Soybean cyst nematode-resistance: Gene identification and breeding strategies

Soybean cyst nematode(SCN,Heterodera glycines Ichinohe)is the most economically damaging disease of soybean worldwide,and breeding host plant resistance is the most feasible option for SCN management.In this review,we summarise the progress made so far in identifying nematode-resistance genes,the currently available sources of resistance,possible mechanisms of SCN resistance and strategies for soybean breeding.To date,only two sources of SCN resistance have been widely used,from the accessions PI 88788 and Peking,which has resulted in a shift in SCN resistance and created a narrow genetic base for SCN resistance.These resistant germplasms for SCN are classified into two types according to their copy number variation in a 31-kb genomic region:PI 88788-type resistance requires high copy numbers of a rhg1 resistance allele(rhg1-b)and Peking-type resistance requires both low copy numbers of a different rhg1 resistance allele(rhg1-a)and a resistant allele at another locus,Rhg4.Resistance related to rhg1 primarily involves impairment of vesicle trafficking through disruption of soluble NSF-attachment protein receptor(SNARE)complexes.By contrast,resistance via Rhg4 involves disturbance of folate homeostasis at SCN feeding sites due to alteration of the enzymatic activity of serine hydroxymethyltransferase(SHMT).Other potential mechanisms,including plant defences mediated by salicylic acid(SA)and jasmonic acid(JA)signalling modulation,have also been suggested for SCN resistance.Indeed,genome-wide association studies(GWAS)have identified other candidate SCN resistance genes,such as Gm SNAP11.Although gene functional analysis in a transient expression system could increase the efficiency of candidate gene identification,information on novel genes and mechanisms for SCN resistance remains limited.Any beneficial candidate genes identified might,when fully exploited,be valuable for improving the efficiency of marker-assisted breeding and dissecting the molecular mechanisms underlying SCN resistance.

Current Research Status of Heterodera glycines Resistance and Its Implication on Soybean Breeding

Heterodera glycines （i.e., soybean cyst nematode, SCN） is the most damaging nematode pest affecting soybean crop worldwide. This nematode is managed by means of crop rotation with selected resistant sources. With increasing reports of virulent SCN populations that are able to break the resistance within commonly used sources, there is an increasing need to find new sources of resistance or to broaden the resistance background. This review summarizes recent findings about the genes controlling SCN resis- tance in soybean, and about how these genes interact to confer resistance against SCN in soybean. It also provides an update on molecular mapping and molecular markers that can be used for the mass selection and differentiation of different resistance lines and cultivars in order to expedite conventional breeding programs. In-depth knowledge of SCN parasitism proteins and soybean resistance responses to the pathogen is critical for the diversification of resistant sources through gene modification, gene stacking, or incorporation of novel sources of resistance through backcrossing or genetic engineering.

Breeding Soybeans for Resistance to Physiological Race 4 of Cyst Nematode

Soybean cyst nematode causes serious damage to soybean production. In 1991, we started breeding studies on the resistance of soybeans to the cyst nematode. We found that near the Beijing area the dominant race of the cyst nematode was race 4. We made more than 50 combinations of cross. The best combination was Dan 8 X PI 437654 which resulted in marked segregation in plant height, pod habit, resistance to cyst nematode and maturity. We obtained many new soybean lines highly resistant to the cyst nematode through the pedigree method of selection, enlarging the number of plants of good combinations, alternative breeding in the North and in the South, and identification at an early generation. We now have released three soybean cultivars, Zhonghuang 12, Zhonghuang 13 and Zhonghuang 17 with moderate resistance to the cyst nematode in Beijing, Anhui, Tianjin and Northern China. In addition, we obtained many lines which were highly resistant to the cyst nematode.

Chemical mutagenesis and soybean mutants potential for identification of novel genes conferring resistance to soybean cyst nematode

The resistance of soybean(Glycine max(L.) Merr.) to soybean cyst nematode(SCN, Heterodera glycines Ichinohe), which is a devastating pathogen in soybean production and causes a large quantity of annual yield loss worldwide, can shift during the long-term interaction and domestication. It is vital to identify more new resistance genetic sources for identification of novel genes underlying resistance to SCN for management of this pathogen. In the present study, first, two ethane methylsulfonate-mutagenesis soybean M2 populations of PI 437654, which shows a broad resistance to almost all of SCN races, and Zhonghuang 13, which is a soybean cultivar in China conferring strong resistance to lodging, were developed. Many types of morphological phenotypes such as four-and five-leaflet leaves were observed from these two soybean M2 populations. Second, 13 mutants were identified and confirmed to exhibit alteration of resistance to SCN race 4 through the forward genetic screening of 400 mutants of the PI 437654 M2 population, the rate of mutants with alteration of SCNinfection phenotype is 3.25%. Third, these identified mutants were further verified not to show any changes in the genomic sequences of the three known SCN-resistant genes, GmSHMT08, GmSNAP18 and GmSANP11, compared to the wildtype soybean; and all of them were still resistant to SCN race 3 similar to the wild-type soybean. Taken together, we can conclude that the 13 mutants identified in the present study carry the mutations of the new gene(s) which contribute(s) to the resistance to SCN race 4 in PI 437654 and can be potentially used as the genetic soybean sources to further identify the novel SCN-resistant gene(s).

Research Advances in Genetic Markers for Resistance to Soybean Cyst Nematodes(SCN)

Soybean cyst nematode(SCN), Heterodera glycine, is one of the important diseases affecting the yield of soybean(Glycine max) worldwide. Host-plant resistance is the most economically effective way to control SCN. Identification of DNA markers linked to SCN resistance genes is one of the important steps in the marker-assisted selection(MAS) for nematode resistance breeding. Quantitative trait loci(QTLs) controlled by mul-tiple resistance genes plays a powerful role in MAS-breeding program. In this paper, we reviewed genetic resistance of SCN, molecular markers of resistance gene and Genome-Wide Associated Study(GWAS) of QTLs linked to SCN resistance, explored the present problems of genetic resistance,and prospected the future of QTL analysis.

A fragment of a 70-kDa Heterodera glycines heat shock protein(HgHSP70)interacts with soybean cyst nematode-resistant GmSHMT08

Soybean cyst nematode(SCN)Heterodera glycines is considered as the major constraint to soybean production.Gm SHMT08 at Rhg4 locus on chromosome 08,encoding a serine hydroxylmethyltransferase,is a major gene underlying resistance against H.glycines in Peking-type soybeans.However,the molecular mechanism underpinning this resistance is less well characterized,and whether Gm SHMT08 could interact with proteins in H.glycines remains unclear.In this study,yeast two-hybrid screening was conducted using Gm SHMT08 as a bait protein,and a fragment of a 70-kDa heat shock protein(Hg HSP70)was screened from H.glycines that exhibited interaction with Gm SHMT08.This interaction was verified by both GST pull-down and bimolecular fluorescence complementation assays.Our finding reveals Hg HSP70 could be applied as a potential candidate gene for further exploring the mechanism on Gm SHMT08-mediated resistance against SCN H.glycines.

Genetic Diversity of Soybean and the Establishment of a Core Collection Focused on Resistance to Soybean Cyst Nematode

Soybean cyst nematode （SCN; Heterodera glycines） Is one of the most Important pests affecting soybean production. The best method of control of SCN is through the development of resistant cultlvars. However, limited progress has been made in soybean breeding In China because most modern cultlvars have no resistance to SCN. The distribution and phenotype of 432 immune or highly resistant Chinese accessions were surveyed and a primary core collection was selected as a representative sample for further analyses. Using evenly distributed simple sequence repeat markers, five selection methods were applied to the primary core collection and the optimal method was chosen to establish a core collection, which consisted of 28 accessions. These encompassed 70.8% of the ailelic variation present in the overall resistant collection. The 28 accessions differed from the reference resistant accessions at the genomlc level, Indicating that Chinese resistant accessions are distinct from known resistant accessions. This applied core collection provides a rational framework for undertaking diversity surveys, using genetic variation for the investigation of complex traits and for the discovery of novel traits.

大豆胞囊线虫病研究进展

大豆胞囊线虫(soybean cyst nematode, SCN)病是大豆生产中一种严重的病害,造成极大的生产及经济损失。目前在SCN综合防治方面,筛选种植抗病品种、农业防治、生物防治和化学防治是常见的防治方法。在抗病研究方面,大豆中的rhg1和rhg4位点是SCN病最重要的抗性位点。文章综述近年来对SCN病相关研究,以期为SCN抗性机制研究、提高防控技术提供参考。

东北地区大豆种质资源对SCN3抗性表型评价

为明确东北地区种质资源对大豆胞囊线虫3号生理小种(SCN3)抗性,以东北地区常用作亲本的620份大豆品种(系)为材料,经2020-2021年SCN3号生理小种田间病圃及室内盆栽接种鉴定。结果表明,2020年田间病圃鉴定对SCN3号生理小种表现中抗以上品种(系)有30份,抗病种质仅占鉴定种质总数的4.84%,2021年对这30份中抗以上材料进行室内盆栽接种鉴定,除白农9号、嫩丰15外,其余品种(系)抗性级别鉴定与田间病圃结果一致。其中农庆豆24、农庆豆28、齐农5号、丰豆1号等13个中抗以上品种可在大豆胞囊线虫病发区直接应用,MN0902CN、MN1701CN、中品03-5373、中品03-5297等9份抗病品系可用作种质资源创新抗病亲本,其他8份中抗品系可用作拓宽抗性基因遗传基础的复合杂交亲本。

国家大豆区域试验品种对SMV和SCN的抗性分析

人工接种我国黄淮、长江流域及南方大豆产区流行SMV株系SC3、SC7和SC15、SC18及黄淮海流行SCN1号生理小种，对国内主要育种单位近年来选育的参加2010—2012国家大豆新品种区域试验的122个参试品种进行抗性鉴定和评价。结果表明：对SC3表现较好抗性（高抗、抗病）的品种32个，占接种该株系品种总数的32％，对SC7表现较好抗性的品种34个，占接种该株系品种总数的34％，同时对SC3和SC7表现较好抗性的品种22个，占接种2个株系品种总数的22％；对SC15表现较好抗性的品种3个，占接种该株系品种总数的13．6％，对SC18表现较好抗性的品种3个，占接种该株系品种总数的13．6％，同时对SC15和SC18表现较好抗性品种的2个，占接种2个株系品种总数的9．09％；近10年SMV抗性鉴定结果分析表明，我国抗SMV育种水平有所提高，新培育的中抗品种比率显著增加，感病品种比率下降。SCN抗性鉴定结果显示，仅沧豆11为高抗，高感品种34个，分别占参试品种总数的1．96％和66．67％，其余为中间型（中抗和中感）。近10年SCN抗性鉴定结果显示我国抗SCN育种水平没有明显改善。鉴定出鲁98011-14、沧豆11、开豆41、鲁97013-1兼抗SMV和SCN两种病害。

大豆种质资源对大豆孢囊线虫3号生理小种抗性鉴定研究

1986～1990五年内,应用田间自然发病和盆栽接种病土鉴定方法,对河南、河北、安徽、山东、山西、陕西等14个省市保存的8183份大豆种质资源进行了大豆孢囊线虫3号生理小种的抗性鉴定,筛选出免疫品种29份,占参试材料0.35％,抗病品种209份,占参试材料2.55％。鉴定结果表明,抗源材料多为黑种皮大豆,而且不同地区大豆种质资源对大豆抱囊线虫3号生理小种的抗性差异较大。

大豆抗胞囊线虫4号生理小种新品系SSR标记分析

培育抗病品种是大豆胞囊线虫(Soybean Cyst Nematode,SCN)病经济、有效的防治方法。利用130个SSR标记对26份抗SCN4号生理小种(SCN4)新品系和15份感病品系进行基因型分析,旨在明确抗病品系与SCN4抗性相关联的SSR标记,提出抗性基因分子标记鉴定方法,以提高抗病品系在育种中的利用效率。研究表明,Hartwig与晋品系亲本具有不同的SCN4抗病基因,其遗传相似系数为0.362。与抗性显著关联的22个SSR位点分布在11个连锁群(LG),推测LGD1b上分布的SSR标记附近存在1个新的SCN4抗病基因;而Satt684、Sat_230、Sat_222、Satt615和Satt231位点,来自亲本Hartwig等位基因与抗病相关联,而来自晋品系的等位基因与感病相关联,在Sat_400、Satt329和Satt557等其他17个SSR位点,来自Hartwig等位基因与感病相关联,来自晋品系亲本的等位基因与抗病相关联。利用非连锁不平衡SSR标记Satt684和Sat_400可对供试品系进行有效的抗性辅助选择。

大豆抗胞囊线虫病种质rhg_1和Rhg_4位点的单核苷酸多态性(SNPs)

研究以 5 7份中美大豆抗胞囊线虫病种质资源为实验材料 ,利用基于检测微珠的单碱基延伸方法 ,对与大豆胞囊线虫病 (SCN)抗性基因rhg1和Rhg4紧密连锁的SNPs进行分析 ,目的是阐明我国大豆抗性种质在这两个位点的SNPs等位变异分布频率 ,为中国大豆种质抗SCN资源的利用奠定基础。分析结果表明 ,SNPs的抗性等位基因与中国大豆种质综合抗性的关系比不同生理小种的抗性关系更为密切。在rhg1和Rhg4位点 ,美国的 9份抗性种质中 ,有 7份抗性种质的SNPs均为纯合抗病基因型 ,而中国 4 8份抗性种质中有 32份 ,分别占鉴定总数的 77 8%和 6 6 7% ,推测大豆抗SCN种质中 ,以rhg1和Rhg4这两个基因协同作用表现出的抗性可能占多数 ,但还存在其他的抗性机制。

中国大豆抗(耐)胞囊线虫病品种及其系谱分析

大豆胞囊线虫病是大豆生产上的重要病害,给大豆生产造成巨大损失。种植抗病品种是经济有效、环境友好型防治方法,国内外大豆抗胞囊线虫病育种取得了较大成绩。汇总我国自1978年以来所审定的大豆抗(耐)胞囊线虫病品种,系谱分析了其抗病基因来源,指出了我国抗病品种遗传基础狭窄,抗病品种抗性单一的问题,提出了利用新的抗源或新型抗病基因是拓宽抗病品种遗传基础的重要途径,并就未来研究从3个方面进行了探讨,以期能够对我国抗病育种提供参考。

不同抗性的大豆品种对田间大豆胞囊线虫群体动态的影响

对不同抗性的大豆品种与大豆胞囊线虫的田间动态关系的研究。研究结果表明 ,不同抗性大豆品种对田间大豆胞囊线虫群体均有较大的影响。感病品种辽豆 10根际中J2 含量在 5月 2 4日达高峰 ,每 10 0ml土壤中 6 0 .4条 ,而抗病品种Peking根际与休闲地中J2 的变化趋势相似 ;胞囊量在 6月 6日有一高峰 ,为 2 3.3个 /10 0ml土 ;抗病品种PI90 76 3、哈尔滨小黑豆、应县小黑豆、Franklin根内的J2 数量在 5月 2 4日达高峰 ,但从J2 、J3、J4 整体动态变化结果来看 ,可初步认为辽K8910 2为抗侵入品种 ,PI90 76 3为抗发育品种 ,辽豆 10和开育

抗大豆孢囊线虫4号生理小种育种骨干亲本抗性差异分析

研究对抗大豆孢囊线虫病育种中常用的 4 0份骨干亲本进行 4号生理小种抗性鉴定 ,其中感病品种 30份 ,黄粒抗病品系 2份 ,黑粒抗病品系 2份 ,黑粒抗源 6份。结果表明 :品种间的抗性有极显著差异 ;抗性的主要差异首先出现在抗性和非抗性品种之间 ,其次出现在非抗性品种内 ;抗源材料的抗性非常稳定 ;亲本对大豆孢囊线虫 4号生理小种的抗性呈连续性变化 ,符合正态分布规律。抗性愈强的品种抗性愈稳定 ,抗性愈弱的品种抗性愈易受环境的影响。大豆抗大豆孢囊线虫的广义遗传力约为 5 3.9%。

抗大豆胞囊线虫病野生大豆种质资源的初步筛选

对来自河北东部沿海地区的119份野生大豆资源进行了大豆胞囊线虫的抗性鉴定,结果表现抗病的有48份,占40.3%,表现感病的资源有71份,占59.7%。通过对供试材料的部分农艺性状与雌虫指数进行相关分析,发现单荚粒数和根瘤数与野生大豆抗胞囊线虫反应呈极显著正相关。对野生大豆资源的来源分析表明,抗大豆胞囊线虫病野生大豆资源在冀东分布广泛,其中滦南野生大豆抗性资源比较丰富。

中国小黑豆对大豆胞囊线虫3号生理小种的抗性遗传研究

用大豆胞囊线虫（Ｈｅｔｅｒｏｄｅｒａｇｌｙｃｉｎｅｓ）３号生理小种接种抗病品种小粒黑豆、连毛会黑豆、磨石黑豆与感病品种铁丰２４号、铁丰１８号、开育１０号杂交组合，根据Ｆ２代分析结果，小粒黑豆在铁丰２４号背景下表现出有两对抗病基因，在开育１０号的背景下由４对显性抗病基因控制对３号小种的抗性，磨石黑豆在铁丰２４号背景下有两对隐性抗病基因，铁丰１８号×连毛会黑豆组合Ｆ２代分离表现为三对基因的互补作用。

东北地区大豆孢囊线虫病发生和防控技术研究进展

大豆孢囊线虫(Heterodera glycines Ichinohe)病是大豆生产上重要经济病害之一。东北地区作为我国大豆主产区,大豆种植面积增加同时该地区病害呈逐年加重趋势。为有效防控大豆孢囊线虫病,文章阐述东北地区大豆孢囊线虫生理小种种类、分布和变异及病害发生程度等规律。根据该区大豆孢囊线虫病害发生特点综述已有防控技术研究进展,主要包括农业措施、化学防治、生物防治、利用抗病品种等。最后展望未来潜在防控技术,以期为东北地区大豆丰产和农业可持续发展提供理论依据和技术支撑。

大豆孢囊线虫病研究进展及其抗病育种展望

综述了国内外大豆孢囊线虫的分布与危害、寄主范围、抗源筛选与利用、生化抗性机制;论述了研究该病的意义。在综述了抗病育种进展的同时,也指出了抗病育种中存在的问题;指出注意综合农艺性状改进,合理组配杂交,加强抗性鉴定,注重抗病性持久性等问题;还提出了深化抗病分子研究,开展基因转移和分子辅助育种等抗病育种工作的建议。