Caffeic acid-O-methyltransferase(COMT)is a crucial enzyme in the phenylpropanoid metabolic pathway,with significant roles in both the lignin and coumarin pathways.The function of COMT in plant disease resistance has b...Caffeic acid-O-methyltransferase(COMT)is a crucial enzyme in the phenylpropanoid metabolic pathway,with significant roles in both the lignin and coumarin pathways.The function of COMT in plant disease resistance has been demonstrated in several species.Our research identified the potato COMT gene family on a genome-wide scale and StCOMT1 as a candidate gene for enhancing potato disease resistance under DON induction through phylogenetic analyses combined with previously identified metabolic differences and weighted gene co-expression network analysis(WGCNA)results.In order to better understand the function of StCOMT1,heterologous expression and overexpression assays were conducted.StCOMT1 is localized in chloroplasts and was found to catalyze the methylation of substrates to produce ferulic acid and melatonin in vitro.Physiological parameters showed that,compared with wild-type potato plants,StCOMT1-overexpressing plants infected with Fusarium sporotrichioides exhibited smaller lesion areas and lower reactive oxygen species(ROS)levels.High-performance liquid chromatography(HPLC)and RT-qPCR analyses revealed organ-specific accumulation of coumarin-related compounds and organ-specific expression of their corresponding genes in StCOMT1-overexpressing plants post-inoculation.The results indicate that StCOMT1 overexpression in potatoes enhanced resistance to F.sporotrichioides by enhancing reactive oxygen species clearance and promoting organ-specific accumulation of coumarin-related compounds.展开更多
ASMT/coMT,as a key rate-limiting enzyme regulating melatonin biosynthesis,has garnered significant attention.This study investigates the evolutionary mechanisms of the ASMT/COMT gene family in melatonin biosynthesis.A...ASMT/coMT,as a key rate-limiting enzyme regulating melatonin biosynthesis,has garnered significant attention.This study investigates the evolutionary mechanisms of the ASMT/COMT gene family in melatonin biosynthesis.A total of 28010 ASMT/COMT genes from 1o52 species were identified through an integrated approach combining large-scale identifications and analyses.At the pan-genome level,we identified 5186,336,2137,and 1814ASMT/COMT genes respectively in Triticum aestivum,Aegilops tauschii,diploid and tetraploid Solanum tuberosum haplotype genomes(247,86,670,and 96 orthologous gene groups).Expansion patterns of the ASMT/cOMT gene family were explored through synteny networks in 104 Poaceae and 88Solanaceae plants.Further investigation of copy number variation(CNV)in the 1o52 species,along with a focused analysis of hexaploid wheat and its diploid progenitor Ae.tauschii,indicated a functional divergence linked to gene dosage.The catalytically efficient COMT is maintained at low-copy conditions,whereas the less active ASMT is amplified under highcopy conditions.Intriguingly,in polyploid potatoes,the total ASMT/cOMT copy number was lower in tetraploids than in diploids,suggesting a distinct dosage balance mechanism operating in polyploids.In contrast,the melatonin receptor CAND2consistently remained in a low-copy state,with no significant correlation to AsMT/COMT copy number.Expression analysis revealed that COMT is generally expressed at higher levels than ASMT,highlighting a compensatory relationship between gene dosage and transcriptional regulation.Collectively,our findings uncover a dosage balance mechanism that fine-tunes melatonin biosynthetic homeostasis through coordinated cNV and expression regulation,offering a new perspective on the evolution of metabolic enzymes.展开更多
Melatonin is a pleiotropic signaling molecule that regulates plant growth and responses to various abiotic stresses.The last step of melatonin synthesis in plants can be catalyzed by caffeic acid O-methyltransferase(C...Melatonin is a pleiotropic signaling molecule that regulates plant growth and responses to various abiotic stresses.The last step of melatonin synthesis in plants can be catalyzed by caffeic acid O-methyltransferase(COMT),a multifunctional enzyme reported to have N-acetylserotonin O-methyltransferase(ASMT)activity;however,the ASMT activity of COMT has not yet been characterized in nonmodel plants such as watermelon(Citrullus lanatus).Here,a total of 16 putative O-methyltransferase(ClOMT)genes were identified in watermelon.Among them,ClOMT03(Cla97C07G144540)was considered a potential COMT gene(renamed ClCOMT1)based on its high identities(60.00–74.93%)to known COMT genes involved in melatonin biosynthesis,expression in almost all tissues,and upregulation under abiotic stresses.The ClCOMT1 protein was localized in the cytoplasm.Overexpression of ClCOMT1 significantly increased melatonin contents,while ClCOMT1 knockout using the CRISPR/Cas-9 system decreased melatonin contents in watermelon calli.These results suggest that ClCOMT1 plays an essential role in melatonin biosynthesis in watermelon.In addition,ClCOMT1 expression in watermelon was upregulated by cold,drought,and salt stress,accompanied by increases in melatonin contents.Overexpression of ClCOMT1 enhanced transgenic Arabidopsis tolerance against such abiotic stresses,indicating that ClCOMT1 is a positive regulator of plant tolerance to abiotic stresses.展开更多
基金supported by the National Natural Science Foundation of China(U22A20443)the Heilongjiang Provincial Research Institutes Scientific Research Operating Expenses Project,China(CZKYF2023-1-B020)+1 种基金the Key Research and Development Plan Project of Heilongjiang Province,China(GA23B015)the Young Scientists Fund of the National Natural Science Foundation of China(32201717)。
摘要Caffeic acid-O-methyltransferase(COMT)is a crucial enzyme in the phenylpropanoid metabolic pathway,with significant roles in both the lignin and coumarin pathways.The function of COMT in plant disease resistance has been demonstrated in several species.Our research identified the potato COMT gene family on a genome-wide scale and StCOMT1 as a candidate gene for enhancing potato disease resistance under DON induction through phylogenetic analyses combined with previously identified metabolic differences and weighted gene co-expression network analysis(WGCNA)results.In order to better understand the function of StCOMT1,heterologous expression and overexpression assays were conducted.StCOMT1 is localized in chloroplasts and was found to catalyze the methylation of substrates to produce ferulic acid and melatonin in vitro.Physiological parameters showed that,compared with wild-type potato plants,StCOMT1-overexpressing plants infected with Fusarium sporotrichioides exhibited smaller lesion areas and lower reactive oxygen species(ROS)levels.High-performance liquid chromatography(HPLC)and RT-qPCR analyses revealed organ-specific accumulation of coumarin-related compounds and organ-specific expression of their corresponding genes in StCOMT1-overexpressing plants post-inoculation.The results indicate that StCOMT1 overexpression in potatoes enhanced resistance to F.sporotrichioides by enhancing reactive oxygen species clearance and promoting organ-specific accumulation of coumarin-related compounds.
基金supported by National Natural Science Foundation of China(no.32501846)Shandong Provincial Natural Science Foundation(no.ZR2023QC278)+1 种基金the Undergraduate Scientific Research Innovation Projects at Shandong University(no.202510422024)the Youth Student Fundamental Research Funds of Shandong University(no.SDUQM2523).
摘要ASMT/coMT,as a key rate-limiting enzyme regulating melatonin biosynthesis,has garnered significant attention.This study investigates the evolutionary mechanisms of the ASMT/COMT gene family in melatonin biosynthesis.A total of 28010 ASMT/COMT genes from 1o52 species were identified through an integrated approach combining large-scale identifications and analyses.At the pan-genome level,we identified 5186,336,2137,and 1814ASMT/COMT genes respectively in Triticum aestivum,Aegilops tauschii,diploid and tetraploid Solanum tuberosum haplotype genomes(247,86,670,and 96 orthologous gene groups).Expansion patterns of the ASMT/cOMT gene family were explored through synteny networks in 104 Poaceae and 88Solanaceae plants.Further investigation of copy number variation(CNV)in the 1o52 species,along with a focused analysis of hexaploid wheat and its diploid progenitor Ae.tauschii,indicated a functional divergence linked to gene dosage.The catalytically efficient COMT is maintained at low-copy conditions,whereas the less active ASMT is amplified under highcopy conditions.Intriguingly,in polyploid potatoes,the total ASMT/cOMT copy number was lower in tetraploids than in diploids,suggesting a distinct dosage balance mechanism operating in polyploids.In contrast,the melatonin receptor CAND2consistently remained in a low-copy state,with no significant correlation to AsMT/COMT copy number.Expression analysis revealed that COMT is generally expressed at higher levels than ASMT,highlighting a compensatory relationship between gene dosage and transcriptional regulation.Collectively,our findings uncover a dosage balance mechanism that fine-tunes melatonin biosynthetic homeostasis through coordinated cNV and expression regulation,offering a new perspective on the evolution of metabolic enzymes.
基金This study was supported by the National Key Research and Development Program of China(2018YFD1000800)the National Natural Science Foundation of China(31972479,31801884)+1 种基金the Earmarked Fund for Modern Agroindustry Technology Research System of China(CARS-25)the funding for Tang Scholar of Northwest A&F University.
摘要Melatonin is a pleiotropic signaling molecule that regulates plant growth and responses to various abiotic stresses.The last step of melatonin synthesis in plants can be catalyzed by caffeic acid O-methyltransferase(COMT),a multifunctional enzyme reported to have N-acetylserotonin O-methyltransferase(ASMT)activity;however,the ASMT activity of COMT has not yet been characterized in nonmodel plants such as watermelon(Citrullus lanatus).Here,a total of 16 putative O-methyltransferase(ClOMT)genes were identified in watermelon.Among them,ClOMT03(Cla97C07G144540)was considered a potential COMT gene(renamed ClCOMT1)based on its high identities(60.00–74.93%)to known COMT genes involved in melatonin biosynthesis,expression in almost all tissues,and upregulation under abiotic stresses.The ClCOMT1 protein was localized in the cytoplasm.Overexpression of ClCOMT1 significantly increased melatonin contents,while ClCOMT1 knockout using the CRISPR/Cas-9 system decreased melatonin contents in watermelon calli.These results suggest that ClCOMT1 plays an essential role in melatonin biosynthesis in watermelon.In addition,ClCOMT1 expression in watermelon was upregulated by cold,drought,and salt stress,accompanied by increases in melatonin contents.Overexpression of ClCOMT1 enhanced transgenic Arabidopsis tolerance against such abiotic stresses,indicating that ClCOMT1 is a positive regulator of plant tolerance to abiotic stresses.