Genome-wide analysis of the mango YUCCA family and overexpression of MiYUCCA10A/B confers early flowering and stress tolerance in transgenic Arabidopsis and tomato.

Auxin is a fundamental phytohormone that orchestrates developmental processes in plants. Flavin monooxygenase (YUCCA) serves as the rate-limiting enzyme in the indole-3-pyruvic acid pathway (IPA) pathway, and its main function is to convert IPA into IAA. In this study, 12 members of the MiYUCCA gene family were mined and identified from the genomic data of mango (Mangifera indica). Phylogenetic tree analysis classified mango YUCCA into five categories. Cis-elements analysis of the promoter indicated that the promoter region contained a large number of hormone response elements and abiotic elements. Expression analysis revealed that the majority of MiYUCCA gene family members displayed high expression abundance at the early developmental stages of fruits, and their expression decreased or even remained unexpressed with the fruit growth and development. MiYUCCA10A and MiYUCCA10B were selected for functional verification. Overexpression of MiYUCCA10A and MiYUCCA10B promoted the early flowering in transgenic Arabidopsis and tomato, enhanced the salt and drought resistance, and also increased the content of IAA in transgenic plants. In addition, MiYUCCA10A and MiYUCCA10B significantly reduced the seed number of transgenic Arabidopsis and tomato plants, exerted no effect on the pod length of Arabidopsis, but markedly decreased the fruit size of tomato. The interaction of MiYUCCA10A/B with the SHORT VEGETATIVE PHASE 1/2/3/4/5 (MiSVP1/2/3/4/5) and FLOWERING LOCUS C (MiFLC) was revealed using both yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) analyses. These results indicate that the MiYUCCA10A/B were not only involved in flowering, but also related to stress tolerance and fruit development.