(BIOEN-FAPESP) Gene expression profile and carbon isotope discrimination in sugarcane genotypes under water deficit stress

• Grant number: 08/57923-5
• Support type: Program for Research on Bioenergy (BIOEN) - Regular Program Grants
• Duration: May 01, 2009 - April 30, 2012
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Principal researcher: Antonio Vargas de Oliveira Figueira
• Grantee: Antonio Vargas de Oliveira Figueira
• Home Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Sugarcane (Saccharum spp.) is major crop in Brazil as feedstock for the sugar and ethanol industries. To attend the increasing ethanol demand, the sugarcane industry must expand the cultivated area, incorporating land from 'cerrado' and pastures, characterized by a dry winter with a long water deficit period. For the last 10 years, more than 80 cultivars have been released in Brazil, but few with yield potential to be cultivated in drought-prone environments. Mechanisms of response and tolerance to water stress have been investigated in model species, whose genes were classified into two groups: one includes proteins that act directly on dehydration tolerance, and the other comprises regulatory genes. Previous work on sugarcane response to water deficit stress detected similar induced regulatory genes to the ones from rice and Arabidopsis, but structural genes associated with stress response have not been evaluated. Elucidation of sugarcane mechanisms involved in tolerance to water deficit would be valuable to develop cultivars productive and adapted to drought-prone regions, promoting the sustainability of the sugarcane industry in these marginal regions. This proposal intends to establish an efficient and dependable method to evaluat water deficit stress in sugarcane by evaluation of several protocols, to enable the analysis of gene expression profiles between genotypes tolerant or susceptible to water stress using microarrays, followed by validation of differential gene expression by quantitative amplification of reversed transcripts (RT-qPCR). Analyses of marker gene expression (drought- or ABA-related structural or regulatory genes) will be conducted using RT-qPCR to validate the observed responses. At the same time, 13C discrimination technique (O) will be tested and optimized to evaluate the genetic diversity available for the trait, together with biochemical and physiological measurements, associated with water use efficiency and, consequently, water stress tolerance. (AU)