Transcriptional profiling of Zea mays genotypes with different drought tolerances – new perspectives for gene expression markers selection

Drought is considered to be one of the greatest limiting factors in agriculture. Therefore, the ability of plants to adapt to drought conditions is crucial to sustain worldwide crop production. The aim of this work was to identify gene expression markers for drought tolerance in Zea mays with the potential to assist breeding. Selected maize genotypes were characterized with respect to drought tolerance by measurements of the relative water content after drought stress conditions. Tolerant genotypes were screened for up-regulated genes in drought conditions detected by previous microarray hybridizations. Five cDNAs coding for drought inducible genes in maize were identified and further characterized by semi-quantitative reverse transcription polymerase chain reactions. The expression levels of two of them (MZ00023411 and MZ00037881) allow a significant discrimination between toler¬ant and susceptible genotypes. In tolerant genotypes (MK01, MK01xRF7, 002x250) the expression level of these genes was at least twice higher as compared to susceptible genotypes (XL12, 005, 005x301) throughout all condi¬tions tested. Almost for all tolerant genotypes were registered significant differences (P≤0.05), versus susceptible ones, in expression of these genes. Specific primers for these two genes allow discrimination of drought tolerant and susceptible maize genotypes even after 2h of dehydration stress based on expression level and are suitable as potential gene expression markers, associated with drought tolerance