The NAC transcription factor is a type of plant-specific transcription factor that can regulate plant salt tolerance,but the underlying mechanism is unclear in grafted vegetables.H2O2 and ABA in pumpkin rootstocks can...The NAC transcription factor is a type of plant-specific transcription factor that can regulate plant salt tolerance,but the underlying mechanism is unclear in grafted vegetables.H2O2 and ABA in pumpkin rootstocks can be transported to cucumber scion leaves,promoting stomatal closure to improve salt tolerance of grafted cucumbers.Despite these observations,the regulatory mechanism is unknown.Here,our research revealed that CmoNAC1 is a key transcription factor that regulates H_(2)O_(2) and ABA signaling in pumpkin roots under salt stress.The function of CmoNAC1 was analyzed using root transformation and RNA-seq,and we found that pumpkin CmoNAC1 promoted the production of H_(2)O_(2) and ABA via CmoRBOHD1 and CmoNCED6,respectively,and regulated K^(+)/Na^(+) homeostasis via CmoAKT1;2,CmoHKT1;1,and CmoSOS1 to improve salt tolerance of grafted cucumbers.Root knockout of CmoNAC1 resulted in a significant decrease in H_(2)O_(2)(52.9%and 32.1%)and ABA(21.8%and 42.7%)content and K^(+)/Na^(+) ratio(81.5%and 56.3%)in leaf and roots of grafted cucumber,respectively,while overexpression showed the opposite effect.The root transformation experiment showed that CmoNCED6 could improve salt tolerance of grafted cucumbers by regulating ABA production and K^(+)/Na^(+) homeostasis under salt stress.Finally,we found that CmoNAC1 bound to the promoters of CmoRBOHD1,CmoNCED6,CmoAKT1;2,and CmoHKT1;1 using yeast one-hybrid,luciferase,and electrophoretic mobility shift assays.In conclusion,pumpkin CmoNAC1 not only binds to the promoters of CmoRBOHD1 and CmoNCED6 to regulate the production of H_(2)O_(2) and ABA signals in roots,but also binds to the promoters of CmoAKT1;2 and CmoHKT1;1 to increase the K^(+)/Na^(+) ratio,thus improving salt tolerance of grafted cucumbers.展开更多
Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between fou...Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane(MPM)motifs in OsHKT1;5.HKT1;5 sequences from more recently evolved Oryza species(O.sativa/O.officinalis complex species)contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains,potentially governing transport characteristics,while more ancestral HKT1;5 sequences have shorter intracellular loops.We compared homology models for homoeologous OcHKT 1;5-K and OcHKT1;5-L from halophytic O.coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na+.Using haplotyping,we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species(O.nivara and O.rufipogon).Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance.Within Asian rice accessions,10 non-synonymous HKT1;5 haplotypic groups occur.More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica.Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups,corresponding to haplotypes in O.sativa salt-sensitive and salt-tolerant landraces,respectively.This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica,or from different haplotypes selected during domestication.Predominance of specific HKT1;5 haplotypes within the 3000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts.展开更多
The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe su...The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na^＋- and K^＋-permeable mutants function as ion channels rather than K^＋ transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na^＋-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap.展开更多
基金supported by grants from the National Natural Science Foundation of China(31772357,32072653)the Natural Science Foundation of Hubei Province(2019CFA017)+1 种基金the Fundamental Research Funds for the Central Universities(2662023YLPY008)the Ningbo Scientific and Technological Project(2021Z006).
文摘The NAC transcription factor is a type of plant-specific transcription factor that can regulate plant salt tolerance,but the underlying mechanism is unclear in grafted vegetables.H2O2 and ABA in pumpkin rootstocks can be transported to cucumber scion leaves,promoting stomatal closure to improve salt tolerance of grafted cucumbers.Despite these observations,the regulatory mechanism is unknown.Here,our research revealed that CmoNAC1 is a key transcription factor that regulates H_(2)O_(2) and ABA signaling in pumpkin roots under salt stress.The function of CmoNAC1 was analyzed using root transformation and RNA-seq,and we found that pumpkin CmoNAC1 promoted the production of H_(2)O_(2) and ABA via CmoRBOHD1 and CmoNCED6,respectively,and regulated K^(+)/Na^(+) homeostasis via CmoAKT1;2,CmoHKT1;1,and CmoSOS1 to improve salt tolerance of grafted cucumbers.Root knockout of CmoNAC1 resulted in a significant decrease in H_(2)O_(2)(52.9%and 32.1%)and ABA(21.8%and 42.7%)content and K^(+)/Na^(+) ratio(81.5%and 56.3%)in leaf and roots of grafted cucumber,respectively,while overexpression showed the opposite effect.The root transformation experiment showed that CmoNCED6 could improve salt tolerance of grafted cucumbers by regulating ABA production and K^(+)/Na^(+) homeostasis under salt stress.Finally,we found that CmoNAC1 bound to the promoters of CmoRBOHD1,CmoNCED6,CmoAKT1;2,and CmoHKT1;1 using yeast one-hybrid,luciferase,and electrophoretic mobility shift assays.In conclusion,pumpkin CmoNAC1 not only binds to the promoters of CmoRBOHD1 and CmoNCED6 to regulate the production of H_(2)O_(2) and ABA signals in roots,but also binds to the promoters of CmoAKT1;2 and CmoHKT1;1 to increase the K^(+)/Na^(+) ratio,thus improving salt tolerance of grafted cucumbers.
基金supported by the Department of Biotechnology,Government of India(Grant No.BT/PR11396/NDB/52/118/2008)and Council for Scientific and Industrial Research,India for Senior Research Fellowship(Grant No.09/656(0018)/2016-EMR-1)to Shalini PULIPATIfunding and support provided by JC Bose Fellowship(Grant No.SB/S2/JC-071/2015)from Science and Engineering Research Board,India and Bioinformatics Centre Grant funded by Department of Biotechnology,India(Grant No.BT/PR40187/BTIS/137/9/2021)。
文摘Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane(MPM)motifs in OsHKT1;5.HKT1;5 sequences from more recently evolved Oryza species(O.sativa/O.officinalis complex species)contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains,potentially governing transport characteristics,while more ancestral HKT1;5 sequences have shorter intracellular loops.We compared homology models for homoeologous OcHKT 1;5-K and OcHKT1;5-L from halophytic O.coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na+.Using haplotyping,we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species(O.nivara and O.rufipogon).Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance.Within Asian rice accessions,10 non-synonymous HKT1;5 haplotypic groups occur.More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica.Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups,corresponding to haplotypes in O.sativa salt-sensitive and salt-tolerant landraces,respectively.This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica,or from different haplotypes selected during domestication.Predominance of specific HKT1;5 haplotypes within the 3000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts.
文摘The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na^＋- and K^＋-permeable mutants function as ion channels rather than K^＋ transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na^＋-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap.
