A plasma membrane aquaporin is potentially involved in moderating water stress and photosynthetic depression by sustaining water transport and CO2 uptake under high VPD stress conditions in Solanum lycopersicum (tomato)

Abstract

The molecular mechanism underlying the plant response to high vapor pressure deficit (VPD) stress remains unclear. In the present study, the roles of the plasma membrane aquaporin SlPIP1;2 in moderating plant water stress and photosynthetic depression in response to a series of VPD stress conditions are investigated. Plant water stress and photosynthetic depression are gradually exacerbated as VPD increases. The effects of SlPIP1;2 in mediating plant water status and photosynthesis are gradually enhanced as VPD increases. SlPIP1;2 exerts no significant effect on plant water status and photosynthesis under low VPD conditions. Overexpression of SlPIP1;2 moderates plant water stress by enhancing root water uptake under high VPD stress conditions, sustaining stomatal and mesophyll conductance for photosynthetic CO2 uptake and transport. Consequently, the relatively high CO2 availability inside chloroplasts in SlPIP1;2-overexpressing plants efficiently moderates photosynthetic depression under high VPD stress conditions. The present study demonstrates that SlPIP1;2 is potentially involved in moderating water stress and photosynthetic depression by sustaining water transport and CO2 uptake under high VPD stress conditions.