Submitted to: Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 15, 2007
Publication Date: June 21, 2007
Citation: Mott, I.W., Wang, R. 2007. Comparative transcriptome analysis of salt-tolerant wheat germplasm lines using genome arrays. Plant Science 173:327-339. Interpretive Summary: Abiotic stresses such as drought, salinity, and temperature have been shown to reduce average crop yield by more than 50% with yield losses for wheat as great as 80%. Development of wheat cultivars tolerant to these abiotic stresses is the best way to ensure the food supply security. Understanding genes responsible for stress tolerance will help scientists select the best plant materials and breeding strategies to develop cultivars. We studied gene expression patterns after salt treatments in five wheat lines varying in salt tolerance by using the powerful microarray technique. We identified the sources of expression variations for the two most salt tolerant wheat germplasm lines W4909 and W4910. We confirmed the results of an earlier study in which W4909 and W4910 were shown to have more genetic materials transferred from their parental line Ph inhibitor than the other parental line AJDAj5. A short list of genes whose expression changes were common in all five lines provides critical pertinent information on these candidate genes that warrant further research.
Technical Abstract: Salt-tolerant wheat lines W4909 and W4910 were derived from a cross between AJDAj5 (a disomic addition line carrying a pair of Eb chromosomes from Thinopyrum junceum) and Ph1 (a line having the Ph1 allele from Aegilops speltoides, which promotes homoeologous recombination). Both lines have greater salt-tolerance than their parental lines, which are more salt-tolerant than the common wheat background, Chinese Spring (CS). Genomic constitution of W4909 and W4910 wheat has been estimated at 1.9% and 2.4% non-CS, respectively. Affymetrix GeneChipR Wheat Arrays were used to identify differentially expressed genes in roots and leaves of the above-mentioned five lines under salt stress at EC=30 dS/m. Based on expression polymorphisms in AJDAj5 and Ph1, differentially expressed genes in W4909 and W4910 were attributed to one or the other parental lines. Nearly twice as many expression polymorphisms in W4909 and W4910 were derived from Ph1 than those from AJDAj5. Nine transcripts in W4910 showed transgression gene expression significantly higher or lower than either parent. The majority of expression polymorphisms had reduced to near-absent expression levels and mapped to three distinct chromosomal locations, 2S, 4L and 2L. Salt treatment responsive gene expression profiles common to all five tested lines provide a short list of candidate salt-tolerance genes in wheat.