The necrotrophic fungus, Sclerotinia sclerotiorum, employs an array of cell wall-degrading enzymes(CWDEs), including cellulase, to dismantle host cell walls. However, the molecular mechanisms through which S. scleroti...The necrotrophic fungus, Sclerotinia sclerotiorum, employs an array of cell wall-degrading enzymes(CWDEs), including cellulase, to dismantle host cell walls. However, the molecular mechanisms through which S. sclerotiorum degrades cellulose remain elusive. Here, we unveil a novel secretory cellobiohydrolase, SsdchA, characterized by a signal peptide and a Glyco_hydro_7(GH7) domain. SsdchA exhibits a robust expression of during early infection stages. Interestingly, colony morphology and growth rates remain unaffected across the wild-type, SsdchA deletion strains and SsdchA overexpression strains on potato dextrose agar(PDA) medium. Nevertheless, the pathogenicity and cellobiohydrolase activity decreased in the SsdchA deletion strains, but enhanced in the SsdchA overexpression strains. Moreover,the heterologous expression of SsdchA in Arabidopsis thaliana leads to reduced cellulose content and heightened susceptibility to S. sclerotiorum. Collectively, our data underscore the pivotal role of the novel cellobiohydrolase SsdchA in the pathogenicity of S. sclerotiorum.展开更多
With the development of tourism at home and abroad,Rapeseed(Brassica napus)has become an important ornamental plant.However,its ornamental value at the inflorescence stage is greatly reduced by Sclerotinia sclerotioru...With the development of tourism at home and abroad,Rapeseed(Brassica napus)has become an important ornamental plant.However,its ornamental value at the inflorescence stage is greatly reduced by Sclerotinia sclerotiorum.Identification of important genes in the defense responses is critical for molecular breeding,which is an important strategy for controlling the disease.In this study,we isolated a B.napus WRKY transcription factor gene,BnaWRKY75.BnaWRKY75 was found to encode a nucleus-localized protein and exhibited relatively high expression in the stems.Arabidopsis thaliana transgenic plants expressing BnaWRKY75 showed enhanced resistance to S.sclerotiorum,and both ProBnaWRKY75:GUS and gene expression analyses showed that BnaWRKY75 was highly responsive to S.sclerotiorum infection,indicating the involvement of BnaWRKY75 in response to this infection.Furthermore,overexpression(OE)of BnaWRKY75 in B.napus significantly enhanced the resistance to S.sclerotiorum,whereas the resistance was reduced in RNAi transgenic B.napus plants.Moreover,the BnaWRKY75-OE B.napus plants exhibited constitutive activation of salicylic acid-,jasmonic acid-,and ethylene-mediated defense responses and the inhibition of both H_(2)O_(2)and O_(2)·^(-)accumulation in response to this pathogen.By contrast,BnaWRKY75-RNAi plants showed a reverse pattern,suggesting that BnaWRKY75 is involved in hormonal signaling pathways and in the control of reactive oxygen species accumulation.In conclusion,these data indicate that BnaWRKY75,a regulator of multiple defense responses,positively regulates resistance against S.sclerotiorum,which may guide the improvement of resistance in rapeseed.展开更多
The present work was aimed to the study of the antifungal activity of essential oils of two aromatic plants against three strains of Sclerotinia sclerotiorum responsible for white rot of bean. The two essential oils (...The present work was aimed to the study of the antifungal activity of essential oils of two aromatic plants against three strains of Sclerotinia sclerotiorum responsible for white rot of bean. The two essential oils (EO) of the studied plants: Thymus vulgaris (HET) and Cymbopogon citratrus (HEC), used at different concentrations: C1 (0.75 ml/ml), C2 (1.5 ml/ml) and C3 (3 ml/ml) presented significant inhibitory activities on the three tested fungal strains namely Bia 1, Bia 2, and Njo 2. Two control treatments (T-: containing no antifungal substance and T+: synthetic fungicide) were also used. The antifungal activity here is related to the inhibition of mycelial growth especially with high concentrations of essential oils. Thus, against S. sclerotiorum, HET showed the highest activity comparable to that of T+ (100% inhibition) at all concentrations on the Bia 1 and Bia 2 strains and at concentration C3 on the Njo 2 strain compared to that of HEC, which certainly inhibited the mycelial growth of the different strains considerably (with a maximum of 78.15% on the Njo 2 strain) but not completely. According to their sensitivity, the Bia 2 strain showed a higher sensitivity to essential oils than the others while the Njo 2 strain was more aggressive. On the basis of MIC<sub>50</sub> and MIC<sub>90</sub> obtained on the Njo 2 strain, the HET turns out to be the most efficient with respective lower values of (1.73 and 23.34 ml/ml) against (4.76 and 26.03 ml/ml) for the HEC. These EO could thus be exploited as biodegradable antifungal substances, likely to control white rot of bean.展开更多
基金financially supported by the National Nature Science Foundation of China (32372077)the Project of Chongqing Science and Technology Commission (CSTB2023NSCQ-MSX0355)the Fundamental Research Funds for the Central Universities (SWU120075)。
文摘The necrotrophic fungus, Sclerotinia sclerotiorum, employs an array of cell wall-degrading enzymes(CWDEs), including cellulase, to dismantle host cell walls. However, the molecular mechanisms through which S. sclerotiorum degrades cellulose remain elusive. Here, we unveil a novel secretory cellobiohydrolase, SsdchA, characterized by a signal peptide and a Glyco_hydro_7(GH7) domain. SsdchA exhibits a robust expression of during early infection stages. Interestingly, colony morphology and growth rates remain unaffected across the wild-type, SsdchA deletion strains and SsdchA overexpression strains on potato dextrose agar(PDA) medium. Nevertheless, the pathogenicity and cellobiohydrolase activity decreased in the SsdchA deletion strains, but enhanced in the SsdchA overexpression strains. Moreover,the heterologous expression of SsdchA in Arabidopsis thaliana leads to reduced cellulose content and heightened susceptibility to S. sclerotiorum. Collectively, our data underscore the pivotal role of the novel cellobiohydrolase SsdchA in the pathogenicity of S. sclerotiorum.
基金supported by the National Natural Science Foundation of China(Grant No.31771836)the National Key Research and Development Program of China(Grant No.2018YFD0201003).
文摘With the development of tourism at home and abroad,Rapeseed(Brassica napus)has become an important ornamental plant.However,its ornamental value at the inflorescence stage is greatly reduced by Sclerotinia sclerotiorum.Identification of important genes in the defense responses is critical for molecular breeding,which is an important strategy for controlling the disease.In this study,we isolated a B.napus WRKY transcription factor gene,BnaWRKY75.BnaWRKY75 was found to encode a nucleus-localized protein and exhibited relatively high expression in the stems.Arabidopsis thaliana transgenic plants expressing BnaWRKY75 showed enhanced resistance to S.sclerotiorum,and both ProBnaWRKY75:GUS and gene expression analyses showed that BnaWRKY75 was highly responsive to S.sclerotiorum infection,indicating the involvement of BnaWRKY75 in response to this infection.Furthermore,overexpression(OE)of BnaWRKY75 in B.napus significantly enhanced the resistance to S.sclerotiorum,whereas the resistance was reduced in RNAi transgenic B.napus plants.Moreover,the BnaWRKY75-OE B.napus plants exhibited constitutive activation of salicylic acid-,jasmonic acid-,and ethylene-mediated defense responses and the inhibition of both H_(2)O_(2)and O_(2)·^(-)accumulation in response to this pathogen.By contrast,BnaWRKY75-RNAi plants showed a reverse pattern,suggesting that BnaWRKY75 is involved in hormonal signaling pathways and in the control of reactive oxygen species accumulation.In conclusion,these data indicate that BnaWRKY75,a regulator of multiple defense responses,positively regulates resistance against S.sclerotiorum,which may guide the improvement of resistance in rapeseed.
文摘The present work was aimed to the study of the antifungal activity of essential oils of two aromatic plants against three strains of Sclerotinia sclerotiorum responsible for white rot of bean. The two essential oils (EO) of the studied plants: Thymus vulgaris (HET) and Cymbopogon citratrus (HEC), used at different concentrations: C1 (0.75 ml/ml), C2 (1.5 ml/ml) and C3 (3 ml/ml) presented significant inhibitory activities on the three tested fungal strains namely Bia 1, Bia 2, and Njo 2. Two control treatments (T-: containing no antifungal substance and T+: synthetic fungicide) were also used. The antifungal activity here is related to the inhibition of mycelial growth especially with high concentrations of essential oils. Thus, against S. sclerotiorum, HET showed the highest activity comparable to that of T+ (100% inhibition) at all concentrations on the Bia 1 and Bia 2 strains and at concentration C3 on the Njo 2 strain compared to that of HEC, which certainly inhibited the mycelial growth of the different strains considerably (with a maximum of 78.15% on the Njo 2 strain) but not completely. According to their sensitivity, the Bia 2 strain showed a higher sensitivity to essential oils than the others while the Njo 2 strain was more aggressive. On the basis of MIC<sub>50</sub> and MIC<sub>90</sub> obtained on the Njo 2 strain, the HET turns out to be the most efficient with respective lower values of (1.73 and 23.34 ml/ml) against (4.76 and 26.03 ml/ml) for the HEC. These EO could thus be exploited as biodegradable antifungal substances, likely to control white rot of bean.