Transcriptome Analysis of Pepper (Capsicum annuum) Revealed a Role of 24-Epibrassinolide in Response to Chilling

Abstract

Brassinosteroids (BRs) have positive effects on many processes during plant growth, development, and various abiotic stress responses. However, little information is available regarding the global gene expression of BRs in response to chilling stress in pepper. In this study, we used RNA sequencing to determine the molecular roles of 24-epibrassinolide (EBR) during a chilling stress response. There were 39,829 transcripts, and, among them, 656 were differently-expressed genes (DEGs) following EBR treatment (Chill+EBR) compared with the control (Chill only), including 335 up-regulated and 321 down-regulated DEGs. We selected 20 genes out of the 656 DEGs for RT-qPCR analysis to confirm the RNA-Seq. Based on GO enrich and KEGG pathway analysis, we found that photosynthesis was significantly up-enriched in biological processes, accompanied by significant increases in the net photosynthetic rate (Pn), Fv/Fm, and chlorophyll content. Furthermore, the results indicate that EBR enhanced endogenous levels of salicylic acid (SA) and jasmonic acid (JA) while suppressing the ethylene (ETH) biosynthesis pathway, suggesting that BRs function via a synergistic cross-talk with SA, JA, and ETH signaling pathways in response to chilling stress. In addition, EBR induced cellulose synthase-like protein and UDP-glycosyltransferase, suggesting a contribution to the formation of cell wall and hormone metabolism. EBR also triggered the calcium signaling transduction in cytoplasm, and activated the expression of cellular redox homeostasis related genes, such as GSTX1, PER72, and CAT2. This work, therefor, identified the specific genes showed different expression patterns in EBR-treated pepper and associated with the processes of hormone metabolism, redox, signaling, transcription, and defense. Our study provides the first evidence of the potent roles of BRs, at the transcription level, to induce the tolerance to chilling stress in pepper as a function of the combination of the transcriptional activities, signaling transduction, and metabolic homeostasis.

Involvement of homocastasterone, salicylic and abscisic acids in the regulation of drought and freezing tolerance in doubled haploid lines of winter barley

“…5a, b). It correspond with the data of Li et al (2016) showing that exogenous application of BR activates the expression of cellular redox homeostasis-related genes, including GSTX1 (probable glutathione S-transferase). The encoded enzyme regulates conjugation of reduced glutathione (the most abundant cellular LMW AOX) to various substrates for cell detoxification.…”

Effects of Brassinosteroids on Photosynthetic Performance and Nitrogen Metabolism in Pepper Seedlings under Chilling Stress

“…Brassinosteroids (BRs), as polyhydroxylated steroidal plant hormones, are involved in plant physiological processes [14,48]. This present study extends our previous work on EBR in the regulation of chilling tolerance from hormone metabolism, calcium signaling transduction, and cellular redox homeostasis [19,49]. Here, we have demonstrated the positive role of EBR in enhancing plant growth and development through maintaining higher photosynthetic capability and nitrogen metabolism (Figure 8).…”

iTRAQ-Based Quantitative Proteomic Analysis Reveals Cold Responsive Proteins Involved in Leaf Senescence in Upland Cotton (Gossypium hirsutum L.)

“…According to our data, as a representative hormone associated with senescence, JA significantly increased in PS compared with NS, indicating that the JA biosynthesis pathway is one of the factors involved in premature cotton senescence. Furthermore, a previous study showed that low temperatures can elevate the levels of JA [ 31 , 59 ], indicating that it may also be closely related to cold temperatures in this study. Therefore, JA may be a hormonal trigger while simultaneously accelerating leaf senescence.…”