National Peanut Research Laboratory, United States Department of Agriculture-Agricultural Research Service, Dawson, GA, USA.
Department of Crop, Soil and Environmental Sciences, Auburn University, Auburn, AL, USA.
Mol Biol Rep. 2021 Jan;48(1):323-334. doi: 10.1007/s11033-020-06049-3. Epub 2021 Jan 5.
Early leaf spot (ELS) and late leaf spot (LLS) are major fungal diseases of peanut that can severely reduce yield and quality. Development of acceptable genetic resistance has been difficult due to a strong environmental component and many major and minor QTLs. Resistance genes (R-genes) are an important component of plant immune system and have been identified in peanut. Association of specific R-genes to leaf spot resistance will provide molecular targets for marker-assisted breeding strategies. In this study, advanced breeding lines from different pedigrees were evaluated for leaf spot resistance and 76 candidate R-genes expression study was applied to susceptible and resistant lines. Thirty-six R-genes were differentially expressed and significantly correlated with resistant lines, of which a majority are receptor like kinases (RLKs) and receptor like proteins (RLPs) that sense the presence of pathogen at the cell surface and initiate protection response. The largest group was receptor-like cytoplasmic kinases (RLCKs) VII that are involved in pattern-triggered kinase signaling resulting in the production reactive oxygen species (ROS). Four R-genes were homologous to TMV resistant protein N which has shown to confer resistance against tobacco mosaic virus (TMV). When mapped to peanut genomes, 36 R-genes were represented in most chromosomes except for A09 and B09. Low levels of gene-expression in resistant lines suggest expression is tightly controlled to balance the cost of R-gene expression to plant productively. Identification and association of R-genes involved in leaf spot resistance will facilitate genetic selection of leaf spot resistant lines with good agronomic traits.
早叶斑病（ELS）和晚叶斑病（LLS）是花生的主要真菌病害，会严重降低产量和品质。由于强烈的环境因素和许多主要和次要的 QTL，开发可接受的遗传抗性一直很困难。抗性基因（R 基因）是植物免疫系统的重要组成部分，已在花生中得到鉴定。特定 R 基因与叶斑病抗性的关联将为标记辅助育种策略提供分子靶标。在这项研究中，来自不同品系的高级育种系被评估为叶斑病抗性，并且对易感和抗性系进行了 76 个候选 R 基因表达研究。36 个 R 基因差异表达，并与抗性系显著相关，其中大多数是受体样激酶（RLKs）和受体样蛋白（RLPs），它们在细胞表面感知病原体的存在并启动保护反应。最大的一组是受体样细胞质激酶（RLCKs）VII，它参与模式触发激酶信号传导，导致活性氧（ROS）的产生。有 4 个 R 基因与 N 蛋白（TMV 抗性蛋白）同源，该蛋白已被证明对烟草花叶病毒（TMV）具有抗性。当映射到花生基因组时，除了 A09 和 B09 之外，大多数染色体都代表了 36 个 R 基因。抗性系中基因表达水平较低表明表达受到严格控制，以平衡 R 基因表达对植物生产力的成本。鉴定和关联参与叶斑病抗性的 R 基因将有助于遗传选择具有良好农艺性状的叶斑病抗性系。
