大豆转录因子基因GmMYBJ6的表达及功能分析

Expressing and functional analysis of GmMYBJ6 from soybean

MYB转录因子是最大的植物转录因子家族之一,对植物的生长发育及生理代谢具有重要的调节作用。Gm MYBJ6(GenBank登录号:DQ902863)是从大豆中分离克隆的新的MYB转录因子基因,本文对其在植物中的表达及功能进行了初步研究。利用Norhern杂交对GmMYBJ6在不同组织中的表达情况进行了检测,结果只在叶片中检测到了GmMYBJ6的表达;酵母表达结果显示,GmMYBJ6具有明显的转录激活功能,β-半乳糖苷酶活性为28.48U/mL;构建绿色荧光蛋白融合表达载体,基因枪法转化洋葱表皮细胞进行瞬时表达,结果表明,GmMYBJ6蛋白定位于细胞核中;半定量RT-PCR检测结果显示,在转化烟草中,GmMYBJ6的表达可提高类黄酮代谢途径中的苯丙氨酸氨基裂解酶(PAL)、肉桂酸-4-羟化酶(C4H)、4-香豆酰辅酶A连接酶(4CL)、查尔酮合成酶(CHS)、黄酮醇合成酶(FLS)等关键酶的表达,并且使烟草中总黄酮的含量增加;此外,在紫外辐射、高盐及干旱(PEG)等处理下,大豆品种吉林3号中GmMYBJ6的表达量明显增加,显示GmMYBJ6对非生物胁迫具有明显的应答反应。

MYB transcription factor is one of the largest families in plants, which plays an important role in regulating plant development and physiological metabolism. In this study, the expression and function of the new MYB transcription factor gene GmMYBJ6 （GenBank No. DQ902863）, isolated from soybean （Glycine max L.）, were characterized. The expression pattern of GmMYBJ6 in different organs was examined using Northern blotting analysis. The expression of GmMYBJ6 was detected only in the leaves. The transcriptional activation ability of GmMYBJ6 protein was confirmed by the yeast assay system and the activity of 13-galactosidase was 28.48 U/mL. The green fluorescent protein expression vector pl63-GFP-GmMYBJ6 was constructed and transformed into the epidermal cells of onion via particle bombardmental method. The results of instantaneous expression showed that GmMYBJ6 proteins were localized in cell nucleus. Semi-quantitative RT-PCR analysis indicated that GmMYBJ6 improved the expression of certain flavonoid biosynthetic genes, such as PAL （Phenylalanine ammonia lyase）, C4H （cinnamate-4-hydroxylase）, 4CL （4-coumaroyl-CoA ligase）, CHS （Chalcone synthase）, CHI （Chalcone isomerase）, F3H （Flavanone 3-hydroxylase）, and FLS （Flavonol synthase）, resulting an increase of the total flavonoid levels in positive tobacco transformants. Additionally, the increasing expression of GmMYBJ6 in soybean cultivar Zhongdou 27, induced by UV-B radiation, drought, and high-salt treatment, indicated that GmMYBJ6 was associated with response to abiotic stresses.