Characterization of Rsg2.a3:A new greenbug resistance allele at the Rsg2 locus from wild barley(Hordeum vulgare ssp.spontaneum)

Greenbug(Schizaphis graminum Rondani)is a destructive insect pest that not only damages plants,but also serves as a vector for many viruses.Host plant resistance is the preferred strategy for managing greenbug.Two greenbug resistance genes,Rsg1 and Rsg2,have been reported in barley.To breed cultivars with effective resistance against various greenbug biotypes,additional resistance genes are urgently needed to sustain barley production.Wild barley accession WBDC053(PI 681777)was previously found to be resistant to several greenbug biotypes.In this study,a recombinant inbred line(RIL)population derived from Weskan×WBDC053 was evaluated for response to two greenbug biotypes(E and TX1)and genotyped using genotyping by sequencing(GBS).A set of 3347 high quality GBS-derived single nucleotide polymorphisms(SNPs)were then used to map the greenbug resistance gene in this wild barley accession.Linkage analysis placed the greenbug resistance gene in a 2.35 Mb interval(0-2,354,645 bp)in the terminal region of the short arm of chromosome 2H.This interval harbors 15 genes with leucine-rich-repeat(LRR)protein domains.An allelism test indicated that the greenbug resistance gene in WBDC053,designated Rsg2.a3,is likely allelic or closely linked to Rsg2.GBS-SNPs 2H_1318811and 2H_1839499 co-segregating with Rsg2.a3 in the RIL population were converted to Kompetitive allele specific PCR(KASP)markers KASP-Rsg2.a3-1 and KASP-Rsg2.a3-2,respectively.The two KASP markers can be used to select Rsg2.a3 and have the potential to tag Rsg2 in barley improvement programs.

Genomic location of Gb1, a unique gene conferring wheat resistance to greenbug biotype F

Greenbug(Schizaphis graminum, Rondani) is a serious insect pest in many wheat growing regions and has been infesting cereal crops in the USA for over a century. Continuous occurrence of new greenbug biotypes makes it essential to explore all greenbug resistant sources available to manage this pest. Gb1, a recessive greenbug resistance gene in DS28A, confers resistance to several economically important greenbug biotypes and is the only gene found to be resistant to greenbug biotype F. A set of 174 F_(2:3)lines from the cross DS28A × Custer was evaluated for resistance to greenbug biotype F in 2020 and 2022. Selective genotyping of the corresponding F_(2) population using single nucleotide polymorphism(SNP) markers generated by genotyping-by-sequencing(GBS) led to the identification of a candidate genomic region for Gb1. Thus, SSR markers previously mapped in this region were used to genotype the entire F2population,and kompetitive allele specific PCR(KASP) markers were also developed from SNPs in the target region.Gb1 was placed in the terminal region of the short arm of chromosome 1A, and its location was confirmed in a second population derived from the cross DS28A × PI 697274. The combined data analysis from the two mapping populations delimited Gb1 to a < 1 Mb interval between 13,328,200 and 14,241,426 bp on1AS.

Seasonal Variation in Krasnodar Greenbug Population for Virulence to Sorghum Genotypes

Intraspecific variability in Schizaphis graminum （Rondani） was studied in 2002-2005. Aphid clones were sampled from sorghum field at the Kuban Experimental Station （Krasnodar region, Northern Caucasus, Russia） in June （active greenbug migration to the field）, July （high rate of the population increasing）, and August （greenbug abundance decreasing） and at the end of September or in the beginning of October （appearance of sexual males and females）. Damage rating was estimated for two plant sets composed of three sorghum differentials. Set A contains Deer （gene for resistance Sgr4）, Sarvasi （Sgrl ＋ Sgr2） and Capbam （Sgrl2）. Set B contains Shallu （Sgr3）, Sorgogradskoe （Sgr5） and Durra Belaya （Sgr5 ＋ Sgr6）. To estimate variability in greenbug subpopulations criteria proposed by Zhivotovsky （1982） were used. Frequencies of greenbug clones with virulence to sorghum accessions essentially differed. Very high overall and seasonal polymorphism of the insect for virulence was revealed. Among 517 aphid clones tested 33 phenotypes for virulence were identified. The aphid subpopulations collected from the same field at different periods of sorghum vegetation varied significantly in share of rare phenotypes. Criteria of similarities varied from 0.268 to 0.739; according to criterion of identity significant differences between 44 summer subpopulations from 66 studied were found.

不同氮肥水平对麦蚜天敌群落的生物多样性及空间格局动态的影响

研究两种氮肥水平条件下麦蚜天敌群落生物多样性差异 ,结果表明其差异不显著 ;同时分析了两种肥力水平对两种麦蚜空间格局的影响 。

小麦品种对麦蚜天敌群落生物多样性的影响

研究几个小麦品种的麦田麦蚜天敌群落生物多样性变化及差异 ,结果表明差异不显著 ,同时比较了安农 84C-1品种 1 995、 1 996年年度间麦田麦蚜天敌群落多样性差异 ,差异也不显著 ,初步表明小麦品种对麦田麦蚜天敌群落生物多样性影响不显著。

天敌对麦长管蚜和麦二叉蚜种群数量影响程度的分析

通过对１９９３～１９９６年两种麦蚜种群数量及其天敌数量的系统调查，并采用灰色关联分析法，研究各种天敌对两种麦蚜种群数量的影响程度，得出对麦长管蚜种群数量影响最大的是龟纹瓢虫、蚜茧蜂和食蚜蝇；对麦二叉蚜种群数量影响最大的是草间小黑蛛，其次是龟纹瓢虫．

高粱抗蚜虫SSR体系的建立

以抗蚜高粱———河农16为试材,采用单因素筛选的方法,摸索SSR反应体系中各个影响因素的浓度和用量,然后采用完全随机试验,进行优化组合,最终获得适宜高粱抗蚜虫基因定位的SSR体系。其中TaqDNA聚合酶0 3μL(5u μL),10×PCRBuffer(Mg2+)2 0μL,引物1 5μL(10μmol L),模板DNA60ng。利用该体系进行扩增,所得谱带清晰、稳定、非特异性带少。

各种天敌对麦长管蚜和麦二叉蚜种群数量影响程度的研究

本文利用灰色系统理论 ,对 1 993— 1 996年两种麦蚜的种群数量及其天敌的捕食总量之间的追随关系进行分析 ,并研究各种天敌与理想优势种天敌之间的联系程度 ,结果显示 ,麦长管蚜的优势种天敌是食蚜蝇、龟纹瓢虫、蚜茧峰和草间小黑蛛 ;对麦二叉蚜种群数量影响大的主要天敌是草间小黑蛛、龟纹瓢虫。

高粱种质资源抗蚜性评价

利用苗期室内鉴定和成株期田间自然感蚜鉴定相结合的方法对292份高粱育种材料进行麦二叉蚜和高粱蚜的抗性鉴定,旨在为高粱抗蚜品种的聚合育种及品种抗蚜性改良提供精准抗源。抗性鉴定结果显示,PB14648-6、PI550607、Tx2737的抗性比较稳定,在苗期和成株期均对麦二叉蚜表现出一定的抗性;3765白B、L27(粉)、R1027、冀蚜2号在苗期和成株期均表现抗高粱蚜;仅在成株期鉴定中筛选到河北糯R、青稞洋、Tx2737同时对高粱蚜和麦二叉蚜有较好抗性,也仅达到抗(R)级水平。从统计结果来看,苗期接种麦二叉蚜14 d抗性呈极显著差异;而接种高粱蚜7 d抗性呈显著差异,接蚜后10 d、14 d抗性呈极显著差异。接蚜14 d后,高感材料出现死亡、干枯现象,抗感性易于鉴别,因此,接蚜后14 d是进行苗期抗、感性分析的最佳调查时期;在高粱成株期抗蚜鉴定中,全生育期平均蚜量与盛发期平均蚜量有较高正相关关系(麦二叉蚜相关系数为0.844,高粱蚜为0.954),盛发期蚜量能够较好的代表供试材料的田间抗性,可以用于高粱抗蚜鉴定复筛试验。

北京地区麦二叉蚜生物型鉴定研究初报

根据小麦苗期１～６级蚜害分级标准，１９９６年～１９９７年利用国际通用的生物型鉴别寄主（品种）对北京地区麦二叉蚜种群进行了生物型鉴定。各鉴别品种的蚜害反应型分级是：小麦ＤＳ２８Ａ（ｇｂ１）为６，Ａｍｉｇｏ（Ｇｂ２）为１，Ｌａｒｇｏ（Ｇｂ３）为２，ＣＩ１７９５９（Ｇｂ４）为６，ＣＩ１７８８２（Ｇｂ５）为３，ＧＲＳ１２０１（Ｇｂ６）为３．５，燕麦ＣＩ１５８０为１，黑麦Ｉｎｓａｖｅ为１。结果表明，北京麦二叉蚜的致害性显著地不同于１０个已知的生物型（从Ａ到Ｊ），是一新的生物型，命名为中国１型（ＢｉｏｔｙｐｅＣＨＮ－１）。此外，针对麦二叉蚜生物型分化问题，对小麦抗蚜育种中的品种抗性持久化与累积抗性品种的培育，以及分子标记辅助育种技术的应用等策略进行了探讨。

Resistance in Barley (<i>Hordeum vulgare</i>L.) to New Invasive Aphid, Hedgehog Grain Aphid (<i>Sipha maydis</i>, Passerini) (Hemiptera: Aphididae)

Sipha maydis Passerini (Hemiptera: Aphididae) is a pest of cereals in many regions of the world and was identified as an invasive pest of the US in 2007. Regional surveys from 2015-2017 revealed this pest was broadly distributed throughout many of the western Great Plains states where it is a potential threat to cereal production. The common name hedgehog grain aphid, HGA, has been associated with Sipha maydis in the US. Cross-resistance where a plant is resistant to one aphid species and is also resistant to another species that is known to occur. Six barleys were evaluated for cross-resistance to HGA: Russian wheat aphid, RWA, resistant germplasms STARS 9301B and STARS 9577B and cultivar “Mesa”;greenbug, GB, resistant germplasm STARS 1501B and cultivar “Post 90”;and RWA and GB resistant experimental line 00BX 11-115. Cultivars “Morex” and “Schuyler” were susceptible controls. Antixenosis was measured 5 days after infestation by HGA. Seedling damage ratings and reductions in seedling growth were recorded after 17 days of infestation. Intrinsic rate of increase, rm, of HGA was determined by following the development of newborn aphids to adulthood and reproduction. 00BX 11-115 and Post 90 had significantly greater antixenosis (fewer aphids/seedling), significantly lower plant damage ratings, and significantly lower intrinsic rates of increase than other entries. Differences in seedling growth were not significant. 00BX 11-115 and Post 90 were the only entries with the Rsg1 greenbug resistance gene. Rsg1 greenbug resistance confers cross-resistance to HGA in the seedling stage.

转录组学分析揭示高粱对麦二叉蚜抗性的响应机制

[目的]麦二叉蚜是高粱生产过程中引起蚜害的主要优势种群之一,前期研究发现高粱抗蚜种质PI550607在苗期和成株期均抗麦二叉蚜,本研究通过转录组测序技术研究PI550607抗蚜相关基因的调控机制和代谢通路,为高粱蚜虫防控技术研究与抗蚜品种选育提供理论指导。[方法]以抗蚜品种PI550607为试验材料,室内培养出苗后2周进行人工接蚜,进行对照组0、12 h以及接蚜后12 h采样,提取RNA,进行转录组测序,对测序数据进行生物信息学分析,筛选差异基因,根据差异基因进行基因功能及代谢通路分析。同时,采用qRT-PCR方法对测序结果进行验证。[结果]PI550607对麦二叉蚜表现出较好的抗性。在蚜虫取食12 h后受蚜虫取食诱导的差异表达基因200个,其中上调基因188个,下调基因12个。基因功能注释显示上调表达的基因主要为植物激素代谢途径、苯丙烷类生物合成、类黄酮生物合成、谷胱甘肽代谢相关的基因以及WRKY转录因子,细胞色素P450等基因。GO富集分析显示在188个上调表达基因中有178个基因获得注释,分布于35个注释条目中,其中与植物抗虫相关的过程主要有苯丙烷类生物合成过程、响应生物胁迫以及非生物胁迫的创伤反应过程、防卫反应过程、茉莉酸介导的信号途径、对茉莉酸的反应以及催化活性调节等过程。差异基因KEGG分析结果显示,蚜虫取食12 h的样品与相应对照间差异表达基因大量富集于苯丙烷类生物合成途径、植物激素信号传导途径以及谷胱甘肽代谢途径、类黄酮代谢合成途径、α-亚麻酸代谢途径、氨基酸生物合成以及植物昼夜节律调控等代谢途径中。参与茉莉酸信号通路与类黄酮代谢途径的基因上调表达较多,这两个代谢途径可能在PI550607抗蚜反应中发挥了重要的作用。选取了6个差异表达基因进行qRT-PCR验证,其基因表达数据与测序数据一致。[结论]高粱品种PI550607在受蚜虫取食早期主要通过提高基因表达量来抵御蚜虫危害,茉莉酸信号途径以及类黄酮代谢途径在PI550607抵御麦二叉蚜的取食过程中发挥了重要的作用。