Pumpkin is of great economic importance not only as food resources but also as the most widely used rootstock to graft cucurbit crops.Pumpkin rootstock improves salt tolerance of cucumber scion through respiratory bur...Pumpkin is of great economic importance not only as food resources but also as the most widely used rootstock to graft cucurbit crops.Pumpkin rootstock improves salt tolerance of cucumber scion through respiratory burst oxidase homolog protein D(CmRbohD)-mediated reactive oxygen species(ROS)burst,which further enhances Na^(+)export and K^(+)uptake.Rboh D activation requires calcium signaling.However,the underlying mechanism remains largely unknown.In this study,we discovered two Rboh D members from pumpkin involved in the ROS burst at the early stage of salt stress.CmRbohD1 and CmRbohD2 were functionally redundant and double mutation significantly impaired salt tolerance in pumpkin.Overexpression of CmRbohD1 and CmRbohD2 mitigated salinity-induced damage and maintained a relatively low Na+content and high K+content.We screened the potential calcineurin B-like interacting protein kinases(Cm CIPKs)which could bind with CmRbohD1 and CmRbohD2.Our results revealed that two Rboh Ds formed complexes specifically with CmCIPK1,thereby bursting ROS production.Overexpression of CmCIPK1 promoted the early ROS burst under salt stress condition and maintained a relatively balanced Na+/K+homeostasis.Altogether,we proposed a CmCIPK1-CmRbohD1/D2 complex for pumpkin salt stress signaling transduction,which regulates the ROS burst and Na+/K+homeostasis.Our findings offer unprecedented insights into the general mechanism of pumpkin salt tolerance.展开更多
Stimulus-specific accumulation of second messengers like reactive oxygen species （ROS） and Ca^＋ are central to many signaling and regulation processes in plants. However, mechanisms that govern the reciprocal inter...Stimulus-specific accumulation of second messengers like reactive oxygen species （ROS） and Ca^＋ are central to many signaling and regulation processes in plants. However, mechanisms that govern the reciprocal interrelation of Ca^＋ and ROS signaling are only beginning to emerge. NADPH oxidases of the respiratory burst oxidase homolog （RBOH） family are critical components contributing to the generation of ROS while Calcineurin B-like （CBL） Ca^＋ sensor proteins together with their interacting kinases （CIPKs） have been shown to function in many Ca^＋- signaling processes. In this study, we identify direct functional interactions between both signaling systems. We report that the CBL-interacting pro- tein kinase ClPK26 specifically interacts with the N-terminal domain of RBOHF in yeast two-hybrid analyses and with the full-length RBOHF protein in plant cells. In addition, CIPK26 phosphorylates RBOHF in vitro and co-expression of either CBL1 or CBL9 with CIPK26 strongly enhances ROS production by RBOHF in HEK293T cells. Together, these findings identify a direct interconnection between CBL-ClPK-mediated Ca^＋ signaling and ROS signaling in plants and provide evidence for a synergistic activation of the NADPH oxidase RBOHF by direct Ca^＋-binding to its EF-hands and Ca2＋-induced phospho-rylation by CBL1/9-ClPK26 complexes.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.32072653,32372794,31772357)Natural Science Foundation of Hubei Province(Grant No.2019CFA017)+1 种基金Ningbo Scientific and Technological Project(Grant No.2021Z006)the Fundamental Research Funds for the Central Universities(Grant No.2662023YLPY008)。
文摘Pumpkin is of great economic importance not only as food resources but also as the most widely used rootstock to graft cucurbit crops.Pumpkin rootstock improves salt tolerance of cucumber scion through respiratory burst oxidase homolog protein D(CmRbohD)-mediated reactive oxygen species(ROS)burst,which further enhances Na^(+)export and K^(+)uptake.Rboh D activation requires calcium signaling.However,the underlying mechanism remains largely unknown.In this study,we discovered two Rboh D members from pumpkin involved in the ROS burst at the early stage of salt stress.CmRbohD1 and CmRbohD2 were functionally redundant and double mutation significantly impaired salt tolerance in pumpkin.Overexpression of CmRbohD1 and CmRbohD2 mitigated salinity-induced damage and maintained a relatively low Na+content and high K+content.We screened the potential calcineurin B-like interacting protein kinases(Cm CIPKs)which could bind with CmRbohD1 and CmRbohD2.Our results revealed that two Rboh Ds formed complexes specifically with CmCIPK1,thereby bursting ROS production.Overexpression of CmCIPK1 promoted the early ROS burst under salt stress condition and maintained a relatively balanced Na+/K+homeostasis.Altogether,we proposed a CmCIPK1-CmRbohD1/D2 complex for pumpkin salt stress signaling transduction,which regulates the ROS burst and Na+/K+homeostasis.Our findings offer unprecedented insights into the general mechanism of pumpkin salt tolerance.
文摘Stimulus-specific accumulation of second messengers like reactive oxygen species （ROS） and Ca^＋ are central to many signaling and regulation processes in plants. However, mechanisms that govern the reciprocal interrelation of Ca^＋ and ROS signaling are only beginning to emerge. NADPH oxidases of the respiratory burst oxidase homolog （RBOH） family are critical components contributing to the generation of ROS while Calcineurin B-like （CBL） Ca^＋ sensor proteins together with their interacting kinases （CIPKs） have been shown to function in many Ca^＋- signaling processes. In this study, we identify direct functional interactions between both signaling systems. We report that the CBL-interacting pro- tein kinase ClPK26 specifically interacts with the N-terminal domain of RBOHF in yeast two-hybrid analyses and with the full-length RBOHF protein in plant cells. In addition, CIPK26 phosphorylates RBOHF in vitro and co-expression of either CBL1 or CBL9 with CIPK26 strongly enhances ROS production by RBOHF in HEK293T cells. Together, these findings identify a direct interconnection between CBL-ClPK-mediated Ca^＋ signaling and ROS signaling in plants and provide evidence for a synergistic activation of the NADPH oxidase RBOHF by direct Ca^＋-binding to its EF-hands and Ca2＋-induced phospho-rylation by CBL1/9-ClPK26 complexes.
