Comparative proteomic analysis of leaves, leaf sheaths, and roots of drought-contrasting sugarcane cultivars in response to drought stress

A better understanding of drought response proteins may improve our understanding of the mechanisms underlying drought tolerance in sugarcane. In this research, drought-tolerant (K86-161) and drought-sensitive (B34-164) sugarcane cultivars were grown and exposed to drought stress. The changes in protein expression in leafs, leaf sheaths and roots were analyzed using proteomics techniques. Proteins that responded to drought in both cultivars could be classified into four major categories, including energy and metabolism, photosynthesis, antioxidant, and defense protein. Interestingly, an increased abundance of fructose-bisphosphate aldolase under drought was observed in all three organs of K86-161. Elevated expression of oxygen-evolving enhancer protein was also found in leaves and leaf sheaths of K86-161, when compared with their controls. Additionally, SOD was abundant in the leaves and roots of K86-161. Importantly, the expression level of these proteins decreased in B34-164 under drought stress. These contrasting results suggest that these proteins were inhibited by drought stress in the drought-sensitive cultivar. This proteomic research is the first to combine analyses of leaves, leaf sheaths and roots in sugarcane, which may enhance our understanding of drought responses at the molecular level and lead to selective breeding for enhanced drought tolerance.