Secondary metabolite pathway of SDG (secoisolariciresinol) was observed to trigger ROS scavenging system in response to Ca2+ stress in cotton

Abstract

Ca²⁺ is an essential nutrient for plants and animals which plays an important role in plant signal transduction. Although the function and regulation of mechanism of Ca²⁺ in alleviating various biotic and abiotic stresses in plants have been studied deeply, the molecular mechanism to adapt high Ca²⁺ stress is still unclear in cotton. In this study, 103 cotton accessions were germinated under 200 mM CaCl₂ stress, and two extremely Ca²⁺-resistant (Zhong 9807, R) and Ca²⁺-sensitive (CRI 50, S) genotypes were selected from 103 cotton accessions. The two accessions were then germinated for 5 days in 0 mM CaCl₂ and 200 mM CaCl₂ respectively, after which they were sampled for transcriptome sequencing. Morphological and physiological analyses suggested that PLR2 specifically expressed in R may enhance the ability of cotton to scavenge ROS by promoting the synthesis of SDG. In conclusion, this study proposed the adaptation mechanisms to response to the high Ca²⁺ stress in cotton which can contribute to improve the stress resistance of cotton.

Keywords: CML; Cotton; High Ca(2+) stress; Reactive oxygen species (ROS); Secoisolariciresinol (SDG).