Different stress responsive strategies to drought and heat in two durum wheat cultivars with contrasting water use efficiency
1 Department of Biological and Environmental Sciences and Technologies, University of Salento, Prov.le Lecce Monteroni, I-73100 Lecce, Italy
2 Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Genomics Research Centre, via San Protaso 302, I-29107 Fiorenzuola d'Arda (PC), Italy
3 Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, CZ-370 05 České Budějovice, Czech Republic
4 Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Cereal Research Centre, SS16 km 675, 71122 Foggia, Italy
BMC Genomics 2013, 14:821 doi:10.1186/1471-2164-14-821Published: 22 November 2013
Durum wheat often faces water scarcity and high temperatures, two events that usually occur simultaneously in the fields. Here we report on the stress responsive strategy of two durum wheat cultivars, characterized by different water use efficiency, subjected to drought, heat and a combination of both stresses.
The cv Ofanto (lower water use efficiency) activated a large set of well-known drought-related genes after drought treatment, while Cappelli (higher water use efficiency) showed the constitutive expression of several genes induced by drought in Ofanto and a modulation of a limited number of genes in response to stress. At molecular level the two cvs differed for the activation of molecular messengers, genes involved in the regulation of chromatin condensation, nuclear speckles and stomatal closure. Noteworthy, the heat response in Cappelli involved also the up-regulation of genes belonging to fatty acid β-oxidation pathway, glyoxylate cycle and senescence, suggesting an early activation of senescence in this cv. A gene of unknown function having the greatest expression difference between the two cultivars was selected and used for expression QTL analysis, the corresponding QTL was mapped on chromosome 6B.
Ofanto and Cappelli are characterized by two opposite stress-responsive strategies. In Ofanto the combination of drought and heat stress led to an increased number of modulated genes, exceeding the simple cumulative effects of the two single stresses, whereas in Cappelli the same treatment triggered a number of differentially expressed genes lower than those altered in response to heat stress alone. This work provides clear evidences that the genetic system based on Cappelli and Ofanto represents an ideal tool for the genetic dissection of the molecular response to drought and other abiotic stresses.