Fusarium wilt, caused by Fusarium oxyporum f. sp. cubense(Foc), is the most serious disease affecting banana production.To clarify the distribution of the Foc races in Fujian Province of China, 79 soil samples were co...Fusarium wilt, caused by Fusarium oxyporum f. sp. cubense(Foc), is the most serious disease affecting banana production.To clarify the distribution of the Foc races in Fujian Province of China, 79 soil samples were collected from four regions of Zhangzhou City, the primary banana production area in Fujian. We isolated and identified 12 Foc strains based on internal transcribed spacer(ITS) sequence analysis, PCR amplification by using Foc-specific primers and pathogenicity assays.Our analysis indicated that 11 isolates belong to Foc race 1, and 1 isolate belongs to the Foc tropical species race 4(TR4).Although TR4 has previously been reported to occur in primary banana-producing provinces, such as Hainan, Guangxi,and Guangdong of China, this is the first report of TR4 isolated from the soil in Fujian Province. Monitoring the presence of Foc, in particular, the TR4 strains in the soil, is the basic strategy to prevent and control Fusarium wilt.展开更多
Fusarium wilt of banana, which is caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), is a serious soil-borne fungal disease. Now, the epigenetic molecular pathogenic basis is elusive. In this stu...Fusarium wilt of banana, which is caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), is a serious soil-borne fungal disease. Now, the epigenetic molecular pathogenic basis is elusive. In this study, with methylation-sensitive amplification polymorphism (MSAP) technique, DNA methylation was compared between the leaves inoculated with Foc TR4 and the mock-inoculated leaves at different pathogenic stages. With 25 pairs of primers, 1 144 and 1 255 fragments were amplified from the infected and mock-inoculated leaves, respectively. DNA methylation was both changed and the average methylated CCGG sequences were 34.81 and 29.26% for the infected and the mock-inoculated leaves. And DNA hypermethylation and hypomethylation were induced by pathogen infection during all pathogenic stages. Further, 69 polymorphic fragments were sequenced and 29 of them showed sequence similarity to genes with known functions. And RT-PCR results of four genes indicated that their expression patterns were consistent with their methylation patterns. Our results suggest that DNA methylation plays important roles in pathogenic response to Foc TR4 for banana.展开更多
Endophytic bacteria colonizing the shoot-tips of banana cv. Grand Naine were isolated and tested for the antagonistic activity against the Panama wilt pathogen Fusarium oxysporum f. sp. cubense (Foc). Pre-isolation, t...Endophytic bacteria colonizing the shoot-tips of banana cv. Grand Naine were isolated and tested for the antagonistic activity against the Panama wilt pathogen Fusarium oxysporum f. sp. cubense (Foc). Pre-isolation, the suckers were given extensive disinfection treatments and the homogenate from the excised shoot-tip portion was plated on nutrient agar (NA) and trypticase soy agar (TSA). This yielded altogether 47 isolates: 26 on NA and 21 on TSA, respectively, from the 10 suckers collected during August to February. The number of bacterial isolates obtained per sucker varied from one to 15 based on colony characteristics registering up to 10 distinct species per shoot-tip based on 16S rRNA sequence analysis. The 47 isolates belonged to 19 genera and 25 species under the phylogenetic classes of Actinobacteria, α- and γ-Proteobacteria and Firmicutes. Actinobacteria constituted the predominant phylum (55% isolates) with the constituent genera of Arthrobacter, Brevibacterium, Corynebacterium, Curtobacterium, Kocuria, Kytococcus, Micrococcus, Naumanella, Rothia and Tessaracoccus spp. and an unidentified isolate belonging to the family Frankiaceae. Proteobacteria constituted the second major phylum (Brevundimonas, Enterobacter, Klebsiella, Pseudomonas, Serratia and Sphingomonas spp.) followed by Firmicutes (Bacillus and Staphylococcus spp.). Antagonistic activity of the endophytes against Foc was tested through agar plate assays (pit and spot applications on fungal lawn) employing potato dextrose agar and NA. Endophytic Pseudomonas aeruginosa (isolate GNS.13.2a) which was associated with a single sucker showed significant growth inhibition effect on Foc while Klebsiella variicola (GNS.13.3a) and Enterobacter cloacae (GNS13.4a) exhibited moderate inhibition. The study brings out considerable sucker to sucker variation in the associated cultivable endophytic bacteria in “Grand Naine” banana and identifies a few bacterial endophytes with biocontrol potential against the devastating Foc pathogen.展开更多
[ Objective] The paper was to study biological characteristics of Fusarium oxysporum f. sp. niveum in watermelon cultivated in plastic greenhouse in Hainan Province of China and to determine indoor toxicity of fungici...[ Objective] The paper was to study biological characteristics of Fusarium oxysporum f. sp. niveum in watermelon cultivated in plastic greenhouse in Hainan Province of China and to determine indoor toxicity of fungicides. [ Method] Effects of various factors on mycelial growth and spore germination were stud- ied, and the lethal temperature of spores and indoor toxicity of fungicides were also determined. [Result] The fungal mycelium had a better growth rate on water- melon juice medium than the others. The optimum temperature for mycelial growth and spore germination were 28 ℃ and 30 ℃, and the optimum pH values were 7 - 8 and 7 - 9, respectively. Light-dark alternation was conducive for mycelial growth. The lethal temperature of spore was 60 ℃ for 5 min. The fungal mycelium grew better while taking fructose and glucose as carbon sources and yeast extract and peptone as nitrogen sources. Toxicity determination showed that 50% pro- chloraz-manganese chloride complex WP had the greatest inhibition effect on mycelial growth, with the ECso value of 0.730 9 μg/mL; followed by 32.5% benzoic azoxystrobin SC, 30% benzoylate· propieanazol EC, 10% difenoconazole WG, 25% bromothalonil · carbendazim WP and 25% bromothalonil WP, with the ECso values from 1.884 7μg/mL to 8. 161 0μg/mL. [Conclusion] The study provided basic data for field control against F. oxysporum f. sp. niveum on watermelon cultivated in plastic greenhouse in Hainan Province.展开更多
The article is based on the use of experimental polyploidy method, with the introduction of new introgressive hybrid forms combining several species genotype with pathogenic Verticillium dahliae Kleb. and the effects ...The article is based on the use of experimental polyploidy method, with the introduction of new introgressive hybrid forms combining several species genotype with pathogenic Verticillium dahliae Kleb. and the effects of mycotoxins separated from the Fusarium oxysporum f.sp. vasinfectum micromicette on the yield of plant seeds. New artificial complex hypertension forms based on experimental polyploidy Verticillium dahliae Kleb. and Fusarium oxysporum f.sp. vasinfectum combine the potential of resistance to mycotoxins separated from microcrystals, making a tremendous contribution to the selection of new varieties and to the effectiveness of selection as a result of the use of genetic selective research as genetic-selective genetic-selector studies.展开更多
Fusarium wilt of banana, caused by Fusarium oxysporum f. sp. cubense tropic race 4(Foc TR4), is a typical vascular and soil-borne disease which has significantly threatened the sustainable development of banana indust...Fusarium wilt of banana, caused by Fusarium oxysporum f. sp. cubense tropic race 4(Foc TR4), is a typical vascular and soil-borne disease which has significantly threatened the sustainable development of banana industry. In order to reveal the infection process and pathogenesis of Foc TR4, the young mycelia(66.7 mg/ml) of wild-type strain of Foc TR4(WT-Foc TR4) cultured for 18-20 h were lysed with enzyme mixture for protoplast formation, which consisted of 25 mg/ml driselase, 0.4 mg/ml chitinase, 15 mg/ml lysing enzyme and 1.2 mol/L potassium chloride. The resulted protoplasts of 2×10~7 cells/ml were used to test the efficiency of transformation mediated by polyethylene glycol, and up to 9 transformants per microgram of DNA were obtained. AmCyan, RFP and YFP genes were stably transferred into the WT-Foc TR4, separately, using the protoplast transformation system. The gene FoOCH1 encoding α-1, 6-mannosyltransferase in the WT-Foc TR4 was knocked out using the split-marker recombination technology. The genetic transformation and gene knockout system in this pathogen lays a foundation for the study of functional genomics and plant-pathogen interactions.展开更多
Wax gourd (Benincasa hispida Thumb. Cogn) is called white gourd, winter melon, Chinese preserving melon, Chinese squash, and don kwa. It has been cultivated in China for over 2 300 years. It probably
The dynamic changes in membrane permeability, activities of disease-related enzymes, and contents of pathogenesis-relevant chemical compounds and photosynthetic pigments in root cells of three watermelon cultivars wer...The dynamic changes in membrane permeability, activities of disease-related enzymes, and contents of pathogenesis-relevant chemical compounds and photosynthetic pigments in root cells of three watermelon cultivars were studied after inoculation with Fusarium oxysporum f. sp. niveum at seedling stage. The results showed that the capacity of self-regulating and returning to normal status of cultivar Kelunsheng (resistant) was greater than that of a susceptible cultivar, Zaohua, in terms of malonaldehyde (MDA) content, relative conductivity, and activity of superoxide dismutase (SOD) and catalase (CAT). The resistant cultivar maintained a higher activity of dehydrogenase, higher content of vitamin C(Vc) , and relatively lower content of soluble sugar than the susceptible cultivar. The content of soluble protein was higher in the resistant cultivar than that in the susceptible one at day 1 after inoculation. The capacities of the resistant cultivar to inhibit chlorophyll deterioration and maintain a higher carotenoid content were significantly stronger than those of the susceptible cultivar.展开更多
Maximum germination distance(MGD) is an important component of Striga resistance in sorghum. The objective of this study was to determine gene action influencing MGD of Striga hermonthica and Striga asiatica among s...Maximum germination distance(MGD) is an important component of Striga resistance in sorghum. The objective of this study was to determine gene action influencing MGD of Striga hermonthica and Striga asiatica among selected sorghum lines treated with a biocontrol agent, Fusarium oxysporum f. sp. strigae(FOS) for effective breeding with Striga resistance, and FOS compatibility. Twelve sorghum genotypes were selected based on their Striga resistance, FOS compatibility, and superior agronomic performance. Selected genotypes were crossed using a bi-parental mating design to generate six families for genetic analysis. Agar-gel assays were used to determine low haustorium initiation factor(LHF) using the 12 parental lines, their F_1 progenies, backcross derivatives, and F_2 segregants in two sets. One set had S. hermonthica seed and the other one had S. asiatica seed. Both were treated with and without FOS. Genotypes were evaluated using a split-plot design with three replications and MGD data were recorded followed by generation mean analysis. FOS reduced MGD by 1cm under both S. hermonthica and S. asiatica infestations. Additive, dominance, and epistatic gene actions were involved in the control of MGD of the two Striga species in the evaluated populations. On average, the relative contribution of additive, additive×additive and dominance×dominance genetic effects on the MGD of S. hermonthica and S. asiatica, with FOS, were 20, 33, and 36%; and 21, 32, and 35%, respectively. Breeding methods exploiting these genetic effects may provide enhanced response to selection for Striga resistance and FOS compatibility in integrated Striga management(ISM) programmes.展开更多
Many species of soil-inhabiting fungus Fusarium, cause severe yield loss in many crops. Experiments were conducted in net house condition with complete randomized block design to determine the individual effect of dif...Many species of soil-inhabiting fungus Fusarium, cause severe yield loss in many crops. Experiments were conducted in net house condition with complete randomized block design to determine the individual effect of different in-oculum levels of root-knot nematode, Meloidogyne incognita, Race-2 and Fusarium oxysporum f sp. lycopersici on plant growth parameters viz., Plant length, fresh and dry weight and number of fruits of tomato var. P21. The experimental results showed that both the pathogens cause significant reduction in plant growth parameters. However, the fungus was not much effective on plant growth parameters in comparison to root-knot nematode. Greatest reduction in plant growth parameters was recorded in plants inoculated with 8000 J2/Kg soil of Meloidogyne in-cognita race 2. The threshold level of root-knot nematode was 1000 J2/kg soil while threshold level of Fusarium was @ 1 g/Kg soil. Inoculum level of Fusarium oxysporum f sp. lycopersici and Meloidogyne in-cognita race-2 was pathogenic and caused significant reduction at and above 1 g/kg soil and 1000 J2/Kg soil respectively.展开更多
[Objective]The paper was to understand the field resistance performance of different banana varieties and the prevention and control ef-fect of different fertilizers,so as to provide technical reference for the preven...[Objective]The paper was to understand the field resistance performance of different banana varieties and the prevention and control ef-fect of different fertilizers,so as to provide technical reference for the prevention and control of Fusarium wilt.[Method]Field trials were set up with three treatments:shrimp peptide organic fertilizer+shrimp peptide special protection+shrimp peptide fruit Yekang(simplified as shrimp peptide organic fertilizer treatment),conventional organic fertilizer+microbial preparations(simplified as microbial treatment),and conventional or-ganic fertilizer(simplified as control).Four different banana varieties of Brazilian banana,Guijiao No.1,Nantianhuang,and Yunjiao No.1 were se-lected for the field trial.The disease incidence of Fusarium wilt and the control effects of three fertilizers were investigated during four time periods.[Result]The disease incidence of four varieties in three treatments varied.The disease incidence of Nantianhuang and Yunjiao No.1 were signifi-cantly lower than that of other two varieties.There was also significant difference in disease incidence of three treatments.The disease incidence from high to low was control>shrimp peptide organic fertilizer treatment>microbial treatment.The average monthly TR4 pathogen content in heavily infected banana plantation was more than 2000 copies,while the highest one reached 15148.9 copies.[Conclusion]Microbial agents reduced the disease incidence of Fusarium wilt to some content.Nantianhuang and Yunjiao No.1 showed the highest disease resistance compared with other varieties.However,their resistance needs to be further improved before practical application.展开更多
Seeds of chickpea cv.Ghab3 were treated with three fungicides;Oxycure,Topsin and Vitaflo,and infected by Fusarium Oxysporum f.sp.Ciceri at culturing under a glasshouse condition.The results showed that Oxycure(Oxychlo...Seeds of chickpea cv.Ghab3 were treated with three fungicides;Oxycure,Topsin and Vitaflo,and infected by Fusarium Oxysporum f.sp.Ciceri at culturing under a glasshouse condition.The results showed that Oxycure(Oxychloride)caused a significant increase in seed germination compared with other treatments,but it could not provide this protection at the post-germination phase,resulting in a significant increase in seedling mortality to 42.1%at 15 days after germination,compared with the other fungicides.In addition,Topspin(Thiophanate-methyl)was an effective protectant at germination stage,and in the seedling one too,since the percent of seedling mortality did not exceed 11.11%,whereas,Vitaflo had the least effect in protecting seeds from fungal infection,but with a significant difference with the positive control,as the percentage of non-germinated seeds was 41.66%and 62.5%,respectively.展开更多
In our previous studies, we identified 3 Trichoderma strains with anti-Fusarium oxysporum activity, including T. asperellum 525, T. harzianum 610, and T. pseudokoningii 886. Here, we evaluated the effects of these 3 T...In our previous studies, we identified 3 Trichoderma strains with anti-Fusarium oxysporum activity, including T. asperellum 525, T. harzianum 610, and T. pseudokoningii 886. Here, we evaluated the effects of these 3 Trichoderma strains on preventing cucumber fusarium wilt through pot culture and greenhouse culture experiments. All 3 Trichoderma strains demonstrated higher control effects toward cucumber fusarium wilt than previous studies, with efficacies over 78%. Additionally, inoculation with the 3 Trichoderma strains significantly promoted the quality and yield of cucumbers. Among the 3 strains, Trichoderma 866 was the most effective, with disease control efficacy of 78.64% and a cucumber yield increase of 33%. Furthermore, seedlings inoculated with Trichoderma exhibited significantly increased measures of plant height, stem diameter, leaf area, aboveground fresh weight, underground fresh weight, chlorophyll content, and nitric nitrogen content, as well as the activities of several stress-resistance enzymes, including superoxide dismutase(SOD), peroxidase(POD), catalase(CAT), polyphenol oxidase(PPO), and ascorbate oxidase(AAO). In addition, the plants inoculated with Trichoderma showed decreased cell membrane permeability and malondialdehyde(MDA) content in the leaves. Together, our results suggest that T. asperellum 525, T. harzianum 610, and T. pseudokoningii 886 inoculations inhibit F. oxysporum infection, stimulate the metabolism in cucumbers, and enhance the activities of stress-resistance enzymes, which consequently promote the growth of cucumber plants, prevent cucumber fusarium wilt, and improve the yield and quality of cucumbers. T. harzianum is a commonly used biocontrol fungus, while few studies have focused on T. asperellum or T. koningense. In this study, strains of T. asperellum and T. pseudokoningii showed excellent plant disease prevention and growth promoting effects on cucumber, indicating that they also have great potential as biocontrol fungi.展开更多
In order to clarify the main pathogens of tomato Fusarium wilt in Shanxi Province, China, morphological identification, elongation factor 1 alpha (EF-1α) sequence analysis, specific primer amplification and pathoge...In order to clarify the main pathogens of tomato Fusarium wilt in Shanxi Province, China, morphological identification, elongation factor 1 alpha (EF-1α) sequence analysis, specific primer amplification and pathogenicity tests were applied to study the isolates which were recovered from diseased plants collected from 17 different districts of Shanxi Province. The results were as follows: 1) Through morphological and molecular identification, the following 7 species of Fusarium were identified: F. oxysporum, F. solani, F. verticillioides, F. subglutinans, F. chlamydosporum, F. sporotrichioides, and F. semitectum; 2) 56 isolates of F. oxysporum were identified using specific primer amplification, among which, 29, 5 and 6 isolates were respectively identified as F. oxysporum f. sp. lycopersici physiological race 1, race 2, and race 3; 3) pathogenicity test indicated the significant pathogenicity of F. oxysporum, F. solani, F. verticillioides, and F. subglutinans to tomato plant. Therefore, among these 4 species confirmed as pathogenic to tomato in Shanxi, the highest isolation rate (53.3%) corresponded to F. oxysporum. Three physiological species, race 1, race 2, and race 3 of F. oxysporum f. sp. lycopersici are detected in Shanxi, among which race 1 is the most widespread pathogen and is also considered as the predominant race.展开更多
基金supported by the National Natural Science Foundation of China (31601583)the Natural Science Foundation of Fujian Province, China (2016J01113)+1 种基金the Young Teacher Education Research Project of Fujian Province, China (JAT160178)the Fujian Agriculture and Forestry University Outstanding Youth Scientific Research Project, China (xjq201625)
文摘Fusarium wilt, caused by Fusarium oxyporum f. sp. cubense(Foc), is the most serious disease affecting banana production.To clarify the distribution of the Foc races in Fujian Province of China, 79 soil samples were collected from four regions of Zhangzhou City, the primary banana production area in Fujian. We isolated and identified 12 Foc strains based on internal transcribed spacer(ITS) sequence analysis, PCR amplification by using Foc-specific primers and pathogenicity assays.Our analysis indicated that 11 isolates belong to Foc race 1, and 1 isolate belongs to the Foc tropical species race 4(TR4).Although TR4 has previously been reported to occur in primary banana-producing provinces, such as Hainan, Guangxi,and Guangdong of China, this is the first report of TR4 isolated from the soil in Fujian Province. Monitoring the presence of Foc, in particular, the TR4 strains in the soil, is the basic strategy to prevent and control Fusarium wilt.
基金supported by the National Natural Science Foundation of China (30860149 and 31360364)the Joint Support Program from Tropical Crop Breeding Engineering Center of Ministry of Education of China+1 种基金the Crop Science National Key Disciplines of China (lhxm-2012-2)the Key Scientific Research Program from Hainan Province,China (ZDZX2013023)
文摘Fusarium wilt of banana, which is caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), is a serious soil-borne fungal disease. Now, the epigenetic molecular pathogenic basis is elusive. In this study, with methylation-sensitive amplification polymorphism (MSAP) technique, DNA methylation was compared between the leaves inoculated with Foc TR4 and the mock-inoculated leaves at different pathogenic stages. With 25 pairs of primers, 1 144 and 1 255 fragments were amplified from the infected and mock-inoculated leaves, respectively. DNA methylation was both changed and the average methylated CCGG sequences were 34.81 and 29.26% for the infected and the mock-inoculated leaves. And DNA hypermethylation and hypomethylation were induced by pathogen infection during all pathogenic stages. Further, 69 polymorphic fragments were sequenced and 29 of them showed sequence similarity to genes with known functions. And RT-PCR results of four genes indicated that their expression patterns were consistent with their methylation patterns. Our results suggest that DNA methylation plays important roles in pathogenic response to Foc TR4 for banana.
文摘Endophytic bacteria colonizing the shoot-tips of banana cv. Grand Naine were isolated and tested for the antagonistic activity against the Panama wilt pathogen Fusarium oxysporum f. sp. cubense (Foc). Pre-isolation, the suckers were given extensive disinfection treatments and the homogenate from the excised shoot-tip portion was plated on nutrient agar (NA) and trypticase soy agar (TSA). This yielded altogether 47 isolates: 26 on NA and 21 on TSA, respectively, from the 10 suckers collected during August to February. The number of bacterial isolates obtained per sucker varied from one to 15 based on colony characteristics registering up to 10 distinct species per shoot-tip based on 16S rRNA sequence analysis. The 47 isolates belonged to 19 genera and 25 species under the phylogenetic classes of Actinobacteria, α- and γ-Proteobacteria and Firmicutes. Actinobacteria constituted the predominant phylum (55% isolates) with the constituent genera of Arthrobacter, Brevibacterium, Corynebacterium, Curtobacterium, Kocuria, Kytococcus, Micrococcus, Naumanella, Rothia and Tessaracoccus spp. and an unidentified isolate belonging to the family Frankiaceae. Proteobacteria constituted the second major phylum (Brevundimonas, Enterobacter, Klebsiella, Pseudomonas, Serratia and Sphingomonas spp.) followed by Firmicutes (Bacillus and Staphylococcus spp.). Antagonistic activity of the endophytes against Foc was tested through agar plate assays (pit and spot applications on fungal lawn) employing potato dextrose agar and NA. Endophytic Pseudomonas aeruginosa (isolate GNS.13.2a) which was associated with a single sucker showed significant growth inhibition effect on Foc while Klebsiella variicola (GNS.13.3a) and Enterobacter cloacae (GNS13.4a) exhibited moderate inhibition. The study brings out considerable sucker to sucker variation in the associated cultivable endophytic bacteria in “Grand Naine” banana and identifies a few bacterial endophytes with biocontrol potential against the devastating Foc pathogen.
基金Supported by Epidemic Monitoring and Control Program of Pests and Diseasesin Tropical Crops in 2013 by Ministry of Agriculture(Issued Document Number:NBK[2013]No.28)
文摘[ Objective] The paper was to study biological characteristics of Fusarium oxysporum f. sp. niveum in watermelon cultivated in plastic greenhouse in Hainan Province of China and to determine indoor toxicity of fungicides. [ Method] Effects of various factors on mycelial growth and spore germination were stud- ied, and the lethal temperature of spores and indoor toxicity of fungicides were also determined. [Result] The fungal mycelium had a better growth rate on water- melon juice medium than the others. The optimum temperature for mycelial growth and spore germination were 28 ℃ and 30 ℃, and the optimum pH values were 7 - 8 and 7 - 9, respectively. Light-dark alternation was conducive for mycelial growth. The lethal temperature of spore was 60 ℃ for 5 min. The fungal mycelium grew better while taking fructose and glucose as carbon sources and yeast extract and peptone as nitrogen sources. Toxicity determination showed that 50% pro- chloraz-manganese chloride complex WP had the greatest inhibition effect on mycelial growth, with the ECso value of 0.730 9 μg/mL; followed by 32.5% benzoic azoxystrobin SC, 30% benzoylate· propieanazol EC, 10% difenoconazole WG, 25% bromothalonil · carbendazim WP and 25% bromothalonil WP, with the ECso values from 1.884 7μg/mL to 8. 161 0μg/mL. [Conclusion] The study provided basic data for field control against F. oxysporum f. sp. niveum on watermelon cultivated in plastic greenhouse in Hainan Province.
文摘The article is based on the use of experimental polyploidy method, with the introduction of new introgressive hybrid forms combining several species genotype with pathogenic Verticillium dahliae Kleb. and the effects of mycotoxins separated from the Fusarium oxysporum f.sp. vasinfectum micromicette on the yield of plant seeds. New artificial complex hypertension forms based on experimental polyploidy Verticillium dahliae Kleb. and Fusarium oxysporum f.sp. vasinfectum combine the potential of resistance to mycotoxins separated from microcrystals, making a tremendous contribution to the selection of new varieties and to the effectiveness of selection as a result of the use of genetic selective research as genetic-selective genetic-selector studies.
基金Supported by Yunnan Science and Technology Innovation Talent Program(2015HA034)National Natural Science Foundation of China(NSFC31560505)
文摘Fusarium wilt of banana, caused by Fusarium oxysporum f. sp. cubense tropic race 4(Foc TR4), is a typical vascular and soil-borne disease which has significantly threatened the sustainable development of banana industry. In order to reveal the infection process and pathogenesis of Foc TR4, the young mycelia(66.7 mg/ml) of wild-type strain of Foc TR4(WT-Foc TR4) cultured for 18-20 h were lysed with enzyme mixture for protoplast formation, which consisted of 25 mg/ml driselase, 0.4 mg/ml chitinase, 15 mg/ml lysing enzyme and 1.2 mol/L potassium chloride. The resulted protoplasts of 2×10~7 cells/ml were used to test the efficiency of transformation mediated by polyethylene glycol, and up to 9 transformants per microgram of DNA were obtained. AmCyan, RFP and YFP genes were stably transferred into the WT-Foc TR4, separately, using the protoplast transformation system. The gene FoOCH1 encoding α-1, 6-mannosyltransferase in the WT-Foc TR4 was knocked out using the split-marker recombination technology. The genetic transformation and gene knockout system in this pathogen lays a foundation for the study of functional genomics and plant-pathogen interactions.
文摘Wax gourd (Benincasa hispida Thumb. Cogn) is called white gourd, winter melon, Chinese preserving melon, Chinese squash, and don kwa. It has been cultivated in China for over 2 300 years. It probably
文摘The dynamic changes in membrane permeability, activities of disease-related enzymes, and contents of pathogenesis-relevant chemical compounds and photosynthetic pigments in root cells of three watermelon cultivars were studied after inoculation with Fusarium oxysporum f. sp. niveum at seedling stage. The results showed that the capacity of self-regulating and returning to normal status of cultivar Kelunsheng (resistant) was greater than that of a susceptible cultivar, Zaohua, in terms of malonaldehyde (MDA) content, relative conductivity, and activity of superoxide dismutase (SOD) and catalase (CAT). The resistant cultivar maintained a higher activity of dehydrogenase, higher content of vitamin C(Vc) , and relatively lower content of soluble sugar than the susceptible cultivar. The content of soluble protein was higher in the resistant cultivar than that in the susceptible one at day 1 after inoculation. The capacities of the resistant cultivar to inhibit chlorophyll deterioration and maintain a higher carotenoid content were significantly stronger than those of the susceptible cultivar.
基金The Alliance for a Green Revolution in Africa(AGRA)is gratefully acknowledged for financial support of the study through the African Centre for Crop Improvement(ACCI)
文摘Maximum germination distance(MGD) is an important component of Striga resistance in sorghum. The objective of this study was to determine gene action influencing MGD of Striga hermonthica and Striga asiatica among selected sorghum lines treated with a biocontrol agent, Fusarium oxysporum f. sp. strigae(FOS) for effective breeding with Striga resistance, and FOS compatibility. Twelve sorghum genotypes were selected based on their Striga resistance, FOS compatibility, and superior agronomic performance. Selected genotypes were crossed using a bi-parental mating design to generate six families for genetic analysis. Agar-gel assays were used to determine low haustorium initiation factor(LHF) using the 12 parental lines, their F_1 progenies, backcross derivatives, and F_2 segregants in two sets. One set had S. hermonthica seed and the other one had S. asiatica seed. Both were treated with and without FOS. Genotypes were evaluated using a split-plot design with three replications and MGD data were recorded followed by generation mean analysis. FOS reduced MGD by 1cm under both S. hermonthica and S. asiatica infestations. Additive, dominance, and epistatic gene actions were involved in the control of MGD of the two Striga species in the evaluated populations. On average, the relative contribution of additive, additive×additive and dominance×dominance genetic effects on the MGD of S. hermonthica and S. asiatica, with FOS, were 20, 33, and 36%; and 21, 32, and 35%, respectively. Breeding methods exploiting these genetic effects may provide enhanced response to selection for Striga resistance and FOS compatibility in integrated Striga management(ISM) programmes.
文摘Many species of soil-inhabiting fungus Fusarium, cause severe yield loss in many crops. Experiments were conducted in net house condition with complete randomized block design to determine the individual effect of different in-oculum levels of root-knot nematode, Meloidogyne incognita, Race-2 and Fusarium oxysporum f sp. lycopersici on plant growth parameters viz., Plant length, fresh and dry weight and number of fruits of tomato var. P21. The experimental results showed that both the pathogens cause significant reduction in plant growth parameters. However, the fungus was not much effective on plant growth parameters in comparison to root-knot nematode. Greatest reduction in plant growth parameters was recorded in plants inoculated with 8000 J2/Kg soil of Meloidogyne in-cognita race 2. The threshold level of root-knot nematode was 1000 J2/kg soil while threshold level of Fusarium was @ 1 g/Kg soil. Inoculum level of Fusarium oxysporum f sp. lycopersici and Meloidogyne in-cognita race-2 was pathogenic and caused significant reduction at and above 1 g/kg soil and 1000 J2/Kg soil respectively.
基金Supported by Major Crop Pests Monitoring,Disaster Regulation and Prevention and Control Mecha-nism Project in Yunnan Province(2018BB016)Yunling Scholar Programme of Yunnan Provincial Government,Science and Technology Innovation Talents Program in Yunnan Province(2015HA034)+1 种基金Special Project of National Banana Industry Technical System(CARS-31-08)Key Laboratory of Green Prevention and Control of Agricultural Transboundary Pests of Yunnan Province&the CGIAR Research Program on Roots,Tubers and Bananas(RTB)。
文摘[Objective]The paper was to understand the field resistance performance of different banana varieties and the prevention and control ef-fect of different fertilizers,so as to provide technical reference for the prevention and control of Fusarium wilt.[Method]Field trials were set up with three treatments:shrimp peptide organic fertilizer+shrimp peptide special protection+shrimp peptide fruit Yekang(simplified as shrimp peptide organic fertilizer treatment),conventional organic fertilizer+microbial preparations(simplified as microbial treatment),and conventional or-ganic fertilizer(simplified as control).Four different banana varieties of Brazilian banana,Guijiao No.1,Nantianhuang,and Yunjiao No.1 were se-lected for the field trial.The disease incidence of Fusarium wilt and the control effects of three fertilizers were investigated during four time periods.[Result]The disease incidence of four varieties in three treatments varied.The disease incidence of Nantianhuang and Yunjiao No.1 were signifi-cantly lower than that of other two varieties.There was also significant difference in disease incidence of three treatments.The disease incidence from high to low was control>shrimp peptide organic fertilizer treatment>microbial treatment.The average monthly TR4 pathogen content in heavily infected banana plantation was more than 2000 copies,while the highest one reached 15148.9 copies.[Conclusion]Microbial agents reduced the disease incidence of Fusarium wilt to some content.Nantianhuang and Yunjiao No.1 showed the highest disease resistance compared with other varieties.However,their resistance needs to be further improved before practical application.
文摘Seeds of chickpea cv.Ghab3 were treated with three fungicides;Oxycure,Topsin and Vitaflo,and infected by Fusarium Oxysporum f.sp.Ciceri at culturing under a glasshouse condition.The results showed that Oxycure(Oxychloride)caused a significant increase in seed germination compared with other treatments,but it could not provide this protection at the post-germination phase,resulting in a significant increase in seedling mortality to 42.1%at 15 days after germination,compared with the other fungicides.In addition,Topspin(Thiophanate-methyl)was an effective protectant at germination stage,and in the seedling one too,since the percent of seedling mortality did not exceed 11.11%,whereas,Vitaflo had the least effect in protecting seeds from fungal infection,but with a significant difference with the positive control,as the percentage of non-germinated seeds was 41.66%and 62.5%,respectively.
基金support from the National Key R&D Program of China (2018YFD0201202)the National Science and Technology Basic Work, China (2014FY120900)the 948 Program of China (2011-G4)
文摘In our previous studies, we identified 3 Trichoderma strains with anti-Fusarium oxysporum activity, including T. asperellum 525, T. harzianum 610, and T. pseudokoningii 886. Here, we evaluated the effects of these 3 Trichoderma strains on preventing cucumber fusarium wilt through pot culture and greenhouse culture experiments. All 3 Trichoderma strains demonstrated higher control effects toward cucumber fusarium wilt than previous studies, with efficacies over 78%. Additionally, inoculation with the 3 Trichoderma strains significantly promoted the quality and yield of cucumbers. Among the 3 strains, Trichoderma 866 was the most effective, with disease control efficacy of 78.64% and a cucumber yield increase of 33%. Furthermore, seedlings inoculated with Trichoderma exhibited significantly increased measures of plant height, stem diameter, leaf area, aboveground fresh weight, underground fresh weight, chlorophyll content, and nitric nitrogen content, as well as the activities of several stress-resistance enzymes, including superoxide dismutase(SOD), peroxidase(POD), catalase(CAT), polyphenol oxidase(PPO), and ascorbate oxidase(AAO). In addition, the plants inoculated with Trichoderma showed decreased cell membrane permeability and malondialdehyde(MDA) content in the leaves. Together, our results suggest that T. asperellum 525, T. harzianum 610, and T. pseudokoningii 886 inoculations inhibit F. oxysporum infection, stimulate the metabolism in cucumbers, and enhance the activities of stress-resistance enzymes, which consequently promote the growth of cucumber plants, prevent cucumber fusarium wilt, and improve the yield and quality of cucumbers. T. harzianum is a commonly used biocontrol fungus, while few studies have focused on T. asperellum or T. koningense. In this study, strains of T. asperellum and T. pseudokoningii showed excellent plant disease prevention and growth promoting effects on cucumber, indicating that they also have great potential as biocontrol fungi.
基金partially supported by the Shanxi Provincial Science and Technology Planning Project,China (20120311019-3)the Shanxi Provincial Science and Technology Foundation Platform Construction Project,China (1105-0104)the Shanxi Provincial Graduate Education Innovation Project,China (2017BY065)
文摘In order to clarify the main pathogens of tomato Fusarium wilt in Shanxi Province, China, morphological identification, elongation factor 1 alpha (EF-1α) sequence analysis, specific primer amplification and pathogenicity tests were applied to study the isolates which were recovered from diseased plants collected from 17 different districts of Shanxi Province. The results were as follows: 1) Through morphological and molecular identification, the following 7 species of Fusarium were identified: F. oxysporum, F. solani, F. verticillioides, F. subglutinans, F. chlamydosporum, F. sporotrichioides, and F. semitectum; 2) 56 isolates of F. oxysporum were identified using specific primer amplification, among which, 29, 5 and 6 isolates were respectively identified as F. oxysporum f. sp. lycopersici physiological race 1, race 2, and race 3; 3) pathogenicity test indicated the significant pathogenicity of F. oxysporum, F. solani, F. verticillioides, and F. subglutinans to tomato plant. Therefore, among these 4 species confirmed as pathogenic to tomato in Shanxi, the highest isolation rate (53.3%) corresponded to F. oxysporum. Three physiological species, race 1, race 2, and race 3 of F. oxysporum f. sp. lycopersici are detected in Shanxi, among which race 1 is the most widespread pathogen and is also considered as the predominant race.