Physiological and Proteomic Analysis of the Rice Mutant cpm2 Suggests a Negative Regulatory Role of Jasmonic Acid in Drought Tolerance

Abstract

It is widely known that numerous adaptive responses of drought-stressed plants are stimulated by chemical messengers known as phytohormones. Jasmonic acid (JA) is one such phytohormone. But there are very few reports revealing its direct implication in drought related responses or its cross-talk with other phytohormones. In this study, we compared the morpho-physiological traits and the root proteome of a wild type (WT) rice plant with its JA biosynthesis mutant coleoptile photomorphogenesis 2 (cpm2), disrupted in the allene oxide cyclase (AOC) gene, for insights into the role of JA under drought. The mutant had higher stomatal conductance, higher water use efficiency and higher shoot ABA levels under severe drought as compared to the WT. Notably, roots of cpm2 were better developed compared to the WT under both, control and drought stress conditions. Root proteome was analyzed using the Tandem Mass Tag strategy to better understand this difference at the molecular level. Expectedly, AOC was unique but notably highly abundant under drought in the WT. Identification of other differentially abundant proteins (DAPs) suggested increased energy metabolism (i.e., increased mobilization of resources) and reactive oxygen species scavenging in cpm2 under drought. Additionally, various proteins involved in secondary metabolism, cell growth and cell wall synthesis were also more abundant in cpm2 roots. Proteome-guided transcript, metabolite, and histological analyses provided further insights into the favorable adaptations and responses, most likely orchestrated by the lack of JA, in the cpm2 roots. Our results in cpm2 are discussed in the light of JA crosstalk to other phytohormones. These results together pave the path for understanding the precise role of JA during drought stress in rice.

Comparative analysis of maca (Lepidium meyenii) proteome profiles reveals insights into response mechanisms of herbal plants to high-temperature stress

“…In the present study, 27 metabolism-related SDEPs were identified and 25 of them were decreased in maca seedlings following HTS (Additional file 3). This is in line with previous transcriptomic data which showed that a specific cluster of genes, which are involved in the metabolism of carbohydrates, amino acids and lipids, are significantly decreased to adapt to the reduced need of primary metabolic products under HTS [6,11,14]. Furthermore, 13 SDEPs involved in secondary metabolism were identified in the present study.…”

Jasmonates: News on Occurrence, Biosynthesis, Metabolism and Action of an Ancient Group of Signaling Compounds

“…Both mutants exhibited deficiency in OPDA, increased salt tolerance and ROS-scavenging activity as well as altered defense against the blast fungus M. oryzae [ 77 , 78 ]. Expression data and a proteomic analysis of the rice mutant cpm2 suggest a negative regulatory role of JA in drought tolerance [ 79 ]. In Arabidopsis, the four members of the AOC gene family are expressed in tissue- and organ-specific manner [ 80 ].…”

Proteomes of Leaf‐Growing Zones in Rice Genotypes with Contrasting Drought Tolerance

“…While some key participating genes have been identified, proteomics has not been widely used in abiotic stress studies on shoot‐growing zones to assess global changes in protein expression. This omission contrasts with the more comprehensive analysis of drought stress response of mature leaf blades and roots of rice.…”