《植物生理学报》 2017, 53(1): 115-125

蓝莓转录因子VcMYB21在果实着色及幼苗UV处理中的响应

刘中帅, 袁义杭, 张通, 张凌云^*

北京林业大学, 省部共建森林培育与保护教育部重点实验室, 北京100083

通信作者：张凌云；E-mail: lyzhang73@sohu.com

摘　要：

本研究通过RACE-PCR从蓝莓中克隆得到一个R2R3-MYB转录因子, 命名为VcMYB21, 该基因全长1 373 bp, 编码区722 bp, 编码233个氨基酸。生物信息学分析发现其理论分子量为58.37 kDa, pI值为5.12, 中部有1个2Fe-2S结合域和1个EGF-like结构域, 属于膜外蛋白, 结构不稳定。酵母双杂交实验表明VcMYB21蛋白无自激活活性, 能自身形成同源二聚体。组织特异性表达实验显示VcMYB21主要在蓝莓的果皮和叶片中表达。在蓝莓果实发育过程中, VcMYB21基因的表达量整体呈下降趋势, 在果实发育早期表达量最高, 之后迅速下降, 全红果时期略微上升; 花青素的含量随果实发育持续上升, 在紫果期达到最大。UV-B与UV-C处理均显著诱导VcMYB21在蓝莓幼苗叶片组织中的表达, 其中对UV-B处理更为敏感。UV-B处理5 min以及UV-C处理10 min均能显著诱导该基因的表达, 随处理时间的延长, 基因表达量下降; 花青素的含量在基因表达量下降后迅速上升, 之后花青素分解, 积累量下降。这些研究结果表明VcMYB21在UV处理后叶片花青素积累过程及蓝莓果实着色过程中可能发挥着负调控作用。

关键词：蓝莓; VcMYB21; 基因表达; 逆境响应

收稿：2016-08-22   修定：2016-12-14

资助：国家自然科学基金项目(31270663)和国家转基因生物新品种培育科技重大专项(2013ZX08009003-002-004)。

Expression characteristics of the transcription factor VcMYB21 in blueberry fruit coloration and response to UV in seedling

LIU Zhong-Shuai, YUAN Yi-Hang, ZHANG Tong, ZHANG Ling-Yun^*

Key Laboratory of Forest Silviculture and Conservation of the Ministry of Education, Beijing Forestry University, Beijing 100083, China

Corresponding author: ZHANG Ling-Yun; E-mail: lyzhang73@sohu.com

Abstract:

VcMYB21 is a transcription factor of R2R3-MYB. In this study, VcMYB21 was cloned by RACEPCR method in blueberry. Bioinformatics analysis showed that the full length of VcMYB21 cDNA was 1 373 bp, including the ORF 722 bp, encoding 233 amino acids. The theoretical molecular weight of VcMYB21 was 58.37 kDa, and the value of isoelectric point (pI) was 5.12. The ScanProsite online software showed that the protein contains a 2Fe-2S and a EGF-like binding sites, and it belongs to the outer membrane with unstable structure. Yeast two-hybrid experiment showed that VcMYB21 did not have autoactivation and had the ability to form homo-dimers itself. Tissue-specific expression showed that VcMYB21 was mostly expressed in peel and leaves. The expression of VcMYB21 was highest at the early development stage of fruit, and then decreased sharply with a slightly elevation in the period of whole red fruit. The anthocyanin content of fruit increased as the coloration of fruit, and reach the highest at the period of purple fruit of blueberry. Furthermore, the expression of VcMYB21 was significantly induced under UV-B and UV-C treatment in the leaves of blueberry seedlings. The data showed that VcMYB21 was more sensitive to UV-B treatment. The expression of VcMYB21 was significantly induced after 5 min of UV-B treatment and 10 min of UV-C treatment. The anthocyanin content rose sharply after VcMYB21 expression declined. Both of the expression of VcMYB21 and the anthocyanin content decreased after 10 min of UV-B treatment and 15 min of UV-C treatment. These results indicated that Vc-MYB21 played a negative role in fruit coloration and played roles during abiotic stress of UV.

Key words: blueberry (Vaccinium corymbosum); VcMYB21; gene expression; stress response