Resumen
Developing biomarkers and bio-indicators that will better indicate stress tolerance is crucial for plant breeding to increase crop resilience and productivity. However, complex interactions between water availability, light intensity, and temperature fluctuations make it difficult to develop standardised properties to monitor performance under field conditions. Sugar alcohols have been shown to function as stress metabolites, demonstrating considerable promise for use as bio-indicators of stress tolerance. This experiment monitored the accumulation of metabolites, including that of the sugar alcohol D-pinitol, in 3 chickpea genotypes grown under field conditions during reproductive stages of development. Further, compound specific carbon isotope abundance (δ13C) of these compounds was quantified to investigate the influence on predictions of water use efficiency. It was found that the magnitude of water deficit did not instigate significant responses in metabolite abundance, however, concentrations of D-pinitol increased significantly over reproductive stages, indicating the accumulation of this sugar alcohol may be under significant developmental control. Significant differences in the δ13C of D-pinitol compared to other metabolites indicate this compound imparts a substantial effect over concentration-weighted predictions of water use efficiency obtained from the soluble fraction of leaves, especially as its proportion in the soluble fraction increases with plant development.