ABA: A two –edged sword in crop production?

A Kingston-Smith, LAJ Mur & H Ougham

Maintaining food security during a period of significant climatic change is an increasingly important target for agriculture. This project concentrates on understanding how multiple stress effects which are the consequence of environmental change interact with the crop genome to affect food quality and yield in three important areas for which control of cell death is a critical factor: susceptibility to pathogens, the onset and progression of leaf senescence and the biotransformation of plant protein by ruminants. It has been suggested that ABA integrates biotic and abiotic stress-response signalling networks. This project seeks to test the hypothesis that environmental stress linked ABA accumulation impacts on induced plant cell death and remobilisation mechanisms relevant to crop yield and quality.

Project outline: The work will use information obtained in Arabidopsis to increase our understanding of ABA effects in perennial ryegrass (Lolium perenne; a major UK and European forage crop) with a view to exploiting the information generated in novel, elite germplasm. First, the effect of exogenous ABA application to perennial ryegrass will be demonstrated in terms of susceptibility to infection by mildew (Blumeria graminis; a major UK-relevant pathogen), onset and progression of senescence, and onset and progression of autolytic breakdown of protein and DNA in simulated rumen conditions. Subsequently the mechanism behind effects observed in ryegrass will be explored in experiments using Arabidopsis mutants which are perturbed in ABA biosynthesis or associated signalling. Lolium germplasm available at Aberystwyth with characterised differential tolerances to abiotic stresses will be used to test the functional significance of endogenous ABA concentrations on induced cell death.