Transcriptome pathways unique to dehydration tolerant relatives of modern wheat

Among abiotic stressors, drought is a major factor responsible for dramatic yield loss in agriculture. In order to reveal differences in global expression profiles of drought tolerant and sensitive wild emmer wheat genotypes, a previously deployed shock-like dehydration process was utilized to compare transcriptomes at two time points in root and leaf tissues using the Affymetrix GeneChip(R) Wheat Genome Array hybridization. The comparison of transcriptomes reveal several unique genes or expression patterns such as differential usage of IP(3)-dependent signal transduction pathways, ethylene- and abscisic acid (ABA)-dependent signaling, and preferential or faster induction of ABA-dependent transcription factors by the tolerant genotype that distinguish contrasting genotypes indicative of distinctive stress response pathways. The data also show that wild emmer wheat is capable of engaging known drought stress responsive mechanisms. The global comparison of transcriptomes in the absence of and after dehydration underlined the gene networks especially in root tissues that may have been lost in the selection processes generating modern bread wheats

TILLING with TILLMore

A TILLING (Targeting Induced Local Lesion IN Genomes) resource in barley (cv. Morex) consisting of 4,906 families was produced by sodium azide (NaN_3 ) seed treatment. This resource has been named TILLMore. TILLMore was screened for mutants at several genes based on the analysis of 8- to 12-fold DNA pools produced from M2 or M3 DNA samples. An average of ca. six alleles per gene was identified, which corresponds to a rate of one mutation every 428 kb. Almost all the mutations detected were CG-TA transitions and several (ca. 58%) implied a change in amino acid sequence, hence possible effects on phenotype. The barley-mutagenized population, although developed for reverse-genetics purposes, is also a valuable resource for forward-genetics studies. A high frequency of M3 families (ca. 33%) showed morphological alterations, which have been scored regularly during the growing seasons in reference to wild-type Morex plants (see www.distagenomics.unibo.it/TILLMore/). In particular, a preliminary screening for phenotypes at the root level showed altered root morphology for ca. 7% of the families. Our results indicate the feasibility of using this collection of materials to investigate gene function in barley and closely related crops