Scaffold protein RhCASPL1D1 stabilizes RhPIP2 aquaporins and promotes flower recovery after dehydration in rose (Rosa hybrida)

Water deficit during flowering can lead to petal wilting, necrosis, and sterility, severely limiting crop fertilization and yield. Therefore, rapid recovery of floral organs after dehydration is essential for angiosperms to achieve their full reproductive potential. Aquaporins (AQPs) are bidirectional membrane channels mediating water transmembrane transport. Plasma membrane intrinsic proteins (PIPs), one of AQP subfamily, play a key role in flower opening and dehydration responses. However, it still needs to be elucidated how PIPs are involved in flower recovery after stress. Cut rose (Rosa hybrida), a globally important ornamental flower, undergoes dehydration and rehydration during the postharvest process. Here, we show that the scaffold protein-encoding gene CASP-LIKE PROTEIN 1D1 (RhCASPL1D1), expressed during flower opening and dehydration, promotes flower recovery after dehydration. Silencing RhCASPL1D1 in rose petals and calli hindered cell recovery following dehydration and reduced the rate of water uptake, whereas RhCASPL1D1 overexpression had the opposite effect. Ethylene upregulated RhCASPL1D1 expression, and RhCASPL1D1 physically interacted with RhPIP2s at the plasma membrane. This interaction facilitated RhPIP2s retention to delay its degradation at the plasma membrane and enhanced proteins abundance under dehydration stress. Taken together, our findings reveal a potential mechanism involved in RhCASPL1D1 scaffold regulating flower recovery after dehydration stress.