Roles of the pepper JAZ protein CaJAZ1‐03 and its interacting partner RING‐type E3 ligase CaASRF1 in regulating ABA signaling and drought responses

Abstract

Plants have developed various defense mechanisms against environmental stresses by regulating hormone signaling. Jasmonic acid (JA) is a major phytohormone associated with plant defense responses. JASMONATE ZIM‐DOMAIN (JAZ) proteins play a regulatory role in repressing JA signaling, impacting plant responses to both biotic and abiotic stresses. Here, we isolated 7 JAZ genes in pepper and selected CA03g31030, a Capsicum annuum JAZ1‐03 (CaJAZ1‐03) gene, for further study based on its expression level in response to abiotic stresses. Through virus‐induced gene silencing (VIGS) in pepper and overexpression in transgenic Arabidopsis plants, we established the functional role of CaJAZ1‐03. Functional studies revealed that CaJAZ1‐03 dampens abscisic acid (ABA) signaling and drought stress responses. The cell‐free degradation assay showed faster degradation of CaJAZ1‐03 in drought‐ or ABA‐treated pepper leaves compared to healthy leaves. Conversely, CaJAZ1‐03 was completely preserved under MG132 treatment, indicating that CaJAZ1‐03 stability is modulated via the ubiquitin‐26s proteasome pathway. We also found that the pepper RING‐type E3 ligase CaASRF1 interacts with and ubiquitinates CaJAZ1‐03. Additional cell‐free degradation assays revealed a negative correlation between CaJAZ1‐03 and CaASRF1 expression levels. Collectively, these findings suggest that CaJAZ1‐03 negatively regulates ABA signaling and drought responses and that its protein stability is modulated by CaASRF1.

Transcriptome Analysis Reveals Key Genes Involved in the Response of Pyrus betuleafolia to Drought and High-Temperature Stress

“…Transcriptome profiling analysis revealed many genes of ABA and JA signaling pathways expressed differently between plants and WT plants overexpressed with OsJAZ1 under drought stress. In Capsicum annuum , CaJAZ1-03 negatively regulates drought and ABA signaling [ 43 ]. However, the function and molecular mechanism of genes related to ABA, auxin, and JA signaling in drought or high-temperature tolerance was still unclear.…”