Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
Division of Genomic Resources, ICAR-National Bureau of Plant Genetic Resources, New Delhi, 110012, India.
World J Microbiol Biotechnol. 2023 Sep 15;39(11):306. doi: 10.1007/s11274-023-03748-4.
Fusarium wilt is a major threat to lentil production in India and worldwide. The presence of evolving virulent races has imposed the necessity of reliable management practices including breeding for resistance using unexplored germplasms. The magnitude of resistance by the plant is determined by rapid recognition of the pathogen and induction of defence genes. Resistance gene analogues have been key factors involved in the recognition and induction of defence response. In the present study, the expression of key RGA previously cloned was determined in three resistant accessions (L65, L83 and L90) and a susceptible accession (L27). The expression was assessed via qPCR at 24, 48 and 72 hpi against virulent race5 (CG-5). All the RGAs differentially transcribed in resistant and susceptible accession showed temporal variation. RGA Lc2, Lc8, Ln1 and Lo6 produced cDNA signals during early infection (24 hpi) predicting its involvement in recognition. LoRGA6 showed significant upregulation in L65 and L83 while downregulating in L27 and the full length of LoRGA6 loci was isolated by 5' and 3' RACE PCR. In-silico characterization revealed LoRGA6 loci code for 912 amino acids long polypeptide with a TIR motif at the N terminal and eight LRR motifs at the C terminal. The tertiary structure revealed a concave pocket-like structure at the LRR domain potentially involved in pathogen effectors interaction. The loci have ADP binding domain and ATPase activity. This has further paved the path for functional analysis of the loci by VIGS to understand the molecular mechanism of resistance.
镰刀菌枯萎病是印度和全球小扁豆生产的主要威胁。致病力不断进化的毒力菌株的出现，迫使人们必须采用可靠的管理措施，包括利用尚未开发的种质资源进行抗性育种。植物的抗性程度取决于对病原体的快速识别和防御基因的诱导。抗性基因类似物是参与识别和诱导防御反应的关键因素。在本研究中，测定了先前克隆的三个抗性品系（L65、L83 和 L90）和一个敏感品系（L27）中关键 RGA 的表达。通过 qPCR 在 24、48 和 72 hpi 时对毒力菌株 5（CG-5）进行表达评估。在抗性和敏感品系中差异转录的所有 RGAs 均表现出时间变化。RGA Lc2、Lc8、Ln1 和 Lo6 在早期感染（24 hpi）时产生 cDNA 信号，表明其参与识别。LoRGA6 在 L65 和 L83 中显著上调，而在 L27 中下调，并通过 5'和 3' RACE PCR 分离出全长 LoRGA6 基因座。计算机分析表明，LoRGA6 基因座编码一个 912 个氨基酸长的多肽，其 N 端具有 TIR 基序，C 端具有 8 个 LRR 基序。三级结构显示 LRR 结构域具有凹形口袋样结构，可能参与病原体效应子的相互作用。该基因座具有 ADP 结合结构域和 ATP 酶活性。这为通过 VIGS 对该基因座进行功能分析，以了解抗性的分子机制，铺平了道路。
