The results showed that the contents of free serine\,glutamate\,proline\,alanine\,cystine\,valine\,isoleucine and total amino acid in the resistant varieties after inoculation during incubation period gradually decrea...The results showed that the contents of free serine\,glutamate\,proline\,alanine\,cystine\,valine\,isoleucine and total amino acid in the resistant varieties after inoculation during incubation period gradually decreased and reached the lowest point at 168 h after inoculation,the contents of the free aspartate\,threonine\,serine\,glycine\,alanine\,cystine\,valine\,isoleucine\,leucine\,phenylalanine and total amino acid in the middle resistant varieties gradually decreased and reached the lowest point at 168 h,the content of free glutamate in the middle susceptible varieties after inoculation during incubation period gradually increased and reached the highest point at 168 h,other kinds of amino acid in the middle susceptible varieties didn′t show regular changes,the content of free proline in the susceptible varieties after inoculation during incubation period gradually increased and the other kinds of amino acid didn′t show regular changes.Before inoculation the contents of total free amino acid in different resistant varieties didn′t show regular changes,but those of free alanine and cystine were positively relative to the susceptibility of the host,and that of the free phenylalanine were positively relative to the resistance of the variety.At 168h after inoculation the contents of free proline\,glutamate\,serine\,glycine\,alanine and cystine were negatively relative to the resistance of variety.展开更多
The impact of chestnut blight, caused by the fungal pathogen Cryphonectria parasitica, has diminished in Europe due to a natural biological control caused by hypovirus infection. Hypovirulence-mediated biological cont...The impact of chestnut blight, caused by the fungal pathogen Cryphonectria parasitica, has diminished in Europe due to a natural biological control caused by hypovirus infection. Hypovirulence-mediated biological control has been far less successful in North America meriting further evaluation of field isolates that have the ability to produce non-lethal cankers, generate hypovirulent inoculum, and exhibit a greater ecological fitness in forest systems. In this study, Cryphonectria hypoviruses (CHV) CHV3-County Line, CHV1-Euro7, and CHV1-Ep713 were evaluated in five different isolates of C. parasitica. One hundred and eighty cankers representing each treatment combination were initiated on American chestnut sprouts in the Monongahela National Forest, West Virginia, USA. The size of cankers, the persistence of hypovirulent (HV) isolates, stroma production, and hypovirus transmission to conidia were assessed four and 12 months after canker expansion. CHV3-County Line infected isolates produced significantly smaller cankers than the isolates infected with either CHV1-type. With regard to CHV1-Euro7 isolates, the fungal genome appeared to contribute to the differences in canker size. After four months, HV isolates harboring either CHV1-type (30%) were retrieved at a significantly higher rate than isolates containing CHV3-County Line (14%). After 12 months, the HV recovery was similar among the three hypoviruses indicating smaller cankers will maintain their HV status after one year. Very few stroma were produced after one year in the field from HV isolates. In vitro, CHV3-County Line (49%) had a significantly lower rate of hypovirus transmission to conidia when compared to CHV1-Euro7 (87%) and CHV1-Ep713 (80%). Significant differences existed among the five different isolates indicating HV transmission is dependent on the fungal genome. This research provided additional evidence that each hypovirus interacts with its host differently and certain isolate/hypovirus combinations have better biological control potential 展开更多
文摘The results showed that the contents of free serine\,glutamate\,proline\,alanine\,cystine\,valine\,isoleucine and total amino acid in the resistant varieties after inoculation during incubation period gradually decreased and reached the lowest point at 168 h after inoculation,the contents of the free aspartate\,threonine\,serine\,glycine\,alanine\,cystine\,valine\,isoleucine\,leucine\,phenylalanine and total amino acid in the middle resistant varieties gradually decreased and reached the lowest point at 168 h,the content of free glutamate in the middle susceptible varieties after inoculation during incubation period gradually increased and reached the highest point at 168 h,other kinds of amino acid in the middle susceptible varieties didn′t show regular changes,the content of free proline in the susceptible varieties after inoculation during incubation period gradually increased and the other kinds of amino acid didn′t show regular changes.Before inoculation the contents of total free amino acid in different resistant varieties didn′t show regular changes,but those of free alanine and cystine were positively relative to the susceptibility of the host,and that of the free phenylalanine were positively relative to the resistance of the variety.At 168h after inoculation the contents of free proline\,glutamate\,serine\,glycine\,alanine and cystine were negatively relative to the resistance of variety.
文摘The impact of chestnut blight, caused by the fungal pathogen Cryphonectria parasitica, has diminished in Europe due to a natural biological control caused by hypovirus infection. Hypovirulence-mediated biological control has been far less successful in North America meriting further evaluation of field isolates that have the ability to produce non-lethal cankers, generate hypovirulent inoculum, and exhibit a greater ecological fitness in forest systems. In this study, Cryphonectria hypoviruses (CHV) CHV3-County Line, CHV1-Euro7, and CHV1-Ep713 were evaluated in five different isolates of C. parasitica. One hundred and eighty cankers representing each treatment combination were initiated on American chestnut sprouts in the Monongahela National Forest, West Virginia, USA. The size of cankers, the persistence of hypovirulent (HV) isolates, stroma production, and hypovirus transmission to conidia were assessed four and 12 months after canker expansion. CHV3-County Line infected isolates produced significantly smaller cankers than the isolates infected with either CHV1-type. With regard to CHV1-Euro7 isolates, the fungal genome appeared to contribute to the differences in canker size. After four months, HV isolates harboring either CHV1-type (30%) were retrieved at a significantly higher rate than isolates containing CHV3-County Line (14%). After 12 months, the HV recovery was similar among the three hypoviruses indicating smaller cankers will maintain their HV status after one year. Very few stroma were produced after one year in the field from HV isolates. In vitro, CHV3-County Line (49%) had a significantly lower rate of hypovirus transmission to conidia when compared to CHV1-Euro7 (87%) and CHV1-Ep713 (80%). Significant differences existed among the five different isolates indicating HV transmission is dependent on the fungal genome. This research provided additional evidence that each hypovirus interacts with its host differently and certain isolate/hypovirus combinations have better biological control potential
