Genomic clustering of non-homologous genes for the biosynthesis of plant defensive compounds is an emerging theme, but insights into their formation and physiological function remain limited. Here we report the identi...Genomic clustering of non-homologous genes for the biosynthesis of plant defensive compounds is an emerging theme, but insights into their formation and physiological function remain limited. Here we report the identification of a newly discovered hydroxycinnamoyl tyramine(HT) gene cluster in rice.This cluster contains a pyridoxamine 50-phosphate oxidase(Os PDX3) producing the cofactor pyridoxal50-phosphate(PLP), a PLP-dependent tyrosine decarboxylase(Os Ty DC1), and two duplicated hydroxycinnamoyl transferases(Os THT1 and Os THT2). These members were combined to represent an enzymological innovation gene cluster. Natural variation analysis showed that the abundance of the toxic tyramine intermediate of the gene cluster among different rice accessions is mainly determined by the coordinated transcription of Os Ty DC1 and Os THT1. Further pathogen incubation assays demonstrated that the end products of the HT gene cluster displayed enhanced resistance to the bacterial pathogen Xanthomonas oryzae pv. Oryzae(Xoo) and fungal pathogen Magnaporthe oryzae(M. oryzae), and the enhanced resistance is associated with the boost of phytoalexins and the activation of defense response. The unique presence of the HT gene cluster in Oryza AA genome, together with the enrichment of transposon elements within this gene cluster region, provides an evolutionary background to accelerate cluster member combinations. Our study not only discovered a gene cluster involved in the phenylpropanoid metabolism but also addressed the key aspects of gene cluster formation. In addition, our results provide a new metabolic pool for plant defense against pathogens.展开更多
Phenolamides(PAs), a diverse group of specialized metabolites, including hydroxycinnamoylputrescine(HP), hydroxycinnamoylagmatine, and hydroxycinnamoyltryptamine, are important in plant resistance to biotic stress. Ho...Phenolamides(PAs), a diverse group of specialized metabolites, including hydroxycinnamoylputrescine(HP), hydroxycinnamoylagmatine, and hydroxycinnamoyltryptamine, are important in plant resistance to biotic stress. However, the genes involved in the biosynthesis and modulation of PAs have not been fully elucidated. This study identified an HP biosynthetic gene cluster in rice(Oryza sativa) comprising one gene(Os ODC) encoding a decarboxylase and two tandem-duplicated genes(Os PHT3 and Os PHT4)encoding putrescine hydroxycinnamoyl acyltransferases coexpressed in different tissues. Os ODC catalyzes the conversion of ornithine to putrescine, which is used in HP biosynthesis involving Os PHT3 and Os PHT4. Os PHT3 or Os PHT4 overexpression causes HP accumulation and cell death and putrescine hydroxycinnamoyl acyltransferases(PHT) activity-dependent resistance against the fungal pathogen Magnaporthe oryzae. Os ODC overexpression plants also confer enhanced resistance to M. oryzae.Notably, the basic leucine zipper transcription factor APIP5, a negative regulator of cell death, directly binds to the Os PHT4 promoter, repressing its transcription. Moreover, APIP5 suppression induces Os PHT4 expression and HP accumulation. Comparative genomic analysis revealed that the HP biosynthetic gene cluster is conserved in monocots. These results characterized a previously unidentified monocot-specific gene cluster that is involved in HP biosynthesis and contributes to defense and cell death in rice.展开更多
Rice(Oryza sativa L)is one of the most important crops world-wide,providing much of the calorific needs for half of the global population[1].Due to the development of the global economy and the improvement of living s...Rice(Oryza sativa L)is one of the most important crops world-wide,providing much of the calorific needs for half of the global population[1].Due to the development of the global economy and the improvement of living standards,people's demand for rice has gradually changed from"being fll"to"eating well",with tasty and nutritious varieties being essential for the latter.In the past few decades,lots of studies have focused on improving the eating and cooking quality(ECQ)of rice to meet the demand for taste[2].Although metabolic engineering has been applied in rice biofortif-cation in recent years[3.4],efforts on improving comprehensive nutrition in rice remain fragmented[5-7].Thus,characterizing QTLs and genes underlying nutrient abundance will provide new guidance for breeding varieties with health benefits.展开更多
基金supported by the National Science Fund for Distinguished Young Scholars of China (31625021)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (31821005)+1 种基金the State Key Program of National Natural Science Foundation of China (31530052)the Hainan University Startup Fund (KYQD(ZR)1866)。
文摘Genomic clustering of non-homologous genes for the biosynthesis of plant defensive compounds is an emerging theme, but insights into their formation and physiological function remain limited. Here we report the identification of a newly discovered hydroxycinnamoyl tyramine(HT) gene cluster in rice.This cluster contains a pyridoxamine 50-phosphate oxidase(Os PDX3) producing the cofactor pyridoxal50-phosphate(PLP), a PLP-dependent tyrosine decarboxylase(Os Ty DC1), and two duplicated hydroxycinnamoyl transferases(Os THT1 and Os THT2). These members were combined to represent an enzymological innovation gene cluster. Natural variation analysis showed that the abundance of the toxic tyramine intermediate of the gene cluster among different rice accessions is mainly determined by the coordinated transcription of Os Ty DC1 and Os THT1. Further pathogen incubation assays demonstrated that the end products of the HT gene cluster displayed enhanced resistance to the bacterial pathogen Xanthomonas oryzae pv. Oryzae(Xoo) and fungal pathogen Magnaporthe oryzae(M. oryzae), and the enhanced resistance is associated with the boost of phytoalexins and the activation of defense response. The unique presence of the HT gene cluster in Oryza AA genome, together with the enrichment of transposon elements within this gene cluster region, provides an evolutionary background to accelerate cluster member combinations. Our study not only discovered a gene cluster involved in the phenylpropanoid metabolism but also addressed the key aspects of gene cluster formation. In addition, our results provide a new metabolic pool for plant defense against pathogens.
基金supported by grants from the National Natural Science Foundation of China (31822041 and 31972225)the National Key Research and Development Program of China (2016YFD0100600) to Yuese Ning+5 种基金the National Natural Science Foundation of China (U20A2021) to Ruyi Wangthe National Natural Science Foundation of China (31801692) to Fan Zhangthe State Key Program of National Natural Science Foundation of China (31530052)the National Science Fund for Distinguished Young Scholars (31625021)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (31821005)the Hainan University Start up Fund (KYQD(ZR)1866 to Jie Luo。
文摘Phenolamides(PAs), a diverse group of specialized metabolites, including hydroxycinnamoylputrescine(HP), hydroxycinnamoylagmatine, and hydroxycinnamoyltryptamine, are important in plant resistance to biotic stress. However, the genes involved in the biosynthesis and modulation of PAs have not been fully elucidated. This study identified an HP biosynthetic gene cluster in rice(Oryza sativa) comprising one gene(Os ODC) encoding a decarboxylase and two tandem-duplicated genes(Os PHT3 and Os PHT4)encoding putrescine hydroxycinnamoyl acyltransferases coexpressed in different tissues. Os ODC catalyzes the conversion of ornithine to putrescine, which is used in HP biosynthesis involving Os PHT3 and Os PHT4. Os PHT3 or Os PHT4 overexpression causes HP accumulation and cell death and putrescine hydroxycinnamoyl acyltransferases(PHT) activity-dependent resistance against the fungal pathogen Magnaporthe oryzae. Os ODC overexpression plants also confer enhanced resistance to M. oryzae.Notably, the basic leucine zipper transcription factor APIP5, a negative regulator of cell death, directly binds to the Os PHT4 promoter, repressing its transcription. Moreover, APIP5 suppression induces Os PHT4 expression and HP accumulation. Comparative genomic analysis revealed that the HP biosynthetic gene cluster is conserved in monocots. These results characterized a previously unidentified monocot-specific gene cluster that is involved in HP biosynthesis and contributes to defense and cell death in rice.
基金supported by the Key Research and Development Program of Hainan(ZDYF2020066)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(31821005)+2 种基金“111”Project(D20024)Hainan Academician Innovation Platform(HD-YSZX-202003 and HD-YSZX-202004)the Hainan University Startup Fund(KYQD(ZR)1866)。
文摘Rice(Oryza sativa L)is one of the most important crops world-wide,providing much of the calorific needs for half of the global population[1].Due to the development of the global economy and the improvement of living standards,people's demand for rice has gradually changed from"being fll"to"eating well",with tasty and nutritious varieties being essential for the latter.In the past few decades,lots of studies have focused on improving the eating and cooking quality(ECQ)of rice to meet the demand for taste[2].Although metabolic engineering has been applied in rice biofortif-cation in recent years[3.4],efforts on improving comprehensive nutrition in rice remain fragmented[5-7].Thus,characterizing QTLs and genes underlying nutrient abundance will provide new guidance for breeding varieties with health benefits.
