The molecular composition and evolution of the chalcone synthase (CHS) gene family from five species in Camellia (Theaceae) are explored in this study. Sixteen CHS exon 2 from four Camellia species were amplified from...The molecular composition and evolution of the chalcone synthase (CHS) gene family from five species in Camellia (Theaceae) are explored in this study. Sixteen CHS exon 2 from four Camellia species were amplified from total DNA by PCR method. Three sequences of the fifth species in Camellia and two sequences of Glycine max as the designated outgroups were obtained from GenBank. Our results indicated that CHS gene family in Camellia was differentiated to three subfamilies (A, B, C) during the evolutionary history with six groups (A1, A2, A3, BI, B2, C). Among them, only group A2 was possessed by all five species in this study. However, the other five groups were detected only in some species of the plants studied. All members of CHS gene family in this study had high sequence similarity, more than 90% among the members in the same subfamily and more than 78% among different subfamilies at nucleotide level., According to the estimated components of amino acids, the function of CHS genes in Camellia had been diverged. The nucleotide substitutions of the different groups were not identical. Based on phylogenetic analyse inferred from sequences of CHS genes and their deduced amino acid sequences, we concluded that the CHS genes with new function in this genus were evolved either by mutations on several important sites or by accumulation of the mutations after the gene duplication. A further analysis showed that the diversification of CHS genes in Camellia still occurred recently, and the evolutionary models were different to some extant among different species. So we assumed that the different evolutionary models resulted from the impacts of variable environmental elements after the events of speciation.展开更多
In the flavonoid biosynthesis pathway, Chalcone synthase (CHS) is involved in the formation of the pigment and has been shown to be a rate-limiting enzyme for the synthesis of flavonoids. In this study, a PCR approach...In the flavonoid biosynthesis pathway, Chalcone synthase (CHS) is involved in the formation of the pigment and has been shown to be a rate-limiting enzyme for the synthesis of flavonoids. In this study, a PCR approach was used to clone a Chalcone synthases cDNA from flower of sweet osmanthus “Chenghong Dangui” and it was designated as OfCHS (O. fragrans, CHS). The cDNA was 1383 bp long and a coding sequence (CDS) of 1173 bp encoding a polypeptide of 391 amino acids with an estimated molecular mass of 39.9 kDa. The theoretical isoelectric point was 6.23. Phylogenetic analysis demonstrated that OfCHS clustered with Olea europaea, Solenostemon scutellarioides, Perilla frutescens, Antirrhinum majus and Digitalis lanata. We also detected the expression of OfCHS in different tissues in “Dangui” and in two cultivars with varied coloration, “Zi Yingui” and “Chenghong Dangui” at different floral stages using quantitative real-time PCR. We observed that OfCHS transcript was higher in leaves than in petals in “Dangui”. The transcripts of OfCHS in “Zi Yingui” petals were higher than those in “Dangui” at three stages especially at xianyan stage and there was no significant difference between the two cultivars in the full flowering stage. “Chenghong Dangui” has a relatively high anthocyanin content compared to “Zi Yingui”. The relative amount of anthocyanin of “Chenghong Dangui” initially increases, and then decreases during the bloom period. However, the expression of CHS is the highest at the initial flowering stage. These data suggest that the OfCHS does not play a key role in the accumulation of total flavonoid in this cultivar. These data could contribute to explain the different accumulation of flavonoids in petals of the two cultivars.展开更多
Chalcone synthases （CHS, EC 2.3.1.74） are key enzymes that catalyze the first committed step in flavonoid biosynthesis. In this study, we isolated a chalcone synthase, named NtCHS6, from Nicotiana tabacum. This synt...Chalcone synthases （CHS, EC 2.3.1.74） are key enzymes that catalyze the first committed step in flavonoid biosynthesis. In this study, we isolated a chalcone synthase, named NtCHS6, from Nicotiana tabacum. This synthase shared high homology with the NSCHSL （Y14507） gene and contained most of the conserved active sites that are in CHS proteins. The phylogenetic analysis suggested that NtCHS6 protein shared a large genetic distance with other Solanaceae CHS proteins and was the most closely-related to an uncharacterized CHS from Solanum lycopersicum. The expression analysis indicated that NtCHS6 was abundantly expressed in leaves, especially in mature leaves. By scrutinizing its upstream promoter sequences, multiple cis-regulatory elements involved in light and drought responsive were detected. Furthermore, NtCHS6 expression decreased significantly under dark treatment and increased significantly under drought stress suggested that NtCHS6 expression exhibited both light responsiveness and drought responsiveness, and important roles in ultraviolet protection and drought tolerance. Our results might play展开更多
文摘The molecular composition and evolution of the chalcone synthase (CHS) gene family from five species in Camellia (Theaceae) are explored in this study. Sixteen CHS exon 2 from four Camellia species were amplified from total DNA by PCR method. Three sequences of the fifth species in Camellia and two sequences of Glycine max as the designated outgroups were obtained from GenBank. Our results indicated that CHS gene family in Camellia was differentiated to three subfamilies (A, B, C) during the evolutionary history with six groups (A1, A2, A3, BI, B2, C). Among them, only group A2 was possessed by all five species in this study. However, the other five groups were detected only in some species of the plants studied. All members of CHS gene family in this study had high sequence similarity, more than 90% among the members in the same subfamily and more than 78% among different subfamilies at nucleotide level., According to the estimated components of amino acids, the function of CHS genes in Camellia had been diverged. The nucleotide substitutions of the different groups were not identical. Based on phylogenetic analyse inferred from sequences of CHS genes and their deduced amino acid sequences, we concluded that the CHS genes with new function in this genus were evolved either by mutations on several important sites or by accumulation of the mutations after the gene duplication. A further analysis showed that the diversification of CHS genes in Camellia still occurred recently, and the evolutionary models were different to some extant among different species. So we assumed that the different evolutionary models resulted from the impacts of variable environmental elements after the events of speciation.
文摘In the flavonoid biosynthesis pathway, Chalcone synthase (CHS) is involved in the formation of the pigment and has been shown to be a rate-limiting enzyme for the synthesis of flavonoids. In this study, a PCR approach was used to clone a Chalcone synthases cDNA from flower of sweet osmanthus “Chenghong Dangui” and it was designated as OfCHS (O. fragrans, CHS). The cDNA was 1383 bp long and a coding sequence (CDS) of 1173 bp encoding a polypeptide of 391 amino acids with an estimated molecular mass of 39.9 kDa. The theoretical isoelectric point was 6.23. Phylogenetic analysis demonstrated that OfCHS clustered with Olea europaea, Solenostemon scutellarioides, Perilla frutescens, Antirrhinum majus and Digitalis lanata. We also detected the expression of OfCHS in different tissues in “Dangui” and in two cultivars with varied coloration, “Zi Yingui” and “Chenghong Dangui” at different floral stages using quantitative real-time PCR. We observed that OfCHS transcript was higher in leaves than in petals in “Dangui”. The transcripts of OfCHS in “Zi Yingui” petals were higher than those in “Dangui” at three stages especially at xianyan stage and there was no significant difference between the two cultivars in the full flowering stage. “Chenghong Dangui” has a relatively high anthocyanin content compared to “Zi Yingui”. The relative amount of anthocyanin of “Chenghong Dangui” initially increases, and then decreases during the bloom period. However, the expression of CHS is the highest at the initial flowering stage. These data suggest that the OfCHS does not play a key role in the accumulation of total flavonoid in this cultivar. These data could contribute to explain the different accumulation of flavonoids in petals of the two cultivars.
基金supported by the Agricultural Science and Technology Innovation Program, China (ASTIP-TRIC01)
文摘Chalcone synthases （CHS, EC 2.3.1.74） are key enzymes that catalyze the first committed step in flavonoid biosynthesis. In this study, we isolated a chalcone synthase, named NtCHS6, from Nicotiana tabacum. This synthase shared high homology with the NSCHSL （Y14507） gene and contained most of the conserved active sites that are in CHS proteins. The phylogenetic analysis suggested that NtCHS6 protein shared a large genetic distance with other Solanaceae CHS proteins and was the most closely-related to an uncharacterized CHS from Solanum lycopersicum. The expression analysis indicated that NtCHS6 was abundantly expressed in leaves, especially in mature leaves. By scrutinizing its upstream promoter sequences, multiple cis-regulatory elements involved in light and drought responsive were detected. Furthermore, NtCHS6 expression decreased significantly under dark treatment and increased significantly under drought stress suggested that NtCHS6 expression exhibited both light responsiveness and drought responsiveness, and important roles in ultraviolet protection and drought tolerance. Our results might play
