[Expressing and functional analysis of GmMYBJ6 from soybean]

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 beta-galactosidase was 28.48 U/mL. The green fluorescent protein expression vector p163-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.