致病疫霉拮抗内生细菌的筛选及离体防病作用

Screening of endophytic bacteria against Phytophthora infestans and prevention of potato late blight

为了筛选对致病疫霉菌丝有显著抑制作用的植物内生细菌菌株,并测试其在马铃薯离体组织上对晚疫病的预防效果,本试验利用传统的分离培养方法从常见几种茄科植物组织内分离纯化内生细菌,以平板对峙法和滤纸片法分别测试细菌活体、无菌体发酵液和菌液对致病疫霉菌丝生长的抑制作用,在马铃薯块茎切片和离体叶片上测试菌液对晚疫病的预防效果。结果表明,分离纯化的81株内生细菌中,活体菌株对致病疫霉有抑制作用的有63株,抑制率达到50%以上的31株菌,其中以分离自辣椒果实的LJ-6和马铃薯块茎的TD-12菌株的抑制作用最强,抑菌率分别为93.12%和92.24%;同时发现活体菌株抑制率达到50%以上的31株菌的发酵液原液均无明显抑制作用,但这些菌株菌液的抑制作用普遍优于活体菌株;TD-12菌株的菌液在马铃薯块茎切片上对晚疫病具有显著的预防及诱导抗病效果,保护率均在91%以上;在马铃薯离体叶片上对晚疫病的防效为76.23%。这些结果表明TD-12菌株在防治马铃薯晚疫病方面有较大的应用潜力。

The objective of this paper is to obtain some endophytic bacteria inhibiting mycelial growth of Phytophthora infestans and evaluate their prevention effectivities of potato detached tissues from potato late blight. The endophytic bacterial strains were isolated and purified with the traditional method from inside the potato, tomato, eggplant and pepper tissues. The sup- pression of bacterial livings, fermentation liquids, and bacterial fluids on mycelial growth of P. infestans were tested by dual-culture method and filter paper method. Disease control effects of bacterial fluid on potato tuber slices and leaves were investigated. The results showed that 81 endophytic strains were isolated and purified, 63 of them could significantly restrain mycelial growth of P. infestans, in which the inhibition rates of 31 strains reached more than 50%. LT-6 isolated from pepper fruit and TD-12 from potato tuber among them displayed the stron- gest repressing effects on P. infestans, the inhibition rates were 93.12% and 92.24%, respec- tively. However, the fermentation liquids of all strains had no depressing effect on P. infestans.addition, it was interested that inhibitory efficiencies of bacterial fluids from these strains on infestans were stronger than that of their livings. TD-12 strain fluid could not only directly event potato tuber slices , but enhance resistance is concluded that TD-12 future. and leaves, protection eff of potato tuber slices to p strain might have a great ect was 91.89 athogen （prot potential role and 76.23 ~if0, ection effect was in control potato respect^ve- 91.35~）. late blight