Plant & Animal Genomes XIV Conference Plant & Animal Genomes XIV ConferenceJanuary 14-18, 2006
Town & Country Convention Center
San Diego, CA
Gang-Ping Xue1 , C. Lynne McIntyre1 , Neil I. Bower1,2 , Heather Way1 , Antonio Reverter2 , Scott Chapman1 , Bryan Clarke 3 , Ray Shorter1
High water use efficiency or transpiration efficiency (TE) in wheat is a desirable physiological trait for increasing grain yield under water-limited environments. The identification of genes associated with this trait would facilitate the selection for genotypes with higher TE using molecular markers. We performed an expression profiling (microarray) analysis of approximately 16,000 unique wheat ESTs to identify genes differentially expressed between wheat lines with contrasting levels of TE from a cross between wheat cultivars, Quarrion (high TE) and Genaro 81 (low TE). We also conducted a second microarray analysis to identify genes in wheat leaves that were responsive to drought stress. Approximately 100 genes differentially expressed between high and low TE progeny lines were identified. One fifth of these genes were markedly responsive to drought stress. A number of potential growth regulatory genes, which were down-regulated by drought, were expressed at a higher level in the high TE lines than the low TE lines and are potentially associated with a higher biomass production rate of Quarrion. Ten of the TE differentially expressed genes were further confirmed using quantitative RT-PCR in a separate set of plant samples from those used for microarray analysis. The expression levels of nine out of the ten genes were positively correlated with the high TE trait, measured as carbon isotope discrimination (Delta 13C). These data indicate that some of these TE differentially expressed genes are candidates for investigating processes underlying the high TE trait or for use as expression quantitative trait loci (eQTLs) for TE.