Soyasaponins are major small molecules that accumulate in soybean(Glycine max)seeds.Among them,type-A soyasaponins,fully acetylated at the terminal sugar of their C22 sugar chain,are responsible for the bitter taste o...Soyasaponins are major small molecules that accumulate in soybean(Glycine max)seeds.Among them,type-A soyasaponins,fully acetylated at the terminal sugar of their C22 sugar chain,are responsible for the bitter taste of soybean-derived foods.However,the molecular basis for the acetylation of type-A soyasaponins remains unclear.Here,we identify and characterize Gm SSAc T1,encoding a BADH-type soyasaponin acetyltransferase that catalyzes three or four consecutive acetylations on type-A soyasaponins in vitro and in planta.Phylogenetic analysis and biochemical assays suggest that Gm SSAc T1 likely evolved from acyltransferases present in leguminous plants involved in isoflavonoid acylation.Loss-of-function mutants of Gm SSAc T1 exhibited impaired seed germination,which attribute to the excessive accumulation of null-acetylated type-A soyasaponins.We conclude that Gm SSAc T1 not only functions as a detoxification gene for high accumulation of type-A soyasaponins in soybean seeds but is also a promising target for breeding new soybean varieties with lower bitter soyasaponin content.展开更多
Horizontal gene transfer(HGT) refers to the flow of genetic materials to non-offspring,and occasionally HGT in plants can improve the adaptation of organisms in new niches due to expanded metabolic capability.Anthocya...Horizontal gene transfer(HGT) refers to the flow of genetic materials to non-offspring,and occasionally HGT in plants can improve the adaptation of organisms in new niches due to expanded metabolic capability.Anthocyanins are an important group of water-soluble red,purple,or blue secondary metabolites,whose diversity results from modification after the main skeleton biosynthesis.Cuscuta is a stem holoparasitic genus,whose members form direct connection with hosts to withdraw water,nutrients,and macromolecules.Such intimate association is thought to increase the frequency of HGT.By transcriptome screening for foreign genes in Cuscuta australis,we discovered that one gene encoding a putative anthocyanin acyltransferase gene of the BAHD family,which is likely to be involved in anthocyanin modification,was acquired by C.australis from Fabaceae through HGT.The anthocyanin acyltransferase-like(AT-like) gene was confirmed to be present in the genome assembly of C.australis and the transcriptomes of Cuscuta pentagona.The higher transcriptional level in old stems is consistent with its putative function in secondary metabolism by stabilizing anthocyanin at neutral pH and thus HGT of this AT-like gene may have improved biotic and abiotic resistance of Cuscuta.展开更多
Cutinized and suberized cell walls in plants constitute physiologically important environment interfaces. They act as barriers limiting the loss of water and nutrients and protecting against radiation and invasion of ...Cutinized and suberized cell walls in plants constitute physiologically important environment interfaces. They act as barriers limiting the loss of water and nutrients and protecting against radiation and invasion of pathogens. The roles of cutin- and suberin polyesters are often attributed to their dominant aliphatic components, but the contri- bution of aromatic composition to their physiological function remains unclear. By functionally screening a subset of Populus trichocarpa BAHD/HXXXD acyltransferases, we identified a hydroxycinnamoyltransferase that shows specific transacylation activity on ~0-hydroxyacids using both feruloyl- and p-coumaroyl- CoA as the acyl donors. We named this enzyme P. trichocarpa hydroxyacid/fatty alcohol hydroxycinnamoyltransferase 1 （PtFHT1）. The ectopic expression of the PtFHT1 gene in Arabidopsis increased the incorporation of ferulate in root and seed suberins and in leaf cutin, but not that of p-coumarate, while the aliphatic load in both suberin and cutin polyesters essentially remained unaffected. The overaccumulation of ferulate in lipophilic polyester significantly increased the tolerance of transgenic plants to salt stress treatment; under sub-lethal conditions of salt stress, the ratios of their seed germination and seedling establishment were 50% higher than those of wild-type plants. Our study suggests that, although aromatics are the minor component of polyesters, they play important role in the sealing function of lipidic polymers in planta.展开更多
基金financially supported by National Key Research and Development Projects (2021YFF1001200 and 2018YFA0900603)“Priority Research Program”of the Chinese Academy of Science (Grant No.ZDRW-ZS-2019-2)the State Key Laboratory of Plant Genomics of China (SKLPG2016A-13)to GW。
文摘Soyasaponins are major small molecules that accumulate in soybean(Glycine max)seeds.Among them,type-A soyasaponins,fully acetylated at the terminal sugar of their C22 sugar chain,are responsible for the bitter taste of soybean-derived foods.However,the molecular basis for the acetylation of type-A soyasaponins remains unclear.Here,we identify and characterize Gm SSAc T1,encoding a BADH-type soyasaponin acetyltransferase that catalyzes three or four consecutive acetylations on type-A soyasaponins in vitro and in planta.Phylogenetic analysis and biochemical assays suggest that Gm SSAc T1 likely evolved from acyltransferases present in leguminous plants involved in isoflavonoid acylation.Loss-of-function mutants of Gm SSAc T1 exhibited impaired seed germination,which attribute to the excessive accumulation of null-acetylated type-A soyasaponins.We conclude that Gm SSAc T1 not only functions as a detoxification gene for high accumulation of type-A soyasaponins in soybean seeds but is also a promising target for breeding new soybean varieties with lower bitter soyasaponin content.
基金Acknowledgments This work was supported by the National Natural Science Foundation of China （No. 31301037 and 31470012 to G.S.）, the Natural Science Foundation of Yunnan Province of China （No. 2013FB068 to G.S.）, the Young Academic and Technical Leader Raising Foundation of Yunnan Province （No. 2014HB046, to G.S.）, the Western Light Talent Culture Project of the Chinese Academy of Sciences （to G.S.）, and the Yunnan Recruitment Program of Experts in Sciences （2012HA016 to J.W.）.
文摘Horizontal gene transfer(HGT) refers to the flow of genetic materials to non-offspring,and occasionally HGT in plants can improve the adaptation of organisms in new niches due to expanded metabolic capability.Anthocyanins are an important group of water-soluble red,purple,or blue secondary metabolites,whose diversity results from modification after the main skeleton biosynthesis.Cuscuta is a stem holoparasitic genus,whose members form direct connection with hosts to withdraw water,nutrients,and macromolecules.Such intimate association is thought to increase the frequency of HGT.By transcriptome screening for foreign genes in Cuscuta australis,we discovered that one gene encoding a putative anthocyanin acyltransferase gene of the BAHD family,which is likely to be involved in anthocyanin modification,was acquired by C.australis from Fabaceae through HGT.The anthocyanin acyltransferase-like(AT-like) gene was confirmed to be present in the genome assembly of C.australis and the transcriptomes of Cuscuta pentagona.The higher transcriptional level in old stems is consistent with its putative function in secondary metabolism by stabilizing anthocyanin at neutral pH and thus HGT of this AT-like gene may have improved biotic and abiotic resistance of Cuscuta.
基金the Division of Chemical Sciences,Geosciences,and Biosciences,Office of Basic Energy Sciences of the US Department of Energy (DOE)，the transgenic Arabidopsis analyses were also partially supported by National Science Foundation，by the oversea collaborative project of National Science Foundation of China
文摘Cutinized and suberized cell walls in plants constitute physiologically important environment interfaces. They act as barriers limiting the loss of water and nutrients and protecting against radiation and invasion of pathogens. The roles of cutin- and suberin polyesters are often attributed to their dominant aliphatic components, but the contri- bution of aromatic composition to their physiological function remains unclear. By functionally screening a subset of Populus trichocarpa BAHD/HXXXD acyltransferases, we identified a hydroxycinnamoyltransferase that shows specific transacylation activity on ~0-hydroxyacids using both feruloyl- and p-coumaroyl- CoA as the acyl donors. We named this enzyme P. trichocarpa hydroxyacid/fatty alcohol hydroxycinnamoyltransferase 1 （PtFHT1）. The ectopic expression of the PtFHT1 gene in Arabidopsis increased the incorporation of ferulate in root and seed suberins and in leaf cutin, but not that of p-coumarate, while the aliphatic load in both suberin and cutin polyesters essentially remained unaffected. The overaccumulation of ferulate in lipophilic polyester significantly increased the tolerance of transgenic plants to salt stress treatment; under sub-lethal conditions of salt stress, the ratios of their seed germination and seedling establishment were 50% higher than those of wild-type plants. Our study suggests that, although aromatics are the minor component of polyesters, they play important role in the sealing function of lipidic polymers in planta.
