Molecular adaptation of barley to cold and drought conditions

Abstract

SummaryMolecular adaptation to cold and drought involves a series of biochemical and molecular changes leading plants to improve their winter hardiness or drought resistance.We are interested to study the molecular basis of cold acclimation and drought response of barley to survive under stress. Several genes regulated by low temperatures and sometimes by drought have been isolated from the barley genome. In this review the most significant results of our recent work will be presented and discussed.The protein encoded by eDNA clone pt59 and induced in barley by cold was over-expressed in E. coli to produce the matching antibody, which in vivo recognizes a cold-induced protein of 14 kDa (CORI4). The COR14 is stored in amounts only slightly greater in the cold resistant 'Onice' than in the susceptible 'Gitane', although the former has a higher induction-temperature threshold of COR14 than the latter. This fact is an evolutionary advantage enabling the resistant varieties in the field to prepare for the cold well ahead of the susceptible ones.Two other eDNA clones, paj93 and cdr29, are regulated by low temperature and drought stress but not by exogenous ABA treatment. Indeed during the early stage of dehydration, the mRNAs are expressed before the induction of known ABA regulated genes such as dehydrins and when only a small increase occurs in ABA content. The sequence analysis revealed that paj93 encodes for a protein homologous to the cold-regulated protein COR47 of Arabi do psis, whereas cdr29 represents a plant gene homologous to yeast and mammalian sequences coding for acyl-Coenzyme A oxidase.

Winter cold tolerance and the geographic range separation of Bromus tectorum and Bromus rubens, two severe invasive species in North America

“…Nonetheless, because the rate of frost hardening varies between species and acclimation stages, species with the same absolute tolerance limits might show different winter survival rates (Greer, 1983). Frost-resistant cultivars of wheat and barley, for instance, usually harden faster than frost-sensitive cultivars which results in variation in their rates of winter survival (Stanca et al, 1996;Saulescu & Braun, 2001). Different induction temperatures could also contribute to species differences (Fuchigami et al, 1971;Greer & Warrington, 1982;Stanca et al, 1996).…”

“…Frost-resistant cultivars of wheat and barley, for instance, usually harden faster than frost-sensitive cultivars which results in variation in their rates of winter survival (Stanca et al, 1996;Saulescu & Braun, 2001). Different induction temperatures could also contribute to species differences (Fuchigami et al, 1971;Greer & Warrington, 1982;Stanca et al, 1996). In frost-resistant cultivars of barley, for example, cold-induced proteins (COR14) have higher induction temperatures than those in frost-sensitive cultivars (Stanca et al, 1996).…”

The Enigmatic LEA Proteins and Other Hydrophilins

“…Consistent with the fact that the ABA-responsive element was first described for a group 2 LEA gene from rice (Oryza sativa; Mundy and Chua, 1988), there are genes for this group of proteins whose expression during seed development or in response to stress is mediated by ABA (Nylander et al, 2001). However, some others are not responsive to ABA or are regulated by ABA during development but not in response to stress (Stanca et al, 1996;Giordani et al, 1999). Moreover, there are examples of dual regulation; that is, their response to stress is mediated by more than one pathway, one of which may be ABA dependent (Welling et al, 2004).…”

The Arabidopsis RGA Gene Encodes a Transcriptional Regulator Repressing the Gibberellin Signal Transduction Pathway

“…domain of CDR29 that shares homology to RGA is not in the conserved acyl-CoA oxidase region. cdr29 expression is induced in barley in response to both dehydration and cold stress (Stanca et al, 1996). Because GA is important in modulating a plant's response to environmental stimuli, this homologous domain may interact with other factors during periods of environmental stress.…”