基于SSR标记关联分析挖掘大豆灰斑病10号生理小种抗病资源

培育灰斑病抗性品种可降低灰斑病对大豆生产的危害。本研究以202份黑龙江省近25年主栽的大豆品种构建关联群体,在人工接种条件下鉴定大豆品种对灰斑病10号生理小种抗病指数。利用187对SSR标记对遗传多样性、群体结构和连锁不平衡位点进行分析,通过GLM 和MLM两种模型对大豆品种的灰斑病抗性与标记进行关联分析,进一步分析抗性关联位点等位变异与抗性表型效应关系。结果表明：202份大豆品种对灰斑病10号生理小种抗性遗传变异系数为14.26%;187个标记在群体中共获得809个等位变异,平均等位变异为4.42个,变幅2~10个,其中17号染色体的平均PIC值最高（0.64）,12号染色体的平均PIC值最低（0.26）;检测到稀有等位变异146个,特有等位变异位点58个;无论共线性组合位点还是非共线性组合位点均存在不同程度LD,连锁不平衡P<0.05支持的对数占总对数的21.65%;202份大豆品种被划分为3个亚群,亚群POP1与POP3之间遗传距离最小（0.03）,亚群POP2与POP3之间遗传距离最大（0.35）;两种模型共同检测到11个SSR标记与灰斑病10号生理小种抗性显著关联,其中位于3号染色体上的Satt549的贡献率最大,可解释表型变异14.74%;具有增效效应的等位变异共有24个,增效效应超过10的等位变异有7个,增效效应最大为Satt703-247（19.62）,典型载体材料为合丰29;其次是Satt587-185（19.58）,典型载体材料为东农50;Satt549位点增效等位变异的平均效应值最高（13.87）,Sat_366位点增效等位变异的平均效应值最低（0.84）。聚合优异等位变异和载体材料可为培育抗灰斑病品种的亲本选配和后代等位条带辅助选择提供依据。     

Elucidation of factors contributing to onset of Cercospora leaf blight during later reproductive development of soybean

In Louisiana, Cercospora leaf blight (CLB) of soybean is primarily caused by Cercospora cf. flagellaris, which can be detected in asymptomatic leaves as early as V3 (third trifoliate) growth stage, while symptoms appear around R5 (beginning seed). The fungus produces cercosporin, an important virulence factor, the in vitro production of which is significantly reduced in the absence of simple sugars. Our objective was to investigate the role of foliar simple sugars and endophytic bacteria in CLB symptom onset. C. cf. flagellaris was cultured in filter-sterilized, untreated extracts made from asymptomatic R2 and R5 leaves; in extracts treated with chloroform to isolate hydrophilic molecules, including simple sugars; or with antibiotics to assess the role of endophytic bacteria. Endophytic bacteria were also isolated from leaves and leaf extracts and their interaction with C. cf. flagellaris was investigated. The fungus produced more cercosporin in total R5 and simple sugar-amended R2 leaf extracts, than in R2 leaf extracts. Furthermore, it produced more cercosporin in chloroform-treated R5 leaf extracts, which contained significantly higher levels of simple sugars, especially fructose, than the R2. To our knowledge, this is the first reported connection between foliar sugar content and cercosporin production. Additionally, morphologically diverse bacteria were isolated from different stages of soybean development. Also, bacterial endophytes in R5 leaf extracts and Paenibacillus polymyxa, isolated from R2 leaves, significantly reduced the growth of C. cf. flagellaris. These findings implicated soybean leaf fructose in CLB development and highlighted the potential of using foliar bacterial endophytes for CLB management.     

Field evaluation of mungbeans for resistance to Cercospora leaf spot and powdery mildew

Abstract

Cercospora leaf spot, caused by Cercospora canescens and powdery mildew, caused by Erysiphe polygoni are two of the most important fungal diseases of mungbeans. Nearly 4000 accessions of the global mungbean collection at the Asian Vegetable Research and Development Center were screened for resistance to these two pathogens. Less than 4% and 12% of the accessions showed resistance to Cercospora leaf spot and powdery mildew, respectively. The level of resistance to Cercospora leaf spot varied and highly resistant lines were not found. A few lines were rated highly resistant to powdery mildew over several years but others were rated moderately resistant or susceptible in other years.     

Variability in aggressiveness,cultural characteristics,cercosporin production and fatty acid profile of Cercospora piaropi,a biocontrol agent of water hyacinth

The extent of variation in aggressiveness, growth and pigmentation in culture, phytotoxin production and fatty acid profile were determined in a population of 55 isolates of Cercospora piaropi, a fungus used as a biocontrol agent of the aquatic weed water hyacinth (Eichhornia crassipes). Besides differences in the colour of mycelium and diffusible pigments in culture, isolates of C. piaropi grown under standard conditions differed significantly in their ability to produce the phytotoxin cercosporin, as well as in aggressiveness and growth rate. A positive correlation existed between the ability of the isolates to produce cercosporin and their aggressiveness, and a negative correlation between growth rate and cercosporin production or growth rate and aggressiveness. Based on thin‐layer chromatographic separation of extracts and comparison with beticolin‐1, used as a standard, there was no evidence of production of beticolins. In discriminant analysis, fatty acid methyl ester (FAME) profiles had low resolution for differentiating populations among isolates of the fungus, and the level of resolution was influenced by the age of the colonies. Diffusible pigments in culture and cercosporin production are useful adjuncts to aggressiveness screening for choosing the most effective isolate of C. piaropi for biological control.     

大豆抗感品种间作提高感病品种抗灰斑病能力的研究

为了研究和探讨用抗病品种和感病品种间作栽培方式来提高感病品种抗灰斑病的能力,采用小区试验和多年对黑龙江省大豆品种（系）进入区试和生试进行灰斑病鉴定结果分析,结果表明,抗感品种间作可提高感病大豆品种抗灰斑病能力;抗性不同的品种间作使同一品种在区试、生试中表现出不同的抗性,与对照相比表现出不同增产幅度。     

黑龙江省甜菜褐斑病病区和品种抗病性分类研究

为了解决甜菜褐斑病病防治问题,2009—2016年,对黑龙江省10个地区166个甜菜品种,采取田间调查发病率的方法进行分类研究。将地区分为轻病区、中病区和重病区3类;将品种的抗性水平分为高抗、抗病、中抗、中感、感病、高感6个级别：甜菜褐斑病病情指数(DI)≤15的地区为轻病区,15相似文献   

绿豆尾孢菌叶斑病研究进展

综述了近年来绿豆尾孢菌叶斑病的病害症状、侵染循环、生长特性、病害防治和互作关系等研究进展,并展望了绿豆尾孢菌病今后的研究方向,为今后的绿豆尾孢菌叶斑病的防治及培育绿豆抗病品种提供了参考。     

大豆对主要病害多抗性种质资源鉴定

近年黑龙江省生产上大豆病害发生严重,已成为影响大豆高产、优质的限制因素之一,调查、发现、了解大豆生产上病害发生危害情况,筛选和培育抗病品种是控制病害危害的最经济有效途径。本试验大量收集了国内外大豆资源材料,分别鉴定各品种（系）对大豆灰斑病、疫霉病和根腐病的抗性,然后进行双抗和多抗性鉴定。共筛选出3份抗灰斑病和疫霉病的双抗资源,筛选出3份抗根腐病和疫霉病的双抗资源,筛选出2份抗病毒病和灰斑病的双抗资源。为抗病育种提供了宝贵的多抗亲本。     

绿豆叶斑病病原鉴定及生物学特性研究

对绿豆叶斑病菌进行形态学和分子特征鉴定,结果表明,分离物在V8培养基上菌落近圆形,菌落边缘泛紫色,分生孢子无色;用通用引物18SF和28SR扩增6个分离物的rDNA-ITS部分序列和测序,并到GenBank(登录号:KM435076)数据库进行比对,6个分离物与变灰尾孢分离物序列相似性为99%,基于形态和分子特征将绿豆叶斑病病原菌鉴定为变灰尾孢。致病性测定结果表明,6个分离物对绿豆‘中绿一号’叶片均致病且存在致病力差异。不同培养基、温度和pH对病原菌生长的影响研究表明,V8培养基最适宜该病菌生长,病菌生长的最适温度为25℃,最适pH为6。