油料作物油脂合成调控研究进展

植物油脂不仅是人类可食用油的主要来源,也是人类生产生活中重要的可再生原料。本文概述了植物油脂的生物合成途径,从母体效应、QTL、GWAS等多个方面总结了油料作物油脂合成的遗传学研究进展,同时探讨了已知的油脂合成调控相关基因的功能。本文综述了该领域的研究现状,为深入了解油料作物油脂合成调控网络提供了参考,也为油料作物的分子改良和遗传育种提供了理论基础。     

SSCP Marker Development and Analysis of Candidate Restorer Gene Rf1 for Cotton Cytoplasmic Male Sterility

[Objective] Locating the cotton cytoplasmic male sterility (CMS) restorer gene Rf₁ is important for investigating restorer gene mechanisms and improving restorer lines. In our previous study, a gene cluster, with nine Pentatricopeptide repeat(PPR) genes and nine other genes, was found within the 160-kb Rf₁ target region in Scaffold 333. The objective here was to improve the density of Rf1-linked markers in the target region and determine the expression profiles of candidate genes. [Method] Using the sequences of the 18 genes, we designed 155 single-strand conformation polymorphism (SSCP) primers covering all of the gene sequences to identify the polymorphic SSCP markers between the fertile and sterile pools. Additionally, real-time polymerase chain reaction(PCR) was performed to analyze the expression profiles of eight candidate genes in the four developmental stages of buds of sterile, maintainer and restoring lines, respectively. [Result] In total, 15 polymorphic primers were identified. A genotype analysis of the F₂ population was conducted using the 15 primers and 3 other polymorphic simple sequence repeats (SSR) markers. The markers were distributed in a 4.8 cM range. In addition, owing to the influence of sterile cytoplasm or restorer genes, most of the genes showed different expression patterns in the four developmental stages of the three lines' buds. [Conclusion] SSCP markers tightly linked to Rf₁ were identified and the expression profiles of candidate genes were determined. This study provides a basis for the further fine mapping of restorer genes and for candidate gene screening.     

翠竹及菲白竹LEA3同源基因的克隆及序列分析

竹类植物在中国有着非常悠久的栽培历史,并被广泛应用于园林、造林、庭院以及食品等行业。本研究以翠竹和菲白竹为材料提取其叶片总DNA,采用PCR方法获得翠竹SpLEA3基因与菲白竹SfLEA3-1、SfLEA3-2基因;其中SpLEA3全长804 bp,编码195个氨基酸,GC含量为68.4%;SfLEA3-1全长803 bp,编码195个氨基酸,GC含量为68.2%;SfLEA3-2全长557 bp,编码144个氨基酸,GC含量为67.8%。通过ProtParamy等生物软件分析,SpLEA3、SfLEA3-1和SfLEA3-2与贵州悬竹LEA3基因同源性高达61%以上,且3个基因编码蛋白均属于亲水性蛋白。源自2个竹种LEA3基因均包含一个完整的开放阅读框,其编码的氨基酸含有4~6个由11个氨基酸组成的保守基元序列。本研究不仅为深入了解竹类植物抗旱的分子机理研究提供了基础数据,也为竹类植物的抗旱育种后续研究提供了科学依据。     

Molecular identification of blast resistance genes in rice landraces from northeastern India

Rice blast disease caused by the fungus Magnaporthe oryzae is one of the most devastating diseases causing huge losses worldwide. In the present study, major blast resistance genes were investigated in landraces originating from northeastern India. Based on phenotypic evaluation, 288 landraces were classified into three distinct groups: resistant (75), moderately resistant (127) and susceptible (86). The genetic frequencies of the 18 major blast resistance genes were between 6.2% and 27.4%, with only two genotypes possessing a maximum of nine blast resistance genes. The cluster and population structure analysis grouped the landraces into two groups. Through principal coordinate analysis, the scatter plots partitioned the resistant and moderately resistant landraces into different groups. Analysis of molecular variance showed maximum (96%) diversity within populations and least (4%) diversity between populations. Association analysis identified six markers, CRG4_2, RM72, tk59-2, pi21_79-3, RM1233 and RM6648, that are significantly associated with blast disease and explained a phenotypic variance of 1.1–6.5%. The associated genes could be used in marker-assisted rice breeding programmes for gene pyramiding to develop rice varietal resistance against blast disease. The present study represents a valuable blast resistance genetic resource that could be used for identification of new R genes, donors for blast resistance, and genomic studies.     

茶树叶片响应茶饼病侵染的转录组分析

采用高通量测序技术对被茶饼病病菌侵染的茶树叶片进行转录组测序,筛选得到差异基因359个,其中248个上调表达,111个下调表达。差异基因中有216个获得GO（Gene ontology）数据库功能注释,主要涉及到生物合成过程、催化活性、细胞过程等诸多生理生化过程;KEGG（Kyoto encyclopedia of genes and genomes）数据库富集分析发现,共有106个基因被注释到47个代谢通路中,其中,单萜生物合成、卟啉和叶绿素代谢、核糖体、氮代谢、双萜生物合成、植物病原互作等通路显著富集。有32个差异基因被鉴定为转录因子,分布在16个转录因子家族中。利用实时荧光定量PCR（Real time quantitative PCR,qRT-PCR）验证了随机挑选的差异基因在感病叶片和未感病叶片中的相对表达量,与转录组测序结果的变化趋势一致。结果表明,茶树响应病原菌侵染是一个复杂的过程,大量基因被诱导或抑制表达,与抗病相关的转录因子被大量激活且上调表达。本研究为深入挖掘茶树抗病基因及进一步研究抗病分子机制提供了理论依据。     

转Pi9抗稻瘟病基因水稻株系的比较转录组分析

【目的】在转录水平上解析Pi9基因介导的稻瘟病抗性调控机理,为培育抗病水稻品种提供理论依据。【方法】向水稻品种日本晴(NPB)及其转Pi9抗稻瘟病基因株系(NPB/Pi9)接种稻瘟菌。分别于接种后0 h、12 h、24 h、36 h提取叶组织样品,选取12503个水稻基因定制基因芯片,进行水稻基因转录组分析,并通过qRT-PCR对部分差异表达基因进行验证。【结果】NPB/Pi9在接种后12 h、24 h和36 h的基因表达量分别与其接种0 h表达量比较,共检测到7754个差异表达基因;相应地,感病水稻NPB在以上时间点共检测到7385个差异表达基因;在接种后36 h,NPB/Pi9的差异表达基因数目显著多于NPB。比较NPB/Pi9和NPB相同时间点的基因表达量,共获得4065个差异表达基因,其中接种后36 h的差异表达基因显著多于接种后0 h、12 h或24 h。因此,NPB/Pi9的稻瘟病防御反应更强烈。对NPB/Pi9与NPB相同时间点的差异表达基因进行GO和KEGG分析,细胞外区域、植物对刺激应答、转录调控、氧化还原、离子结合、次生代谢和植物激素相关的GO分类在接种后呈显著富集,苯丙氨酸代谢、类黄酮生物合成和植物激素信号途径的KEGG通路在接种后显著富集。与效应分子触发的免疫反应(ETI)相关的水杨酸信号途径、几丁质酶,以及与病原相关分子模式触发的免疫反应(PTI)相关的胞外区域、对刺激的应答、木质素合成等,均在抗感水稻之间差异表达。而且PTI/ETI共有的WRKY转录因子、MAPK激酶、茉莉酸和乙烯信号途径等发生差异表达。综上所述,NPB/Pi9和NPB的差异表达模式与ETI和PTI相关,两者相互联系并在Pi9介导的稻瘟病抗性中发挥作用。【结论】与日本晴比较,抗病基因型NPB/Pi9对稻瘟病防御反应更强烈。转录因子、激酶、NBS-LRR基因、几丁质酶、水杨酸、茉莉酸和乙烯信号途径,以及植物次生代谢在Pi9介导的稻瘟病抗病反应中发挥重要作用。     

Genome-wide detection of selective signatures in a Jinhua pig population

The aim of this study was to detect evidence for signatures of recent selection in the Jinhua pig genome. These results can be useful to better understand the regions under selection in Jinhua pigs and might shed some lights on groups of genes that control production traits. In the present study, we performed extended haplotype homozygosity(EHH) tests to identify significant core regions in 202 Jinhua pigs. A total of 26 161 core regions spanning 636.42 Mb were identified, which occupied approximately 28% of the genome across all autosomes, and 1 158 significant(P0.01) core haplotypes were selected. Genes in these regions were related to several economically important traits, including meat quality, reproduction, immune responses and exterior traits. A panel of genes including ssc-mir-365-2, KDM8, RABEP2, GSG1L, RHEB, RPH3AL and a signal pathway of PI3K-Akt were detected with the most extreme P-values. The findings in our study could draw a comparatively genome-wide map of selection signature in the pig genome, and also help to detect functional candidate genes under positive selection for further genetic and breeding research in Jinhua and other pigs.