Abstract: Plant R2R3-myb genes are widely distributed in higher plants and comprise one of the largest known families of regulatory proteins. In the past decades, its biochemical and molecular characteristics were extensively studied and reported to be involved in many physiological and biochemical processes. On the based of its conserved DNA-binding domain, two MYB-like genes from soybean cultivar Jilin 3 were cloned by RT-PCR and RACE methods, named GmMYBJ6 and GmMYBJ7 (GenBank accession No. DQ902863 and DQ902864), which contained an ORF of 786 bp and 969 bp encoding 261 and 322 amino acids respectively. Genomic DNA sequences analysis showed that both the two genes contained two introns. Meanwhile, the transcription level of the two genes was investigated by semi-quantitative RT-PCR, and the result showed that the two genes were expressed in root, stems, leaves, flowers and immature seeds of soybean. Furthermore, the yeast one-hybrid assay showed that the two MYB proteins had transcriptional activation functions. But the levels of their transcriptional activity were lower when the introns existed. Fluorescence real-time quantification PCR analysis indicated that the expression of GmMYBJ6 and GmMYBJ7 genes could be induced by ABA and NAA, respectively. And their expressions were changed with the inducible time. In conclusion, GmMYBJ6 and GmMYBJ7 genes isolated from soybean are new members of MYB transcription factor family, which may play key roles in the signal transduction related to ABA and NAA in soybean.

Key words: MYB transcription factor, Gene expression and regulation, Intron, Transcriptional activity