Proteomic analysis offers a new approach to identify a broad spectrum of genes that are expressed in living systems. We applied a proteomic approach to study changes in wheat grain in response to drought, a major environmental parameter adversely affecting development and crop yield. Three wheat genotypes differing in genetic background were cultivated in field under well-watered and drought conditions by following a randomized complete block design with four replications. The overall effect of drought was highly significant as determined by grain yield and total dry matter. About 650 spots were reproducibly detected and analyzed on 2-DE gels. Of these, 121 proteins showed significant change under drought condition in at least one of the genotypes. Mass spectrometry analysis using MALDI-TOF/TOF led to the identification of 57 proteins. Two-thirds of identified proteins were thioredoxin (Trx) targets, in accordance with the link between drought and oxidative stress. Further, because of contrasting changes in the tolerant and susceptible genotypes studied, several proteins emerge as key participants in the drought response. In addition to providing new information on the response to water deprivation, the present study offers opportunities to pursue the breeding of wheat with enhanced drought tolerance using identified candidate genetic markers. The 2-DE database of wheat seed proteins is available for public access at http://www.proteome.ir.

The genetic diversity among 10 Iranian bread wheat (Triticum aestivum) genotypes was analysed using 12 quality traits, 320 amplified fragment length polymorphisms (AFLP) polymorphic fragments, 491 simple sequence repeats (SSR) alleles and 294 proteome markers. The results revealed that the genotypes differed for quality traits, AFLP, SSR and proteome markers. The average genetic diversity based on quality traits (0.684 with a range of 0.266-0.997) was higher than AFLP (0.502 with a range of 0.328-0.717), SSR (0.503 with a range of 0.409-0.595) and proteome (0.464 with a range of 0.264-0.870) markers. Although there were apparent similarities between the groupings of particular genotypes, the overall correspondence between the distance matrices appeared to be rather low. In this study, the cluster analysis based on AFLP data showed the closest agreement with genotypes' regions of origin or pedigree information. In addition to the genetic diversity assessment, specific proteins with known function were detected uniquely for the studied genotypes. Our results suggest that the classification based on quality traits and genotypic markers of these wheat genotypes will be useful for wheat breeders to plan crosses for positive traits.

The aim of this research was to determine the effect of cold stress on chlorophyll content, proline accumulation and the cell membrane stability of 15 bread wheat (Triticum aestivum L.) at two stage of growth (2 leaf stage and 4 leaf stage). Experiment was carried out in complete block design with tree replications at year 2009 in west Azerbaijan Agriculture science and research center laboratory. 15 cultivar (five genotypes with types winters names Sayson, Martin, Gaskoghen, C-82-12, C-81-14, 5 genotype with type intermediate including Alvand, Mahdavi, Zarrin, Marvdasht, Toos and five genotypes with type spring names Shiraz, Pishtaz, M-79-7, M-81-13 and Kavir) were sown in lab condition. According to the results, cold stress had a significant effect on chlorophyll a and b, total chlorophyll, prolin content and cell membrane stability. At the other hand variety and growing stage have significant effect on treats (P>0.01). The result showed that the M-81-13 with 53.05 mΩ EC has the highest cell membrane stability and the lowest EC was obtaining from gaskoghen with 18.987 mΩ. Also M-79-7 with 2.315 mg chlorophyll a per 1 g leaf fresh weight has highest chlorophyll content. It was determining the ratio of maximal chlorophyll content after cold stress is reliable and a method to determine the frost hardness of wheat variety. The proline content of the leaf however increased in both growth stages in all variety of wheat. Gaskoghen with 0.340 (µg/0.5 g dwt) in 2 leaf growing stage had the highest rate of proline amino acid and Marvdasht variety from inter mediate type in 4 leaf growing stage with 0.003 (µg/0.5 g dwt) had the lowest rate of proline

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