title: BRI1-EMS-suppressor 1 gain-of-function mutant shows higher susceptibility to necrotrophic fungal infection.
abstract: Brassinosteroids (BRs) are plant-specific steroids that are involved in plant growth and defense responses. However, the exact roles of BR in plant defense are unclear. We used the bes1-D gain-of-function mutant to define the underlying relationship between plant growth and defense through BR signaling and innate immunity. In bes1-D, further downstream component BES1 transcription factor is stabilized, leading to the activation of BR signaling. Previous reports on BES1 target genes showed that approximately 10% are related to biotic stress responses. Therefore, the bes1-D PTI responses were examined. The bes1-D mutant was specifically susceptible to Alternaria brassicicola, a necrotrophic fungus, which successfully produced spore, resulting in considerable cell death. However, it was not affected by a biotrophic pathogen, Pseudomonas syringae pv. tomato (Pst) DC3000. Instead of a ROS burst, a representative initial PTI responses, higher ROS accumulation was sustained in bes1-D than in the wild type plant. PDF1.2 expression was not induced in response to fungal pathogen infection in bes1-D. These results suggest that BES1 is also involved in JA-related defense responses, especially in response to necrotrophic pathogens.
authors.affiliation: Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, Republic of Korea.
authors.forename: Seo Youn
authors.initials: SY
authors.lastname: Shin
authors.affiliation: Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, Republic of Korea.
authors.forename: Hayung
authors.initials: H
authors.lastname: Chung
authors.affiliation: Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, Republic of Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, Republic of Korea. Electronic address: khnam514@sookmyung.ac.kr.
authors.forename: Kyoung Hee
authors.initials: KH
authors.lastname: Nam
mesh_terms: D000528:Alternaria / Q000502:physiology*; D017360:Arabidopsis / Q000235:genetics* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics*; D004268:DNA-Binding Proteins; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology*; D013329:Structure-Activity Relationship
chemical_list: D029681:Arabidopsis Proteins; C456160:BES1 protein, Arabidopsis; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins
keywords: Alternaria brassicicola; BRI1-EMS-suppressor 1 (bes1-D); Fungal infection; PDF1.2 expression; ROS accumulation