A novel fungal effector from Puccinia graminis suppressing RNA silencing and plant defense responses

First author: Chuntao Yin; Affiliations: Washington State University (华盛顿州立大学): Pullman, USA

Corresponding author: Scot H. Hulbert

Fungal plant pathogens, like rust‐causing biotrophic (活体营养型) fungi, secrete hundreds of effectors into plant cells to subvert (破坏) host immunity and promote pathogenicity on their host plants by manipulating specific physiological processes or signal pathways, but the actual function has been demonstrated for very few of these proteins. Here, we show that the PgtSR1 effector proteins, encoded by two allelic genes (PgtSR1‐a and PgtSR1‐), from the wheat stem rust pathogen Puccinia graminis f. sp. tritici (Pgt), suppress RNA silencing in plants and impede (阻碍) plant defenses by altering the abundance of small RNAs that serve as defense regulators. Expression of the PgtSR1s in plants revealed that the PgtSR1s promote susceptibility to multiple pathogens and partially suppress cell death triggered by multiple R proteins. Overall, our study provides the first evidence that the filamentous fungus P. graminishas evolved to produce fungal suppressors of RNA silencing and indicates that PgtSR1s suppress both basal defenses and effector triggered immunity.

真菌植物病原菌，像引起锈病的活体营养型真菌会分泌数百种的效应物进入到植物细胞中，进而破坏寄主免疫， 并通过改变特定的生理进程或者信号通路来促进其在寄主植物中的致病性。但目前对于这一类效应物功能的报道并不多。本文中，作者的研究显示来自小麦锈病病原菌Pgt中两个等位基因PgtSR1‐a和PgtSR1‐编码的PgtSR1效应物蛋白能够抑制植物中的RNA沉默，通过改变作为植物防御调控因子小RNA的丰度来妨碍植物的防御。PgtSR1在植物中的表达揭示了PgtSR1促进植株对多个病原菌的易感性，并部分抑制了由多个R蛋白诱导的细胞死亡。综上，本文的研究第一次提供了丝状真菌Pgt演化产生真菌抑制子来抑制寄主植物中的RNA沉默的证据，同时揭示了PgtSR1抑制植物基础的防御和效应物诱导的免疫。

通讯：Scot H. Hulbert (http://css.wsu.edu/people/faculty/scot-h-hulbert/)

个人简介：1980年，华盛顿州立大学，园艺学学士；1982年，加利福尼亚大学戴维斯分校，蔬菜作物学硕士；1987年，加州大学戴维斯分校，遗传学博士。

研究方向：作物病理学。

doi: https://doi.org/10.1111/nph.15676

Journal: New Phytologist

First Published: January 09, 2019