Genome-wide identification of in and the role of in rubber biosynthesis.

Oliv., a Tertiary period relict tree species endemic to China, is a rubber-producing plant valued for both medicinal and edible applications. rubber is a high-quality natural rubber prized for its excellent elasticity, abrasion resistance, and insulation properties, leading to broad industrial applications. Previous research identified the gene, encoding a protein containing rubber particle protein peptides. While overexpression of in tobacco enhanced drought tolerance, its role in rubber biosynthesis remained undefined. In this study, we identified 29 genes at the whole-genome level in . Following low-temperature and drought treatments, the expression level of the gene was found to be positively correlated with changes in rubber content (), suggesting its potential regulatory role in rubber synthesis. In subjected to Agrobacterium-mediated gene overexpression or silencing, the expression levels of key rubber biosynthesis enzyme genes, such as , exhibited corresponding increases and decreases, respectively. Furthermore, rubber content in -overexpressing callus increased by 254.51% compared to wild-type callus. These findings indicate that regulates rubber biosynthesis by modulating the expression of these genes. The 1,967 bp promoter region upstream of the ATG start codon contains several responsive elements, including MBS (MYB-binding site; CAACTG), LTR (low-temperature responsive element; CCGAAA), ABRE (ABA-responsive element; ACGTG), and a Dof transcription factor binding motif (AAAG). Promoter activity assays showed that promoter activity was induced by low temperature and drought but repressed by abscisic acid (ABA) treatment. Furthermore, using yeast one-hybrid screening, we identified a Cys2-Cys2 zinc finger domain-containing transcription factor, designated EuDof. Interaction analysis revealed that the EuDof transcription factor enhances the activity of the promoter. The binding of EuDof to the promoter was enhanced under low temperature and drought stress but inhibited by ABA. Collectively, this study provides crucial insights into the regulatory mechanism of in rubber biosynthesis.