Flavonoids are important bioactive components in Dendrobium officinale,a medicinal orchid.They are involved in many biological activities,including protecting plants against biotic and abiotic stresses.Research on the...Flavonoids are important bioactive components in Dendrobium officinale,a medicinal orchid.They are involved in many biological activities,including protecting plants against biotic and abiotic stresses.Research on the key genes related to flavonoid biosynthesis in D.officinale is limited.In this study,one of the key flavonoid biosynthesis genes,flavanone 3-hydroxylase(F3H),was characterized from D.officinale.The open reading frame of DoF3H was 1134 bp long and it encoded a 377-amino acid protein.The DoF3H protein showed considerably high homology with F3H proteins from other plant species and shared a common evolutionary ancestor with other F3Hs.DoF3H transcripts were detected in different organs of adult plants and mainly accumulated in flowers,followed by roots,stems and leaves,a pattern that was similar to the content of flavonoids.Recombinant DoF3H protein,which was localized in the cytosol,could convert naringenin to dihydrokaempferol.The mRNA levels of DoF3H were significantly induced by salt and cold stresses.Furthermore,the heterologous expression of DoF3H in Escherichia coli conferred it higher tolerance to salt and cold stresses.These results provide insight into the molecular function of DoF3H in the biosynthesis of flavonoids,and provide a new application for improvement of abiotic tolerance in D.officinale.展开更多
Coumarate 3-hydroxylase(C3h)genes participate in the synthesis of lignin and may affect the properties of wood that are important for its commercial value.A better understanding of the natural variation in C3h genes a...Coumarate 3-hydroxylase(C3h)genes participate in the synthesis of lignin and may affect the properties of wood that are important for its commercial value.A better understanding of the natural variation in C3h genes and their associations to wood properties is required to effectively improve wood quality.We used a candidate gene-based association mapping approach to identify CfC3h allelic variants associated with traits that affect the wood properties of Catalpa fargesii.We first isolated the full-length CfC3h cDNA(1825 bp),which was expressed at relatively high levels in xylem according to real time-polymerase chain reaction.In totally,17 common single-nucleotide polymorphisms(minor allele frequency>5%)were identified through cloning and sequencing the CfC3h locus from a mapping population(including 88 unrelated natural C.fargesii individuals collected from main distribution area).Nucleotide diversity and linkage disequilibrium(LD)in CfC3h indicate that CfC3h has low nucleotide diversity(π_(t)=0.0031 andθ_(w)=0.0103)and relatively low LD(within 1800 bp;r^(2)≥0.1).An association analysis identified eight common single-nucleotide polymorphisms(SNPs)(false discovery rate,Q<0.10)and ten haplotypes(Q<0.10)associated with wood properties,explaining 4.92-12.09%of the phenotypic variance in an association population consisted of 125 unrelated natural individuals(The 88 individuals from the mapping population were comprised in the association population).Our study would provide new insight into C3h gene affecting wood quality,and the SNP markers identified would have potential applications in marker-assisted breeding in the future.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31871547)。
文摘Flavonoids are important bioactive components in Dendrobium officinale,a medicinal orchid.They are involved in many biological activities,including protecting plants against biotic and abiotic stresses.Research on the key genes related to flavonoid biosynthesis in D.officinale is limited.In this study,one of the key flavonoid biosynthesis genes,flavanone 3-hydroxylase(F3H),was characterized from D.officinale.The open reading frame of DoF3H was 1134 bp long and it encoded a 377-amino acid protein.The DoF3H protein showed considerably high homology with F3H proteins from other plant species and shared a common evolutionary ancestor with other F3Hs.DoF3H transcripts were detected in different organs of adult plants and mainly accumulated in flowers,followed by roots,stems and leaves,a pattern that was similar to the content of flavonoids.Recombinant DoF3H protein,which was localized in the cytosol,could convert naringenin to dihydrokaempferol.The mRNA levels of DoF3H were significantly induced by salt and cold stresses.Furthermore,the heterologous expression of DoF3H in Escherichia coli conferred it higher tolerance to salt and cold stresses.These results provide insight into the molecular function of DoF3H in the biosynthesis of flavonoids,and provide a new application for improvement of abiotic tolerance in D.officinale.
基金This work was supported by the National Key Research and Development Program of China[No.2017YFD0600201]Forestry Industry Research Special Funds for Public Welfare Projects[No.201404101].
文摘Coumarate 3-hydroxylase(C3h)genes participate in the synthesis of lignin and may affect the properties of wood that are important for its commercial value.A better understanding of the natural variation in C3h genes and their associations to wood properties is required to effectively improve wood quality.We used a candidate gene-based association mapping approach to identify CfC3h allelic variants associated with traits that affect the wood properties of Catalpa fargesii.We first isolated the full-length CfC3h cDNA(1825 bp),which was expressed at relatively high levels in xylem according to real time-polymerase chain reaction.In totally,17 common single-nucleotide polymorphisms(minor allele frequency>5%)were identified through cloning and sequencing the CfC3h locus from a mapping population(including 88 unrelated natural C.fargesii individuals collected from main distribution area).Nucleotide diversity and linkage disequilibrium(LD)in CfC3h indicate that CfC3h has low nucleotide diversity(π_(t)=0.0031 andθ_(w)=0.0103)and relatively low LD(within 1800 bp;r^(2)≥0.1).An association analysis identified eight common single-nucleotide polymorphisms(SNPs)(false discovery rate,Q<0.10)and ten haplotypes(Q<0.10)associated with wood properties,explaining 4.92-12.09%of the phenotypic variance in an association population consisted of 125 unrelated natural individuals(The 88 individuals from the mapping population were comprised in the association population).Our study would provide new insight into C3h gene affecting wood quality,and the SNP markers identified would have potential applications in marker-assisted breeding in the future.