E3 ubiquitin ligase PbrATL18 is a positive factor in pear resistance to drought and Colletotrichum fructicola infection

Abstract

The Arabidopsis Tóxicos en Levadura (ATL) protein is a subfamily of the E3 ubiquitin ligases, which exists widely in plants and is extensively involved in plant growth and development. Although the ATL family has been identified in other species, such as Arabidopsis , Oryza sativa , and grapevine, few reports on pear ATL gene families have been reported. In this study, 92 PbrATL genes were identified and analyzed from the Pyrus breschneideri genome. Motif analysis and phylogenetic tree generation divided them into nine subgroups, and chromosome localization analysis showed that the 92 PbrATL genes were distributed in 16 of 17 pear chromosomes. Transcriptome data and quantitative real-time polymerase chain reaction (qRT-PCR) experiments demonstrated that PbrATL18 , PbrATL41 , and PbrATL88 were involved in both pear drought resistance and Colletotrichum fructicola infection. In addition, Arabidopsis thaliana overexpressing PbrATL18 showed greater resistance to drought stress than the wild type (WT), and PbrATL18 -silenced pear seedlings showed greater sensitivity to drought and C. fructicola infection than the controls. PbrATL18 regulated plant resistance by regulating chitinase (CHI), phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities. This study provided a reference for further exploring the functions of the PbrATL gene in drought resistance and C. fructicola infection.