The protected agricultural production has become one of the fast growing and wid espread cultivation technology in the north parts of China. Continuous cultivati on of single crop or less rotation of crops usually res...The protected agricultural production has become one of the fast growing and wid espread cultivation technology in the north parts of China. Continuous cultivati on of single crop or less rotation of crops usually resulted in the large amount of accumulation of soilborne pathogens and serious crop diseases in the greenho use. After a few years of investigation of soilborne fungi in the north parts of China, nearly one hundred species of mictosporic fungi have been identified by the authors. Among these fungi 11 species of Trichoderma have been morphol ogically identified, namely T. atroviride, T. aureoviride, T. citrinoviride, T. fertile, T. harzianum, T. inhamatum,T. longibrachiatum, T. parceramosum, T. r eeseii, T. virens and T. viride. Trichoderm is found to be a frequently occurring genus of fungi in greenhouse soil. As an important component of effec tive beneficial antibiotic mycoparasites in soil Trichoderma plays an impo rtant part to regulate the balance of beneficial and harmful soilborne microorga nisms.展开更多
Recently there have been many reports about soil diseases controlled by Trichoderma, but few could be applied on agriculture production in large areas. T23 isolated from soil around plant roots in the field by Biopest...Recently there have been many reports about soil diseases controlled by Trichoderma, but few could be applied on agriculture production in large areas. T23 isolated from soil around plant roots in the field by Biopesticide Engineering Center of Shenyang Agricultural University could control effectively Cucurbits Fusarium Wilt. The effects of 9 microelements which include copper, zinc, iron, boron, molybdenum, calcium, manganese, magnesium, potassium and frequently-used chemical fungicides, such as-carbendazim, thiram, thiophanate-methyl, chlorothalonil and hymexazol on the growth and the amounts of spores of Fusarium oxysporum FJ and Trichoderma T23 were studied. The effects of those factors on control effect of T23 to melon diseases were discussed and gave basis for the screening of synergistic agents and fungicides in controlling synergistically the pathogen. The results showed that copper sulfate, zinc sulfate, ferric sulfate and boric acid at concentration of 10-1000 μg/mL had the stronger inhibition to F. oxysporum, while weaker inhibition to Trichoderma. Ammonium molybdate, ferrous sulfate, calcium sulfate and potassium dihydrogen phosphate were the ideal the synergistic agent for accelerating the growth and sporulation of Trichoderma, and germination of melon seeds and growth of melon radicle. Melon Fusarium wilt was controlled by Trichoderma combined with ammonium molybdate and calcium sulfate. The relative control effect reached to 73.95%-71.36%. Several fungicides used generally in soil had a different effect on the growth of F. oxysporum and Trichoderma. Carbendazim appeared a strong inhibition to the growth of two strains, with EC50 of 3.01 mg/L and 0.75. mg/L, respectively. Trichoderma had the strong resistance to thiram which control to Fusarium oxysporum was not ideal in field. Hymexazol which EC50 was 261 mg/L and Trichoderma had the synergistical effect on controlling to F. oxysporum. Trichoderma could reproduce in soil treated with hymexazol at ratio of 2000-4000. Relative control effect of hymexazol combined with Trichoderma to oxysporum reached to 79.26%,. which was higher by 15.19% and 38.75% than the solo controlling effect respectively.展开更多
The transformed Trichoderma strains Ttrm31, Ttrm34 and Ttrm55 were obtained from Trichoderma wild strain T21 mutated by REMI technique for more effective biocontrol of tomato gray mold (Botrytis cinerea) with Trichode...The transformed Trichoderma strains Ttrm31, Ttrm34 and Ttrm55 were obtained from Trichoderma wild strain T21 mutated by REMI technique for more effective biocontrol of tomato gray mold (Botrytis cinerea) with Trichoderma agent. Those transformants appeared much better in biocontrol activity in vitro or in vivo against tomato gray mold were better than that of wild strain T21. The main results were as follow: The transformed Trichoderma strains were detected in their genetic stability by consecutive culture for several generations, growing them on hygromycin-contained medium, and then further detection by PCR. The results showed that the REMI was very useful to construct the transformed Trichoderma strains even though some non-transformants concurrently appeared with positive reaction, but which could be distinguished and avoided by southern blotting. The biological characteristics of transformed Trichoderma strains varied among themselves or differed in parts as compared with wild one. Much changes were detected in the conidia germination, sporulation, tolerance to high-temperature, growth at a certain range of temperature, cultural characteristics under different pH condition as well as utilization of carbon and nitrogen nutrition. Some transformants performed better in the most of mentioned characteristics compared with wild one, others not. For example, conidia germination of strain Ttrm31 was higher than that of wild strain T21. Conidia productivity of Ttrm34 was higher than that of wild strain T21. As the tolerance to high-temperature, Ttrm31 and Ttrm34 were enhanced remarkably relative to wild strain. Meanwhile, it was interested that the growth of transformed Trichoderma strains improved much once treated under high-temperature (50℃) for 1 h. Differently, Ttrm55 grew faster at low-temperature (15℃) ,Ttrm31,Ttrm34 and Ttrm55 grew fast as the wild one at 20-30℃. The transformed Trichoderma strains differed in cultural morphology including color and sporulation at different pH, and even on PDA. Protein and asparagines were screened as better nitrogen, and glucose and maltose as better carbon source. There were several mechanisms expected among transformed Trichoderma strains against Botrytis cinerea. Ttrm31, Ttrm55 and Ttrm111,for instance, had more ability for the nutrition and space competition over pathogen, while Ttrm34 and Ttrm76 inhibited pathogen in the way of mycoparasitism which subsequently confirmed by the higher activities of chitinase and β-glucanase needed for parasitizing pathogen. Similarly Ttrm34 and Ttrm55 were higher in both enzyme activities than those of T21. Additionally a putative role of induced resistance might be involved in the biocontrol mechanism because a series of defensive enzyme in tomato were increased in activities such as PAL, POD, CAT, PPO, SOD, chitinase and β-glucanase once tomato plants treated with transformants, but the level of the induction depended on the transformed Trichoderma strains used. Comparatively, PAL, POD, CAT, PPO and chitinase activities in tomato induced by Ttrm55 were great different from other transformants except SOD and β-glucanase. SOD activity in tomato stimulated by strain Ttrm55 was higher than that induced by others, while β-glucanase activity was lower. The CAT, PAL, PPO activities induced by Ttrm31 were higher than those by other transformants, but lower in SOD, POD and chitinase than those by others. In general POD, PPO, PAL and chitinase activities were higher in tomato induced by Ttrm34 than other enzymes. β-glucanase activities induced by T21 were higher than those of others, but contrary in other enzymes. Transformed Trichoderma strains had the same ability in the colonization on the tomato leaf surface as the wild strain T21, however no much differences were seen between transformants and wild one in the trait. More importantly 3 transformed Trichoderma strains were proved to be very effective in the control of gray mold in flowers and leaves and 14%-18.5% and 7%-9% were increased over wild strain展开更多
The screening of isolates and the assay of biocontrol mechanisms of Trichoderma were studied systematically in laboratory and greenhouse in vivo. The proteins tolerant to benzimidazole in Trichoderma strains were puri...The screening of isolates and the assay of biocontrol mechanisms of Trichoderma were studied systematically in laboratory and greenhouse in vivo. The proteins tolerant to benzimidazole in Trichoderma strains were purified, and their physical and chemical properties were detected. Compared their biological activities in vitro and vivo in greenhouse, nine biocontrol strains (including Ty-10-2,LTR-2,Tj-5-1,Tj-5-4,Ty-11-1,Tj-11-3,Ty-11-3,Tj-3-3-2,Tj-3-3-4) were screened. These biocontrol strains had faster rates of growth and higher inhibition to gray mould (Bortrytis cinerea), and the inhibition was stable. The effects of controlling gray mould in greenhouse with the screened Trichoderma strains were 70% and 50% in vivo. Induced by the substrates including benzimidazole, UV rays and nitrosoguanidine, four strains were screened. They were Ty-10-2,LTR-2,Tj-5-4,Ty-11-3. After being cultured for 24 h, conidiospores of tolerant strains germinated but the sensitive ones didn’t. Compared with the hyphae of the tolerant strains, the sensitive hyphae, front became thinner and shorter. Experiments of biocontrol mechanisms showed as followed: some genes had mutated, transcripted at different levels and translated into some tolerant proteins, while some genes had opposite changes. In the whole, the soluble proteins in cells had increased in quantity. The esterase isoenzymes in the tolerant strains decreased at different levels. After being induced, some genes mutated and some genes, transcription decreased and even diminished. None were screened from UV rays and nitrosoguanidine.展开更多
The pectin is a backbone of the plant cell wall, its network structure will systemicly resolve when the plant cell splits up and forms. The pectinase produced by Rhizoctonia mainly acts on the pectin of cell wall, and...The pectin is a backbone of the plant cell wall, its network structure will systemicly resolve when the plant cell splits up and forms. The pectinase produced by Rhizoctonia mainly acts on the pectin of cell wall, and causes the maceration of tissue and the death of protoplast. Polygalacturonase (PG) can decompose the galacturonic acid of disease tissue. The research defined the PG activities of extracellular metabolite of the different virulence Rhizoctonia isolates, and testifid the effect of Trichoderma viride to PG activities, and clarified the mechanisms of biocontrol by Trichoderma. The test methods as following: Firstly, to select the isolates of different virulence: WK-47, WK-141 and WK-160 strain of Rhizoctonia AG-D and YW-2 strain of Rhizoctonia AG1-IA and TCS-1 strain of Trichoderma viride. Secondly, to culture TCS-1 on PD, and draw a group of fermented liquid in every 24 hours, and draw 7 times. Thirdly, to culture quietly Rhizoctonia isolates with Czapek-Dox at 25℃ for 15 days, filter and centrifuge (2350 g×30 min), fetch the clear liquid, put it into the ammonium sulfate according to 60% saturation degree, put it quietly for 30 min at 4℃, centrifuge (21000 g×30 min) at 4℃, remove the clear liquid, dissolve the deposit with sodium acetate buffer (25 mmol/L, pH5.5), dialysis for 48 h in the same buffer,and change the buffer every 12 h, Fourthly, to put TCS-1 fermented broth of different times in the tubes, one mL per a tube, add 0.5 mL PG to every tube, react for 4 h in 30 ℃ water, the same time fetch the test tube filled with the same treated liquid that was not dealed in 30℃ water.Finally,to testify PG activities with DNS’s test. In all, PG of Rhizoctonia had high activities and virulence. The conrtrol efficacy of T.viride to PG activities of WK-47, WK-141, WK-160 and YW-2 were 95%,94%,95%,92% separately, fermented time had a great influence to control efficacy, the third fermented broth did the best. Through effect to PG activities T. viride can reduce the virulence of Rhizoctonia, and protect the hosts. The specific mechanism, qualitative and quantitative research of antagonistic substance in the fermented broth will be further carried out.展开更多
Gliocladium and Trichoderma are common fungi in agricultural soil. Several species of them were isolated and identified, great diversity was displayed in different agricultural soils of different crops, agricultural c...Gliocladium and Trichoderma are common fungi in agricultural soil. Several species of them were isolated and identified, great diversity was displayed in different agricultural soils of different crops, agricultural climate zones, different seasons, depths, different treated soybean cyst nematode soil, healthy and diseased crop soil. Among five crops soil samples, wheat and corn soil were found to possess the largest number of Gliocladium and Trichoderma separately. Gliocladium and Trichoderma of three major crops showed consistent changing patterns with seasonal variation. Corn soil displayed distinct vertical distribution of Trichoderma. There is a different distribution of the two fungi in diseased and healthy plant soil. Among the various isolated methods, diluted plate method is the best for isolating Gliocladium, and Trichoderma could be found in plant residue method and be tolerant to steam for two minutes. In the soybean cyst nematode soil mycobiota, the frequency of Gliocladium is higher than that of the others fungi, and Trichoderma may have the role of bioremediation in herbicide treated soil. Similarly, Gliocladium occurred frequently in different climate zones.展开更多
One hundred and fifty one isolates of Trichoderma were collected mainly from more than 40 soil samples and other materials in Guangdong Province (including Chigang, Zhanjiang, Wuchuan, Panyu, Zhaoqing, Dongguan, Humen...One hundred and fifty one isolates of Trichoderma were collected mainly from more than 40 soil samples and other materials in Guangdong Province (including Chigang, Zhanjiang, Wuchuan, Panyu, Zhaoqing, Dongguan, Humen, Qingyuan, Guanzhou) and the soil samples were also from different plant rhizosphere (including rice, different fruits and different vegetables). It was shown that 39 isolates of Trichoderma grew faster than other isolates using growth velocity experiments. The 39 isolates could effectively inhibit Fusarium oxysporum f.sp. cubense (E.F.Sm) Sny.&Hans. by dual cultural experiments. The inhibited activity included the antifungal activities of its metabolite, mycoparasitic activities and the lytic enzymes by dual culture, electronic microcopy and enzyme assay. At present, studies on the taxonomy of the 151 isolates of Trichoderma are carried out in our experiments, some Trichoderma species aggregates will be identified according to the taxonomy system revised by Rifai and Bissett.展开更多
A trusty and intuitionistic method for screening chitinase produced by Trichoderma spp. was developed. 38 isolates of Trichoderma spp. were cultured in liquid medium with chitin or colloidal chitin as the sole carbon ...A trusty and intuitionistic method for screening chitinase produced by Trichoderma spp. was developed. 38 isolates of Trichoderma spp. were cultured in liquid medium with chitin or colloidal chitin as the sole carbon source for 4 days. The supernatant of the fermented broth was mixed with colloidal chitin and heated in water-bath at 37℃ for 30 min, then 3,5-dinitrosalicylic acid reagent (DNS) was added to the mixture, and let them react for 10 min in water-bath. According to the different colour of the mixture, the isolates of Trichoderma spp. which can produce chitinase could be screened.展开更多
文摘The protected agricultural production has become one of the fast growing and wid espread cultivation technology in the north parts of China. Continuous cultivati on of single crop or less rotation of crops usually resulted in the large amount of accumulation of soilborne pathogens and serious crop diseases in the greenho use. After a few years of investigation of soilborne fungi in the north parts of China, nearly one hundred species of mictosporic fungi have been identified by the authors. Among these fungi 11 species of Trichoderma have been morphol ogically identified, namely T. atroviride, T. aureoviride, T. citrinoviride, T. fertile, T. harzianum, T. inhamatum,T. longibrachiatum, T. parceramosum, T. r eeseii, T. virens and T. viride. Trichoderm is found to be a frequently occurring genus of fungi in greenhouse soil. As an important component of effec tive beneficial antibiotic mycoparasites in soil Trichoderma plays an impo rtant part to regulate the balance of beneficial and harmful soilborne microorga nisms.
文摘Recently there have been many reports about soil diseases controlled by Trichoderma, but few could be applied on agriculture production in large areas. T23 isolated from soil around plant roots in the field by Biopesticide Engineering Center of Shenyang Agricultural University could control effectively Cucurbits Fusarium Wilt. The effects of 9 microelements which include copper, zinc, iron, boron, molybdenum, calcium, manganese, magnesium, potassium and frequently-used chemical fungicides, such as-carbendazim, thiram, thiophanate-methyl, chlorothalonil and hymexazol on the growth and the amounts of spores of Fusarium oxysporum FJ and Trichoderma T23 were studied. The effects of those factors on control effect of T23 to melon diseases were discussed and gave basis for the screening of synergistic agents and fungicides in controlling synergistically the pathogen. The results showed that copper sulfate, zinc sulfate, ferric sulfate and boric acid at concentration of 10-1000 μg/mL had the stronger inhibition to F. oxysporum, while weaker inhibition to Trichoderma. Ammonium molybdate, ferrous sulfate, calcium sulfate and potassium dihydrogen phosphate were the ideal the synergistic agent for accelerating the growth and sporulation of Trichoderma, and germination of melon seeds and growth of melon radicle. Melon Fusarium wilt was controlled by Trichoderma combined with ammonium molybdate and calcium sulfate. The relative control effect reached to 73.95%-71.36%. Several fungicides used generally in soil had a different effect on the growth of F. oxysporum and Trichoderma. Carbendazim appeared a strong inhibition to the growth of two strains, with EC50 of 3.01 mg/L and 0.75. mg/L, respectively. Trichoderma had the strong resistance to thiram which control to Fusarium oxysporum was not ideal in field. Hymexazol which EC50 was 261 mg/L and Trichoderma had the synergistical effect on controlling to F. oxysporum. Trichoderma could reproduce in soil treated with hymexazol at ratio of 2000-4000. Relative control effect of hymexazol combined with Trichoderma to oxysporum reached to 79.26%,. which was higher by 15.19% and 38.75% than the solo controlling effect respectively.
文摘The transformed Trichoderma strains Ttrm31, Ttrm34 and Ttrm55 were obtained from Trichoderma wild strain T21 mutated by REMI technique for more effective biocontrol of tomato gray mold (Botrytis cinerea) with Trichoderma agent. Those transformants appeared much better in biocontrol activity in vitro or in vivo against tomato gray mold were better than that of wild strain T21. The main results were as follow: The transformed Trichoderma strains were detected in their genetic stability by consecutive culture for several generations, growing them on hygromycin-contained medium, and then further detection by PCR. The results showed that the REMI was very useful to construct the transformed Trichoderma strains even though some non-transformants concurrently appeared with positive reaction, but which could be distinguished and avoided by southern blotting. The biological characteristics of transformed Trichoderma strains varied among themselves or differed in parts as compared with wild one. Much changes were detected in the conidia germination, sporulation, tolerance to high-temperature, growth at a certain range of temperature, cultural characteristics under different pH condition as well as utilization of carbon and nitrogen nutrition. Some transformants performed better in the most of mentioned characteristics compared with wild one, others not. For example, conidia germination of strain Ttrm31 was higher than that of wild strain T21. Conidia productivity of Ttrm34 was higher than that of wild strain T21. As the tolerance to high-temperature, Ttrm31 and Ttrm34 were enhanced remarkably relative to wild strain. Meanwhile, it was interested that the growth of transformed Trichoderma strains improved much once treated under high-temperature (50℃) for 1 h. Differently, Ttrm55 grew faster at low-temperature (15℃) ,Ttrm31,Ttrm34 and Ttrm55 grew fast as the wild one at 20-30℃. The transformed Trichoderma strains differed in cultural morphology including color and sporulation at different pH, and even on PDA. Protein and asparagines were screened as better nitrogen, and glucose and maltose as better carbon source. There were several mechanisms expected among transformed Trichoderma strains against Botrytis cinerea. Ttrm31, Ttrm55 and Ttrm111,for instance, had more ability for the nutrition and space competition over pathogen, while Ttrm34 and Ttrm76 inhibited pathogen in the way of mycoparasitism which subsequently confirmed by the higher activities of chitinase and β-glucanase needed for parasitizing pathogen. Similarly Ttrm34 and Ttrm55 were higher in both enzyme activities than those of T21. Additionally a putative role of induced resistance might be involved in the biocontrol mechanism because a series of defensive enzyme in tomato were increased in activities such as PAL, POD, CAT, PPO, SOD, chitinase and β-glucanase once tomato plants treated with transformants, but the level of the induction depended on the transformed Trichoderma strains used. Comparatively, PAL, POD, CAT, PPO and chitinase activities in tomato induced by Ttrm55 were great different from other transformants except SOD and β-glucanase. SOD activity in tomato stimulated by strain Ttrm55 was higher than that induced by others, while β-glucanase activity was lower. The CAT, PAL, PPO activities induced by Ttrm31 were higher than those by other transformants, but lower in SOD, POD and chitinase than those by others. In general POD, PPO, PAL and chitinase activities were higher in tomato induced by Ttrm34 than other enzymes. β-glucanase activities induced by T21 were higher than those of others, but contrary in other enzymes. Transformed Trichoderma strains had the same ability in the colonization on the tomato leaf surface as the wild strain T21, however no much differences were seen between transformants and wild one in the trait. More importantly 3 transformed Trichoderma strains were proved to be very effective in the control of gray mold in flowers and leaves and 14%-18.5% and 7%-9% were increased over wild strain
文摘The screening of isolates and the assay of biocontrol mechanisms of Trichoderma were studied systematically in laboratory and greenhouse in vivo. The proteins tolerant to benzimidazole in Trichoderma strains were purified, and their physical and chemical properties were detected. Compared their biological activities in vitro and vivo in greenhouse, nine biocontrol strains (including Ty-10-2,LTR-2,Tj-5-1,Tj-5-4,Ty-11-1,Tj-11-3,Ty-11-3,Tj-3-3-2,Tj-3-3-4) were screened. These biocontrol strains had faster rates of growth and higher inhibition to gray mould (Bortrytis cinerea), and the inhibition was stable. The effects of controlling gray mould in greenhouse with the screened Trichoderma strains were 70% and 50% in vivo. Induced by the substrates including benzimidazole, UV rays and nitrosoguanidine, four strains were screened. They were Ty-10-2,LTR-2,Tj-5-4,Ty-11-3. After being cultured for 24 h, conidiospores of tolerant strains germinated but the sensitive ones didn’t. Compared with the hyphae of the tolerant strains, the sensitive hyphae, front became thinner and shorter. Experiments of biocontrol mechanisms showed as followed: some genes had mutated, transcripted at different levels and translated into some tolerant proteins, while some genes had opposite changes. In the whole, the soluble proteins in cells had increased in quantity. The esterase isoenzymes in the tolerant strains decreased at different levels. After being induced, some genes mutated and some genes, transcription decreased and even diminished. None were screened from UV rays and nitrosoguanidine.
文摘The pectin is a backbone of the plant cell wall, its network structure will systemicly resolve when the plant cell splits up and forms. The pectinase produced by Rhizoctonia mainly acts on the pectin of cell wall, and causes the maceration of tissue and the death of protoplast. Polygalacturonase (PG) can decompose the galacturonic acid of disease tissue. The research defined the PG activities of extracellular metabolite of the different virulence Rhizoctonia isolates, and testifid the effect of Trichoderma viride to PG activities, and clarified the mechanisms of biocontrol by Trichoderma. The test methods as following: Firstly, to select the isolates of different virulence: WK-47, WK-141 and WK-160 strain of Rhizoctonia AG-D and YW-2 strain of Rhizoctonia AG1-IA and TCS-1 strain of Trichoderma viride. Secondly, to culture TCS-1 on PD, and draw a group of fermented liquid in every 24 hours, and draw 7 times. Thirdly, to culture quietly Rhizoctonia isolates with Czapek-Dox at 25℃ for 15 days, filter and centrifuge (2350 g×30 min), fetch the clear liquid, put it into the ammonium sulfate according to 60% saturation degree, put it quietly for 30 min at 4℃, centrifuge (21000 g×30 min) at 4℃, remove the clear liquid, dissolve the deposit with sodium acetate buffer (25 mmol/L, pH5.5), dialysis for 48 h in the same buffer,and change the buffer every 12 h, Fourthly, to put TCS-1 fermented broth of different times in the tubes, one mL per a tube, add 0.5 mL PG to every tube, react for 4 h in 30 ℃ water, the same time fetch the test tube filled with the same treated liquid that was not dealed in 30℃ water.Finally,to testify PG activities with DNS’s test. In all, PG of Rhizoctonia had high activities and virulence. The conrtrol efficacy of T.viride to PG activities of WK-47, WK-141, WK-160 and YW-2 were 95%,94%,95%,92% separately, fermented time had a great influence to control efficacy, the third fermented broth did the best. Through effect to PG activities T. viride can reduce the virulence of Rhizoctonia, and protect the hosts. The specific mechanism, qualitative and quantitative research of antagonistic substance in the fermented broth will be further carried out.
文摘Gliocladium and Trichoderma are common fungi in agricultural soil. Several species of them were isolated and identified, great diversity was displayed in different agricultural soils of different crops, agricultural climate zones, different seasons, depths, different treated soybean cyst nematode soil, healthy and diseased crop soil. Among five crops soil samples, wheat and corn soil were found to possess the largest number of Gliocladium and Trichoderma separately. Gliocladium and Trichoderma of three major crops showed consistent changing patterns with seasonal variation. Corn soil displayed distinct vertical distribution of Trichoderma. There is a different distribution of the two fungi in diseased and healthy plant soil. Among the various isolated methods, diluted plate method is the best for isolating Gliocladium, and Trichoderma could be found in plant residue method and be tolerant to steam for two minutes. In the soybean cyst nematode soil mycobiota, the frequency of Gliocladium is higher than that of the others fungi, and Trichoderma may have the role of bioremediation in herbicide treated soil. Similarly, Gliocladium occurred frequently in different climate zones.
文摘One hundred and fifty one isolates of Trichoderma were collected mainly from more than 40 soil samples and other materials in Guangdong Province (including Chigang, Zhanjiang, Wuchuan, Panyu, Zhaoqing, Dongguan, Humen, Qingyuan, Guanzhou) and the soil samples were also from different plant rhizosphere (including rice, different fruits and different vegetables). It was shown that 39 isolates of Trichoderma grew faster than other isolates using growth velocity experiments. The 39 isolates could effectively inhibit Fusarium oxysporum f.sp. cubense (E.F.Sm) Sny.&Hans. by dual cultural experiments. The inhibited activity included the antifungal activities of its metabolite, mycoparasitic activities and the lytic enzymes by dual culture, electronic microcopy and enzyme assay. At present, studies on the taxonomy of the 151 isolates of Trichoderma are carried out in our experiments, some Trichoderma species aggregates will be identified according to the taxonomy system revised by Rifai and Bissett.
文摘A trusty and intuitionistic method for screening chitinase produced by Trichoderma spp. was developed. 38 isolates of Trichoderma spp. were cultured in liquid medium with chitin or colloidal chitin as the sole carbon source for 4 days. The supernatant of the fermented broth was mixed with colloidal chitin and heated in water-bath at 37℃ for 30 min, then 3,5-dinitrosalicylic acid reagent (DNS) was added to the mixture, and let them react for 10 min in water-bath. According to the different colour of the mixture, the isolates of Trichoderma spp. which can produce chitinase could be screened.
