Investigating the role of gibberellin signalling in the response to drought

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

Lack of water is one of the most important limitations to global crop productivity. An understanding of the mechanisms by which plants adapt to water deficit is an important first step to identifying suitable targets when breeding to minimise the detrimental effects on yield. Adaptive responses to drought include restriction of growth, which enhances stress tolerance. The gibberellin (GA) signalling pathway has been shown to be a major target for stress responses. A common response to stress is increased expression of GA 2-oxidase (GA2ox) genes, which encode GA-inactivating enzymes. We aim to utilise the extensive genetic, mutant and gene reporter resources we have established for Arabidopsis to define the mechanisms by which GAs mediate drought responses in this species. We will determine the effect of water deficit on expression levels of potential gene targets in the GA-biosynthetic and signal transduction pathways, including all GA2ox genes, and on the accumulation of DELLA proteins. We will use gene reporter lines to determine whether water stress alters the expression domains of GA-biosynthetic genes in specific tissues of roots and shoots. We will use inducible GA-inactivation and mutants with reduced or increased GA biosynthesis or response to determine how changes in GA-signalling alters drought tolerance and the specificity of this response in terms of downstream gene regulation. We will determine whether drought modifies GA signalling through the action of AP2-type transcription factors, as is the case for cold and salt stress. GA signalling could influence drought tolerance through its effect on plant morphology and/or by a more direct mechanism. We will investigate the mechanisms involved by determining the impact of GA signalling on the profile of drought-induced gene expression. We will also compare the drought tolerance of GA-deficient plants with those in which growth is blocked down-stream of DELLA proteins or by independent pathways.

unavailable