Superexpressão em plantas transgênicas de milho do gene SbMATE, que confere tolerância ao alumínio em sorgo

Abstract

The toxicity of aluminum (Al+3) is a major limiting factor for plant growth in acid soils which represent 68% or 250 million hectares of Brazilian territory and nearly 50% of arable land on the planet. Recently, in sorghum was identified and isolated by positional cloning technique aided by comparative genomics, a gene of major effect for aluminum tolerance, called SbMATE. This gene encodes a member of a membrane transporter family responsible for the efflux of citrate in roots of sorghum. This work, conducted at Embrapa Maize and Sorghum in Sete Lagoas / MG, Brazil, is based on the use of this gene to generate transgenic maize cultivars with higher levels of adaptation to acid soils. Callus and immature embryos of hybrid maize Hi II, were transformed via Agrobacterium tumefaciens and Biolistic., with the gene SbMATE. The gene construction used in the process containing the SbMATE gene under the control of the ubiquitin promoter and the bar gene driven by CaMV35S promoter. Transformed cells were selected in media containing the herbicide ammonium glufosinate. The presence of the SbMATE and bar genes was confirmed in 80% of the T0 transgenic plants generated, and in 87.5% and 57.14% of T1 plants generated via biolistic and Agrobacterium, respectively, by PCR and Southern blot. SbMATE gene expression could be confirmed through the analysis of root growth in hydroponic solution supplemented with {60} M Al, and real-time PCR.