化感水稻内生真菌发酵产物的抑菌活性评价及其对水稻保护性酶活性的影响

为探究化感水稻内生真菌对植物病原真菌的抑制作用及其对水稻生理特性的影响,本研究采用来自化感水稻6173中分离得到的12株内生真菌菌株,以水稻纹枯病、稻瘟病、恶苗病菌为指示菌株,通过平板对峙法研究了内生真菌菌株的抑菌活性,再采用牛津杯扩散法对初筛获得的抗性菌株进行抑菌活性复筛,并对筛选到的抑菌菌株抗菌物质的热稳定性及其对非化感水稻93067相关保护性酶活性的影响进行了研究。结果表明,菌株REF-04抑菌活性强,其对纹枯病菌抑制率达到50.63%,发酵液乙酸乙酯提取物抑制效果显著,抑菌圈直径达到18.6 mm;菌株REF-04发酵液乙酸乙酯提取物中抗菌成分具有较强的热稳定性,其发酵液能显著提高水稻苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性。本研究筛选获得的水稻内生真菌REF-04具有较好的抗菌活性,同时还能促进水稻幼苗保护性酶活性的提高,其作为生物农药具有一定的应用价值和开发前景。

Investigation on Inhibitory Activity of Fermentation Products of Endophytic Fungi From Allelopathic Rice and Their Effects on Activities of Protective Enzymes in Rice

In order to explore the antifungal effect of endophytic fungi from allelopathic rice on plant pathogenic fungi and its influence on physiological characteristics of rice, totally twelve strains of endophytic fungi were isolated from an allelopathic rice accession 6173. Using Thanatephorus cucmeris,Magnaporthe oryzae and Fusarium moniliforme Sheld as indicative fungi strains, antibacterial activities of the isolated endophytic fungi were studied with the plate confrontation method, then the antifungal activities of fermentation products from the antagonistic strains were further screened by the Oxford cup diffusion method. Moreover, heat stabilities of fermentation products from the selected antagonistic strains and their effects on activities of enzymes related to protection in non allelopathic rice 93067 were studied. The results showed that the endophytic fungi REF-04 exhibited the strongest inhibition effect against pathogenic fungi, inhibition rate to Thanatephorus cucmeris reached 50.63%. Ethyl acetate extract of fermentation product from the REF-04 had the best inhibition effect on Thanatephorus cucmeris, and its inhibitory zone diameter reached 18.6 mm. Ethyl acetate extract of the REF-04 fermentation product also showed high heat stability compared to other endophytic fungi, and its fermented liquid could significantly improve the activities of AL,SOD and POD in rice seedlings. The present results indicate that fermentation products from the endophytic fungi REF-04 has a good bacteriostatic activity and can improve activities of the protective enzyme of rice, which may have certain application and prospect for the development of biological pesticide.