Jasmonate signaling pathway confers salt tolerance through a NUCLEAR FACTOR-Y trimeric transcription factor complex in Arabidopsis

Jasmonate (JA) is a well-known phytohormone essential for plant response to biotic stress. Recently, a crucial role of JA signaling in salt resistance has been highlighted; however, the specific regulatory mechanism remains largely unknown. In this study, we found that the NUCLEAR FACTOR-Y (NF-Y) subunits NF-YA1, NF-YB2, and NF-YC9 form a trimeric complex that positively regulates the expression of salinity-responsive genes, whereas JASMONATE-ZIM DOMAIN protein 8 (JAZ8) directly interacts with three subunits and acts as the key repressor to suppress both the assembly of the NF-YA1-YB2-YC9 trimeric complex and the transcriptional activation activity of the complex. When plants encounter high salinity, JA levels are elevated and perceived by the CORONATINE INSENSITIVE (COI) 1 receptor, leading to the degradation of JAZ8 via the 26S proteasome pathway, thereby releasing the activity of the NF-YA1-YB2-YC9 complex, initiating the activation of salinity-responsive genes, such as MYB75, and thus enhancing the salinity tolerance of plants. [Display omitted] •High salinity triggers the 26S proteasome-dependent degradation of JAZ8 in Arabidopsis•Arabidopsis heterotrimeric NF-YA1-YB2-YC9 complex positively regulates plant salt tolerance•JAZ8 represses the assembly and transcriptional activity of the NF-YA1-YB2-YC9 complex•JA enhances plant tolerance to high salinity via COI1-mediated degradation of JAZ8 Li et al. report that the heterotrimeric NF-YA1-YB2-YC9 complex positively regulates salt-responsive genes. High salinity elevates JA signaling to degrade JAZ8, thereby releasing the NF-YA1-YB2-YC9 transcription factor complex from the inhibitory effect of JAZ8. This study elucidates the regulatory mechanism of JA signaling in plant responses to high salinity.