Sorbitol induces flower bud formation via the MADS-box transcription factor EjCAL in loquat  

作　　者：Hong-Xia Xu Dong Meng Qing Yang Ting Chen Meng Qi Xiao-Ying Li Hang Ge Jun-Wei Chen 

机构地区：[1]Institute of Horticulture,Zhejiang Academy of Agricultural Sciences,Hangzhou 310021,China [2]Beijing Advanced Innovation Center for Tree Breeding by Molecular Design,Beijing Forestry University,Beijing 100000,China [3]College of Forestry,Beijing Forestry University,Beijing 100083,China

出　　处：《Journal of Integrative Plant Biology》2023年第5期1241-1261,共21页植物学报（英文版）

基　　金：the financial support by the National Key R&D Program of China (2020YFD100103);the Major Science and Technology Project of New Agricultural Variety Breeding in Zhejiang Province (2021C02066-3);the Six Party Program of Agriculture, Rural Areas, and Farmers in Zhejiang Province (2020SNLF025);the Major Agricultural Technology Collaborative Promotion Program in Zhejiang Province (2022XTTGGP02)。

摘　　要：Sorbitol is an important signaling molecule in fruit trees. Here, we observed that sorbitol increased during flower bud differentiation(FBD) in loquat(Eriobotrya japonica Lindl.). Transcriptomic analysis suggested that bud formation was associated with the expression of the MADS-box transcription factor(TF) family gene, EjCAL. RNA fluorescence in situ hybridization showed that EjCAL was enriched in flower primordia but hardly detected in the shoot apical meristem. Heterologous expression of EjCAL in Nicotiana benthamiana plants resulted in early FBD. Yeast-one-hybrid analysis identified the ERF12 TF as a binding partner of the EjCAL promoter. Chromatin immunoprecipitation-PCR confirmed that EjERF12 binds to the EjCAL promoter, and β-glucuronidase activity assays indicated that EjERF12 regulates EjCAL expression.Spraying loquat trees with sorbitol promoted flower bud formation and was associated with increased expression of EjERF12 and EjCAL. Furthermore, we identified EjUF3GaT1 as a target gene of EjCAL and its expression was activated by EjCAL. Function characterization via overexpression and RNAi reveals that EjUF3GaT1 is a biosynthetic gene of flavonoid hyperoside. The concentration of the flavonoid hyperoside mirrored that of sorbitol during FBD and exogenous hyperoside treatment also promoted loquat bud formation. We identified a mechanism whereby EjCAL might regulate hyperoside biosynthesis and confirmed the involvement of EjCAL in flower bud formation in planta. Together,these results provide insight into bud formation in loquat and may be used in efforts to increase yield.

关 键 词：EjCAL flower bud differentiation HYPEROSIDE LOQUAT SORBITOL 

分 类 号：S667.3[农业科学—果树学]