Abstract: Developmentally-regulated plasma membrane polypeptide (DREPP), acting as a kind of plant-specific protein, is involved in the response and regulation of plants to biologic and abiotic stresses. CDS sequence encoding the GmDREPP protein was cloned from an aluminum-resistance cultivar Glycine max cv. Tamba, and pCXSN-GmDREPP, the overexpression vector, was constructed and transformed into wild type tobaccos via transformation mediated by agrobacterium to obtain transgenic tobaccos. The expression of GmDREPP in Tamba Black soybean was analyzed by qRT-PCR, and the results showed that GmDREPP expressed in roots, stems, leaves and cotyledons, while the expression level in root tips was the highest in root system. Besides, the mRNA level of GmDREPP increased with the increase of the Al³⁺ concentration, and had no significant changes when Al³⁺ concentration was higher than 50 μmol·L^-1. To investigate the aluminum resistance, the transgenic tobacco lines (GmDREPP-2, GmDREPP-4, GmDREPP-5) selected by RT-PCR were challenged by Al (pH 4.5, 0.5 mmol·L^-1 CaCl₂, 50 μmol·L^-1 AlCl₃) compared with wild type (WT). The results were as following: (1) Root elongation, citrate content and the expression of NtALS3 and NtMATE were significantly (P<0.01) increased in transgenic tobacco lines compared with WT. (B) By contrast, POD and SOD activities significantly (P<0.01) increased and MDA content significantly (P<0.01) decreased in roots of transgenic tobacco lines. (C) Root tips stains using Evans blue and hematoxylin manifested transgenic tobaccos were lighter than WT, indicating a reduction in aluminum toxicity. This research verified that over-expression of GmDREPP could enhance the resistance of the transgenic tobaccos to aluminum and provide new genetic resources to breed new varieties with aluminum resistance.

Key words: GmDREPP, aluminum tolerance, citrate secretion, transgene