Fan Huidong, Yu Gang, Liu Yanzhi, Zhang Xianghui, Liu Jinliang, Zhang Yanhua, Rollins Jeffrey A, Sun Fengjie, Pan Hongyu
College of Plant Sciences, Jilin University, Changchun, 130062, China.
Department of Plant Pathology, University of Florida, Gainesville, FL, 32611, USA.
Mol Plant Pathol. 2017 Sep;18(7):963-975. doi: 10.1111/mpp.12453. Epub 2016 Aug 21.
Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic plant pathogen with a worldwide distribution. The sclerotia of S. sclerotiorum are pigmented multicellular structures formed from the aggregation of vegetative hyphae. These survival structures play a central role in the life and infection cycles of this pathogen. Here, we characterized an atypical forkhead (FKH)-box-containing protein, SsFKH1, involved in sclerotial development and virulence. To investigate the role of SsFkh1 in S. sclerotiorum, the partial sequence of SsFkh1 was cloned and RNA interference (RNAi)-based gene silencing was employed to alter the expression of SsFkh1. RNA-silenced mutants with significantly reduced SsFkh1 RNA levels exhibited slow hyphal growth and sclerotial developmental defects. In addition, the expression levels of a set of putative melanin biosynthesis-related laccase genes and a polyketide synthase-encoding gene were significantly down-regulated in silenced strains. Disease assays demonstrated that pathogenicity in RNAi-silenced strains was significantly compromised with the development of a smaller infection lesion on tomato leaves. Collectively, the results suggest that SsFkh1 is involved in hyphal growth, virulence and sclerotial formation in S. sclerotiorum.
核盘菌（Sclerotinia sclerotiorum (Lib.) de Bary）是一种分布于全球的坏死营养型植物病原菌。核盘菌的菌核是由营养菌丝聚集形成的有色素的多细胞结构。这些存活结构在该病原菌的生活和侵染循环中起着核心作用。在此，我们鉴定了一种非典型的含叉头（FKH）盒蛋白SsFKH1，它参与菌核发育和毒力。为了研究SsFkh1在核盘菌中的作用，克隆了SsFkh1的部分序列，并采用基于RNA干扰（RNAi）的基因沉默来改变SsFkh1的表达。SsFkh1 RNA水平显著降低的RNA沉默突变体表现出菌丝生长缓慢和菌核发育缺陷。此外，一组假定的与黑色素生物合成相关的漆酶基因和一个编码聚酮合酶的基因在沉默菌株中的表达水平显著下调。病害试验表明，RNAi沉默菌株的致病性显著受损，在番茄叶片上形成的侵染病斑较小。总体而言，结果表明SsFkh1参与核盘菌的菌丝生长、毒力和菌核形成。
