A field under rice-wheat rotation was selected near Chengdu, China, to study thepopulation of Rhizoctonia solani anastomosis group 1 (AG-1), pathogen causing ricesheath blight disease, in natural soil ecosystem. Inocu...A field under rice-wheat rotation was selected near Chengdu, China, to study thepopulation of Rhizoctonia solani anastomosis group 1 (AG-1), pathogen causing ricesheath blight disease, in natural soil ecosystem. Inocula of the fungus recovered fromthe field were divided into three types, i.e., sclerotia, free mycelium retained in thesoil passed through a 0.355mm sieve, and colonized plant debris which was subdividedinto small colonized debris retained between 2.00 and 0.355mm sieves and large colonizeddebris retained on 2.00mm sieve after wet screening. Quantitative estimation of thethree types of inocula in one year indicated that small colonized debris was the dominantinoculum type for most of the time. The population peaked in March and September at 1210and 480 colonized debris 100g-1 air-dry soil respectively, and fell down in December andAugust to 0 and 177 colonized debris 100g-1 air-dry soil respectively. Free mycelium wasonly detectable in March, September and October with 1209, 7.9 and 14.5g fresh wtmyceliumg-1 air-dry soil respectively, which corresponded to the two peaks and the secondhighest level of small debris density in the year. Viable sclerotia and large colonizeddebris were rare with populations ranging from 0 to 3 for sclerotia and 0 to 14 for largecolonized debris 100g-1 air-dry soil, but were the main structures to survive overwinter. It was expected that soil temperature was the main factor determining populationdynamics of R.solani AG-1 in natural soil. Optimum temperature for population increasingis predicted to be around 15℃, with a range from 10 to 25℃. Viability tests indicatedthat 60.9% sclerotia could survive after 265d being buried in natural sandy loam in fieldconditions in Beijing, while colonized rice straw debris (0.5-1.0cm long) could notyield the fungus on medium plates after 88d of being buried under the same conditions.展开更多
Trehalose metabolism is related to the sclerotial development of Rhizoctonia solani AG-1 IA,the causal agent of rice sheath blight(RSB).Here,we further elucidated the functions of three genes Rstre,Rstps1 and Rstpp th...Trehalose metabolism is related to the sclerotial development of Rhizoctonia solani AG-1 IA,the causal agent of rice sheath blight(RSB).Here,we further elucidated the functions of three genes Rstre,Rstps1 and Rstpp that encode three key enzymes trehalase(TRE),alpha,alpha-trehalosephosphate synthase(TPS1)and trehalose 6-phosphate phosphatase(TPP)in the sclerotial development of R.solani AG-1 IA.Due to the lack of a stable genetic transformation system for R.solani,the heterologous expression of these three genes in Pichia pastoris GS115 was performed.The results showed that reactive oxygen species(ROS)contents and enzyme activities in R.solani decreased significantly in the treatments of the fermentation broths of Rstps1 and Rstpp transformants,and that in the treatment of the fermentation broth of Rstre transformant visibly increased.Furthermore,the fermentation broths of the transformants of all the three genes were added to potato dextrose agar(PDA)medium for the cultivation of R.solani,as a result,the dry weight of sclerotia in each PDA plate containing the fermentation broths of Rstps1 and Rstpp transformants significantly increased compared with the control,and that of Rstre transformant obviously decreased.Finally,178 proteins were found to interact with RSTPS1,and 16 of them were associated with ROS.Taken together,the findings suggest that all these three genes related to trehalose metabolism play important roles in the sclerotial development of R.solani AG-1 IA,and can be used as new targets for the development of novel high-efficiency fungicides for the controlling of RSB.展开更多
文摘A field under rice-wheat rotation was selected near Chengdu, China, to study thepopulation of Rhizoctonia solani anastomosis group 1 (AG-1), pathogen causing ricesheath blight disease, in natural soil ecosystem. Inocula of the fungus recovered fromthe field were divided into three types, i.e., sclerotia, free mycelium retained in thesoil passed through a 0.355mm sieve, and colonized plant debris which was subdividedinto small colonized debris retained between 2.00 and 0.355mm sieves and large colonizeddebris retained on 2.00mm sieve after wet screening. Quantitative estimation of thethree types of inocula in one year indicated that small colonized debris was the dominantinoculum type for most of the time. The population peaked in March and September at 1210and 480 colonized debris 100g-1 air-dry soil respectively, and fell down in December andAugust to 0 and 177 colonized debris 100g-1 air-dry soil respectively. Free mycelium wasonly detectable in March, September and October with 1209, 7.9 and 14.5g fresh wtmyceliumg-1 air-dry soil respectively, which corresponded to the two peaks and the secondhighest level of small debris density in the year. Viable sclerotia and large colonizeddebris were rare with populations ranging from 0 to 3 for sclerotia and 0 to 14 for largecolonized debris 100g-1 air-dry soil, but were the main structures to survive overwinter. It was expected that soil temperature was the main factor determining populationdynamics of R.solani AG-1 in natural soil. Optimum temperature for population increasingis predicted to be around 15℃, with a range from 10 to 25℃. Viability tests indicatedthat 60.9% sclerotia could survive after 265d being buried in natural sandy loam in fieldconditions in Beijing, while colonized rice straw debris (0.5-1.0cm long) could notyield the fungus on medium plates after 88d of being buried under the same conditions.
基金supported by the Major Program of Guangdong Basic and Applied Basic Research(Grant No.2019B030302006)the National Natural Science Foundation of China(Grant No.31801677)。
文摘Trehalose metabolism is related to the sclerotial development of Rhizoctonia solani AG-1 IA,the causal agent of rice sheath blight(RSB).Here,we further elucidated the functions of three genes Rstre,Rstps1 and Rstpp that encode three key enzymes trehalase(TRE),alpha,alpha-trehalosephosphate synthase(TPS1)and trehalose 6-phosphate phosphatase(TPP)in the sclerotial development of R.solani AG-1 IA.Due to the lack of a stable genetic transformation system for R.solani,the heterologous expression of these three genes in Pichia pastoris GS115 was performed.The results showed that reactive oxygen species(ROS)contents and enzyme activities in R.solani decreased significantly in the treatments of the fermentation broths of Rstps1 and Rstpp transformants,and that in the treatment of the fermentation broth of Rstre transformant visibly increased.Furthermore,the fermentation broths of the transformants of all the three genes were added to potato dextrose agar(PDA)medium for the cultivation of R.solani,as a result,the dry weight of sclerotia in each PDA plate containing the fermentation broths of Rstps1 and Rstpp transformants significantly increased compared with the control,and that of Rstre transformant obviously decreased.Finally,178 proteins were found to interact with RSTPS1,and 16 of them were associated with ROS.Taken together,the findings suggest that all these three genes related to trehalose metabolism play important roles in the sclerotial development of R.solani AG-1 IA,and can be used as new targets for the development of novel high-efficiency fungicides for the controlling of RSB.
