Journal of Integrative Agriculture

Editorial —— The Hot Spots in Cereal Rusts and Powdery Mildew Research

CHEN Wan-quan, DUAN Xia-yu

2014, 13(2): 229-232. DOI: 10.1016/S2095-3119(13)60688-7

Abstract ( ) PDF in ScienceDirect

Messages from Powdery Mildew DNA: How the Interplay with a Host Moulds Pathogen Genomes

Pietro D Spanu

2014, 13(2): 233-236. DOI: 10.1016/S2095-3119(13)60650-4

Abstract ( ) PDF in ScienceDirect

The genomes of the barley, Arabidopsis and pea powdery mildew are significantly larger than those of related fungi. This is due to an extraordinary expansion of retro-trasposons that are evident as repetitive elements in the sequence. The protein coding genes are fewer than expected due to an overall reduction in the size of gene families, a reduction in the number of paralogs and because of the loss of certain metabolic pathways. Many of these changes have also been observed in the genomes of other taxonomically unrelated obligate biotrophic pathogens. The only group of genes that bucks the trend of gene loss, are those encoding small secreted proteins that bear the hall marks of effectors

Flor Revisited (Again): eQTL and Mutational Analysis of NB-LRR Mediated Immunity to Powdery Mildew in Barley

Roger Wise, Priyanka Surana, Greg Fuerst, Ruo Xu, Divya Mistry, Julie Dickerson

2014, 13(2): 237-243. DOI: 10.1016/S2095-3119(13)60651-6

Abstract ( ) PDF in ScienceDirect

Genes encoding early signaling events in pathogen defense often are identified only by their phenotype. Such genes involved in barley-powdery mildew interactions include Mla, specifying race-specific resistance; Rar1 (Required for Mla12-specified resistance1), and Rom1 (Restoration of Mla-specified resistance1). The HSP90-SGT1-RAR1 complex appears to function as chaperone in MLA-specified resistance, however, much remains to be discovered regarding the precise signaling underlying plant immunity. Genetic analyses of fast-neutron mutants derived from CI 16151 (Mla6) uncovered a novel locus, designated Rar3 (Required for Mla6-specified resistance3). Rar3 segregates independent of Mla6 and Rar1, and rar3 mutants are susceptible to Blumeria graminis f. sp. hordei (Bgh) isolate 5874 (AVRa6), whereas, wild-type progenitor plants are resistant. Comparative expression analyses of the rar3 mutant vs. its wild-type progenitor were conducted via Barley1 GeneChip and GAIIx paired-end RNA-Seq. Whereas Rar1 affects transcription of relatively few genes; Rar3 appears to influence thousands, notably in genes controlling ATP binding, catalytic activity, transcription, and phosphorylation; possibly membrane bound or in the nucleus. eQTL analysis of a segregating doubled haploid population identified over two-thousand genes as being regulated by Mla (q value/FDR=0.00001), a subset of which are significant in Rar3 interactions. The intersection of datasets derived from mla-loss-of-function mutants, Mla-associated eQTL, and rar3-mediated transcriptome reprogramming are narrowing the focus on essential genes required for Mla-specified immunity.

How Specific is Non-Hypersensitive Host and Nonhost Resistance of Barley to Rust and Mildew Fungi?

Niks R E

2014, 13(2): 244-254. DOI: 10.1016/S2095-3119(13)60648-6

Abstract ( ) PDF in ScienceDirect

Full nonhost resistance can be defined as immunity, displayed by an entire plant species against all genotypes of a plant pathogen. Interesting biological questions are, whether the genes responsible for the nonhost status of a plant species have a general or a specific effectiveness to heterologous (“nonhost”) pathogens? Is the nonhost resistance to pathogens of plant species that are related to the nonhost based on R-genes or on other types of genes? We study this question in barley (Hordeum vulgare L.), which is a near-nonhost to several rusts (Puccinia) of cereals and grasses. By crosses and selection we accumulated susceptibility and developed an experimental line, SusPtrit, with high susceptibility to at least nine different heterologous rust taxa such as the wheat and Agropyron leaf rusts (P. triticina and P. persistens, respectively). At the microscopic level there is also some variation among barley accessions in the degree that the heterologous wheat powdery mildew (Blumeria graminis f.sp. tritici) is able to form haustoria in epidermal cells. So, also the genetics of the variation in level of nonhost resistance to heterologous mildew fungi can be studied in barley. Our data obtained on mapping populations involving three regular nonhost-immune accessions (Vada, Cebada Capa and Golden Promise) suggest that nonhost resistance is the joined effect of multiple, quantitative genes (QTLs) and very occasionally a major gene (R-gene?) is involved. Most QTLs have effect to only one or two heterologous rusts, but some have a wider spectrum. This was confirmed in a set of QTL-NILs. Those QTL-NILs are used to fine-map the effective genes. In some cases, a QTL region with effectiveness to several heterologous rusts might be a cluster of genes with a more narrow spectrum of effectiveness. Our evidence suggests that nonhost resistance in barley to rust and powdery mildew fungi of related Gramineae is not due to R-genes, but to pathogen species-specific quantitative resistance genes.

Progress Towards Genetics and Breeding for Minor Genes Based Resistance to Ug99 and Other Rusts in CIMMYT High-Yielding Spring Wheat

Ravi Prakash Singh, Sybil Herrera-Foessel, Julio Huerta-Espino, Sukhwinder Singh, Sridhar Bhavani, Caixia Lan , Bhoja Raj Basnet

2014, 13(2): 255-261. DOI: 10.1016/S2095-3119(13)60649-8

Abstract ( ) PDF in ScienceDirect

Wheat rusts continue to cause significant losses worldwide despite major efforts given to their genetic control. This is due to frequent evolution and selection of virulence in pathogen overcoming the deployed race-specific resistance genes. Although the life of effective race-specific resistance genes can be prolonged by using gene combinations, an alternative approach being implemented at CIMMYT is to deploy varieties that posses adult plant resistance (APR) based on combinations of minor, slow rusting genes. When present alone, the APR genes do not confer adequate resistance especially under high disease pressure; however, combinations of 4 or 5 minor genes usually result in “near-immunity” or a high level of resistance. Although only a few APR genes are catalogued, various APR QTLs are now known and could lead to further characterization of additional genes. Four characterized genes have pleiotropic effects in conferring partial APR to all 3 rusts and powdery mildew, thus simplifying the task of breeding wheat varieties that are resistant to multiple diseases. Significant progress was made recently in developing high-yielding wheat germplasm that possesses high levels of APR to all three rusts by implementing a Mexico- Kenya shuttle breeding scheme. Parents with APR to Ug99 were hybridized with high-yielding parents that had adequate to high levels of APR to leaf rust and yellow rust. Segregating populations and advanced lines from these crosses were selected under high rust pressures in Mexico (leaf rust and yellow rust) and Kenya (Ug99 stem rust and yellow rust) to identify high- yielding progenies that possess high to adequate APR to all three rusts. International distribution of these high-yielding wheats is underway through CIMMYT international yield trials and screening nurseries. It is expected that several wheat varieties with APR to three rusts will be released and grown in various countries in the near-future that will allow determining the durability of resistance.

Population Diversity of Puccinia graminis is Sustained Through Sexual Cycle on Alternate Hosts

Yue Jin, Matt Rouse , Jim Groth

2014, 13(2): 262-264. DOI: 10.1016/S2095-3119(13)60647-4

Abstract ( ) PDF in ScienceDirect

A high degree of virulence diversity has been maintained in the population of Puccinia graminis f. sp. tritici (Pgt) in northwestern United States. Although Berberis vulgaris is present in the region and Pgt has been isolated from aecial infections on B. vulgaris, the population is too diverse to be explained by the limited presence of B. vulgaris alone. Since 2008, we have isolated P. graminis from aecial infections on fruits of Mahonia repens and Mahonia aquifolium from northwestern United States. These two native woody shrub species, widely distributed in western North America, were once classified as resistant to P. graminis based on artificial inoculations. By isolating P. graminis from aecia, we established that M. repens and M. aquifolium along with B. vulgaris (albeit infrequent) serve as the alternate hosts of P. graminis in the region. The isolates of P. graminis from Mahonia of North America had diverse virulence patterns and most of the isolates could be differentiated on Morocco, Line E, Chinese Spring, Little Club, LMPG-6, Rusty, and other genotypes that are considered to be universally susceptible to most Pgt isolates. This discovery explained the persistence of virulence diversity of Pgt observed in isolates derived from uredinia on cereal crops in the region. In addition to cereal crops, uredinial stage of the P. graminis population is sustained by wild grasses, especially Elymus glaucus, a native grass sharing the same habitat with the rusted Mahonia spp. Although virulence to some important stem rust resistance genes was observed in some isolates derived from Mahonia of North America when tested against single stem rust resistance gene stocks, the overall virulence is very limited in these isolates. This is likely a result of limited selection pressure on the rust population. In contrast to northwestern United Sates, the Pgt population in east of the Rocky Mountains of North America has declined steadily with a single race, QFCSC, being predominant in the last decade. This decline is likely due to a combination of factors, of which a lack of sexual recombination in the region is perhaps the most important one.

IPM Strategies and Their Dilemmas Including an Introduction to www. eurowheat.org

Lise Nistrup J?rgensen, Mogens St?vring Hovm?ller, Jens Gr?nb?k Hansen, Poul Lassen, Bill Clark, Rosemary Bayles, Bernd Rodemann, Kerstin Flath, Margot Jahn, Tomas Goral, Jerzy Czembor J, Philip Cheyr

2014, 13(2): 265-281. DOI: 10.1016/S2095-3119(13)60646-2

Abstract ( ) PDF in ScienceDirect

Information about disease management in winter wheat (Triticum aestiva) in eight European countries was collated and analysed by scientists and extension workers within the European Network for the Durable Exploitation of Crop Protection Strategies (ENDURE). This included information about specific disease thresholds, decision support systems, host varieties, disease prevalence and pathogen virulence. Major differences in disease prevalence and economic importance were observed. Septoria tritici blotch (Mycosphaerella graminicola) was recognized as the most yield reducing disease in countries with intensive wheat production, but also rust diseases (Puccinia striiformis and Puccinia triticina), powdery mildew (Blumeria graminis) and Fusarium head blight (Fusarium spp.) were seen as serious disease problems. Examples of current integrated pest management (IPM) strategies in different countries have been reported. Disease management and fungicide use patterns showed major differences, with an average input equivalent to 2.3 full dose rates (TFI) in the UK and a TFI of 0.6 in Denmark. These differences are most likely due to a combination of different cropping systems, climatic differences, disease prevalence, and socio-economic factors. The web based information platform www.eurowheat.org was used for dissemination of information and results including information on control thresholds, cultural practices which can influence disease attack, fungicide efficacy, fungicide resistance, and pathogen virulence, which are all elements supporting IPM for disease control in wheat. The platform is open to all users. The target groups of EuroWheat information are researchers, advisors, breeders, and similar partners dealing with disease management in wheat.

Development of EST-PCR Markers for the Chromosome 4V of Haynaldia villosa and Their Application in Identification of 4V Chromosome Structural Aberrants

ZHAO Ren-hui, WANG Hai-yan, JIA Qi, XIAO Jin, YUAN Chun-xia, ZHANG Ya-jun, HU Qing-shan , WANG Xiu-e

2014, 13(2): 282-289. DOI: 10.1016/S2095-3119(13)60359-7

Abstract ( ) PDF in ScienceDirect

EST-PCR based molecular markers specific for alien chromosomes are not only useful for the detection of the introgressed alien chromatin in the wheat background, but also provide evidence of the syntenic relationship between homoeologous chromosomes. In the present study, in order to develop high density and evenly distributed molecular markers on chromosome 4V of Haynaldia villosa, a total of 607 primer pairs were designed according to the EST sequences, which were previously located in 23 different bins of wheat chromosomes 4A, 4B and 4D. By using the Triticum durum-H. villosa amphiploid and T. aestivum-H. villosa alien chromosome lines involving chromosome 4V, it was found that 9.23% of the tested primers could amplify specific bands for chromosome 4V. Thirty and twenty-six specific markers could be assigned to chromosome arms 4VS and 4VL, respectively. These 4V specific markers provided efficient tools for the characterization of structural variation involving the chromosome 4V as well as for the selection of useful genes located on chromosome 4V in breeding programs.

Identification of a Group of Novel γ-Gliadin Genes

QI Peng-fei, WEI Yu-ming, Ouellet Thérèse, CHEN Qing, WANG Zhao, WEI Zhen-zhen , ZHENG You-liang

2014, 13(2): 290-298. DOI: 10.1016/S2095-3119(13)60358-5

Abstract ( ) PDF in ScienceDirect

γ-Gliadins are an important component of wheat seed storage proteins. Four novel γ-gliadin genes (Gli-ng1 to Gli-ng4) were cloned from wheat (Triticum aestivum) and Aegilops species. The novel γ-gliadins were much smaller in molecular size when compared to the typical γ-gliadins, which was caused by deletion of the non-repetitive domain, glutamine-rich region, 3´ part of the repetitive domain, and 5´ part of the C-terminal, possibly due to illegitimate recombination between the repetitive domain and the C-terminal. As a result, Gli-ng1 and Gli-ng4 only contained two and three cysteine residues, respectively. Gli-ng1, as the representative of novel γ-gliadin genes, has been sub-cloned into an Escherichia coli expression system. SDS- PAGE indicated that the both cysteine residues of Gli-ng1 could participate in the formation of intermolecular disulphide bonds in vitro. Successful cloning of Gli-ng1 from seed cDNA of T. aestivum cv. Chinese Spring suggested that these novel γ-gliadin genes were normally transcribed during the development of seeds. Phylogenic analysis indicated that the four novel γ-gliadin genes had a closer relationship with those from the B (S) genome of wheat.

Major Gene Identification and Quantitative Trait Locus Mapping for Yield- Related Traits in Upland Cotton (Gossypium hirsutum L.)

XIA Zhe, ZHANG Xin, LIU Yang-yang, JIA Zi-fang, ZHAO Hai-hong, LI Cheng-qi , WANG；Qing-lian

2014, 13(2): 299-309. DOI: 10.1016/S2095-3119(13)60508-0

Abstract ( ) PDF in ScienceDirect

Segregation analysis of the mixed genetic model of major gene plus polygene was used to identify the major genes for cotton yield-related traits using six generations P1, P2, F1, B1, B2, and F2 generated from the cross of Baimian 1 × TM-1. In addition to boll size and seed index, the major genes for the other five traits were detected: one each for seed yield, lint percentage, boll number, lint index; and two for lint yield. Quantitative trait locus/loci (QTL) mapping was performed in the F2 and F2:3 populations of above cross through molecular marker technology, and a total of 50 QTL (26 suggestive and 24 significant) for yield-related traits were detected. Four common QTL were discovered: qLP-3b(F2)/qLP-3(F2:3) and qLP-19b (F2)/qLP-19(F2:3) for lint percentage, qBN-17(F2)/qBN-17(F2:3) for boll number, and qBS-26b(F2)/qBS-26(F2:3) for boll size. Especially, qLP- 3b(F2)/qLP-3(F2:3), not only had LOD scores >3 but also exceeded the permutation threshold (5.13 and 5.29, respectively), correspondingly explaining 23.47 and 29.55% of phenotypic variation. This QTL should be considered preferentially in marker assisted selection (MAS). Segregation analysis and QTL mapping could mutually complement and verify, which provides a theoretical basis for genetic improvement of cotton yield-related traits by using major genes (QTL).

Identification of QTLs for Starch Content in Sweetpotato (Ipomoea batatas (L.) Lam.)

YU Xiao-xia, ZHAO Ning, LI Hui, JIE Qin, ZHAI Hong, HE Shao-zhen, LI Qiang , LIU Qing-chang

2014, 13(2): 310-315. DOI: 10.1016/S2095-3119(13)60357-3

Abstract ( ) PDF in ScienceDirect

Sweetpotato (Ipomoea batatas (L.) Lam.) breeding is challenging due to its genetic complexity. In the present study, interval mapping (IM) and multiple quantitative trait locus (QTL) model (MQM) analysis were used to identify QTLs for starch content with a mapping population consisting of 202 F1 individuals of a cross between Xushu 18, a cultivar susceptible to stem nematodes, with high yield and moderate starch, and Xu 781, which is resistant to stem nematodes, has low yield and high starch content. Six QTLs for starch content were mapped on six linkage groups of the Xu 781 map, explaining 9.1-38.8% of the variation. Especially, one of them, DMFN_4, accounted for 38.8% of starch content variation, which is the QTL that explains the highest phenotypic variation detected to date in sweetpotato. All of the six QTLs had a positive effect on the variation of the starch content, which indicated the inheritance derived from the parent Xu 781. Two QTLs for starch content were detected on two linkage groups of the Xushu 18 map, explaining 14.3 and 16.1% of the variation, respectively. They had a negative effect on the variation, indicating the inheritance derived from Xu 781. Seven of eight QTLs were co-localized with a single marker. This is the first report on the development of QTLs co-localized with a single marker in sweetpotato. These QTLs and their co-localized markers may be used in marker-assisted breeding for the starch content of sweetpotato.

Natural Variation of Leaf Thickness and Its Association to Yield Traits in indica Rice

LIU Chuan-guang, ZHOU Xin-qiao, CHEN Da-gang, LI Li-jun, LI Ju-chang and CHEN You-ding

2014, 13(2): 316-325. DOI: 10.1016/S2095-3119(13)60498-0

Abstract ( ) PDF in ScienceDirect

Leaf thickness is an important morphological trait in rice. Its association to the yield potential, as of now has not been documented because of the shortage of the equipment which could conveniently measure the leaf thickness in rice. In this study, the thickness of top three leaves of 208 cultivars had been determined by a nondestructive rice leaf thickness instrument for the research of the natural variation of leaves thickness and its association to yield traits in indica rice. The results showed that the flag leaf was the thickest, and the 2nd leaf was thicker than the 3rd leaf. Analysis of variance indicated the existence of wide genetic diversity of leaf thickness among the investigated indica rice genotypes. The tight correlation among the thicknesses of the top three leaves means that the leaf thickness traits share one genetic control system. Leaf thickness had a significant positive correlation with leaf length and a positive correlation with leaf width, indicated that thicker leaf was beneficial to increasing the single leaf area. The results of correlation analysis revealed that thicker leaf should be profitable to the leaf erection, higher numbers of grains per panicle and higher grains weight per panicle. However, the significantly negative correlation between leaf thickness and number of panicles per plant counteracted the profitability from increased grains weight per panicle, so that the correlations of the thicknesses of the top three leaves to yield and biomass were positive but not significantly. It has made great progress in the genetic improvement of leaves thickness in inbred indica rice breeding in Guangdong Province, China, since the 1990s.

Effect of Phosphorus Fertilization to P Uptake and Dry Matter Accumulation in Soybean with Different P Efficiencies

AO Xue, GUO Xiao-hong, ZHU Qian, ZHANG Hui-jun, WANG Hai-ying, MA Zhao-hui, HAN , Xiao-ri , ZHAO Ming-hui , XIE Fu-ti

2014, 13(2): 326-334. DOI: 10.1016/S2095-3119(13)60390-1

Abstract ( ) PDF in ScienceDirect

Phosphorus (P) is an essential element for plant growth and yield. Improving phosphorus use efficiency of crops could potentially reduce the application of chemical fertilizer and alleviate environmental damage. Soybean (Glycine max (L.) Merr.) is sensitive to phosphorus (P) in the whole life history. Soybean cultivars with different P efficiencies were used to study P uptake and dry matter accumulation under different P levels. Under low P conditions, the P contents of leaf in high P efficiency cultivars were greater than those in low P efficiency cultivars at the branching stage. The P accumulation in stems of high P efficiency cultivars and in leaves of low P efficiency cultivars increased with increasing P concentration at the branching stage. At the late podding stage, the P accumulation of seeds in high and low P efficiency cultivars were 22.5 and 26.0%, respectively; and at the mature stage were 69.8 and 74.2%, respectively. In average, the P accumulation in whole plants and each organ was improved by 24.4% in high P efficiency cultivars compared to low P efficiency cultivars. The biomass between high and low P efficiency cultivars were the same under extended P condition, while a significant difference was observed at late pod filling stage. At the pod setting stage, the biomass of high P efficiency cultivars were significant greater (17.4%) than those of low P efficiency cultivars under high P condition. Meanwhile, under optimum growth conditions, there was little difference of biomass between the two types of cultivars, however, the P agronomic efficiency and P harvest index were significant higher in high P efficiency cultivars than those in low P efficiency cultivars.

Advances in Effects of Sound Waves on Plants

Reda H E Hassanien, HOU Tian-zhen, LI Yu-feng , LI Bao-ming

2014, 13(2): 335-348. DOI: 10.1016/S2095-3119(13)60492-X

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Sound waves technology has been applied to different plants. It has been found that sound waves were at different frequencies, sound pressure levels (SPLs), exposure periods, and distances from the source of sound influence plant growth. Experiments have been conducted in the open field and under greenhouse growing conditions with different levels of audible sound frequencies and sound pressure levels. Sound waves at 1 kHz and 100 dB for 1 h within a distance of 0.20 m could significantly promote the division and cell wall fluidity of callus cells and also significantly enhance the activity of protective enzymes and endogenous hormones. Sound waves stimulation could increase the plant plasma-membrane H+-ATPase activity, the contents of soluble sugar, soluble protein, and amylase activity of callus. Moreover, sound waves could increase the content of RNA and the level of transcription. Stress-induced genes could switch on under sound stimulation. Sound waves at 0.1-1 kHz and SPL of (70±5) dB for 3 h from plant acoustic frequency technology (PAFT) generator within a distance ranged from 30 to 60 m every other day significantly increased the yield of sweet pepper, cucumber and tomato by 30.05, 37.1 and 13.2%, respectively. Furthermore, the yield of lettuce, spinach, cotton, rice, and wheat were increased by 19.6, 22.7, 11.4, 5.7, and 17.0%, respectively. Sound waves may also strengthen plant immune systems. It has been proved that spider mite, aphids, gray mold, late blight and virus disease of tomatoes in the greenhouses decreased by 6.0, 8.0, 9.0, 11.0, and 8.0%, respectively, and the sheath blight of rice was reduced by 50%. This paper provides an overview of literature for the effects of sound waves on various growth parameters of plant at different growth stages.

Putrescine Plays a Positive Role in Salt-Tolerance Mechanisms by Reducing Oxidative Damage in Roots of Vegetable Soybean

ZHANG Gu-wen, XU Sheng-chun, HU Qi-zan, MAO Wei-hua , GONG Ya-ming

2014, 13(2): 349-357. DOI: 10.1016/S2095-3119(13)60405-0

Abstract ( ) PDF in ScienceDirect

Polyamines play important roles in plant tolerance to environmental stress. With the aim of investigating the possible involvement of putrescine (Put) in salt-tolerance mechanisms in vegetable soybean roots, exogenous Put (10 mmol L-1) and its biosynthetic inhibitor D-arginine (D-Arg) (0.5 mmol L-1) were added to nutrient solution when vegetable soybean (Glycine max L. cv. Huning 95-1) seedlings were exposed to 100 mmol L-1 sodium chloride (NaCl). The results showed that Put ameliorated but D-Arg aggravated the detrimental effects of NaCl on plant growth and biomass production. Under NaCl stress, levels of free, soluble conjugated and insoluble bound types of Put in roots of vegetable soybean were reduced, whereas those of free, soluble conjugated, and insoluble bound types of spermidine (Spd) and spermine (Spm) were increased. Exogenous Put eliminated the decrease in Put but promoted the increase of Spd and Spm. However, these changes could be reversed by D-Arg. Under NaCl stress, activities of arginine decarboxylase (ADC), S-adenosylmethionine decarboxylase (SAMDC), diamine oxidase (DAO), and polyamine oxidase (PAO) were induced, with exogenous Put promoting and D-Arg reversing these changes. Furthermore, NaCl stress decreased activities of antioxidant enzymes. Exogenous Put alleviated but D-Arg exaggerated these effects of NaCl stress, resulting in the same changes in membrane damage and reactive oxygen species (ROS) production. These results indicated that Put plays a positive role in vegetable soybean roots by activating antioxidant enzymes and thereby attenuating oxidative damage.

Accumulation of Carbohydrate and Regulation of 14-3-3 Protein on Sucrose Phosphate Synthase (SPS) Activity in Two Tomato Species

WANG Li, CUI Na, ZHAO Xiao-cui, FAN Hai-yan , LI Tian-lai

2014, 13(2): 358-364. DOI: 10.1016/S2095-3119(13)60373-1

Abstract ( ) PDF in ScienceDirect

To explore the differences of carbohydrate metabolism in two tomato species and discuss the possible regulation of 14-3-3 proteins on the sucrose phosphate synthase (SPS) activity, we determined the contents of soluble sugar and starch through high performance liquid chromatography (HPLC). The activities of sugar-metabolizing enzymes were assayed in desalted extract, and the relative expression levels of related genes in sugar metabolism were determined though real-time RT-PCR. The results indicated that glucose and fructose were mainly accumulated during the maturation of the fruit because of the high acid invertase (AI) and neutral invertase (NI) in Micro-Tom (Solanum lycopersicum) fruit, while in Solanum chmielewskii fruit, SPS which went along with the change of sucrose content led to the rapid sucrose increase during the fruit ripening. TFT1 and TFT10, belonging to 14-3-3 protein in tomato, were likely to down-regulated SPS activity during young and intumescence period.

Studies on Methane Emissions from Pastoral Farming in New Zealand

LI Meng-meng, ZHANG Gui-guo, SUN Xue-zhao, DONG Shu-ting , Simone O Hoskin

2014, 13(2): 365-377. DOI: 10.1016/S2095-3119(13)60272-5

Abstract ( ) PDF in ScienceDirect

The aim of this paper was to give a basic understanding of studies on methane emissions of New Zealand, as we know the agriculture of New Zealand is pastoral farming, most livestock animals are grazed in pasture, and quantities of methane were released from the digestive tract and animals excreta. In New Zealand some 50% greenhouse gases (GHG) sources are attributed to agriculture and one third is methane from livestock enteric formation. For many years, many researchers have been exploiting the techniques and methods to measure the emission of methane of New Zealand, further more studing the available options to alleviate the methane emissions. Their pioneering work and successful experiences including the determined methods and mitigation strategies are worth learning for scholars around the world. Some of their approaches were not only suitable for New Zealand grazed livestock, but for many other countries, even the animals are intensively bred in pen. The calorimeter/respiration chamber is the most exactly method in present, but it needs expensive equipments and skilled manipulators, so there are still some difficulty in applying this approach extensively in practice. Sulfur hexafluoride (SF6) trace technique is much adopted for grazed livestock evaluating the methane emission, though its veracity was doubted by some researchers, it is still a good option in present for studying the GHG emissions for grazing animals. By measuring the rumen volatile fatty acid (VFA) concentration to estimate the methane emission is a relatively simple approach, it is just only a rough evaluation, and it is unsuitable for exact study, but this method may be used in China for extensively raised ruminant. In present China, the ruminants are fed in an extensively managed state, the diversities of roughage and animals varieties caused difficult to exactly estimate the methane emission. So exploiting the available options is much important for constituting the exhaustive emission inventory. This review just outline some practical techniques of New Zealand, those maybe a good reference for researchers to carry out their studies in this field, after all New Zealand have been persisting many years and acquired great achievements in methane mitigation area.

Generation and Analysis of Expressed Sequence Tags (ESTs) from Muscle Full-Length cDNA Library of Wujin Pig

ZHAO Su-mei, LIU Yong-gang, PAN Hong-bing, ZHANG Xi, GE Chang-rong, JIA Jun-jing , GAO Shi-zheng

2014, 13(2): 378-386. DOI: 10.1016/S2095-3119(13)60414-1

Abstract ( ) PDF in ScienceDirect

Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Construction of a full-length cDNA library is an effective way to understand the expression of functional genes in muscle tissues. In addition, novel genes for further research could be identified in the library. In this study, we constructed a full-length cDNA library from porcine muscle tissue. The estimated average size of the cDNA inserts was 1 076 bp, and the cDNA fullness ratio was 86.2%. A total of 1 058 unique sequences with 342 contigs (32.3%) and 716 singleton (67.7%) expressed sequence tags (EST) were obtained by clustering and assembling. Meanwhile, 826 (78.1%) ESTs were categorized as known genes, and 232 (21.9%) ESTs were categorized as unknown genes. 65 novel porcine genes that exhibit no identity in the TIGR gene index of Sus scrofa and 124 full-length sequences with unknown functions were deposited in the dbEST division of GenBank (accession numbers: EU650784-EU650788, GE843306, GH228978-GH229100). The abundantly expressed genes in porcine muscle tissue were related to muscle fiber development, energy metabolism and protein synthesis. Gene ontology analysis showed that sequences expressed in porcine muscle tissue contained a high percentage of binding activity, catalytic activity, structural molecule activity and motor activity, which involved mainly in metabolic, cellular and developmental process, distributed mainly in intracellular region. The sequence data generated in this study would provide valuable information for identifying porcine genes expressed in muscle tissue and help to advance the study on the structure and function of genes in pigs.

Effects of Dietary Isoflavone Supplementation on Meat Quality and Oxidative Stability During Storage in Lingnan Yellow Broilers

JIANG Shou-qun, JIANG Zong-yong, ZHOU Gui-lian, LIN Ying-cai , ZHENG Chun-tian

2014, 13(2): 387-393. DOI: 10.1016/S2095-3119(13)60386-X

Abstract ( ) PDF in ScienceDirect

To investigate the effects of a synthetic isoflavone (SI) on meat quality and oxidative stability, 1 500 43-d-old Lingnan yellow male broilers were randomly assigned to five dietary treatments: diets supplemented with 0, 10, 20, 40, or 80 mg SI kg-1, fed ad libitum for a period of 3 wk. After refrigerated storage, a* value of the meat increased with dietary SI supplementation using 10 and 40 mg kg-1 level (P<0.05), L* value decreased (P<0.05), and 40 mg kg-1 increased the pH (P<0.05). Supplementation with SI, at all levels, increased water holding capacity (P<0.05) and decreased lactic acid content of meat (P<0.05). The concentration of malondialdehyde at 72 h decreased linearly (P=0.005) and quadratically (P=0.004) with increasing levels of SI. Dietary SI at 20 and 40 mg kg-1 levels enhanced total superoxide dismutase activity in meat (P<0.05). Meat pH quadratically decreased as the storage time increased (P<0.05), with the highest value at 24 h (P<0.05). Lactic acid and malondialdehyde concentrations of meat increased over time, with value at 96 h being far higher than at earlier times (P<0.05). Supplemental SI linearly and quadratically increased the mRNA abundance of glutathione peroxidase (GPX) (P=0.001 and P=0.002) and catalase (CAT) (P=0.003 and P=0.006) in breast muscle. The results from this study indicate that dietary supplementation with SI can improve meat quality during refrigerated storage by decreasing lipid peroxidation and enhancing oxidative stability and, for male broilers from 43 to 63 d of age, the optimal level of SI was 40 mg kg-1.

RNA Interference-Mediated Downregulation of sAC Gene Inhibits Sperm Hyperactivation in Male Rats (Rattus norvegicus)

YU Jing, JIANG Xiao-qiang, ZHOU Shuai , WANG Gen-lin

2014, 13(2): 394-401. DOI: 10.1016/S2095-3119(13)60294-4

Abstract ( ) PDF in ScienceDirect

Hyperactivation is one of the most critical parts for fertilization. cAMP generated by soluble adenylyl cyclase (sAC) is necessary to activate sperm and is a prerequisite for sperm hyperactivation. The aim of this study is to investigate the function of sAC in hyperactivation in male rats. Four siRNAs of sAC gene were designed and separately transformed into rat sperm using electrotransformation method. Cultured for 12 and 24 h, physiological and biochemical indexes of these sperm were analyzed, and the expressions of some hyperactivation-related genes were detected using real-time PCR. We demonstrated 26.3-30.8% and 49.1-50.5% reduction in sAC at the protein by Western blot and mRNA levels by real-time PCR, respectively. The results showed that two siRNAs, Actb-717 and Actb-4205, were the best RNAi sites for silencing sAC. The VCL (curvilinear velocity) and ALH (amplitude of lateral head displacement) of RNA interference (RNAi)-transfected sperm were reduced. cAMP and protein phosphorylation in RNAi transfected sperm were also decreased. The hyperactivation-related genes, such as CatSper2, LDHC and PKA, were downregulated in the sperm, which sAC was knockdown. These findings demonstrated that sAC might play a critical role in cAMP signaling in the rat sperm hyperactivation, and downregulated sAC gene might prevent the expression of these hyperactivation-ralated genes resulting in sperm dysfunction. These findings suggest that these hyperactivation-ralated genes and sAC are functionally related in sperm hyperactivation and sAC falls into an expanding group of sperm proteins that appear to be promising targets for the development of male contraceptives.

Trends of Yield and Soil Fertility in a Long-Term Wheat-Maize System

YANG Xue-yun, SUN Ben-hua , ZHANG Shu-lan

2014, 13(2): 402-414. DOI: 10.1016/S2095-3119(13)60425-6

Abstract ( ) PDF in ScienceDirect

The sustainability of the wheat-maize rotation is important to China’s food security. Intensive cropping without recycling crop residues or other organic inputs results in the loss of soil organic matter (SOM) and nutrients, and is assumed to be non- sustainable. We evaluated the effects of nine different treatments on yields, nitrogen use efficiency, P and K balances, and soil fertility in a wheat-maize rotation system (1991-2010) on silt clay loam in Shaanxi, China. The treatments involved the application of recommended dose of nitrogen (N), nitrogen and phosphorus (NP), nitrogen and potassium (NK), phosphorus and potassium (PK), combined NPK, wheat or maize straw (S) with NPK (SNPK), or dairy manure (M) with NPK (M1NPK and M2NPK), along with an un-treated control treatment (CK). The mean yields of wheat and maize ranged from 992 and 2 235 kg ha-1 under CK to 5 962 and 6 894 kg ha-1 under M2NPK treatment, respectively. Treatments in which either N or P was omitted (N, NK and PK) gave significantly lower crop yields than those in which both were applied. The crop yields obtained under NP, NPK and SNPK treatments were statistically identical, as were those obtained under SNPK and MNPK. However, M2NPK gave a significant higher wheat yield than NP, and MNPK gave significant higher maize yield than both NP and NPK. Wheat yields increased significantly (by 86 to 155 kg ha-1 yr-1) in treatments where NP was applied, but maize yields did not. In general, the nitrogen use efficiency of wheat was the highest under the NP and NPK treatments; for maize, it was the highest under MNPK treatment. The P balance was highly positive under MNPK treatment, increasing by 136 to 213 kg ha-1 annually. While the K balance was negative in most treatments, ranging from 31 to 217 kg ha-1 yr-1, levels of soil available K remained unchanged or increased over the 20 yr. SOM levels increased significantly in all treatments. Overall, the results indicated that combinations of organic manure and inorganic nitrogen, or returning straw with NP is likely to improve soil fertility, increasing the yields achievable with wheat-maize system in a way which is environmentally and agronomically beneficial on the tested soil.

Variation of Potential Nitrification and Ammonia-Oxidizing Bacterial Community with Plant-Growing Period in Apple Orchard Soil

LIU Ling-zhi, QIN Si-jun, Lü De-guo, WANG Bing-ying , YANG Ze-yuan

2014, 13(2): 415-425. DOI: 10.1016/S2095-3119(13)60424-4

Abstract ( ) PDF in ScienceDirect

In this study, we investigated the potential nitrification and community structure of soil-based ammonia-oxidizing bacteria (AOB) in apple orchard soil during different growth periods and explored the effects of environmental factors on nitrification activity and AOB community composition in the soil of a Hanfu apple orchard, using a culture-dependent technique and denaturing gradient gel electrophoresis (DGGE). We observed that nitrification activity and AOB abundance were the highest in November, lower in May, and the lowest in July. The results of statistical analysis indicated that total nitrogen (N) content, NH4 +-N content, NO3 --N content, and pH showed significant correlations with AOB abundance and nitrification activity in soil. The Shannon-Winner diversity, as well as species richness and evenness indices (determined by PCR-DGGE banding patterns) in soil samples were the highest in September, but the lowest in July, when compared to additional sampled dates. The DGGE fingerprints of soil-based 16S rRNA genes in November were apparently distinct from those observed in May, July, and September, possessing the lowest species richness indices and the highest dominance indices among all four growth periods. Fourteen DGGE bands were excised for sequencing. The resulting analysis indicated that all AOB communities belonged to the β-Proteobacteria phylum, with the dominant AOB showing high similarity to the Nitrosospira genus. Therefore, soil-based environmental factors, such as pH variation and content of NH4 +-N and NO3 --N, can substantially influence the abundance of AOB communities in soil, and play a critical role in soil-based nitrification kinetics.

Responses of Ryegrass (Lolium perenne L.) Grown in Mudflats to Sewage Sludge Amendment

BAI Yan-chao, GU Chuan-hui, TAO Tian-yun, ZHU Xiao-wen, XU Yi-ran, SHAN Yu-hua , FENG Ke

2014, 13(2): 426-433. DOI: 10.1016/S2095-3119(13)60564-X

Abstract ( ) PDF in ScienceDirect

Sewage sludge amendment (SSA) is an alternative waste disposal technique and a potential way to increase fertility of mudflats for crop growth. The present study aimed to assess the suitability of SSA by assessing the nitrogen (N) and phosphorous (P) uptakes, heavy metal accumulation, growth, biomass, and yield response of ryegrass (Lolium perenne L.) at 0, 30, 75, 150, and 300 t ha-1 SSA rates at various growth stages. The results showed that the highest biomass of ryegrass at seedling and vegetative stages were at 300 and 150 t ha-1 SSA rate, respectively. The increments of ryegrass yield at reproductive stage at 30, 75, 150, and 300 t ha-1 SSA rates were 98.0, 122.6, 88.1, and 61.2%, compared to unamended soil. N and P concentrations in ryegrass increased with increasing SSA rates at all stages except N and P in roots dropped significantly at 300 t ha-1 rate at vegetative stage. The metal concentration for Mn, Cu, Zn, Ni, Cd, Cr, and Pb in shoot of ryegrass at 300 t ha-1 SSA rate increased by 0.63-, 2.34-, 15.02-, 0.97-, 10.00-, 0.01- and 1.13-fold, respectively, compared to unamended soil. However, heavy metal concentrations in shoot of ryegrass were lower than the standard for forage products in China. The study suggested that sewage sludge amendment in mudflat soils might be feasible. However, the impacts of sludge application on edible crop plants and soil environment need further investigations.

Use of Human Excreta as Manure in Rural China

LIU Ying, HUANG Ji-kun , Precious Zikhali

2014, 13(2): 434-442. DOI: 10.1016/S2095-3119(13)60407-4

Abstract ( ) PDF in ScienceDirect

Empirical research has shown that the use of manure significantly improves crop yield, soil fertility and water and moisture conservation. Despite these documented benefits, however, there is a concern on the downward trend of manure use in agriculture in China. This paper examines factors contributing to this downward trend, with a particular focus on human excreta used in agriculture. Empirical analysis based on data from stratified random sampling of rural households in five provinces of China shows that about 85% of human excreta was still used as manure in agriculture in 2007 which was less than a decade ago when nearly all human excreta was used as manure. Econometric results suggest that income growth, rising population density and improvement in rural transportation significantly contribute to declining use of human excreta as manure in agriculture. These results imply that the current downward trend will continue given China’s rising economic growth, urbanization and rural infrastructural improvement.

Technological Options to Ameliorate Waste Treatment of Intensive Pig Production in China: An Analysis Based on Bio-Economic Model

LU Wen-cong, MA Yong-xi , Holger Bergmann

2014, 13(2): 443-454. DOI: 10.1016/S2095-3119(13)60582-1

Abstract ( ) PDF in ScienceDirect

Ameliorating waste treatment by technological improvements affects the economic and the ecological-environment benefits of intensive pig production. The objective of the research was to develop and test a method to determine the technical optimization to ameliorate waste treatment methods and gain insight into the relationship between technological options and the economic and ecological effects. We developed an integrated bio-economic model which incorporates the farming production and waste disposal systems to simulate the impact of technological improvements in pig manure treatment on economic and environmental benefits for the case of a pilot farm in Beijing, China. Based on different waste treatment technology options, three scenarios are applied for the simulation analysis of the model. The simulation results reveal that the economic-environmental benefits of the livestock farm could be improved by reducing the cropland manure application and increasing the composting production with the current technologies. Nevertheless, the technical efficiency, the waste treatment capacity and the economic benefits could be further improved by the introduction of new technologies. It implies that technological and economic support policies should be implemented comprehensively on waste disposal and resource utilization to promote sustainable development in intensive livestock production in China.

The Two Cultures of Science: Implications for University-Industry Relationships in the U.S. Agriculture Biotechnology

William B Lacy, Lel , L Glenna, Dina Biscotti, Rick Welsh , Kate Clancy

2014, 13(2): 455-466. DOI: 10.1016/S2095-3119(13)60667-X

Abstract ( ) PDF in ScienceDirect

Partnerships between U.S. universities and industries have existed for several decades and in recent years have become generally more varied, wider in scope, more aggressive and experimental and higher in public visibility. In addition, in the last few decades, public and private interests have advocated for government policies and laws to globally promote the commercialization of university science. This paper examines the persistence or convergence of the two cultures of science and the implications of this commercialization for university-industry relationships in agriculture biotechnology. The perceptions and values of over 200 U.S. university and industry scientists, managers and administrators who participate in or oversee research collaborations in agricultural biotechnology were analyzed. The findings revealed that the participants in these research relationships continue to perceive very distinct cultures of science and identify a wide range of concerns and disadvantages of these partnerships. Several actions were discussed to ensure that the two cultures serve complementary roles and that they maximize the public benefits from these increasing collaborations.

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