苹果树主要病害内生拮抗真菌的筛选及拮抗特性

Screening fungal endophytes from apple trees and their antagonistic characteristics

【目的】筛选苹果树腐烂病菌Valsa malimiyabe与苹果树炭疽病菌Glomeralla cingalata的内生拮抗真菌,并研究其抑菌效果。【方法】分离发病地区健康苹果树的根、茎及其根际土壤中的拮抗内生真菌,室内抑菌试验测定其对苹果树腐烂病菌和苹果树炭疽病菌的抑制作用;发酵培养试验检测其内生真菌中抑菌物质的耐热性。【结果】分离到的18株内生真菌分属3个属,其中茎分离到的内生真菌的种类和数量较多;对峙试验表明,对苹果树腐烂病菌和炭疽病菌的抑菌率高于60%的有8株,其中菌株J2、J16、J17对苹果树腐烂病的抑制率分别为82.75%、84.31%和82.35%,菌株T1对苹果树菌株炭疽病的抑制率为80.67%。拮抗真菌J2、J16、J17、J24、T1发酵液对2种病原菌分生孢子萌发的抑制率均不小于39.55%,最高达69.75%;在121℃时,J11和T1无菌滤液的热稳定性较好,而J2无菌滤液在100°C时就失去了生物活性。【结论】拮抗真菌J2、J11、J16、J17、T1均对苹果树腐烂病菌及苹果树炭疽病菌有较强拮抗作用,可为开展这2种病害的生物防治研究提供潜在资源。

[ Objective] To screen fungal endophytes against Valsa malimiyabe and Glomeralla cingulata from apple trees and explore their inhibitory effects. [ Method ] Fungal endophytes were isolated from roots, stems and rhizosphere soil of healthy apple plants. Their antifungal activities against V. malimiyabe and G. cingulata were examined using in vitro dual culture assay. Heat-resistant properties of antifungal sub- stances were tested using the fermentation culture of the isolated fungal endophytes. [ Result ] Eighteen en- dophytic fungus strains belonging to three genera were isolated and half of the 18 strains were from stem. The dual culture assay showed eight strains had above 60% inhibition rate against V. malimiyabe and G. cingulata. J2, J16 and J17 strains strongly inhibited V. malimiyabe with the inhibition rates of 82. 75%, 84. 31% and 82. 35% respectively. The inhibition rate of T1 to G. cingulata reached 80. 67%. The culture filtrates of fungal endophytes J2 ,J16 ,J17 ,J24 ,Tx inhibited the conidia germination of both pathogens, and all of the inhibition rates were not less than 39. 55% and the highest value was 69.75%. The sterile filtrate of J, and T1 showed high heat stability at 121 ℃, while J2 lost bioactivity at 100 ℃. [ Conclusion] Fungal endophytes 32, J11, J16, J17 and T1 have strong inhibitory effects against V. malimiyabe and G. cingulata, and therefore are potential candidates for biological control of these two pathogens.