Apple scab caused by Venturia inaequalis has a tendency to spread and threatens the development of apple production in recent years in China.The genetic diversity and population structure were investigated by using si...Apple scab caused by Venturia inaequalis has a tendency to spread and threatens the development of apple production in recent years in China.The genetic diversity and population structure were investigated by using simple sequence repeat(SSR) markers.51 strains were classified into 3 groups by UPGMA method as Xunyi,Xingping and U.K.population,each of them mainly including strains from its original place.A relatively high level of genetic diversity was revealed: H=0.425 3,I=0.675 8,PPL=66.67%(at species level);H=0.149 1,I=0.228 0,PPL=44.44%(at population level).A high level of genetic differentiation was detected among/within populations with Nei’s Gst analysis and AMOVA.Molecular genetic variance within populations was greater than that among populations.Genetic variance among populations might result from barriers to gene flow(Nm=0.675 8).Genetic variance within populations might result from sexual pro-pagation of V.inaequalis.展开更多
Resistance of Venturia inaequalis to the first IBS triazoles occurred in the 80’s in Italy and other countries. Successively number of applications sensibly decreased and problems of resistance to IBS generally disap...Resistance of Venturia inaequalis to the first IBS triazoles occurred in the 80’s in Italy and other countries. Successively number of applications sensibly decreased and problems of resistance to IBS generally disappeared. In 2010 suspects of resistance to the newer IBS difenoconazole, the actually most used IBS, appeared in several countries. In vitro tests the results confirmed the previous researches: the monoconidia from populations which were poorly controlled showed moderate reduced sensitivity respect to well controlled and wild-types. New in vivo tests were realized with preventive and curative applications on seedlings. No different activity among the three types of populations (poorly, well-controlled and wild-types) was found in preventive applications. On the contrary, in curative applications, wild-types and well controlled populations showed a visible and statistically significant activity respect to the poorly controlled. A survey of sensitivity to difenoconazole was carried out in two Italian apple areas in 2013-2015 and showed the presence of populations resistant to difenoconazole. Probably the cause of the resistance spread was the increase of the number of applications of this IBS in the last years. However the problem appears more complex because nowadays resistance regards about all fungicides and with a higher severity respect previous decades. An increase of virulence of V. inaequalis strains appears to be the cause of this situation also for the high presence of cultivars with high or moderate susceptibility to scab. Foreseeable remedies consist in a differentiate and appropriate setting of each chemical groups of fungicides in apple scab control, but in long terms new strategies in apple cultivation should be necessary.展开更多
The phytopathogenic fungus Venturia inaequalis causes scab of apple. Once this fungus penetrates the plant surface, it forms a specialized body called a stroma between the inner cuticle surface and the epidermal cell ...The phytopathogenic fungus Venturia inaequalis causes scab of apple. Once this fungus penetrates the plant surface, it forms a specialized body called a stroma between the inner cuticle surface and the epidermal cell wall. A novel Venturia inaequalis 5704 (Cin3) and three expressed sequence tags (ESTs);38, 6987, and 4010 are strongly up-regulated in the early stages of infection. The CIN3 and three ESTs using two vectors pMAL-c2 and pET 21 were expressed in Escherichia coli. Recombinant proteins expression, solubility and yields were analyzed. 38, 5704 (Cin3) and 6987 re- combinant proteins were expressed in soluble form and while 4010 was expressed in inclusion bodies. Re- solution on native-PAGE, the recombinant proteins;38, 5704 (Cin3), 6987 were shown to be present in dimmer, tetramer and polymer. A method was de- veloped, consisting of induction of expression at va- rious temperatures, and using enriched broth with 4% glycerol together with slow shaking, led to a decrease in concentration of nascent polypeptide and production of soluble recombinant proteins of;38, 5704 (Cin3), 6987 and 4010. Resolution on native- PAGE, the recombinant proteins were shown to be present as monomer.展开更多
文摘Apple scab caused by Venturia inaequalis has a tendency to spread and threatens the development of apple production in recent years in China.The genetic diversity and population structure were investigated by using simple sequence repeat(SSR) markers.51 strains were classified into 3 groups by UPGMA method as Xunyi,Xingping and U.K.population,each of them mainly including strains from its original place.A relatively high level of genetic diversity was revealed: H=0.425 3,I=0.675 8,PPL=66.67%(at species level);H=0.149 1,I=0.228 0,PPL=44.44%(at population level).A high level of genetic differentiation was detected among/within populations with Nei’s Gst analysis and AMOVA.Molecular genetic variance within populations was greater than that among populations.Genetic variance among populations might result from barriers to gene flow(Nm=0.675 8).Genetic variance within populations might result from sexual pro-pagation of V.inaequalis.
文摘Resistance of Venturia inaequalis to the first IBS triazoles occurred in the 80’s in Italy and other countries. Successively number of applications sensibly decreased and problems of resistance to IBS generally disappeared. In 2010 suspects of resistance to the newer IBS difenoconazole, the actually most used IBS, appeared in several countries. In vitro tests the results confirmed the previous researches: the monoconidia from populations which were poorly controlled showed moderate reduced sensitivity respect to well controlled and wild-types. New in vivo tests were realized with preventive and curative applications on seedlings. No different activity among the three types of populations (poorly, well-controlled and wild-types) was found in preventive applications. On the contrary, in curative applications, wild-types and well controlled populations showed a visible and statistically significant activity respect to the poorly controlled. A survey of sensitivity to difenoconazole was carried out in two Italian apple areas in 2013-2015 and showed the presence of populations resistant to difenoconazole. Probably the cause of the resistance spread was the increase of the number of applications of this IBS in the last years. However the problem appears more complex because nowadays resistance regards about all fungicides and with a higher severity respect previous decades. An increase of virulence of V. inaequalis strains appears to be the cause of this situation also for the high presence of cultivars with high or moderate susceptibility to scab. Foreseeable remedies consist in a differentiate and appropriate setting of each chemical groups of fungicides in apple scab control, but in long terms new strategies in apple cultivation should be necessary.
文摘The phytopathogenic fungus Venturia inaequalis causes scab of apple. Once this fungus penetrates the plant surface, it forms a specialized body called a stroma between the inner cuticle surface and the epidermal cell wall. A novel Venturia inaequalis 5704 (Cin3) and three expressed sequence tags (ESTs);38, 6987, and 4010 are strongly up-regulated in the early stages of infection. The CIN3 and three ESTs using two vectors pMAL-c2 and pET 21 were expressed in Escherichia coli. Recombinant proteins expression, solubility and yields were analyzed. 38, 5704 (Cin3) and 6987 re- combinant proteins were expressed in soluble form and while 4010 was expressed in inclusion bodies. Re- solution on native-PAGE, the recombinant proteins;38, 5704 (Cin3), 6987 were shown to be present in dimmer, tetramer and polymer. A method was de- veloped, consisting of induction of expression at va- rious temperatures, and using enriched broth with 4% glycerol together with slow shaking, led to a decrease in concentration of nascent polypeptide and production of soluble recombinant proteins of;38, 5704 (Cin3), 6987 and 4010. Resolution on native- PAGE, the recombinant proteins were shown to be present as monomer.
