that the Simpson’s diversity index of the bacterial community was significantly correlated with microbial biomass carbon (MBC, r=0.394, P<0.05), and the richness index abundance-based coverage estimator (ACE) of the bacterial community was significantly correlated with microbial biomass nitrogen (MBN, r=0.407, P<0.05). Overall, results of this study suggested that substantial residual resin and water-soluble coatings with 0–50 times quantities of residual coating from conventional application amount of coated CRFs did not generate obviously negative impacts on the bacterial community in black soil.

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Assessing soil nitrous oxide emission as affected by phosphorus and nitrogen addition under two moisture levels Bashir Ullah, Muhammad Shaaban, HU Rong-gui, ZHAO Jin-song, LIN Shan 2016, 15(12): 2865-2872.  DOI: 10.1016/S2095-3119(16)61353-9 Abstract ( )   PDF in ScienceDirect       Agricultural soils are deficient of phosphorus (P) worldwide. Phosphatic fertilizers are therefore applied to agricultural soils to improve the fertility and to increase the crop yield. However, the effect of phosphorus application on soil N2O emissions has rarely been studied. Therefore, we conducted a laboratory study to investigate the effects P addition on soil N2O emissions from P deficient alluvial soil under two levels of nitrogen (N) fertilizer and soil moisture. Treatments were arranged as follows: P (0 and 20 mg P kg–1) was applied to soil under two moisture levels of 60 and 90% water filled pore space (WFPS). Each P and moisture treatment was further treated with two levels of N fertilizer (0 and 200 mg N kg–1 as urea). Soil variables including mineral nitrogen (NH4+-N and NO3–-N), available P, dissolved organic carbon (DOC), and soil N2O emissions were measured throughout the study period of 50 days. Results showed that addition of P increased N2O emissions either under 60% WFPS or 90% WFPS conditions. Higher N2O emissions were observed under 90% WFPS when compared to 60% WFPS. Application of N fertilizer also enhanced N2O emissions and the highest emissions were 141 µg N2O kg–1 h–1 in P+N treatment under 90% WFPS. The results of the present study suggest that P application markedly increases soil N2O emissions under both low and high soil moisture levels, and either with or without N fertilizer application.

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Effects of collapsing gully erosion on soil qualities of farm fields in the hilly granitic region of South China XIA Dong, DING Shu-wen, LONG Li, DENG Yu-song, WANG Qiu-xia, WANG Shu-ling, CAI Chong-fa 2016, 15(12): 2873-2885.  DOI: 10.1016/S2095-3119(16)61348-5 Abstract ( )   PDF in ScienceDirect   Collapsing gully erosion is a specific form of soil erosion types in the hilly granitic region of tropical and subtropical South China, and can result in extremely rapid water and soil loss. Knowledge of the soil physical and chemical properties of farmland influenced by collapsing gully erosion is important in understanding the development of soil quality. This study was conducted at the Wuli Watershed of the Tongcheng County, south of Hubei Province, China. The aim is to investigate soil physical and chemical properties of three soil layers (0–20, 20–40 and 40–60 cm) for two farmland types (paddy field and upland field) in three regions influenced by collapsing gully erosion. The three regions are described as follows: strongly influenced region (SIR), weakly influenced region (WIR) and non-influenced region (NIR). The results show that collapsing gully erosion significantly increased the soil gravel and sand content in paddy and upland fields, especially the surface soil in the SIR and WIR. In the 0–20 cm layer of the paddy field, the highest gravel content (250.94 g kg–1) was in the SIR and the lowest (78.67 g kg–1) was in the NIR, but in the upland filed, the surface soil (0–20 cm) of the SIR and the 40–60 cm soil layer for the NIR had the highest (177.13 g kg–1) and the lowest (59.96 g kg–1) values of gravel content, respectively. The distribution of gravel and sand decreased with depth in the three influenced regions, but silt and clay showed the inverse change. In the paddy field, the average of sand content decreased from 58.6 (in the SIR) to 49.0% (in the NIR), but the silt content was in a reverse order, increasing from 27.9 to 36.9%, and the average of the clay content of three regions showed no significant variation (P<0.05). But in the upland filed, the sand, silt and clay fluctuated in the NIR and the WIR. Soils in the paddy and upland field were highly acidic (pH<5.2) in the SIR and WIR; moreover lower nutrient contents (soil organic matter (SOM), total N and available N, P, K) existed in the SIR. In the 0–20 cm soil layer of the paddy field, compared with the NIR and the WIR, collapsing gully erosion caused a very sharp decrease in the SOM and total N of the SIR (5.23 and 0.56 g kg–1, respectively). But in the surface soil (0–20 cm) of the upland field, the highest SOM, total N, available N, available P and available K occurred in the NIR, and the lowest ones were in the SIR. Compared with the NIR, the cation exchange capacity (CEC) in the SIR and WIR was found to be relatively lower. These results suggest that collapsing gully erosion seriously affect the soil physical and chemical properties of farmland, lead to coarse particles accumulation in the field and decrease pH and nutrient levels.

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Effects of saline irrigation on soil salt accumulation and grain yield in the winter wheat-summer maize double cropping system in the low plain of North China LIU Xiu-wei, Til Feike, CHEN Su-ying, SHAO Li-wei, SUN Hong-yong, ZHANG Xi-ying 2016, 15(12): 2886-2898.  DOI: 10.1016/S2095-3119(15)61328-4 Abstract ( )   PDF in ScienceDirect       In the dominant winter wheat (WW)-summer maize (SM) double cropping system in the low plain located in the North China, limited access to fresh water, especially during dry season, constitutes a major obstacle to realize high crop productivity. Using the vast water resources of the saline upper aquifer for irrigation during WW jointing stage, may help to bridge the peak of dry season and relieve the tight water situation in the region. A field experiment was conducted during 2009–2012 to investigate the effects of saline irrigation during WW jointing stage on soil salt accumulation and productivity of WW and SM. The experiment treatments comprised no irrigation (T1), fresh water irrigation (T2), slightly saline water irrigation (T3: 2.8 dS m–1), and strongly saline water irrigation (T4: 8.2 dS m–1) at WW jointing stage. With regard to WW yields and aggregated annual WW-SM yields, clear benefits of saline water irrigation (T3 & T4) compared to no irrigation (T1), as well as insignificant yield losses compared to fresh water irrigation (T2) occurred in all three experiment years. However, the increased soil salinity in early SM season in consequence of saline irrigation exerted a negative effect on SM photosynthesis and final yield in two of three experiment years. To avoid the negative aftereffects of saline irrigation, sufficient fresh water irrigation during SM sowing phase (i.e., increase from 60 to 90 mm) is recommended to guarantee good growth conditions during the sensitive early growing period of SM. The risk of long-term accumulation of salts as a result of saline irrigation during the peak of dry season is considered low, due to deep leaching of salts during regularly occurring wet years, as demonstrated in the 2012 experiment year. Thus, applying saline water irrigation at jointing stage of WW and fresh water at sowing of SM is most promising to realize high yield and fresh irrigation water saving.

Food Science

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Evaluation of genetically modified rice detection methods 2011/884/ EU and 2008/289/EC proposed by the European Union XIAO Qi-sheng, XU Wen-tao, YANG Jie-lin, PAN Liang-wen 2016, 15(12): 2899-2910.  DOI: 10.1016/S2095-3119(16)61378-3 Abstract ( )   PDF in ScienceDirect       Increases in the number of cases of identified genetically modified (GM) rice contamination can be traced back to the first Rapid Alert System for Food and Feed (RASFF) in 2006. In response to the lack of reliable detection methods, Decision 2011/884/EU proposed that new screening methods replace Decision 2008/289/EC, to identify all possible GM rice products originating in China. However, the synergy brands (SYBR) Green real-time PCR assay proposed by Decision 2011/884/EU has been shown to lack conformity with other TaqMan methods currently in use. To evaluate the specificity and repeatability of the methods recommended in Decision 2011/884/EU and Decision 2008/289/EC, we collected 74 rice products originating from six countries or districts. The 74 rice samples were tested using the Decision 2011/884/EU and Decision 2008/289/EC methods. The parallel use of different instruments and reagents were used for testing in parallel, and the results were analyzed statistically. To avoid the limitations of specific laboratories, eight GM organism detection laboratories in China participated in a collaborative trial. In our tests, 24.3% (18/74) of the samples tested were positive with the SYBR Green real-time PCR assay using the Decision 2011/884/EU method, but were negative with the TaqMan real-time PCR assay using the Decision 2011/884/EU and Decision 2008/289/EC methods. Sequencing the PCR-amplified CryIA(b/c) genes in three samples (6, 30 and 43) showed that the products consisted of primer dimers rather than the targeted sequence. The combined experimental results showed that testing for the nopaline synthase gene (NOS) of Agrobacterium tumefasciens terminator and CryIA(b/c) produced false-positive results when the Decision 2011/884/EU method was used. Because of the high rate of false-positive results, the Decision 2011/884/EU SYBR Green method to detect GM rice requires improvement.

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Difference in volatile profile between pericarp tissue and locular gel in tomato fruit WANG Li-bin, Jinhe Bai, YU Zhi-fang 2016, 15(12): 2911-2920.  DOI: 10.1016/S2095-3119(15)61324-7 Abstract ( )   PDF in ScienceDirect       Aroma, a complex mixture of volatile compounds, plays an important role in the perception and acceptability of tomato products by consumers. Numerous studies have reported volatile profiles in tomatoes based on measurement of the whole fruit or pericarp tissue, however, little is understood regarding the volatile compositions in the inner tissues. The objective of this study was to investigate the differences in volatile profile between pericarp tissue and locular gel in tomato fruit. Based on HS-SPME-GC-MS analysis, totally 42 volatile compounds were detected in FL 47 and Tasti-Lee tomato fruits. Regardless of cultivars, a substantial higher concentration of total volatile compounds was observed in pericarp than that in locular gel, associated with higher levels of aldehydes, hydrocarbons, and nitrogen compounds. Pericarp tissue possessed higher levels of cis-3-hexenal, hexanal, heptanal, octanal, nonanal, cymene, terpinolene, undecane, dodecane, 2-phenylethanol, 6-methyl-5-hepten-2-one, 2-methylbutyl acetate, 1-nitro-pentane, and 1-nitro-2-phenylethane, while the abundances of 2-methylpropanal, butanal, 2-methylbutanal, 2-methyl-2-butenal, 2-methylpropanol, 3-methylbutanol, 2-methylbutanol, and 2-butanone were higher in locular gel. Principal component analysis (PCA) and cluster analysis using GC-MS and electronic nose (E-nose) data discriminated the two tissues.

Short Communication

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Accumulation characteristic of protein bodies in different regions of wheat endosperm under drought stress CHEN Xin-yu, LI Bo, SHAO Shan-shan, WANG Lei-lei, ZHU Xiao-wei, YANG yang, WANG Wen-jun, YU Xu-run, XIONG Fei 2016, 15(12): 2921-2930.  DOI: 10.1016/S2095-3119(16)61332-1 Abstract ( )   PDF in ScienceDirect       The structural characteristics of protein body accumulation in different endosperm regions of hard wheat cultivar (XM33) and soft wheat cultivar (NM13) under drought stress were investigated. Drought stress treatment was implemented from plant regreening to the caryopsis mature stage. Microscope images of endosperm cells were obtained using resin semi-thin slice technology to observe the distribution and relative area of protein body (PB). Compared with NM13, relative PB area of XM33 was significantly higher in sub-aleurone endosperm region. The amount of accumulation, including the size and relative area of PB, in two wheat cultivars was higher in sub-aleurone region than that in central region at 18 days post anthesis (DPA). Drought stress significantly enhanced the sizes and relative areas of PBs in the dorsal and abdominal endosperms in two wheat cultivars. Particularly for dorsal endosperm, drought stress enhanced the relative PB area at 18 DPA and NM13 (5.0% vs. 6.73%) showed less enhancement than XM33 (5.49% vs. 8.96%). However, NM13 (9.58% vs. 12.02%) showed greater enhancement than XM33 (10.25% vs. 11.7%) at 28 DPA. The protein content in the dorsal and abdominal endosperms of the two wheat cultivars decreased at 12 DPA and then increased until 38 DPA. Drought stress significantly increased the protein contents in the two main regions. From 12 to 38 DPA, the amount of PB accumulation and the protein content were higher in XM33 than those in NM13. The results revealed that PB distribution varied in different endosperm tissues and that the amount of PB accumulation was remarkably augmented by drought stress.