Rice sheath blight, a major devastating disease caused by Rhizoctonia solani, poses huge threat to global rice production. Despite being the most hostile necrotrophic fungus with a wide host range, the mechanism involved in R. solani pathobiology is poorly understood. The evolutionarily developed nonhost resistance (NHR) provides broad-spectrum disease resistance to food crops. According to previous reports, Arabidopsis PEN1, PEN2 and PEN3 act as key components of cell wall-based pre-haustorial defenses against non-adapted pathogens. However, the involvement of these PEN genes in NHR against R. solani has remained unexplored till date. Therefore, the objective of this work is to study the efficacy of Arabidopsis PEN genes in NHR against R. solani. For this, hyphal colonization and penetration structures were monitored in Arabidopsis wild type Columbia-0 (Col-0) and mutants- pen1, pen2–3 and pen3–1. Comparatively, R. solani colonization on the leaves of Arabidopsis wild types was less than that on the rice leaf surface. Also, among the pen mutants studied, pen2–3 allowed maximum penetration and colonization by R. solani during early hours of infection as evidenced by both microscopic and macroscopic observations. Advanced lesion area, reduced chlorophyll content and increased fungal biomass accumulation also corroborated with the disease severity in pen2–3. However, R. solani resistance was restored in complemented PEN2-GFP comparable to Col-0. Altogether, our results demonstrate major involvement of PEN2 during pre-penetration, and its contribution to NHR against R. solani for enhanced disease resistance.

水稻纹枯病，一个主要的破坏性疾病引起的立枯病，对全球大米产量巨大的威胁。尽管是最恶劣的死体营养性真菌与寄主范围广，参与机构纹枯病病理学知之甚少。进化发展的非宿主抗性（NHR）为粮食作物提供了广谱抗病性。根据以前的报告，拟南芥PEN1，PEN2和PEN3充当基于细胞壁的针对未适应病原体的排空前防御的关键成分。然而，迄今为止，这些PEN基因是否参与了针对NHR的抗R. solani的研究。因此，这项工作的目的是研究拟南芥PEN基因在NHR中对sol。solani的功效。为此，在拟南芥野生型Columbia-0（Col-0）和突变体pen1，pen2-3和pen3-1中监测了菌丝的定殖和穿透结构。相比之下，拟南芥野生型叶片上的茄红菌的定殖少于水稻叶片表面上的定殖。另外，在所研究的笔突变体中，pen2–3允许R. solani的最大渗透和定植。微观和宏观观察均表明，在感染的最初几个小时内就可以发现。病灶的晚期，叶绿素含量降低和真菌生物量积累增加也与pen2-3中的病情严重程度相关。然而，在互补的PEN2-GFP中，与Col-0相当，恢复了茄根霉的抗性。总而言之，我们的结果证明了PEN2在预渗透过程中的主要参与，以及其对NHR抵抗茄红梭菌的抗病性增强的作用。