Genome-Wide Identification and Expression Analysis during Bud Regeneration of AUX/LAX Genes in Watermelon

Wang Duo; Xu Xinyang; Shen Jia; Shou Weisong; He Yanjun; Xuan Zhengying

doi:10.14083/j.issn.1001-4942.2025.03.001

Abstract：Auxin is one of the most important plant hormones.Auxin internal flow vector AUX/LAX(AUXIN RESISTENT1/LIKE AUX1)is related to multiple membrane span proteins and amino acid transport-ers of auxin flow between cells,and participates in the active transport process of auxin.AUX/LAX genes have been identified in several species and found to play very important roles in multiple plant growth and develop-ment processes,but no study has been reported in watermelon.In this study,five watermelon AUX/LAX genes were identified at the genome-wide level,and all contained a conserved Aa_trans domain.Phylogenetic analy-sis showed that 21 AUX/LAX proteins from watermelon,Arabidopsis,rice and cucumber were clustered into two subfamilies,and almost every AUX/LAX of watermelon corresponded to that of cucumber.In addition,the abscisic acid,methyl jasmonate and salicylic acid response elements,hormones such as erythromycin response elements,and defense and abiotic stress such as anaerobic induction,low temperature and drought response elements were identified from the ClAUX/LAXs promoters.Real-time quantitative PCR(RT-qPCR)results showed that the expression level of ClAUX/LAXs was the lowest in male flowers except ClAUX/LAX4,which showed significant tissue specificity.Their expressions were different in watermelon materials with different re-generation capacities,and the expression level of ClAUX/LAX5 was significantly higher in the high-regenerated material than that in the low-regenerated material on the 5th day of differentiation,suggesting that ClAUX/LAXs probably play very important roles during bud regeneration process of watermelon.The results of this study could provide evidence for further research on the role of auxin during bud regeneration,and lay a foun-dation for exploring the regulatory genes of watermelon bud regeneration.