Effects of Organic Phosphorus on Growth and Pathogenicity of Fusarium graminearum
Fusarium graminearum,the main pathogen of maize stalk rot in the northeast of China,was used as the research object in this study.The effects of lecithin and phytic acid from different stable organic phosphorus sources on the mycelial growth and pathogenicity of Fusarium gra-minearum were studied by cross method,dry weight method,biological detection method and fluores-cence immunoquantitative analysis.The results showed that:lecithin can significantly promote the growth of Fusarium graminearum.In the plate culture experiment,when the phosphorus concentra-tion was 4.38 mmol/L,the colony diameter of lecithin group on the sixth day of growth has reached 8.5 cm,while that of phytic acid group and K2HPO4 group on the seventh day of culture did not reach 7 cm.The result of biomass measurement was consistent with it.Different organic phosphorus not only affects the growth of Fusarium graminearum,but also affects its metabolism.When the phospho-rus concentration was 43.8 mmol/L,the inhibition rate of lecithin and phytic acid fermentation me-dium on maize seed germination was 56.7％and 43.3％,which were 3.4 and 2.6 times that of K2HPO4,respectively.The inhibition substance of maize seed growth in fermentation medium was de-oxynivalenol(DON).The highest concentration of DON in lecithin group was 978.55 μg/L,followed by phytic acid group(580.79 μg/L),which was significantly higher than K2HPO4(104.51 µg/L),and the DON concentration increased with the increase of phosphorus concentration.The production of DON toxin from organic phosphorus was the main pathogenic mechanism of maize stalk rot caused by Fusarium graminearum infection.The pathogenicity test was set up according to the DON measure-ment results.The results showed that the incidence rate of maize seedlings reached 98.33％and 90％,respectively,with lecithin and phytic acid as phosphorus sources,and the disease index was 94 and 89,respectively,compared with K2HPO4(incidence rate 76.66％,disease index 72).The pathoge-nicity of Fusarium graminearum increased significantly.In addition,we also discussed the effect of soil organic phosphorus bioavailability and its influencing factors on the occurrence of maize stalk rot.
万方数据
维普
