Genome-Wide Identification and Evolution Analysis of the Subfamily in Rice ().

The subfamily, a member of the superfamily, plays crucial roles in the biosynthesis of phytohormones in plants, involving biosynthesis of secondary metabolites, hormone signaling, and response to environmental stresses. Here, we conducted a genome-wide analysis of the subfamily in seven AA genome species: ssp. , ssp. , , , , and These were identified and classified into three groups, and it was found that Group 1 contained the largest number of members. Analysis of cis-acting elements revealed a large number of elements related to jasmonic acid and light response. The gene duplication analysis revealed that the subfamily expanded mainly in SD/WGD and tandem forms and underwent strong purifying selection during evolution. Expression pattern analysis of in various developmental stages revealed that the majority of exhibit relatively restricted expression patterns in leaves and roots. We further analyzed the expression of CYP76s in , , and , under cold, flooding, drought, and salt abiotic stresses by qRT-PCR. We found that showed a huge increase in relative expression after drought and salt stresses. After flooding stress, showed a greater increase in expression compared to other genes. CYP76 in and showed different response patterns to the same abiotic stresses, revealing functional divergence in the gene family during evolution; these may be the key genes responsible for the differences in tolerance to indica japonica. Our results provide valuable insights into the functional diversity and evolutionary history of the subfamily and pave the way for the development of new strategies for improving stress tolerance and agronomic traits in rice.