Transcriptomic and proteomic analyses of a pale-green durum wheat mutant shows variations in photosystem components and metabolic deficiencies under drought stress
1 Agrotecnio Center, Av. Alcalde Rovira Roure 191, Lleida E-25198, Spain
2 Field Crops Program, IRTA (Institute for Food and Agricultural Research and Technology), Av. Alcalde Rovira Roure 191, Lleida E-25198, Spain
3 Consiglio per la ricerca e la sperimentazione in agricoltura – Genomics Research Centre, Via S. Protaso 302, Fiorenzuola d'Arda 29017, (PC), Italy
4 Department of Environmental and Biological Technologies and Sciences, University of Salento, Provinciale Lecce-Monteroni, Lecce 73100, Italy
5 Center for Genome Research, Biomedical Sciences Department, Biological Chemistry Section, University of Modena and Reggio Emilia, Via G. Campi 287, Modena 41125, Italy
BMC Genomics 2014, 15:125 doi:10.1186/1471-2164-15-125Published: 12 February 2014
Leaf pigment content is an important trait involved in environmental interactions. In order to determine its impact on drought tolerance in wheat, we characterized a pale-green durum wheat mutant (Triticum turgidum L. var. durum) under contrasting water availability conditions.
The pale-green mutant was investigated by comparing pigment content and gene/protein expression profiles to wild-type plants at anthesis. Under well-watered (control) conditions the mutant had lower levels of chlorophylls and carotenoids, but higher levels of xanthophyll de-epoxidation compared to wild-type. Transcriptomic analysis under control conditions showed that defense genes (encoding e.g. pathogenesis-related proteins, peroxidases and chitinases) were upregulated in the mutant, suggesting the presence of mild oxidative stress that was compensated without altering the net rate of photosynthesis. Transcriptomic analysis under terminal water stress conditions, revealed the modulation of antioxidant enzymes, photosystem components, and enzymes representing carbohydrate metabolism and the tricarboxylic acid cycle, indicating that the mutant was exposed to greater oxidative stress than the wild-type plants, but had a limited capacity to respond. We also compared the two genotypes under irrigated and rain-fed field conditions over three years, finding that the greater oxidative stress and corresponding molecular changes in the pale-green mutant were associated to a yield reduction.
This study provides insight on the effect of pigment content in the molecular response to drought. Identified genes differentially expressed under terminal water stress may be valuable for further studies addressing drought resistance in wheat.