PbrChiA: a key chitinase of pear in response to Botryosphaeria dothidea infection by interacting with PbrLYK1b2 and down-regulating ROS accumulation
Author:
Chen Qiming1,
Dong Huizhen1,
Li Qionghou1,
Sun Xun1,
Qiao Xin1,
Yin Hao1,
Xie Zhihua1,
Qi Kaijie1,
Huang Xiaosan1,
Zhang Shaoling1ORCID
Affiliation:
1. Nanjing Agricultural University State Key Laboratory of Crop Genetics and Germplasm Enhancement, Centre of Pear Engineering Technology Research, , Nanjing 210095, China
Abstract
Abstract
Pear ring rot, caused by the pathogenic fungi Botryosphaeria dothidea, seriously affects pear production. While the infection-induced reactive oxygen species (ROS) burst of infected plants limits the proliferation of B. dothidea during the early infection stage, high ROS levels can also contribute to their growth during the later necrotrophic infection stage. Therefore, it is important to understand how plants balance ROS levels and resistance to pathogenic B. dothidea during the later stage. In this study, we identified PbrChiA, a glycosyl hydrolases 18 (GH18) chitinase-encoding gene with high infection-induced expression, through a comparative transcriptome analysis. Artificial substitution, stable overexpression, and virus induced gene silencing (VIGS) experiments demonstrated that PbrChiA can positively regulate pear resistance as a secreted chitinase to break down B. dothidea mycelium in vitro and that overexpression of PbrChiA suppressed infection-induced ROS accumulation. Further analysis revealed that PbrChiA can bind to the ectodomain of PbrLYK1b2, and this interaction suppressed PbrLYK1b2-mediated chitin-induced ROS accumulation. Collectively, we propose that the combination of higher antifungal activity from abundant PbrChiA and lower ROS levels during later necrotrophic infection stage confer resistance of pear against B. dothidea.
Funder
Bioinformatics Center of Nanjing Agricultural University
Jiangsu Agriculture Science and Technology Innovation Fund
Earmarked Fund for China Agriculture Research System
Fundamental Research Funds for the Central Universities
National Science Foundation of China
National Key Research and Development Program of China
Publisher
Oxford University Press (OUP)
Subject
Horticulture,Plant Science,Genetics,Biochemistry,Biotechnology