The objective was to probe the site where the biosynthesis of chlorophyll was blocked under Mo deficiency at low temperature, which led to the decrease of chlorophyll in winter wheat cultivars. The intermediates of ch...The objective was to probe the site where the biosynthesis of chlorophyll was blocked under Mo deficiency at low temperature, which led to the decrease of chlorophyll in winter wheat cultivars. The intermediates of chlorophyll biosynthesis were analyzed in winter wheat cultivars in soil culture, miniblock culture, and solution culture to study the effects of Mo on chlorophyll biosynthesis without Mo addition （CK, soil available Mo 0.112 mg kg^-1） and Mo addition （＋ Mo, 0.13 mg kg^-1 Mo was added）. Laevulinic acid （LA）, the competitive analog of δ-aminolaevulinic acid （ALA） was also introduced in the experiment. The ratio of Chl a/Chl b was constant between CK and ＋ Mo treatment, whereas it increased at low temperature, which indicated that Mo deficiency did not inhibit the transformation of Chl a to Chl b at low temperature. Under Mo deficiency, the contents of protochlorophyll （Pchl）, Mg-protoporphyrin Ⅸ （Mg-Proto Ⅸ）, protoporphyrin Ⅸ （proto IX）, and uroporphyrinogen Ⅲ （Uro Ⅲ） decreased [Uro Ⅲ decreased significantly （P 〈0.01）], whereas ALA and glutamate increased significantly （P 〈 0.01） compared with that of Mo addition, which suggested that the transformation from ALA to Uro Ⅲ might be inhibited. The content of ALA reversed after addition of LA, it was significantly higher （P 〈 0.01） in Mo addition than in CK. The results indicated that the transformation from ALA to Uro Ⅲ was blocked under Mo deficiency, which resulted in the inhibition of the biosynthesis of chlorophyll and led to the decrease of chlorophyll in winter wheat cultivars.展开更多
UroporphyrinogenⅢsynthetase(UROS)is an important enzyme involved in the structural formation of porphyrin,which is responsible for color intensity.A UROS homolog was isolated and characterized from the pearl mussel,H...UroporphyrinogenⅢsynthetase(UROS)is an important enzyme involved in the structural formation of porphyrin,which is responsible for color intensity.A UROS homolog was isolated and characterized from the pearl mussel,Hyriopsis cumingii(HcUros).The HcUros cDNA was 858 bp in length with an open reading frame that encoded a 285 amino acid protein,which contained a conserved HemD domain.HcUros exhibited widespread tissue distribution,displaying particular enrichment in the mantle and haemolymph of purple mussels,compared to white mussels.In situ hybridization of HcUros in mantle tissue demonstrated that it was specifically expressed in the dorsal epithelial cells of the mantle pallia.Additionally,HcUros expression was upregulated following implantation of the pearl sac to produce pearls.The data suggest that HcUros contributes to shell pigmentation,and nacre formation and coloring in H.cumingii.展开更多
Bacterial wilt caused by the soil-borne plant pathogen Ralstonia solanacearum is a devastating disease worldwide.Upon plant colonization,R.solanacearum replicates massively,causing plant wilting and death;collapsed in...Bacterial wilt caused by the soil-borne plant pathogen Ralstonia solanacearum is a devastating disease worldwide.Upon plant colonization,R.solanacearum replicates massively,causing plant wilting and death;collapsed infected tissues then serve as a source of inoculum.In this work,we show that the plant metabolic pathway mediated by pyruvate decarboxylases(PDCs)contributes to plant tolerance to bacterial wilt disease.Arabidopsis and tomato plants resp ond to R.solanacearum infection by in creasing PDC activity,and plants with deficient PDC activity are more susceptible to bacterial wilt.Treatment with either pyruvic acid or acetic acid(substrate and product of the PDC pathway,respectively)enhances plant tolerance to bacterial wilt disease.An effector protein secreted by R.solanacearum,RipAK,interacts with PDCs and inhibits their oligomerization and enzymatic activity.Collectively,our work reveals a metabolic pathway involved in plant resistance to biotic and abiotic stresses,and a bacterial virulence strategy to promote disease and the completion of the pathogenic life cycle.展开更多
基金This study was financed by National Natural Science Foundation of China(NSFC,30070431 and 39770428)the Key Project under Nineth Five-Year Plan of China Agricultural Administration(Agriculture 95-18-04).
文摘The objective was to probe the site where the biosynthesis of chlorophyll was blocked under Mo deficiency at low temperature, which led to the decrease of chlorophyll in winter wheat cultivars. The intermediates of chlorophyll biosynthesis were analyzed in winter wheat cultivars in soil culture, miniblock culture, and solution culture to study the effects of Mo on chlorophyll biosynthesis without Mo addition （CK, soil available Mo 0.112 mg kg^-1） and Mo addition （＋ Mo, 0.13 mg kg^-1 Mo was added）. Laevulinic acid （LA）, the competitive analog of δ-aminolaevulinic acid （ALA） was also introduced in the experiment. The ratio of Chl a/Chl b was constant between CK and ＋ Mo treatment, whereas it increased at low temperature, which indicated that Mo deficiency did not inhibit the transformation of Chl a to Chl b at low temperature. Under Mo deficiency, the contents of protochlorophyll （Pchl）, Mg-protoporphyrin Ⅸ （Mg-Proto Ⅸ）, protoporphyrin Ⅸ （proto IX）, and uroporphyrinogen Ⅲ （Uro Ⅲ） decreased [Uro Ⅲ decreased significantly （P 〈0.01）], whereas ALA and glutamate increased significantly （P 〈 0.01） compared with that of Mo addition, which suggested that the transformation from ALA to Uro Ⅲ might be inhibited. The content of ALA reversed after addition of LA, it was significantly higher （P 〈 0.01） in Mo addition than in CK. The results indicated that the transformation from ALA to Uro Ⅲ was blocked under Mo deficiency, which resulted in the inhibition of the biosynthesis of chlorophyll and led to the decrease of chlorophyll in winter wheat cultivars.
基金the National Key R&D Program of China(2018YFD0901406)the National Natural Science Foundation of China(31872565)sponsored by the Program of the Shanghai Academic Research Leader(19XD1421500).
文摘UroporphyrinogenⅢsynthetase(UROS)is an important enzyme involved in the structural formation of porphyrin,which is responsible for color intensity.A UROS homolog was isolated and characterized from the pearl mussel,Hyriopsis cumingii(HcUros).The HcUros cDNA was 858 bp in length with an open reading frame that encoded a 285 amino acid protein,which contained a conserved HemD domain.HcUros exhibited widespread tissue distribution,displaying particular enrichment in the mantle and haemolymph of purple mussels,compared to white mussels.In situ hybridization of HcUros in mantle tissue demonstrated that it was specifically expressed in the dorsal epithelial cells of the mantle pallia.Additionally,HcUros expression was upregulated following implantation of the pearl sac to produce pearls.The data suggest that HcUros contributes to shell pigmentation,and nacre formation and coloring in H.cumingii.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(grant XDB27040204)the National Natural Science Foundation of China(grant 31571973)+1 种基金the Chinese 1000 Talents Programthe Shanghai Center for Plant Stress Biology(Chinese Academy of Sciences).
文摘Bacterial wilt caused by the soil-borne plant pathogen Ralstonia solanacearum is a devastating disease worldwide.Upon plant colonization,R.solanacearum replicates massively,causing plant wilting and death;collapsed infected tissues then serve as a source of inoculum.In this work,we show that the plant metabolic pathway mediated by pyruvate decarboxylases(PDCs)contributes to plant tolerance to bacterial wilt disease.Arabidopsis and tomato plants resp ond to R.solanacearum infection by in creasing PDC activity,and plants with deficient PDC activity are more susceptible to bacterial wilt.Treatment with either pyruvic acid or acetic acid(substrate and product of the PDC pathway,respectively)enhances plant tolerance to bacterial wilt disease.An effector protein secreted by R.solanacearum,RipAK,interacts with PDCs and inhibits their oligomerization and enzymatic activity.Collectively,our work reveals a metabolic pathway involved in plant resistance to biotic and abiotic stresses,and a bacterial virulence strategy to promote disease and the completion of the pathogenic life cycle.
