Infection Difference Of Fusarium Oxysporum F.Sp. Cubense Race 1 And Race 4 In The Different Banana Varieties

Abstrct:Banana fusarium wilt,caused by Fusarium oxysporum f. sp. cubense(Foc), is a worldwidebanana devastating disease.Many banana industry growing areas in the world have been hurt by the banana fusarium wilt, and the banana fusarium wilt in the south of China has become one of the limiting factors of the development of the banana industry.Study the differet factors of Foc1 and Foc4 in the pathogenic process and the interaction between the pathogen and the host can provide further reference and theoretical basis for the prevention and treatment of breeding for disease resistance and banana fusarium wilt disease.Banana Fusarium Wilt in the infected host will secrete a series of toxins, including fusaric acid, beauvericin and so on.These toxins are considered to be an important virulence factor in Fusarium wilt pathogenic process.In this study,with Foc1 and Foc4 in Pisang awak and Brazil two varieties of bananas as research materials.Comparedthe differet of Foc1 and Foc4 in fusaric acid, cell wall degrading enzymes andprocess of infection.To explore the relationship between these factors and Fusarium wilt disease.The results showed that:At 1 day postinoculation, in the treatment of Foc1 infection Pisang awka and Foc4 infection Brazil and Pisang awka,microconidium started attached to the root epidermal cells; At 3 days postinoculation,the spores can germinate and invade the intercellular layer of the epidermal cells, and grow along the gap between the cells; At 5 days postinoculation,and then entered into xylem vessels.But in the treatment of Foc1 infection Brazil, spore germination is slow, spores and hyphae in the root is limited expansion and the number of hyphae and spores is less.In the study, we found that Fo4 in Pisang awka spreaded faster in the xylem vessels than in the Brazilian.It’s showed that Foc spreaded easiser in the Pisang awka than in the Brazilian.The results of Fusarium acid content showed that:(1) Foc1 and Foc4 respectively infect Pisang awak and Brazil,the toxin content in the root is gradually increased with the inoculation time;(2) The toxin content in the treatment of Foc1 in Brazil bananais the lowest;(3)The treatments of Foc1 in Pisang awakand Foc4 in Pisang awak and Foc4 in Brazil,the toxin content within the root showed a relatively stable rising, and the content in Pisang awakis more than thecontentof Brazil;(4) The toxin content of Foc1 and Foc4 in Pisang awak areno significant difference in P=0.05 level.The result of infection by Fusarium oxysporum observations: PG, PMG and Cx were detectedin the treatments of Foc1 and Foc4 in Brazil and Pisang awak,and the activity of PG was highest.In the treatment of Foc1 in Pisang awakand Foc4 in Pisang awakand Brazil,the activity of PG has two peaksat 3 days postinoculationand 6days postinoculation,and the content of 3 d is higher than the content of 6d.The activity of PMG has one peak at 3 days postinoculation,this show that PG and PMG played a positive role in the infection process.In the treatment of Foc1 in Brazil,PG and PMG just have one peak,which meet the different condition that in the treatment of Foc1 in Pisang awakand Brazil.In the course of the test, it was found that the activity of Cx was the lowest in the three kinds of enzymes, and the activity was not obvious. It was speculated that Cx might not be an important pathogenic factor or only play a supporting role in the infection process.