The plasma membrane aquaporin SlPIP2;11 alleviates the inhibition of photosynthesis in tomato under high VPD by refining stomatal morphology and enhancing antioxidant function

Abstract

Vapor pressure deficit (VPD), as a key environmental factor, at elevated levels can lead to restricted photosynthesis, reduced water use efficiency, and decreased plant productivity. Plasma membrane intrinsic proteins (PIPs) function as the core channels for transmembrane water transport in cells, thereby playing a critical regulatory role in phytophysiological adaptation mechanisms under environmental stressors. Consequently, conducting an in-depth analysis of the functional characteristics and regulatory systems of PIPs in response to high VPD stress is vital for elucidating the mechanisms of plant resistance to air dryness and improving crop stress tolerance. This study comprehensively utilized tomato (Solanum lycopersicum L.) genetic transformation technology and tobacco rattle virus (TRV)-mediated virus-induced gene silencing (VIGS) techniques to systematically elucidate the molecular mechanism by which SlPIP2;11 reacts to high VPD stress. The findings revealed that in high VPD environments, the SlPIP2;11 overexpression line optimizes root morphology, thereby enhancing soil water absorption and utilization efficiency and promoting plant growth. Meanwhile, this line improves antioxidant enzyme activity, enhances PSII reaction center activity, refines stomatal morphology, and optimizes water and gas exchange capacity, enabling plants to maintain a dynamic balance between water utilization and photosynthetic under high VPD stress. Thus, SlPIP2;11 effectively alleviates the inhibition of photosynthesis in tomato plants under high VPD stress though refining stomatal morphology and strengthening antioxidant functions. These results provide an important theoretical basis and experimental foundation for in-depth understanding of tomato responses to high VPD stress.