Late wilt, a severe vascular disease of maize caused by the fungus Harpophora maydis, is characterized by relatively rapid wilting of maize plants, before tasseling and until shortly before maturity. In Israel, the di...Late wilt, a severe vascular disease of maize caused by the fungus Harpophora maydis, is characterized by relatively rapid wilting of maize plants, before tasseling and until shortly before maturity. In Israel, the disease becomes a major problem in recent years. The pathogen currently controlled using varieties of maize has reduced sensitivity. In earlier work, we modified a molecular method for use as a diagnostic tool to evaluate the disease progress in field infested plants. Several fungicides suppressed H. maydis in vitro and in a detached root pathogenicity assay. Seedling pathogenicity assay enables us to identified H. maydis DNA in the host root and stem tissues 18 days after sowing in both susceptible and tolerant maize plants. Although the infested plants exhibited no wilt symptoms, their roots were significantly shorter in length. This seedling assay was used to demonstrate the suppressive effect of the fungicide Flutriafol on H. maydis virulence. The method of assaying the pathogen in a series of trials starting in a plate assay, followed by a detached root and resulting in a seedlings pathogenicity assay, using molecular and morphological approaches could be generalized to other plant pathogens.展开更多
Late wilt, a severe vascular disease of maize caused by the fungus Harpophora maydis, is characterized by relatively rapid wilting of maize plants before tasseling and until shortly before maturity. In Egypt and Israe...Late wilt, a severe vascular disease of maize caused by the fungus Harpophora maydis, is characterized by relatively rapid wilting of maize plants before tasseling and until shortly before maturity. In Egypt and Israel, the disease is considered to be a major problem. The pathogen is currently controlled using cultivars of maize having reduced sensitivity, but the fungi can undergo pathogenic variations and become a threat to resistance cultivars as well. The abiotic and biotic factors influencing the infection and disease development are not fully determined. To impose stress in a uniform and chronic manner, we expose the Israeli H. maydis isolates colonies or spores to light, different pH, ionic and hyperosmotic pressures (induced with KCl or sorbitol) or oxygen-related stresses (induced with oxygen enrichment, menadione or peroxide). The optimum pH for both hyphal development and spore germination was pH = 5 - 6, similar to reports for the Egyptian, Indian and Hungarian isolates of H. maydis. In the hyperosmotic regime, hyphal growth was affected in a dosage-dependent curve. Although inoculation under high salt stress also inhibited spore germination, the spores were relatively resistant to this stress in comparison to the hypha. An opposite picture was revealed under menadione/peroxide stress: under high dosage of these compounds, the spore germination was virtually abolished while the colony growth was moderately affected. A daily oxygen enrichment of liquid medium cultures caused an increased growth in the pathogen wet and dry biomass, but daily double treatments led to growth suppression. These findings are a preliminary step towards the inspection of the fungal-host interaction under these different stressful environments. This is important for the future development of new strategies to restrict the disease burst and to protect field corps.展开更多
The study was conducted with 75 tomato entries at the farm of Olericulture Division, Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh during the winter season ...The study was conducted with 75 tomato entries at the farm of Olericulture Division, Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh during the winter season of 2020-21 to evaluate insect and disease reaction. Among the various insect and diseases of tomatoes, the late blight, TYLCV, bacterial wilt infection and leaf miner, fruit borer infestation are most common in Bangladesh. The TYLCV infection was observed 0% to 27% infection, while 47 entries showed zero percent infection. The range of bacterial wilt infection was 0% to 10% and zero percent infection was observed in 62 entries. In case of leaf miner infestation and fruit borer infestation, the range was 0% to 43% and 0% to 10%, respectively. Considering tolerance to late blight, TYLCV, bacterial wilt infection and leaf miner, fruit borer infestation, fruit size, fruit shape, plant growth nature, cluster nature of fruit, type of fruit ten entries AVTO 1010, AVTO 1706, AVTO 1713, AVTO 1829, AVTO 1909, AVTO 1911, AVTO 1915, AVTO 1921, AVTO 1954 and SLA 011 were found zero percent late blight, TYLCV, bacterial wilt infection and leaf miner, fruit borer infestation. So, these ten entries can be selected for disease and insect tolerant tomato varieties development as well as developing disease and insect tolerant hybrid tomato varieties.展开更多
文摘Late wilt, a severe vascular disease of maize caused by the fungus Harpophora maydis, is characterized by relatively rapid wilting of maize plants, before tasseling and until shortly before maturity. In Israel, the disease becomes a major problem in recent years. The pathogen currently controlled using varieties of maize has reduced sensitivity. In earlier work, we modified a molecular method for use as a diagnostic tool to evaluate the disease progress in field infested plants. Several fungicides suppressed H. maydis in vitro and in a detached root pathogenicity assay. Seedling pathogenicity assay enables us to identified H. maydis DNA in the host root and stem tissues 18 days after sowing in both susceptible and tolerant maize plants. Although the infested plants exhibited no wilt symptoms, their roots were significantly shorter in length. This seedling assay was used to demonstrate the suppressive effect of the fungicide Flutriafol on H. maydis virulence. The method of assaying the pathogen in a series of trials starting in a plate assay, followed by a detached root and resulting in a seedlings pathogenicity assay, using molecular and morphological approaches could be generalized to other plant pathogens.
文摘Late wilt, a severe vascular disease of maize caused by the fungus Harpophora maydis, is characterized by relatively rapid wilting of maize plants before tasseling and until shortly before maturity. In Egypt and Israel, the disease is considered to be a major problem. The pathogen is currently controlled using cultivars of maize having reduced sensitivity, but the fungi can undergo pathogenic variations and become a threat to resistance cultivars as well. The abiotic and biotic factors influencing the infection and disease development are not fully determined. To impose stress in a uniform and chronic manner, we expose the Israeli H. maydis isolates colonies or spores to light, different pH, ionic and hyperosmotic pressures (induced with KCl or sorbitol) or oxygen-related stresses (induced with oxygen enrichment, menadione or peroxide). The optimum pH for both hyphal development and spore germination was pH = 5 - 6, similar to reports for the Egyptian, Indian and Hungarian isolates of H. maydis. In the hyperosmotic regime, hyphal growth was affected in a dosage-dependent curve. Although inoculation under high salt stress also inhibited spore germination, the spores were relatively resistant to this stress in comparison to the hypha. An opposite picture was revealed under menadione/peroxide stress: under high dosage of these compounds, the spore germination was virtually abolished while the colony growth was moderately affected. A daily oxygen enrichment of liquid medium cultures caused an increased growth in the pathogen wet and dry biomass, but daily double treatments led to growth suppression. These findings are a preliminary step towards the inspection of the fungal-host interaction under these different stressful environments. This is important for the future development of new strategies to restrict the disease burst and to protect field corps.
文摘The study was conducted with 75 tomato entries at the farm of Olericulture Division, Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh during the winter season of 2020-21 to evaluate insect and disease reaction. Among the various insect and diseases of tomatoes, the late blight, TYLCV, bacterial wilt infection and leaf miner, fruit borer infestation are most common in Bangladesh. The TYLCV infection was observed 0% to 27% infection, while 47 entries showed zero percent infection. The range of bacterial wilt infection was 0% to 10% and zero percent infection was observed in 62 entries. In case of leaf miner infestation and fruit borer infestation, the range was 0% to 43% and 0% to 10%, respectively. Considering tolerance to late blight, TYLCV, bacterial wilt infection and leaf miner, fruit borer infestation, fruit size, fruit shape, plant growth nature, cluster nature of fruit, type of fruit ten entries AVTO 1010, AVTO 1706, AVTO 1713, AVTO 1829, AVTO 1909, AVTO 1911, AVTO 1915, AVTO 1921, AVTO 1954 and SLA 011 were found zero percent late blight, TYLCV, bacterial wilt infection and leaf miner, fruit borer infestation. So, these ten entries can be selected for disease and insect tolerant tomato varieties development as well as developing disease and insect tolerant hybrid tomato varieties.
