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    Crop Genetics · Breeding · Germplasm Resources
    Comparison and analysis of QTLs for grain and hull thickness related traits in two recombinant inbred line (RIL) populations in rice (Oryza sativa L.)
    YAO Xiao-yun, WANG Jia-yu, LIU Jin, WANG Wei, YANG Sheng-long, ZHANG Yu, XU Zheng-jin
    2016, 15(11): 2437-2450.  DOI: 10.1016/S2095-3119(15)61311-9
    Abstract ( )   PDF in ScienceDirect  
        Grain traits are major constraints in rice production, which are key factors in determining grain yield and market values. This study used two recombinant inbred line (RIL) populations, RIL-JJ (japonica/japonica) and RIL-IJ (indica/japonica) derived from the two crosses Shennong 265/Lijiangxintuanheigu (SN265/LTH) and Shennong 265/Luhui 99 (SN265/LH99). Sixty-eight quantitative trait loci (QTLs) associated with 10 grain traits were consistently detected on the 12 chromosomes across different populations and two environments. Although 61.75% of the QTLs clustered together across two populations, only 16.17% could be detected across two populations. Eight major QTLs were detected on the 9, 10 and 12 chromosomes in RIL-JJ under two environments, a novel QTL clustered on the 10 chromosome, qGT10, qBT10 and qTGW10, have a higher percentage of explained phenotypic variation (PVE) and additive effect; 15 major QTLs were detected on the 5, 8, 9, and 11 chromosomes in RIL-IJ under two environments, a novel clustered QTL, qGT8 and qTGW8, on the 8 chromosome have a higher additive effect. Finally, the analysis of major QTL-BSA mapping narrowed the qTGW10 to a 1.47-Mb region flanked by simple sequence repeat markers RM467 and RM6368 on chromosome 10. A comparison of QTLs for grain traits in two different genetic backgrounds recombinant inbred line populations confirmed that genetic background had a significant impact on grain traits. The identified QTLs were stable across different populations and various environments, and 29.42% of QTLs controlling grain traits were reliably detected in different environments. Fewer QTLs were detected for brown rice traits than for paddy rice traits, 7 and 17 QTLs brown rice out of 25 and 43 QTLs under RIL-JJ and RIL-IJ populations, respectively. The identification of genes constituting the QTLs will help to further our understanding of the molecular mechanisms underlying grain shape.
    The expression and binding properties of the rice WRKY68 protein in the Xa21-mediated resistance response to Xanthomonas oryzae pv. Oryzae
    YANG Shuo, ZHOU Liang, MIAO Liu-yang, SHI Jia-nan, SUN Cai-qiang, FAN Wei, LAN Jin-ping, CHEN Hao, LIU Li-juan, DOU Shi-juan, LIU Guo-zhen, LI Li-yun
    2016, 15(11): 2451-2460.  DOI: 10.1016/S2095-3119(15)61265-5
    Abstract ( )   PDF in ScienceDirect  
        Plant WRKY transcription factors are involved in various physiological processes, including biotic and abiotic stress responses, as well as developmental processes. In this study, the expression patterns of the WRKY68 protein during interactions between rice 4021 containing the bacterial blight resistance gene Xa21 and Xanthomonas oryzae pv. oryzae (Xoo) were investigated. A possible modified form of the WRKY68 protein appeared in the Xa21-mediated disease resistance response, and its expression levels were similar in compatible and incompatible responses, but differed significantly from that of the mock control treatment, suggesting that WRKY68 may be involved in the bacterial blight response in rice. To further understand WRKY68’s roles in the resistance signaling pathway, WRKY68 recombinant protein was expressed in Escherichia coli and a microscale thermophoresis analysis was performed to investigate the interactions between WRKY68 and cis-elements in crucial pathogenesis-related (PR) genes. The results showed that the WRKY68 protein binds to W-boxes in the PR1b promoter region, with an apparent dissociation constant of 25 nmol L–1, while the binding between WRKY68 and PR10a was W-box independent. The results suggested that a possible modified form of the WRKY68 protein was induced during the interaction between rice and Xoo, which then regulated the activity of the downstream PR genes by binding with the W-boxes in the PR1b gene’s promoter region. Moreover, the constitutive transcription of the WRKY68 gene in dozens of rice tissues and the expression of the WRKY68 protein in leaves during all growth stages suggests that WRKY68 plays important roles in rice during normal growth processes.
    Identification of a new stripe rust resistance gene in Chinese winter wheat Zhongmai 175
    LU Jia-ling, CHEN Can, LIU Peng, HE Zhong-hu, XIA Xian-chun
    2016, 15(11): 2461-2468.  DOI: 10.1016/S2095-3119(16)61379-5
    Abstract ( )   PDF in ScienceDirect  
    Stripe rust is a serious foliar disease posing a grave threat to wheat production worldwide.  The most economical and environmentally friendly way to control this disease is to breed and deploy resistant cultivars.  Zhongmai 175 is an elite winter wheat cultivar conferring resistance to a broad spectrum of Puccinia striiformis f. sp. tritici (Pst) races.  To identify the resistance gene in the cultivar, genetic analysis was conducted using the parents, F1, F2 and F2:3 populations derived from the cross of Lunxuan 987/Zhongmai 175.  Segregations in the F2 and F2:3 populations indicated a single dominant gene conferring resistance to stripe rust in Zhongmai 175, temporarily designated YrZM175.  Bulked segregant analysis (BSA) with wheat iSelect 90K SNP array determined a preliminary location of YrZM175.  Subsequently, YrZM175 was mapped on chromosome 2AS using simple sequence repeats (SSR), expressed sequence tags (EST) and newly-developed kompetitive allele specific PCR (KASP) markers, being flanked by Xgwm636 and Xwmc382 at genetic distances of 4.9 and 8.1 cM, respectively.  Comparison of reaction patterns of YrZM175 on 23 Pst races or isolates and pedigree analysis with other genes on chromosome 2AS suggested that it is likely to be a new gene for resistance to stripe rust.  The resistance gene and linked molecular markers will be useful in wheat breeding targeting for the improvement of stripe rust resistance.
    Identification and expression analysis of group III WRKY transcription factors in cotton
    DOU Ling-ling, GUO Ya-ning, Ondati Evans, PANG Chao-you, WEI Heng-ling, SONG Mei-zhen, FAN Shu-li, YU Shu-xun
    2016, 15(11): 2469-2480.  DOI: 10.1016/S2095-3119(15)61306-5
    Abstract ( )   PDF in ScienceDirect  
        The WRKY proteins constitute a large family of transcription factors in plants containing highly conserved WRKYGQK sequences and zinc-finger-like motifs. To comprehensively study WRKY III genes in cotton, we analyzed the genome sequences of Gossypium hirsutum, G. raimondii and G. arboreum. According to the three genome sequences, 18 group III GhWRKY genes were identified in G. hirsutum, 12 both in G. raimondii and G. arboreum. Phylogenetic and motif analysis showed that proteins with high similarities could be clustered together and had the same motif components. The ratios of non-synonymous (Ka) to synonymous (Ks) of the GhWRKY to GrWRKY or GaWRKY were lower than 1, which indicated that group III WRKY genes in Gossypium species are under purifying selection. Expression analysis revealed that group III GhWRKY genes expressed during fiber development and leaf senescence, and most of them could be induced by salicylic acid (SA), jasmonic acid (JA), ethylene, abscisic acid (ABA), mannitol, and NaCl both in roots and cotyledons. Our study gives a briefly introduction on cotton group III WRKY genes and implicates their potential function in cotton fiber development, leaf senescence and abiotic stresses.
    Genetic diversity center of cultivated soybean (Glycine max) in China - New insight and evidence for the diversity center of Chinese cultivated soybean
    WANG Li-xia, LIN Fan-yun, LI Lin-hai, LI Wei, YAN Zhe, LUAN Wei-jiang, PIAO Ri-hua, GUAN Yuan, NING Xue-cheng, ZHU Li, MA Yan-song, DONG Zhi-min, ZHANG Hai-yan, ZHANG Yue-qiang, GUAN Rongxia, ......
    2016, 15(11): 2481-2487.  DOI: 10.1016/S2095-3119(15)61289-8
    Abstract ( )   PDF in ScienceDirect  
        Information on the center of genetic diversity of soybean (Glycine max) will be helpful not only for designing efficient strategies for breeding programs, but also for understanding the domestication and origin of this species. Here, we describe an analysis of genetic diversity based on simple-sequence repeat (SSR) variations within a core collection of 2 111 accessions of Chinese soybean landraces. Prior to the diversity assessment, the geographic origin of each accession was mapped. The map was then divided into grids each 2.5° in latitude and 5° in longitude. We found two regions that had higher number of alleles (NA) and greater polymorphic information content (PIC) values than the others. These regions are adjacently located within grid position of 30°–35°N×105°–110°E, which includes the valley of the middle and lower reaches of the Wei River, and the valley of the upper reaches of the Hanjiang River. It was also observed that in many regions, genetic diversity decreased with the increase in distance from the center. Another region, in northern Hebei Province (115°–120°E×40°–42.5°N), was observed having higher diversity than any surrounding regions, indicating that this is a sub-center of soybean diversity. Based on the presented results, the domestication and origin of soybean are also discussed.
    Chromosome painting of telomeric repeats reveals new evidence for genome evolution in peanut
    DU Pei, LI Li-na, ZHANG Zhong-xin, LIU Hua, QIN Li, HUANG Bing-yan, DONG Wen-zhao, TANG Feng-shou, QI Zeng-jun, ZHANG Xin-you
    2016, 15(11): 2488-2496.  DOI: 10.1016/S2095-3119(16)61423-5
    Abstract ( )   PDF in ScienceDirect  
        Interspecific hybridization is an important approach to improve cultivated peanut varieties. Cytological markers such as tandem repeats will facilitate alien gene introgression in peanut. Telomeric repeats have also been frequently used in chromosome research. Most plant telomeric repeats are (TTTAGGG)n that are mainly distributed at the chromosome ends, although interstitial telomeric repeats (ITRs) are also commonly identified. In this study, the telomeric repeat was chromosomally localized in 10 Arachis species through sequential GISH (genomic in situ hybridization) and FISH (fluorescence in situ hybridization) combined with 4’,6-diamidino-2-phenylindole (DAPI) staining. Six ITRs were identified such as in the centromeric region of chromosome Bi5 in Arachis ipaënsis, pericentromeric regions of chromosomes As5 in A. stenosperma, Bho7 in A. hoehnei and Av5 in A. villosa, nucleolar organizer regions of chromosomes As3 in A. stenosperma and Adi3 in A. diogoi, subtelomeric regions of chromosomes Bho9 in A. hoehnei and Adu7 in A. duranensis, and telomeric region of chromosome Es7 in A. stenophylla. The distributions of the telomeric repeat, 5S rDNA, 45S rDNA and DAPI staining pattern provided not only ways of distinguishing different chromosomes, but also karyotypes with a higher resolution that could be used in evolutionary genome research. The distribution of telomeric repeats, 5S rDNA and 45S rDNA sites in this study, along with inversions detected on the long arms of chromosomes Kb10 and Bho10, indicated frequent chromosomal rearrangements during evolution of Arachis species.
    Effects of short-term osmotic stress on leaf hydraulic conductivity and ZmPIPs mRNA accumulation in maize seedlings
    WANG Wei-feng, ZONG Yu-zheng, ZHANG Sui-qi
    2016, 15(11): 2497-2506.  DOI: 10.1016/S2095-3119(16)61466-1
    Abstract ( )   PDF in ScienceDirect  
    Plants maintain water balance by varying hydraulic properties, and plasma membrane intrinsic proteins (PIPs) may be involved in this process.  Leaf xylem and root hydraulic conductivity and the mRNA contents of four highly expressed ZmPIP genes (ZmPIP1;1, ZmPIP1;2, ZmPIP2;2, and ZmPIP2;5) in maize (Zea mays) seedlings were investigated.  Under well-watered conditions, leaf hydraulic conductivity (Kleaf) varied diurnally and was correlated with whole-plant hydraulic conductivity.  Similar diurnal rhythms of leaf transpiration rate (E), Kleaf and root hydraulic conductivity (Kroot) in well-watered plants are important for maintaining whole-plant water balance.  After 2 h of osmotic stress treatment induced by 10% polyethylene glycol 6000, the Kroot of stressed plants decreased but Kleaf increased, compared with well-watered plants.  The mRNA contents of four ZmPIPs were significantly up-regulated in the leaves of stressed plants, especially for ZmPIP1;2.  Meanwhile, ZmPIP2;5 was significantly down-regulated in the roots of stressed plants.  After 4 h of osmotic stress treatment, the E and leaf xylem water potentials of stressed plants unexpectedly increased.  The increase in Kleaf and a partial recovery of Kroot may have contributed to this process.  The mRNA content of ZmPIP1;2 but not of the other three genes was up-regulated in roots at this time.  In summary, the mRNA contents of these four ZmPIPs associated with Kleaf and Kroot change in maize seedlings during short-term osmotic stress, especially for ZmPIP1;2 and ZmPIP2;5, which may help to further reveal the hydraulic resistance adjustment role of ZmPIPs.  
    Non-leguminous winter cover crop and nitrogen rate in relation to double rice grain yield and nitrogen uptake in Dongting Lake Plain, Hunan Province, China
    ZHU Bo, YI Li-xia, XU He-shui, GUO Li-mei, HU Yue-gao, ZENG Zhao-hai, CHEN Fu, LIU Zhang-yong
    2016, 15(11): 2507-2514.  DOI: 10.1016/S2095-3119(16)61331-X
    Abstract ( )   PDF in ScienceDirect  
          Annual ryegrass (Lolium multiflorum Lam.), a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year (2009–2011) field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass (RG) as a winter cover crop and winter fallow (WF) without weed. Subplots were three N treatments for each rice season: 0 (N0), 100 (N100) and 200 kg N ha–1 (N200). In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice (0.4–1.7 t ha–1 for grain yield and 4.6–20.3 kg ha–1 for N uptake) and double rice (0.6–2.0 t ha–1 for grain yield and 6.3–27.0 kg ha–1 for N uptake) when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N100 and N200 plots than in N0 plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.
    Increased plant density and reduced N rate lead to more grain yield and higher resource utilization in summer maize
    SHI De-yang, LI Yan-hong, ZHANG Ji-wang, LIU Peng, ZHAO Bin, DONG Shu-ting
    2016, 15(11): 2515-2528.  DOI: 10.1016/S2095-3119(16)61355-2
    Abstract ( )   PDF in ScienceDirect  
          Planting at an optimum density and supplying adequate nitrogen (N) to achieve higher yields is a common practice in crop production, especially for maize (Zea mays L.); however, excessive N fertilizer supply in maize production results in reduced N use efficiency (NUE) and severe negative impacts on the environment. This research was conducted to determine the effects of increased plant density and reduced N rate on grain yield, total N uptake, NUE, leaf area index (LAI), intercepted photosynthetically active radiation (IPAR), and resource use efficiency in maize. Field experiments were conducted using a popular maize hybrid Zhengdan 958 (ZD958) under different combinations of plant densities and N rates to determine an effective approach for maize production with high yield and high resource use efficiency. Increasing plant density was clearly able to promote N absorption and LAI during the entire growth stage, which allowed high total N uptake and interception of radiation to achieve high dry matter accumulation (DMA), grain yield, NUE, and radiation use efficiency (RUE). However, with an increase in plant density, the demand of N increased along with grain yield. Increasing N rate can significantly increase the DMA, grain yield, LAI, IPAR, and RUE. However, this increase was non-linear and due to the input of too much N fertilizers, the efficiency of N use at NCK (320 kg ha–1) was low. An appropriate reduction in N rate can therefore lead to higher NUE despite a slight loss in grain production. Taking into account both the need for high grain yield and resource use efficiency, a 30% reduction in N supply, and an increase in plant density of 3 plants m–2, compared to LD (5.25 plants m–2), would lead to an optimal balance between yield and resource use efficiency.
    Impact of chilling accumulation and hydrogen cyanamide on floral organ development of sweet cherry in a warm region
    WANG Lei, ZHANG Lu, MA Chao, XU Wen-ping, LIU Zong-rang, ZHANG Cai-xi, Whiting D. Matthew, WANG Shi-ping
    2016, 15(11): 2529-2538.  DOI: 10.1016/S2095-3119(16)61341-2
    Abstract ( )   PDF in ScienceDirect  
          The microscopic investigation of the floral development of sweet cherry (Prunus avium L. cv. Hongdeng) from a warm winter climate (Shanghai) and cold winter climate (Tai’an, Shandong Province, China) was conducted to explore the reason of low fruit set. The effect of hydrogen cyanamide (HCN) on floral development under warm winter conditions was also investigated. Trees grown in Shanghai with insufficient chilling accumulation exhibited little difference in the progression of microspore development compared to trees in Tai’an that accumulated adequate chilling, but showed substantial delays in ovule and embryo sac development. The growth of nucelli did not proceed beyond the macrospore mother cell and macrospore stages with abortion rates of 13, 15 and 45% by 6, 3 and 0 d before full bloom, respectively. These abnormalities in the ovule and embryo sac in the Shanghai-grown trees were eliminated by HCN application. These results suggest that chilling regulates the development of female floral organs in winter dormancy; therefore, insufficient chilling accumulation, causing abnormality of the female floral organs, restricts the cultivation of sweet cherry in warm winter regions. Interestingly, HCN application, which decreased the chilling requirements for Hongdeng, may be a potential strategy for sweet cherry cultivation in warm winter regions.
    Plant Protection
    RNAi-mediated transgenic rice resistance to Rice stripe virus
    LI Li, GUO Cheng, WANG Biao, ZHOU Tong, LEI Yang, DAI Yu-hua, HE Wen, LIANG Chun, WANG Xi-feng
    2016, 15(11): 2539-2549.  DOI: 10.1016/S2095-3119(16)61369-2
    Abstract ( )   PDF in ScienceDirect  
        Rice stripe virus (RSV) often causes severe rice yield loss in temperate regions of East Asia. Although the correlation of small interfering RNAs (siRNAs) with transgenic virus resistance of plants using RNA interference (RNAi) is known for decades, no systematical research has been done on the profiling of siRNAs from a genomic scale. Our research is aiming to systematically study the RNAi impact in RSV-resistant transgenic rice, which was generated by introducing an inverted repeat construct that targets RSV nucleocapsid protein (NCP) gene. In this paper, three independent RSV-resistant transgenic rice lines were generated, their stable integration of the T-DNA fragment and the expression of siRNAs were confirmed by Southern blotting and Northern blotting analyses, and the majority of siRNAs were in lengths of 21, 22, and 24 nucleotides (nt), which have validated a connection between the presence of the RSV NCP homologous siRNAs and the RSV resistance in those transgenic rice lines. In one of these transgenic lines (T4-B1), the T-DNA fragment was found to have been inserted at chromosome 1 of the rice genome, substituting the rice genome fragment from 32 158 773 to 32 158 787 nt. Bioinformatics analysis of small RNA-Seq data on the T4-B1 line also confirmed the large population of NCP-derived siRNAs in transgenic plants, and the RSV-infected library (T4-B1-V) possessed more siRNAs than its mock inoculated libraries (T4-B1-VF), these results indicating the inverted repeat construct and RSV could introduce abundance of siRNAs in transgenic rice. Moreover, a varied expression level of specific siRNAs was found among different segments of the NCP gene template, about 47% of NCP-derived siRNAs reads aligned with the fragment from 594 to 832 nt (239 nt in length) in NCP gene (969 nt in length) in the T4-B1-V, indicating a potential usage of hotspot regions for RNAi silencing in future research. In conclusion, as the first study to address the siRNA profile in RSV-resistant transgenic plant using next generation sequencing (NGS) technique, we confirmed that the massive abundance of siRNA derived from the inverted repeat of NCP is the major reason for RSV-resistance.
    Effect of temperature on the development of sclerotia in Villosiclava virens
    FAN Lin-lin, YONG Ming-li, LI Dan-yang, LIU Yi-jia, LAI Chao-hui, CHEN Hong-ming, CHENG Fang-min, HU Dong-wei
    2016, 15(11): 2550-2555.  DOI: 10.1016/S2095-3119(16)61400-4
    Abstract ( )   PDF in ScienceDirect  
        The sclerotia of Villosiclava virens were found commonly in high altitude and the temperate regions, where the temperatures are relatively low in rice filling stage. To make sure if low temperature induce the sclerotial formation in V. virens, the inoculated rice panicles in laboratory and the diseased rice panicles cut from paddy fields were treated under different temperatures. The results showed that 3 days of night temperature at 15°C were enough to induce the sclerotial formation. The low temperature was much more effective for young balls with intact membranes. After appearance of chlamydospores on the ball surfaces, the sclerotium could not differentiate anymore. The sclerotia began to differentiate below the chlamydospore layer and gradually grew onto the ball surfaces. This suggests that low temperature in the early development stage of false smut balls is an important factor to induce the sclerotial differentiation, and rice cultivars with long growth periods are able to produce more sclerotium-bearing balls, which will produce mass of spores in paddy field in the coming year.
    A novel Arabidopsis miRNA, ath-miR38-3P, is involved in response to Sclerotinia sclerotiorum infection
    ZHAO Xu, SHAN Ya-nan, ZHAO Yan, WANG Ai-rong, WANG Zong-hua
    2016, 15(11): 2556-2562.  DOI: 10.1016/S2095-3119(16)61382-5
    Abstract ( )   PDF in ScienceDirect  
          Plant defense responses against penetration or colonization of pathogens are mediated by activation and repression of a large array of genes. Host endogenous small RNAs are essential in gene expression reprogramming process. We identified a new Arabidopsis microRNA (miRNA) ath-miR38-3P by high-throughput sequencing and further confirmed it by Northern blot assay. Interestingly, ath-miR38-3P was highly induced after infection of the pathogen Sclerotinia sclerotiorum. Further analysis based on the miRNA target database demonstrated that ath-miR38-3P might target to five putative genes: AT2G03140, AT5G59430, AT5G66320, AT1G36620 and AT3G03820. To confirm the target, we conducted the quantitative real-time PCR to observe the expression pattern of each candidate gene. The results showed that only AT3G03820 was down-regulated after inoculation of S. sclerotiorum. In addition, overexpression of ath-miR38-3P down-regulates AT3G03820, suggesting AT3G03820 might represent the target for ath-miR38-3P. Our results may provide the useful information for further studying the biological function of a novel ath-miR38-3P and its targets in Arabidopsis-Sclerotinia interaction.
    Cross-resistance pattern to four AHAS-inhibiting herbicides of tribenuron-methyl-resistant flixweed (Descurainia sophia) conferred by Asp-376-Glu mutation in AHAS
    DENG Wei, YANG Qian, JIAO Hong-tao, ZHANG Yong-zhi, LI Xue-feng, ZHENG Ming-qi
    2016, 15(11): 2563-2570.  DOI: 10.1016/S2095-3119(16)61432-6
    Abstract ( )   PDF in ScienceDirect  
        Flixweed (Descurainia sophia L.) is a problematic and widespread weed in winter wheat fields and has been controlled by tribenuron-methyl for more than twenty years in China. In this study, a flixweed accession (Hebei 25, HB25) with an Asp-376-Glu mutation in acetohydroxy acid synthase (AHAS) was identified and purified. The purified HB25 accession (pHB25) developed 758.1-fold resistance to tribenuron-methyl and exhibited obvious cross-resistance to four AHAS-inhibiting herbicides. The resistant/susceptible (R/S) ratios of 50% plant growth reduction (GR50) to herbicides of halosulfuron-methyl, flumetsulam, imazethapyr and pyribenzoxim were 346.1, 15.7, 8.1 and 7.1, respectively. The reduced AHAS sensitivities to four different AHAS-inhibiting herbicides, which were caused by the Asp-376-Glu mutation, were responsible for the resistance and cross-resistance to AHAS-inhibiting herbicides. The R/S ratios of 50% inhibition of AHAS activity (I50) to tribenuron-methyl, halosulfuron-methyl, flumetsulam, imazethapyr and pyribenzoxim were 844.5, 532.9, 74.5, 13.3 and 5.5, respectively. The results of AHAS activity in vitro were highly correlated with that of whole-plant response experiments.
    Animal Science · Veterinary Science
    Muscle hypertrophy in transgenic mice due to over-expression of porcine myostatin mutated at its cleavage site
    QIAN Li-li, MA De-zun, GAO Peng-fei, JIANG Sheng-wang, WANG Qing-qing, CAI Chun-bo, XIAO Gao-jun, AN Xiao-rong, CUI Wen-tao
    2016, 15(11): 2571-2577.  DOI: 10.1016/S2095-3119(16)61336-9
    Abstract ( )   PDF in ScienceDirect  
        Myostatin, a member of the transforming growth factor beta (TGF-β) superfamily, is a dominant inhibitor that acts to limit skeletal muscle growth and development. In this study, we generated transgenic mice that express porcine myostatin containg mutations at its cleavage site (RSRR) to evaluate its effect on muscle mass. Results showed that the weight of four skeletal muscles including gastrocnemius, rectus femoris, tibialis anterior, and pectoralis increased by 17.83 and 28.39%, 21.76 and 28.70%, 34.31 and 41.62%, 53.21 and 27.54% in transgenic male and female mice, respectively, compared to their corresponding non-transgenic control mice. Measurement of muscle fiber size and number indicated that the mean myofiber size increased by 50.73 and 61.30% in transgenic male and female mice respectively compared to the non-transgenic controls. However, there was no difference in the number of myofiber between transgenic and non-transgenic male mice. These results clearly demonstrated that the increase in skeletal muscle mass in transgenic mice is caused by hypertrophy instead of hyperplasia.
    Regulatory effects of dietary L-Arg supplementation on the innate immunity and antioxidant ability in broiler chickens
    HU Ya-di, TAN Jian-zhuang, QI Ji, ZHANG Hong-fu
    2016, 15(11): 2578-2587.  DOI: 10.1016/S2095-3119(16)61404-1
    Abstract ( )   PDF in ScienceDirect  
        Here, we investigated the effect of dietary arginine (Arg) supplementation on innate immunity and the antioxidant ability of broiler chickens. The experiment was designed as a single-factorial arrangement (n=8 cages/treatment, six birds/cage), and we used four dietary Arg concentrations (10.0, 15.0, 20.0 or 25.0 g kg–1). On day 21, the birds were killed to obtain spleen, cecal tonsil and liver samples to determine the gene expression and antioxidant characteristics. Increasing the Arg concentration linearly decreased (P<0.05) the mRNA expression of splenic interleukin-18 (IL-18) and tumor necrosis factor-α (TNF-α). Dietary Arg supplementation quadratically decreased (P<0.05) the expression of interleukin-1b (IL-1b) and interferon-γ (IFN-γ) mRNA in the spleen. Increasing Arg concentrations linearly and quadratically reduced the expression of IL-18 mRNA in the spleen. Meanwhile, increasing dietary Arg supplementation linearly and quadratically increased the lymphotactin mRNA (P<0.05) expression, and linearly increased the macrophage inflammatory protein-1β (MIP-1β) and toll-like receptor 15 (TLR15) mRNA expression in the cecal tonsils. Dietary Arg supplementation linearly (P<0.05) increased the glutathione peroxidase (GSH-Px), catalase (CAT), and lysozyme (LZM) activities in the liver. However, the malondialdehyde (MDA) activity in the liver was not influenced by the dietary Arg concentration (P>0.05). No significant (P>0.05) effect was found on the activity of superoxide dismutase (SOD) in the liver. Thus high levels of Arg supplementation (>20.0 g kg–1) may potentially suppress the innate immunity of broiler chickens, and dietary Arg supplementation enhances the antioxidant activity in broiler chickens.
    Impact of direct and indirect heating systems in broiler units on environmental conditions and flock performance
    Shaun Smith, Joseph Meade, James Gibbons, Kevina McGill, Declan Bolton, Paul Whyte
    2016, 15(11): 2588-2595.  DOI: 10.1016/S2095-3119(16)61380-1
    Abstract ( )   PDF in ScienceDirect  
        This study compared the impact of three indirect heating systems to direct gas flame heaters on a selection of flock performance and environmental indicators in commercial broiler units. No statistically significant differences (P≥0.05) were found in flock mortality rates, bird weight, water consumption, stress response, carbon dioxide, ammonia, temperature, relative humidity, litter quality, within-flock Campylobacter levels or mean Campylobacter counts when flock data from any of the three indirect heating systems were compared to flocks reared in houses with direct heating systems. Differences in litter quality were observed between upper and lower litter layers in all houses, regardless of heating type, which may have implications for bird health and welfare. Carbon dioxide concentrations in houses with direct heating systems were significantly higher than those in houses with indirect heating systems during the first 10 days of bird life (P≤0.05). This was due to the increased use of heating systems during this period of the flock cycle. Differences in CO2 concentrations had no effect on flock performance, possibly due to the fact that concentrations did not exceed known safe levels. A statistically significant increase in stress response was observed in birds as a result of partial depopulation (thinning) within houses, irrespective of heating system type used (P≤0.05). Stress associated with thinning may have consequences for bird welfare and food safety. In conclusion, the results of our study suggest that indirect heating systems do not appear to negatively impact on flock performance, stress response, within-flock Campylobacter levels or mean Campylobacter counts and do not appear to significantly alter environmental conditions within broiler houses when compared to houses equipped with direct heating systems. Indirect systems are a viable alternative for heating broiler houses in terms of flock performance, bird welfare and food safety.
    Diversity shifts of rumen bacteria induced by dietary forages in dairy cows and quantification of the changed bacteria using a new primer design strategy
    JIN Di, ZHAO Sheng-guo, ZHANG Yang-dong, SUN Peng, BU Deng-pan, Yves Beckers, WANG Jia-qi
    2016, 15(11): 2596-2603.  DOI: 10.1016/S2095-3119(16)61346-1
    Abstract ( )   PDF in ScienceDirect  
        The partial 16S rRNA gene sequences (100 to 500 bp) were widely used to reveal rumen bacterial composition influenced by diets, while quantification of the changed uncultured bacteria was inconvenient due to difficult designing of specific primers based on short sequences. This study evaluated the effect of forage resources on rumen bacterial diversity and developed new strategy for primer design based on short sequences to quantify the changed uncultured bacteria. Denaturing gradient gel electrophoresis (DGGE) analysis and subsequent band sequencing were used to reveal the distinct rumen bacteria composition in cows fed with two forage sources (single corn stover vs. mixed forages including alfalfa hay and corn silage). The bacterial diversity in the rumen of dairy cows fed with corn stover was lower than that with mixed forages (P<0.05). The bacterium named R-UB affiliating to uncultured Succinivibrionaceae was identified, and it was abundant in the rumen of cows fed with mixed forages compared to corn stover. The full length 16S rRNA gene sequences with identity of >97% to the R-UB 16S rRNA gene sequence were obtained from GenBank and used to design specific primers to quantify uncultured bacterium R-UB. All sequences of amplicon from the new primers were of 100% identity to R-UB sequences indicating the high specificity of new primers. Quantitative PCR confirmed that abundance of R-UB in the rumen of cows fed with corn stover was lower than those fed with mixed forages (P<0.01). New strategy for designing primers based on partial 16S rRNA genes to quantify targeted uncultured bacteria was successfully developed. The rumen bacteria descending significantly in the cows fed corn stover compared to those fed mixed forages was identified as uncultured R-UB from Succinivibrionaceae.
    Sequence and phylogenetic analysis of hemagglutinin genes of H9N2 influenza viruses isolated from chicken in China from 2013 to 2015
    SU Xiao-na, XIE Qing-mei, LIAO Chang-tao, YAN Zhuan-qiang, CHEN Wei-guo, BI Ying-zuo, CHEN Feng
    2016, 15(11): 2604-2612.  DOI: 10.1016/S2095-3119(16)61406-5
    Abstract ( )   PDF in ScienceDirect  
        H9N2 avian influenza virus (AIV) infection is a major problem in poultry industry worldwide. In this study, molecular characterizations and phylogenetic relationships of hemagglutinin (HA) gene sequences of H9N2 AIV of 5 Chinese isolates in 2014 recently available in GenBank, 3 widely used vaccine strains, and 52 novel isolates in China from 2013 to 2015 were analyzed. The homology analysis showed that the nucleotide sequences of HA gene of these recent Chinese H9N2 AIV isolates shared homologies from 94.1 to 99.9%. Phylogenetic analysis showed that all isolates belonged to AIV lineage h9.4.2.5. Fifty-six out of the 57 recent Chinese H9N2 AIV isolates had the motifs PSRSSR↓GLF at the cleavage sites within the HA protein, while one isolate PWH01 harbored LSRSSR↓GLF. Remarkably, all of the recent Chinese H9N2 AIV strains had the Q216L substitution in the receptor binding site, which indicated that they had potential to infect humans. Most of recent Chinese H9N2 AIV isolates lost the potential N-linked glycosylation site at residues 200–202 compared with vaccine strains. This present study demonstrated that AIV lineage h9.4.2.5 was more predominant in China than other lineages as it harbored all the H9N2 AIV isolated between 2013 and 2015. Also we showed the importance of continuous surveillance of emerging H9N2 AIV in China and update of vaccine formulation accordingly in order to prevent and control H9N2 AIV.
    Soil & Fertilization﹒Irrigation﹒Plant Nutrition﹒ Agro-Ecology & Environment
    Application of iron and silicon fertilizers reduces arsenic accumulation by two Ipomoea aquatica varities
    YU Tian-hong, PENG Yang-yang, LIN Chu-xia, QIN Jun-hao, LI Hua-shou
    2016, 15(11): 2613-2619.  DOI: 10.1016/S2095-3119(15)61320-X
    Abstract ( )   PDF in ScienceDirect  
        A 45 d pot experiment was conducted to examine the effects of silicon fertilizer or iron fertilizer on the growth of two typical Ipomoea aquatica cultivars (Daye and Liuye) and arsenic (As) accumuation of Daye and Liuye grown in As-contaminated soils at different As dosage levels. The results showed that the application of these two fertilizers generally enhanced the growth of the plants, which may be partly attributable to the reduction in As toxicity. The addition of these two fertilizers also significantly reduced the uptake of As by the plants though the iron fertilizer was more effective, as compared to the silicon fertilizer. The accumulation of As in shoot portion was weaker for Daye than for Liuye. The research findings obtained from this study have implications for developing cost-effective management strategies to minimize human health impacts from consumption of As-containing I. aquatica.
    Sugar beet yield and industrial sugar contents improved by potassium fertilization under scarce and adequate moisture conditions
    Muhammad Umair Mubarak, Muhammad Zahir, Sagheer Ahmad, Abdul Wakeel
    2016, 15(11): 2620-2626.  DOI: 10.1016/S2095-3119(15)61252-7
    Abstract ( )   PDF in ScienceDirect  
        Sugar beet (Beta vulgaris L.) is an industrial crop, grown worldwide for sugar production. In Pakistan, sugar is mostly extracted from sugarcane, soil and environmental conditions are equally favorable for sugar beet cultivation. Beet sugar contents are higher than sugarcane sugar contents, which can be further increased by potassium (K) fertilization. Total K concentration is higher in Pakistani soils developed from mica minerals, but it does not represent plant available K for sustainable plant growth. A pot experiment was conducted in the wire-house of Institute of Soil and Environmental Sciences at University of Agriculture Faisalabad, Pakistan. K treatments were the following: no K (K0), K application at 148 kg ha–1 (K1) and 296 kg ha–1 (K2). Irrigation levels were used as water sufficient at 60% water holding capacity and water deficient at 40% water holding capacity. The growth, yield and beet quality data were analyzed statistically using LSD. The results revealed that increase in the level of K fertilization at water sufficient level significantly increased plant growth, beet yield and industrial beet sugar content. The response of K fertilization under water deficient condition was also similar, however overall sugar production was less than that in water sufficient conditions. It is concluded from this study that K application could be used not only to enhance plant growth and beet yield but also enhance beet sugar content both under water-deficient as well as water-sufficient conditions.
    Spatio-temporal variations in organic carbon density and carbon sequestration potential in the topsoil of Hebei Province, China
    CAO Xiang-hui, LONG Huai-yu, LEI Qiu-liang, LIU Jian, ZHANG Ji-zong, ZHANG Wen-ju, WU Shu-xia
    2016, 15(11): 2627-2638.  DOI: 10.1016/S2095-3119(15)61239-4
    Abstract ( )   PDF in ScienceDirect  
        Reliable prediction of soil organic carbon (SOC) density and carbon sequestration potential (CSP) plays an important role in the atmospheric carbon dioxide budget. This study evaluated temporal and spatial variation of topsoil SOC density and CSP of 21 soil groups across Hebei Province, China, using data collected during the second national soil survey in the 1980s and during the recent soil inventory in 2010. The CSP can be estimated by the method that the saturated SOC content subtracts the actual SOC associated with clay and silt. Overall, the SOC density and CSP of most soil groups increased from the 1980s to 2010 and varied between different soil groups. Among all soil groups, Haplic phaeozems had the highest SOC density and Endogleyic solonchaks had the largest CSP. Areas of soil groups with the highest SOC density (90 to 120 t C ha–1) and carbon sequestration (120 to 160 t C ha–1carbon sequestration, SOC density, spatial variation, topsoil
    ) also increased over time. With regard to spatial distribution, the north of the province had higher SOC density but lower CSP than the south. With respect to land-use type, cultivated soils had lower SOC density but higher CSP than uncultivated soils. In addition, SOC density and CSP were influenced by soil physicochemical properties, climate and terrain and were most strongly correlated with soil humic acid concentration. The results suggest that soil groups (uncultivated soils) of higher SOC density have greater risk of carbon dioxide emission and that management should be aimed at maximizing carbon sequestration in soil groups (cultivated soils) with greater CSP. Furthermore, soils should be managed according to their spatial distributions of SOC density and carbon sequestration potential under different soil groups.
    The status and distribution characteristics of residual mulching film in Xinjiang, China
    ZHANG Dan, LIU Hong-bin, HU Wan-li, QIN Xiao-hui, MA Xing-wang, YAN Chang-rong, WANG Hongyuan
    2016, 15(11): 2639-2646.  DOI: 10.1016/S2095-3119(15)61240-0
    Abstract ( )   PDF in ScienceDirect  
        Pollution of residual plastic film in arable lands is a severe problem in China. In this study, the status of residual film and influential factors were investigated using the methods of farm survey in combination with questionnaires and quadrat sampling at a large number of field sites in Xinjiang Uygur Autonomous Region, China. The results showed that the amount of film utilization increased largely and reached to 1.8×105 t in 2013. Similarly, the mulching area also substantially increased in recent decades, and reached to 2.7×105 ha in the same year. According to the current survey, 60.7% of the sites presented a greater mulch residue than the national film residue standard (75 kg ha–1), and the maximum residual amount reached 502.2 kg ha–1 in Turpan, Xinjiang. The film thickness, the mulching time and the crop type all influenced mulch residue. The thickness of the film had significantly negative correlation with the amount of residual film (P<0.05), while the mulching years had significantly positive correlation with it (P<0.05). The total amount of residual film in Xinjiang was 3.43×105 t in 2011, which accounted for 15.3% of the cumulative dosage of mulching. Among all the crops, the cotton fields had the largest residual amount of mulch film (158.4 kg ha–1), and also the largest contribution (2.6×105 tons) to the total amount of residual film in Xinjiang.
    Effects of meteorological factors on different grades of winter wheat growth in the Huang-Huai-Hai Plain, China
    HUANG Qing, WANG Li-min, CHEN Zhong-xin, LIU Hang
    2016, 15(11): 2647-2657.  DOI: 10.1016/S2095-3119(16)61464-8
    Abstract ( )   PDF in ScienceDirect  
        The sown area of winter wheat in the Huang-Huai-Hai (HHH) Plain accounts for over 65% of the total sown area of winter wheat in China. Thus, it is important to monitor the winter wheat growth condition and reveal the main factors that influence its dynamics. This study assessed the winter wheat growth condition based on remote sensing data, and investigated the correlations between different grades of winter wheat growth and major meteorological factors corresponding. First, winter wheat growth condition from sowing until maturity stage during 2011–2012 were assessed based on moderate-resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) time-series dataset. Next, correlation analysis and geographical information system (GIS) spatial analysis methods were used to analyze the lag correlations between different grades of winter wheat growth in each phenophase and the meteorological factors that corresponded to the phenophases. The results showed that the winter wheat growth conditions varied over time and space in the study area. Irrespective of the grades of winter wheat growth, the correlation coefficients between the winter wheat growth condition and the cumulative precipitation were higher than zero lag (synchronous precipitation) and one lag (pre-phenophase precipitation) based on the average values of seven phenophases. This showed that the cumulative precipitation during the entire growing season had a greater effect on winter wheat growth than the synchronous precipitation and the pre-phenophase precipitation. The effects of temperature on winter wheat growth varied according to different grades of winter wheat growth based on the average values of seven phenophases. Winter wheat with a better-than-average growth condition had a stronger correlation with synchronous temperature, winter wheat with a normal growth condition had a stronger correlation with the cumulative temperature, and winter wheat with a worse-than-average growth condition had a stronger correlation with the pre-phenophase temperature. This study may facilitate a better understanding of the quantitative correlations between different grades of crop growth and meteorological factors, and the adjustment of field management measures to ensure a high crop yield.
    Food Science
    Hot air treatment activates defense responses and induces resistance against Botrytis cinerea in strawberry fruit
    JIN Peng, ZHENG Cong, HUANG Yu-ping, WANG Xiao-li, LUO Zi-sheng, ZHENG Yong-hua
    2016, 15(11): 2658-2665.  DOI: 10.1016/S2095-3119(16)61387-4
    Abstract ( )   PDF in ScienceDirect  
        The effect of hot air (HA, 45°C, 3.5 h) treatment on reducing gray mold caused by Botrytis cinerea in strawberry fruit and the possible mechanisms were investigated. The results showed that HA treatment significantly reduced lesion diameter and enhanced activities of chitinase (CHI), β-1,3-glucanase and phenylalanine ammonia-lyase (PAL) in strawberry fruit. Total phenolic contents were also increased by HA treatment. The activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were higher in HA treated strawberry fruit than those in control. Expression of three defense related genes such as CAT, CCR-1 allele and PLA6 was greatly induced in HA treated strawberry fruit with or without inoculation by B. cinerea. In addition, the in vitro experiment showed that HA treatment inhibited spore germination and tube growth of B. cinerea. These results suggested that HA treatment directly activated disease resistance against B. cinerea in strawberry fruit without priming response and directly inhibiting growth of B. cinerea.
    Influence of potato flour on dough rheological properties and quality of steamed bread
    LIU Xing-li, MU Tai-hua, SUN Hong-nan, ZHANG Miao, CHEN Jing-wang
    2016, 15(11): 2666-2676.  DOI: 10.1016/S2095-3119(16)61388-6
    Abstract ( )   PDF in ScienceDirect  
        It is a novel idea to make steamed bread by adding potato flour into wheat flour considering the production and nutritional factors of potato. In this study, the influence of potato flour (0–35%) on dough rheology and quality of steamed bread were investigated. Potato flour addition significantly influenced the dough rheological properties and steamed bread quality, such as increased water absorption, the maximum gaseous release height, total volume of CO2 and hardness, while decreased dough stability and specific volume of steamed bread. Moreover, correlation analysis suggested that dough height at the maximum development time, dough stability, water absorption and the phase tangent can be used for predicting the technological quality of steamed bread. Potato-wheat steamed bread had higher dietary fibre, ash content and antioxidant activity than those of wheat steamed bread. The estimated glycemic index decreased from 73.63 (0%) to 60.01 (35%). Considering the sensory evaluation, the steamed bread with 20% potato flour is acceptable. In conclusion, adding appropriate quantity of potato flour to wheat flour for steamed bread production will not only maintain the technological quality, but also can improve the nutritional value of the steamed bread.