Genome-Wide Identification of DlGRAS Family and Functional Analysis of DlGRAS10/22 Reveal Their Potential Roles in...

GRAS family plays a critical role in plant growth and stress responses. In this study, we identified 47 GRAS (DlGRAS) genes in the longan genome and conducted a comprehensive bioinformatics analysis of these genes. RNA-seq analysis revealed that the expression of these DlGRAS genes differed during early SE and across various longan tissues. The quantitative real-time PCR (qRT-PCR) results indicated that the DlGRAS genes exhibited differential expression during the early SE of longan, with most of them showing high expression at the globular embryo (GE) stage. Under GA₃ treatment, the transcript levels of DlGRAS12/15 decreased significantly. In contrast, exogenous ABA promoted the expression of DlGRAS6/10/23, indicating that DlGRAS genes are responsive to hormones. Compared with CaMV35S-driven GUS expression, the promoters of DlGRAS10/22 increased GUS expression, GA₃ and ABA treatments enhanced promoter activity. DlGRAS10/22 were located in the nucleus. Overexpression of DlGRAS10/22 in longan SE significantly promoted the transcription levels of SE-related genes, including DlGID1, DlGA20ox2, DlLEC1, DlFUS3, DlABI3 and DlLEC2. Therefore, DlGRAS may be involved in the early morphogenesis of longan SE through the hormone signaling pathway.