Physiological and Proteomic Responses of Sugarcane to Water Deficit Stress: Insights from a Self-Fertilized Clone

Abiotic stresses, particularly water deficit, are major constraints to global agricultural productivity. This study aimed to evaluate physiological and proteomic responses in two sugarcane genotypes, a cross-commercial cultivar and a self-fertilization clone, subjected to water deficit stress in the field. The experiment was conducted under rain-fed conditions. Organic solutes, photosynthetic pigments, gas exchange, and the quantum efficiency of photosystem II were evaluated. Total protein was extracted using the phenol method, and the peptides were analyzed using mass spectrometry. Elevated proline levels in clone RB061047 suggest a potentially enhanced adaptive response to water-deficit stress. There were no marked differences in the photosynthetic pigments between clone RB061047 and the commercial cultivar, RB867515. Self-fertilization did not negatively affect the physiological performance of RB061047 under water-deficit conditions because the higher photosynthetic rate and the consequent more efficient use of water suggest a marked gain in biomass and productivity. The ATP synthase alpha subunit YABB2 protein, fructose-bisphosphate aldolase, and nucleoside diphosphate kinase 1 emerged as potential candidates for the development of functional molecular markers for the selection and development of new sugarcane cultivars that are more tolerant to water-deficit stress.