Plantas glutationa s-transferase (GSTs) têm sido foco da atenção devido ao seu papel na detoxificação de herbicida. OsGSTL2 é uma glutationa s-transferase, gene da classe lambda de rice (Oryza sativa L.). Plantas transgênicas de arroz superexpressando OsGSTL2 foram geradas de "calus" de arroz via sistema de transformação de Agrobacterium, e foram avaliadas por uma combinação de resistência a higromicina, PCR e análise de "Southern blot". Nos tecidos vegetativos das plantas transgênicas, a superexpressão de OsGSTL2 não somente incrementou os níveis de transcritos OsGSTL2, mas também a expressão de GST e GPX, enquanto reduziu superóxido. Plantas transgênicas também mostraram mais alta tolerância a glifosato e clorosulfuron, os quais frequentemente contaminam solos agrícolas. Essas descobertas demonstram o papel de detoxificação de OsGSTL2 no crescimento e desenvolvimento de plantas de arroz. A partir delas será possível também aplicar tais resultados a outros cultivos para desenvolvimento de tolerância a herbicida e para limitar a contaminação com esse agrotóxico na cadeia alimentar.

Plant glutathione S-transferases (GSTs) have been a focus of attention due to their role in herbicide detoxification. OsGSTL2 is a glutathione S-transferase, lambda class gene from rice (Oryza sativa L.). Transgenic rice plants over-expressing OsGSTL2 were generated from rice calli by the use of an Agrobacterium transformation system, and were screened by a combination of hygromycin resistance, PCR and Southern blot analysis. In the vegetative tissues of transgenic rice plants, the over-expression of OsGSTL2 not only increased levels of OsGSTL2 transcripts, but also GST and GPX expression, while reduced superoxide. Transgenic rice plants also showed higher tolerance to glyphosate and chlorsulfuron, which often contaminate agricultural fields. The findings demonstrate the detoxification role of OsGSTL2 in the growth and development of rice plants. It should be possible to apply the present results to crops for developing herbicide tolerance and for limiting herbicide contamination in the food chain.

The mRNA of OsGSTL1 was detected in the roots and leaves of rice plants at seedling and tillering stages, and their roots, leaves and panicles at the heading stage. The full-length open reading frame of OsGSTL1 cDNA was 732 bp and encoded a putative polypeptide of 243 amino acids with a calculated molecular mass of 27.30 kDa and a theoretical pI of 5.50. The protein sequences of OsGSTL1 exhibited typical feature of the lambda class GST, which contained the conserved domain "GST_C_Lambda" in C-terminal alpha helical domain and a highly conserved Cys42 in active center. In silico predictions showed that the OsGSTL1 protein was strongly hydrophilic. The phylogenetic analysis revealed OsGSTL1 belonged to monocots subgroup and was closer to IN2-1 of Z. may. The OsGSTL1 gene was cloned into pYTV vector and was introduced into yeast strain PEP4. Western blot analysis showed that the exogenous OsGSTL1 was expressed in the transformed yeast. The GST activity of the crude extracts of yeast showed that the OsGSTL1 transgenic yeast had higher levels of GST activities than the control yeasts. These findings suggested that the OsGSTL1 was a glutathione S-transferase and could play an important role during the growth and development processes in rice.