Contribution of CaBPM4, a BTB Domain–Containing Gene, to the Response of Pepper to Phytophthora capsici Infection and Abiotic Stresses

Yu-Mei He,Muhammad Ali,Ke-Ke Liu,Zhen-Hui Gong,Guo-Xin Cheng,Huai-Xia Zhang,Saeed Ul Haq,Ai-Min Wei

doi:10.3390/agronomy9080417

Yu-Mei He, Muhammad Ali + Show 6 more

Open Access

https://doi.org/10.3390/agronomy9080417

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Abstract

The Broad-complex Tramtrack and Bric-a-brac (BTB) domain participates in plant responses to biotic and abiotic stresses, however its role is unknown in pepper plants. CaBPM4 has meprin and TRAF homology (MATH) and BTB domains at its N- and C-termini, respectively, and it contains a 1589-bp full-length cDNA that encodes a protein containing 403 amino acids. In this study, the pepper gene CaBPM4 (Capsicum annuum BTB-POZ and MATH domain protein) was cloned, and its role in responses to Phytophthora capsici, cold, drought, and salt stress were characterized. The results of quantitative RT-PCR revealed that CaBPM4 was down-regulated under P. capsici infection, salicylic acid, H2O2, and abscisic acid treatments, while abiotic stresses, including salt, cold, and drought, enhanced its transcript level. Furthermore, CaBPM4 silencing significantly impaired resistance to P. capsici, apparently by altering the transcript level of defense-related genes CaPR1, CaDEF1, and CaSAR82 and reducing root activity. However, CaBPM4-silenced plants exhibited remarkably increased peroxidase activity and decreased malondialdehyde concentrations, indicating that CaBPM4 may enhance resistance to salt and drought stress. Further study should focus on the mechanism by which CaBPM4 regulates the defense response to P. capsici infection and abiotic stresses.

Highlights

Plants typically encounter several biotic and abiotic stresses, including cold [1], salinity [2], drought [3], and pathogens [4]
BTB domain and the amino acid sequence of CaBPM4 was closely related to BPM from potato (Solanum tuberosum)
CaBPM4 gene has a higher expression in leaf and flower tissue other than in root, stem, fruit tissue and it was induced by both biotic and abiotic stresses

Summary

Introduction

Plants typically encounter several biotic and abiotic stresses, including cold [1], salinity [2], drought [3], and pathogens [4]. Various environmental stresses induce physiological problems in plants and lead to various types of damages. To defend against stress-induced injuries, plants have evolved many defense mechanisms, including transcriptional regulation [5]. Defense mechanisms can positively or negatively regulate reactive oxygen species (ROS) produced by environmental stresses to achieve long-term physiological adaption to adverse environmental conditions [6]. The effect of transcription factors (TFs) on gene expression plays an essential role in various cellular processes that include signaling transduction and cellular stress responses [7]. The numerous transcription factors (TFs) that regulate gene expression by binding to target gene promoters provide mechanisms of well developmental and physiological control that can be shaped by natural selection, thereby enabling adaptive responses to environmental stress [8]. MYB [11] and bZIP [12,13]

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