Lysine acetylation is a dynamic post-translational modification of proteins. Extensive studies have revealed that the acetylation modulated by histone acetyltransferases and histone deacetylases (HDACs) plays a crucial role in regulating protein function. However, there has been limited focus on how HDACs regulate jasmonic acid (JA) biosynthesis in plants. Here, we uncover that the protein stability of OsLOX14, a critical enzyme involved in JA biosynthesis, is regulated by a histone deacetylase, OsHDA706, and is hindered by a viral protein. Our results show that OsHDA706 deacetylates OsLOX14 and enhances the stability of OsLOX14, leading to JA accumulation and an improved broad-spectrum rice antiviral defense. Furthermore, we found that the viral protein P2, encoded by the destructive rice stripe virus, disrupts the association of OsHDA706-OsLOX14, promoting viral infection. Overall, our findings reveal how HDAC manipulates the interplay of deacetylation and protein stability of a JA biosynthetic enzyme to enhance plant antiviral responses.

Phosphorylation can quickly switch on/off protein functions. Here, we reported pre-mRNA processing 4 kinase A (PRP4KA), and its paralogs interact with Serrate (SE), a key factor in RNA processing. PRP4KA phosphorylates at least five residues of SE in vitro and in vivo. Hypophosphorylated, but not hyperphosphorylated, SE variants could readily rescue se phenotypes in vivo. Moreover, hypophosphorylated SE variants had stronger binding affinity to microprocessor component HYL1 and were more resistant to degradation by 20 S proteasome than hyperphosphorylated counterparts. Knockdown of the kinases enhanced the accumulation of hypophosphorylated SE. However, the excessive SE interfered with the assembly and function of SE-scaffolded macromolecule complexes, causing the se -like defects in the mutant and wild-type backgrounds. Thus, phosphorylation of SE via PRP4KA can quickly clear accumulated SE to secure its proper amount. This study provides new insight into how protein phosphorylation regulates miRNA metabolism through controlling homeostasis of SE accumulation in plants.

The RAV family is part of the B3 superfamily and is one of the most abundant transcription factor families in plants. Members have highly conserved B3 or AP2 DNA binding domains. Although the RAV family genes of several species have been systematically identified from genome-wide studies, there has been no comprehensive study to identify rice RAV family genes. Here, we identified 15 genes of the RAV family in the rice genome and analyzed their phylogenetic relationships, gene structure, conserved domains, and chromosomal distribution. Based on domain similarity and phylogenetic topology, rice RAV transcription factors were phylogenetically clustered into four groups. qRT-PCR analyses showed that expression of these RAV genes was significantly up-regulated or down-regulated by plant hormone treatments, including BL, NAA, IAA, MeJA, and SA. Most of the rice RAV genes were dramatically down-regulated in response to rice stripe virus (RSV) and mostly up-regulated in response to Southern rice black-streaked dwarf virus (SRBSDV). These results suggest that the rice RAV genes are involved in diverse signaling pathways and in varied responses to virus infection.

The epigenetic factor FVE synchronizes SGS3-DRB4/DCL2/4 functions to promote transgenic siRNA production in the cytoplasm.