Poonguzhali Pachai, Chauhan Ashish, Kar Abinash, Lavale Shivaji, Nayak Spurthi N, Prashanthi S K
Department of Biotechnology, University of Agricultural Sciences, Dharwad 580005, Karnataka, India.
Department of Plant Pathology, University of Agricultural Sciences, Dharwad 580005, Karnataka, India.
Plant Pathol J. 2022 Dec;38(6):572-582. doi: 10.5423/PPJ.OA.04.2022.0054. Epub 2022 Dec 1.
Sheath blight disease caused by the necrotrophic, soilborne pathogen Rhizoctonia solani Kuhn, is the global threat to rice production. Lack of reliable stable resistance sources in rice germplasm pool for sheath blight has made resistance breeding a very difficult task. In the current study, 101 rice landraces were screened against R. solani under artificial epiphytotics and identified six moderately resistant landraces, Jigguvaratiga, Honasu, Jeer Sali, Jeeraga-2, BiliKagga, and Medini Sannabatta with relative lesion height (RLH) range of 21-30%. Landrace Jigguvaratiga with consistent and better level of resistance (21% RLH) than resistant check Tetep (RLH 28%) was used to develop mapping population. DNA markers associated with ShB resistance were identified in F2 mapping population developed from Jigguvaratiga × BPT5204 (susceptible variety) using bulk segregant analysis. Among 56 parental polymorphic markers, RM5556, RM6208, and RM7 were polymorphic between the bulks. Single marker analysis indicated the significant association of ShB with RM5556 and RM6208 with phenotypic variance (R2) of 28.29 and 20.06%, respectively. Co-segregation analysis confirmed the strong association of RM5556 and RM6208 located on chromosome 8 for ShB trait. This is the first report on association of RM6208 marker for ShB resistance. In silico analysis revealed that RM6208 loci resides the stearoyl ACP desaturases protein, which is involved in defense mechanism against plant pathogens. RM5556 loci resides a protein, with unknown function. The putative candidate genes or quantitative trait locus harbouring at the marker interval of RM5556 and RM6208 can be further used to develop ShB resistant varieties using molecular breeding approaches.
由坏死性土传病原菌立枯丝核菌库恩引起的纹枯病，是对水稻生产的全球性威胁。水稻种质库中缺乏可靠稳定的抗纹枯病资源，使得抗病育种成为一项非常艰巨的任务。在本研究中，在人工发病条件下对101份水稻地方品种进行了抗立枯丝核菌筛选，鉴定出6份中度抗病地方品种，即吉古瓦拉蒂加、霍纳苏、杰尔萨利、杰拉加 - 2、比利卡加和梅迪尼桑巴塔，其相对病斑高度（RLH）范围为21% - 30%。地方品种吉古瓦拉蒂加具有比抗病对照品种特泰普（RLH 28%）更稳定且更好的抗性水平（RLH 21%），被用于构建作图群体。利用混合分组分析法，在由吉古瓦拉蒂加×BPT5204（感病品种）构建的F2作图群体中鉴定出与纹枯病抗性相关的DNA标记。在56个亲本多态性标记中，RM5556、RM6208和RM7在两个混合群体间表现出多态性。单标记分析表明，纹枯病与RM5556和RM6208显著相关，表型变异（R2）分别为28.29%和20.06%。共分离分析证实，位于第8染色体上的RM5556和RM6208与纹枯病性状紧密关联。这是关于RM6208标记与纹枯病抗性关联的首次报道。电子分析显示，RM6208位点存在硬脂酰ACP去饱和酶蛋白，该蛋白参与植物对病原菌的防御机制。RM5556位点存在一个功能未知的蛋白。在RM5556和RM6208标记区间内的假定候选基因或数量性状位点，可进一步用于通过分子育种方法培育抗纹枯病品种。
