Microbiological and molecular studies on Fusarium rot disease of maize plants

Abstract

In this study, Fusarium species were isolated from different maize plant organs (roots, stalks, leaves and kernels) showing rotting symptoms grown in El-Kanater region. These fungi were isolated and identified to species level, and then screened for pathogenicity against maize plant organs by secreting cell wall degrading enzymes and mycotoxins where they detected in vitro and in vivo by helping of scanning electron microscope observations. Briefly, the results can be summarized in the following points: 1- Six Fusarium species were isolated from the pre-harvest maize samples of kernels, leaves, stalks and roots showing rotting symptoms from El-Kanater region on PDA medium where six Fusarium species were obtained from maize ears, one Fusarium species were obtained from maize leaves, three Fusarium species were obtained from maize roots and three Fusarium species were obtained from maize stalks. - In maize ears, Fusarium verticillioides show the highest percentage frequency (68 %) followed by Fusarium proliferatum (48 %).

- In maize roots, Fusarium verticillioides, Fusarium proliferatum showed the same percentage frequency (5.26 %). - In maize stalks, Fusarium verticillioides show the highest percentage frequency (25 %) followed by Fusarium proliferatum (15 %). - In maize leaves, Fusarium verticillioides show 10 % percentage frequency. 2- Pathogenicity tests: a- All Fusarium spp. does not show any significant pathogenic differences from the control experiment on DI % at 14 and 21 DAI except F. Verticillioides. b- Maize plants grown in soil infested with F. Verticillioides developed stalk rot disease and gave the highest significant percentage of DI and SDI of (30 %, 45 %) and (18 %, 34 %) respectively after 7 and 14 days of inoculation. c- F. Verticillioides gave the highest significant percentage of all parameters followed by F. proliferatum (55 %, 40 %, 49 % and 0.91for DI, SDI, FDK % and AUDPCstand respectively) then F. oxysporum (40 %, 18 %, 33 % and 0.98 for DI, SDI, FDK % and AUDPCstand respectively). d- Treatment of maize plants with F. verticillioides gave the highest improvement at seedling, 45 and 100 days of sowing