Functional Analysis of PtMYB86 During Flower Bloom and Anthocyanin Biosynthesis in Tuberose (Polianthes tuberosa)
JIANG Fu-Xing1,*, GAO Tian-Tian1, DU Yue-Wen1, ZHENG Jiang-Kun2, XIAO Te3
1 College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130 China; 2 College of Forest, Sichuan Agricultural University, Chengdu 611130, China; 3 Sichuan Academy of Traditional Chinese Medicine Sciences, Chengdu 610041, China
Abstract：The single-petaled pink tuberose (Polianthes tuberosa) variety 'Sensation' is an excellent variety with excellent color and fragrance. However, during the flowering process, there are phenomena such as difficulty in petal expansion and abnormal flower opening (stiff flowers), and the color becomes severely lighter and whiter during the opening process and anthocyanin synthesis of P. tuberosa. Due to the scarcity of research on its functional genes, the key genes and molecular mechanisms regulating the flowering process and flower color are still unknown. Based on the transcriptome sequencing analysis of tuberose, the MYB86 gene was identified. Bioinformatics analysis showed that encoded protein of PtMYB86 gene (GenBank No. PZ156279) possessed typical conserved regions of homologous proteins. Expression characteristic analysis indicated that its expression level continuously increased during flower blooming. A constitutive expression vector was constructed, and transient overexpression in tuberose petals showed that PtMYB86 had dual functions in tuberose. On the one hand, transient overexpression of PtMYB86 could significantly promote petal expansion and accelerate flower blooming, effectively overcoming the problem of "stiff flowers" problem in cut and potted tuberoses during cultivation, production and transportation. On the other hand, transient overexpression of PtMYB86 in tuberose petals could significantly change the petal color, resulting in a shift from pink to lighter and whiter shades, indicating that PtMYB86 negatively regulated anthocyanin formation. This study provides important functional genes for elucidating the molecular mechanisms underlying flower blooming and dynamic changes in flower color in tuberose.
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