Expression characteristic analysis of MADS-box family members ofgrape transcription factors in berry development and ripening process

Abstract:【Objective】Fruit development and maturation are important stages for fruit quality formation.Fruit ripening regulation is valuable for commercial production of grape. MADS-box Transcription fac⁃tors are a class of proteins which directly or indirectly interact with specific cis acting function in promoter region, and regulate the initiation of gene transcription. However, its function may vary greatly with dif⁃ferent family members and regenerate different regulation modes during grape berry, non- climactericfruit, development and ripening. In this study, the regulation function of 17 MADS-box transcription fac⁃tors during‘Wink’grape berry development and maturation were investigated.【Methods】The potentialfunctions of MADS-box transcription factor members in the processes of grape development and matura⁃tion were predicted by analyzing their promoter motif elements using the Plantcare software. The variety‘Wink’‘( Muscat Bailey A’בRubel Muscat X’) was used as experimental material. The berry sampleswere collected in eight development stages. ABA and NAA were sprayed one week before color changestage. The fruit size, firmness, content of soluble solids, glucose, sucrose, and fructose were measured. Weanalyzed the different spatial and temporal expression modes of various transcription factor members ineight developmental stages of grape berry to preliminarily screen the vital members participating in berrydevelopment process and verify the regulation function acting importantly in coloration and ripening process of grape berry.【Results】Promoters of MADS-box members contained elements related to grape berry development and ripening and the different number of each type of elements, indicating that they partic⁃ipated in regulating berry development and ripening process, although their function were different.MADS-box members expressed in berry development and exhibited different expression modes in differ⁃ent stages. VvAG and VvFBP24 had high expression level only in hard stone stage, indicating the positiveregulation role on fruit development. VvMADS1, VvMADS9, VvSVP-like1 and VvAP3 only exhibited highexpression level in the stages of berry veraison and ripening, indicating the positive regulatory function onfruits ripening. ABA up-regulated the expression levels of 6 members of MADS-box in certain stages,while NAA down regulated their expression. At the same time, NAA up-regulated the expression levels of8 members of MADS-box in certain stages, while ABA down regulated their expression, indicating thatthe members would probably regulate grape berry development and ripening by responding to ABA/NAA.【Conclusion】MADS- box members act importantly in regulating fruits development and maturation,among which 6 members positively promote fruits’coloration and ripening and another 8 members positively promote berry development and negatively regulate fruit ripening .