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
Secondary salinization is a major environmental factor that causes a stress response and growth inhibition in plants in protected agriculture.The positive effect of a low red to far-red light ratio(R:FR)in salt tolera...Secondary salinization is a major environmental factor that causes a stress response and growth inhibition in plants in protected agriculture.The positive effect of a low red to far-red light ratio(R:FR)in salt tolerance through antioxidant defense has been reported,while the underlying model remains obscure.In this study,we used physiological and genetic approaches to investigate the relationship between H_(2)O_(2) signaling and low R:FR-induced salt tolerance and antioxidant capacity in tomato seedlings.This study found that low R:FR treatment with calcium nitrate stress(SL treatment)enhanced the growth of plants and increased the net photosynthetic rate 5 days after stress compared with a higher R:FR ratio and calcium nitrate stress(S treatment).With transcriptomic analysis of tomato leaves at 5 d,compared with CK,most of glutaredoxin genes and antioxidant enzymes were upregulated by S treatment,which were upregulated further by SL treatment.Compared to the S treatment,within 5 days,the H_(2)O_(2) level was increased faster before 24 h and it was slowed down after 24 h by SL treatment,with less H_(2)O_(2) accumulation at 5 d than that of S treatment.The enhancement of gene expression of RBOH genes were also shown at 24 h under SL.It was found that stomatal conductance followed the dynamic change of H_(2)O_(2),with a rapid closure of stomata of a decrease at 3 h and an increase after 9 h in SL treatment compared to S treatment,respectively.There was same trend of stomata opening degrees of tomato leaves observed by optical microscope.However,the inhibitor of H_(2)O_(2) production(DPI pretreatment)weakened the positive effect of low R:FR on the regulation of stomatal movement.In addition,SL treatment increased the antioxidant enzyme activities and proline content and decreased the MDA content as compared to the S treatment,while the enhancement of ROS homeostasis was reduced by the DPI pretreatment.In conclusion,low R:FR improved redox homeostasis and stomatal status under calcium nitrate stress through H_(2)O_(2)signaling,improving the adaptation of tomato seedlings to soil salinization stress.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
Global warming poses a serious threat to crops.Calcium-dependent protein kinases(CDPKs)/CPKs play vital roles in plant stress responses,but their exact roles in plant thermotolerance remains elusive.Here,we explored t...Global warming poses a serious threat to crops.Calcium-dependent protein kinases(CDPKs)/CPKs play vital roles in plant stress responses,but their exact roles in plant thermotolerance remains elusive.Here,we explored the roles of heat-induced ZmCDPK7 in thermotolerance in maize.ZmCDPK7-overexpressing maize plants displayed higher thermotolerance,photosynthetic rates,and antioxidant enzyme activity but lower H2 O2 and malondialdehyde(MDA)contents than wild-type plants under heat stress.ZmCDPK7-knockdown plants displayed the opposite patterns.ZmCDPK7 is attached to the plasma membrane but can translocate to the cytosol under heat stress.ZmCDPK7 interacts with the small heat shock protein sHSP17.4,phosphorylates sHSP17.4 at Ser-44 and the respiratory burst oxidase homolog RBOHB at Ser-99,and up regulates their expression.Site-directed mutagenesis of sHSP17.4 to generate a Ser-44-Ala substitution reduced ZmCDPK7’s enhancement of catalase activity but enhanced ZmCDPK7’s suppression of MDA accumulation in heat-stressed maize protoplasts.sHSP17.4,ZmCDPK7,and RBOHB were less strongly upregulated in response to heat stress in the abscisic acid-deficient mutant vp5 versus the wild type.Pretreatment with an RBOH inhibitor suppressed sHSP17.4 and ZmCDPK7 expression.Therefore,abscisic acid-induced ZmCDPK7 functions both upstream and downstream of RBOH and participates in thermotolerance in maize by mediating the phosphorylation of sHSP17.4,which might be essential for its chaperone function.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.
基金support from the Study on Vegetable Science of Farmland System in Qinghai-Tibet Plateau(Grant No.2019QZKK0303)funded by the Sichuan International Science and Technology Innovation Cooperation/Hong Kong Macao Taiwan Science and Technology Innovation Cooperation Project(Grant No.2022YFH0071)。
文摘Secondary salinization is a major environmental factor that causes a stress response and growth inhibition in plants in protected agriculture.The positive effect of a low red to far-red light ratio(R:FR)in salt tolerance through antioxidant defense has been reported,while the underlying model remains obscure.In this study,we used physiological and genetic approaches to investigate the relationship between H_(2)O_(2) signaling and low R:FR-induced salt tolerance and antioxidant capacity in tomato seedlings.This study found that low R:FR treatment with calcium nitrate stress(SL treatment)enhanced the growth of plants and increased the net photosynthetic rate 5 days after stress compared with a higher R:FR ratio and calcium nitrate stress(S treatment).With transcriptomic analysis of tomato leaves at 5 d,compared with CK,most of glutaredoxin genes and antioxidant enzymes were upregulated by S treatment,which were upregulated further by SL treatment.Compared to the S treatment,within 5 days,the H_(2)O_(2) level was increased faster before 24 h and it was slowed down after 24 h by SL treatment,with less H_(2)O_(2) accumulation at 5 d than that of S treatment.The enhancement of gene expression of RBOH genes were also shown at 24 h under SL.It was found that stomatal conductance followed the dynamic change of H_(2)O_(2),with a rapid closure of stomata of a decrease at 3 h and an increase after 9 h in SL treatment compared to S treatment,respectively.There was same trend of stomata opening degrees of tomato leaves observed by optical microscope.However,the inhibitor of H_(2)O_(2) production(DPI pretreatment)weakened the positive effect of low R:FR on the regulation of stomatal movement.In addition,SL treatment increased the antioxidant enzyme activities and proline content and decreased the MDA content as compared to the S treatment,while the enhancement of ROS homeostasis was reduced by the DPI pretreatment.In conclusion,low R:FR improved redox homeostasis and stomatal status under calcium nitrate stress through H_(2)O_(2)signaling,improving the adaptation of tomato seedlings to soil salinization stress.
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.
基金supported by the National Natural Science Foundation of Henan Joint Fund(U1604101 to XLH)the Key R&D and Promotion Projects of Henan Province(192102110009 to XLH,192102110004 to HY)。
文摘Global warming poses a serious threat to crops.Calcium-dependent protein kinases(CDPKs)/CPKs play vital roles in plant stress responses,but their exact roles in plant thermotolerance remains elusive.Here,we explored the roles of heat-induced ZmCDPK7 in thermotolerance in maize.ZmCDPK7-overexpressing maize plants displayed higher thermotolerance,photosynthetic rates,and antioxidant enzyme activity but lower H2 O2 and malondialdehyde(MDA)contents than wild-type plants under heat stress.ZmCDPK7-knockdown plants displayed the opposite patterns.ZmCDPK7 is attached to the plasma membrane but can translocate to the cytosol under heat stress.ZmCDPK7 interacts with the small heat shock protein sHSP17.4,phosphorylates sHSP17.4 at Ser-44 and the respiratory burst oxidase homolog RBOHB at Ser-99,and up regulates their expression.Site-directed mutagenesis of sHSP17.4 to generate a Ser-44-Ala substitution reduced ZmCDPK7’s enhancement of catalase activity but enhanced ZmCDPK7’s suppression of MDA accumulation in heat-stressed maize protoplasts.sHSP17.4,ZmCDPK7,and RBOHB were less strongly upregulated in response to heat stress in the abscisic acid-deficient mutant vp5 versus the wild type.Pretreatment with an RBOH inhibitor suppressed sHSP17.4 and ZmCDPK7 expression.Therefore,abscisic acid-induced ZmCDPK7 functions both upstream and downstream of RBOH and participates in thermotolerance in maize by mediating the phosphorylation of sHSP17.4,which might be essential for its chaperone function.
