Genome–Wide Identification, Characterization and Expression Profiling of YUCCA Family Genes Responsive to Exogenous Hormones and Abiotic Stress in Peanut

YUCCA (YUC) proteins, serve as crucial rate-limiting enzymes of the tryptophan-dependent auxin biosynthesis pathway, and play essential roles in plant growth, development, and stress adaptation. As of now, a comprehensive examination of the YUC gene family in peanut remains insufficient. In this study, a total of 89 YUC family genes, named AdYUC1-AdYUC25, AiYUC1-AiYUC21 and AhYUC1-AhYUC43, were identified within A. duranensis, A. ipaënsis and A. hypogaea genomes and classified into five phylogenetic clades (Clade I - V). The gene structures and protein motifs were conserved among the majority of AhYUCs. Collinearity analysis indicated that substantial segmental duplication events contributed to the expansion of the AhYUCs, and the majority of duplicated gene pairs underwent strong purifying selection. Promoter prediction analysis detected 3,903 cis-acting elements associated with plant growth and hormone, stress and light responsive. In silico expression profiling of 43 AhYUCs across 22 tissues showed different spatial and temporal expression patterns, with 15 AhYUCs has significant expression difference. Meanwhile, base on previous transcriptome data of lateral branches development, AhYUC9, AhYUC18 and AhYUC29 were identified. Subsequently, the expression patterns of the 8 AhYUCs were analyzed using quantitative real-time polymerase chain reaction (qRT - PCR) under treatments of PEG, NaCl, ABA, GA3, and 6-BA. Notably, AhYUC18 and AhYUC29 also exhibited significant trends under different treatments in two genotypes, which speculated to potentially participate in the growth-survival balance in peanuts. This study provides a valuable foundation for the functional characterization of AhYUC genes in peanut growth and stress physiology.