The Powdery Mildew Effector CSEP0027 Interacts With Barley Catalase to Regulate Host Immunity

Hongbo Yuan; Cong Jin; Hongcui Pei; Lifang Zhao; Xue Li; Jiali Li; Wanting Huang; Renchun Fan; Wende Liu; Qian-Hua Shen

doi:10.3389/fpls.2021.733237

The Powdery Mildew Effector CSEP0027 Interacts With Barley Catalase to Regulate Host Immunity

Front Plant Sci. 2021 Sep 9:12:733237. doi: 10.3389/fpls.2021.733237. eCollection 2021.

Authors

Hongbo Yuan^{1

2}, Cong Jin¹, Hongcui Pei^{1

2}, Lifang Zhao^{1

2}, Xue Li^{1

2}, Jiali Li^{1

2}, Wanting Huang^{1

3}, Renchun Fan^{1

2}, Wende Liu⁴, Qian-Hua Shen^{1

2}

Affiliations

¹ State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences (CAS), Beijing, China.
² CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China.
³ School of Life Sciences, Yunnan University, Kunming, China.
⁴ State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences (CAS), Beijing, China.

Abstract

Powdery mildew is one of the most important fungal pathogen diseases. The genome of barley mildew fungus, Blumeria graminis f. sp. hordei (Bgh), encodes a large number of candidate secreted effector proteins (CSEPs). So far, the function and mechanism of most CSEPs remain largely unknown. Here, we identify a Bgh effector CSEP0027, a member of family 41, triggering cell death in Nicotiana benthamiana. CSEP0027 contains a functional signal peptide (SP), verified by yeast secretion assay. We show that CSEP0027 promotes Bgh virulence in barley infection using transient gene expression and host-induced gene silencing (HIGS). Barley catalase HvCAT1 is identified as a CSEP0027 interactor by yeast two-hybrid (Y2H) screening, and the interaction is verified in yeast, in vitro and in vivo. The coexpression of CSEP0027 and HvCAT1 in barley cells results in altered localization of HvCAT1 from the peroxisome to the nucleus. Barley stripe mosaic virus (BSMV)-silencing and transiently-induced gene silencing (TIGS) assays reveal that HvCAT1 is required for barley immunity against Bgh. We propose that CSEP0027 interacts with barley HvCAT1 to regulate the host immunity and likely reactive oxygen species (ROS) homeostasis to promote fungal virulence during barley infection.

Keywords: Blumeria graminis; CSEP; barley catalase; effector; powdery mildew; virulence.