Growth-promoting effects of Trichoderma asperellum strain PZ6 on banana and its indoor control effect against banana fusarium wilt

ObjectiveThe present study investigated effects of Trichoderma asperellum strain PZ6 on banana growth promoting, antioxidase activities and indoor control effect of fusarium wilt, in order to provide references for prevention and control of fusarium wilt and development of strain PZ6. MethodTaking clear water as control(CK), five different combi-nations involving PZ6 spore liquid and Fusarium oxysporum f. sp. cubense liquid(FOC4) were set:(1)PZ6,(2)PZ6+FOC4,(3)PZ63d+FOC4,(4)FOC43d+PZ6 and (5)FOC4. Inoculation at banana rhizosphere was conducted at 6-7 leaf stage using root-injury irrigating method. The plant traits in different treatments at different stages were measured , including root activity, superoxide dismutase(SOD) activity, catalase(CAT) activity and peroxidase(POD) activity. The corms were dis-sected to check disease index, so as to evaluate indoor control effects of PZ6 on fusarium wilt. ResultCompared to other treatments, PZ6 treatment could significantly enhance plant height increment(6.33 cm) and root activity(487.43μgTTF/g·h)of banana seedlings(P<0.01, the same below). Compared with FOC4 treatment, FOC4 combined with PZ6 solution could significantly enhance root activity. After 50 days of FOC4 inoculation, the plants treated with PZ6(3 d)+FOC4 showed the best performance in disease index(37.50) and control effect(48.28%), followed by PZ6+FOC4 treatment. The performances were the worst in FOC4(3 d)+PZ6. After 45 days of treatment, excepting for POD activity between treatment PZ6 solution and CK, significant difference(P<0.05) in different treatments between CK were found in SOD, CAT and POD activities in leaf. Excepting for CK, SOD, CAT and POD activities showed certain variation regularity among different treatments. The changing trend of SOD activity was similar to root activity, the highest one was found in treatment PZ6(423.71 U/gFW·h), followed by PZ6(3 d)+FOC4, PZ6+FOC4, FOC4(3 d)+PZ6 and FOC4. The performance of POD activity was on the con-trary, the highest one was found in treatment FOC4(355.07 U/g·min), increasing by 82.33 U/g·min compared to CK, and the lowest one was found in PZ6 solution(273.84 U/g·min). ConclusionThe isolated T. asperellum strain PZ6 can enhance the defensive capability of banana seedlings against FOC4 at certain degree. Applying PZ6 solution in advance can prevent invasion of FOC4 to banana seedlings and delay the occurrence of fusarium wilt.