FaMYB73调控草莓果实苹果酸合成的研究  

R2R3-MYB Transcription Factor FaMYB73 Involved in Malic Acid Accumulation of Strawberry Fruits

作　　者：赵静[1] 周多妮 朱宏路 张洋 谢兴斌[1] 方从兵[1] ZHAO Jing;ZHOU Duoni;ZHU Honglu;ZHANG Yang;XIE Xingbin;FANG Congbing(School of Horticulture, Anhui Agricultural University, Hefei 230036, China)

机构地区：[1]安徽农业大学园艺学院,合肥230036

出　　处：《西北植物学报》2020年第10期1638-1645,共8页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家重点研发项目(2018YFD1000200);国家自然科学基金(31701869)。

摘　　要：苹果酸是草莓果实主要的有机酸之一,其含量的高低显著影响草莓果实的风味。该研究以‘红颜’草莓为试材,采用反转录(RT-PCR)的方法克隆得到一个新的MYB转录因子——FaMYB73。该基因包含有756 bp的开放阅读框,编码252个氨基酸,预测其蛋白质分子量为27.6 kD,等电点为6.8。功能域分析表明,FaMYB73蛋白含有保守的R2R3结构域;亚细胞定位于细胞核中。实时荧光定量(qRT-PCR)分析表明,FaMYB73基因在草莓各个组织均有表达,且在花和叶中的表达相对较高;在果实的白果期FaMYB73基因的表达量最高,且随着果实成熟,FaMYB73基因的表达下调,说明该基因的表达具有组织和时期特异性。高效液相色谱法(HPLC)检测结果发现,苹果酸含量在草莓果实发育期呈先上升后下降的趋势,且与FaMYB73基因的表达量呈正相关。草莓瞬时注射结果显示,FaMYB73过表达显著促进了苹果酸的积累,沉默则显著降低了苹果酸的含量。同时,获得了2个转FaMYB73基因烟草稳定表达株系,FaMYB73过量表达显著提高了烟草叶片中苹果酸的含量。研究表明,FaMYB73参与调控草莓果实中苹果酸的合成,为进一步研究其调控机制提供了理论依据。Malic acid is one of the most important organic acids in strawberry fruits,and its content significantly affects the flavor of strawberry fruits.In this study,using Fragaria×ananassa‘Benohoppe’as material,we cloned a new MYB transcription factor(TF)-FaMYB73 by RT-PCR including 756 bp open reading frame,encoding 252 amino acids.It was predicted that the molecular mass of this protein was 27.6 kD,and pI was 6.8.The FaMYB73 protein contained the conserved R2R3-MYB domain and microscopy analysis showed that 35S-FaMYB73-GFP was located exclusively in the nucleus as expected.Quantitative real-time PCR(qRT-PCR)analysis demonstrated that the expression of FaMYB73 had tissue specific and stage specific.FaMYB73 was expressed in different tissues and four developmental stages of fruits.The expression level of FaMYB73 was relatively higher in leaves and flowers,the highest at the white fruit stage and decreased with maturity.The malic acid content detected by HPLC reached the highest at the white fruit stage and decreased thereafter,and was positively correlated with the expression of the FaMYB73 gene.The homologous expression in strawberries found that FaMYB73 over-expression significantly promoted the accumulation of malic acid,and silence distinctly reduced the amounts of malic acid.Two transgenic tobacco lines having the malic acid over-accumulation phenotype were obtained and the transformation was confirmed using quantitative real-time PCR(qRT-PCR).The results indicated that FaMYB73 was involved in regulating the synthesis of malic acid in strawberry fruits and provided a theoretical foundation for further exploring the mechanism of FaMYB73 regulating malic acid in strawberry fruits.

关 键 词：草莓 FaMYB73 苹果酸 品质 

分 类 号：Q786[生物学—分子生物学] Q789