The Use Of Green Fluorescent Protein Marker To Study Infection Of Three Different Banana Varieties With Fusarium Oxysporum F.SP. Cubense Race4

Fusarium Wilt of banana is a devastating vascular system disease caused by Fusarium oxysporum f.sp.cubense. The Foc-4is the greatest harm to banana production in many banana-growing areas in the whole world. The disease is also one of the most devastating diseases of banana in China. Research has important significance through the method of plant pathology in banana fusarium wilt pathogen infection mechanism and analysis resistant characteristics of different resistant varieties banana.Using fresh hyphae as starting materials, we successfully isolated a large number of protoplast. Put the plasmid pSC001carrying GFP gene transformation into Fusarium oxysporum f.sp.cubense (Foe) use PEG-CaCl2According to the transformation of hypha and spores create stable green fluorescent in a fluorescent microscope. So GFP gene has successfully transformed to Foc and gets expression. Continuous training seven generations and vaccinating infection in Brazil to the introduction of GFP genetic and pathogenic is stable.Three banana cultivars were identified for their resistance to Foe through root dipping. The results showed Foe could infect Brazilian banana,Wilt-resistant#1and Haigong banana.On the basis of phenotype, disease index and Morbidity, three were rouped into high resistance, resistance and susceptibility. Brazilian banana was susceptible to Foc. Wilt-resistant#1was resistant to Foc. Haigong banana showed high resistance to Foc.To understand infection of banana by Foc-4, we used GFP-transformed pathogen inoculated to three banana cultivars and studied pathogenesis using fluorescence microscopy. The study showed that, conidia randomLy adsorbed on the surface of roots after inoculation one day. No appressorium was observed when pathogens infected root of banana. Hyphae preferential penetrated through root epidermis, root hair and wound. The massive infectious hyphae of the fungal pathogen was observed extensively in the xylem vessels of banana root. The Foc-4expansion way in the bulb and false stems of banana similar to in the roots.We observed spores were germinated and growed, and hyphae creeping growed in the leaf surface of Brazil banana, tend to the leaf surface around the stoma.Some of hyphae had infecting into the palisade tissue through the pores. The mycelia were growing along the cell wall and expanding.No appressorium was observed.Infection process of Foc-4in high resistance and susceptibility banana were studied using fluorescence microscopy.The study showed that, There were some differences in the germination time of conidia between different resistant varieties of banana, and conidia randomLy adsorbed on the surface of roots after inoculation. Hyphae preferential penetrated through root epidermis, root hair and lateral root. Further observation showed that massive hyphae and conidia of Foc-4appeared in xylem vessels of susceptibility Brazilian banana, and lower in Wilt-resistant#1, and no hyphae in Haigong banana.The results of infection process demonstrated that there were some differences in the infection time and extended mode of Foc-4among with different resistant varieties of banana. Wilt-resistant#1and Haigong banana could inhibit Foc-4to expand and breed in root, showed resistance to Foc-4through physiological and biochemical resistance.