两株抗荔枝霜疫霉和荔枝炭疽病海洋真菌的分离鉴定

Isolation and identification of two strains of marine fungi with antagonistic ability against Peronophythora litchi and Colletrichum gloeosporiodes Penz.

【目的】分离筛选具有抗荔枝霜疫霉菌和荔枝炭疽病菌活性的海洋真菌,为新型生物抗菌剂的研究开发提供理论依据。【方法】采用平板分离法从广西北部湾近岸海域红树林区的海洋沉积物样品中分离单个真菌菌株,以平板对峙法和菌丝块法对具有抗菌活性的菌株进行筛选,对筛选出的真菌进行耐盐度试验,并通过形态学观察及分子生物学试验对海洋真菌的种类进行鉴定。【结果】从海洋沉积物样品中共分离出58株海洋真菌,其中2株海洋真菌(HZ02和HZ05)对荔枝霜疫霉菌和荔枝炭疽病菌具有较好的抑制效果,其发酵液对荔枝霜疫霉菌菌丝相对生长抑制率分别为94.27%和96.44%,对荔枝炭疽病菌菌丝生长相对抑制率分别为56.31%和73.43%。耐盐度试验结果表明,2株海洋真菌可在无盐及低盐条件下生长。形态学观察及分子生物学鉴定结果表明,海洋真菌HZ02为草酸青霉(Penicillium oxalicum),HZ05为阿达青霉(Penicillium adametzii)。【结论】分离筛选出的2株海洋真菌HZ02和HZ05菌株对荔枝霜疫霉、荔枝炭疽病具有良好的拮抗作用,具有作为生物抗菌剂的潜力。

[Objective]The present experiment was conducted to isolate and screen marine fungi with antagonistic ability against Peronophythora litchi and Colletrichum gloeosporiodes Penz., in order to provide theoretical basis for research and development of new biological antibacterial agent. [Method]The marine fungi were isolated from marine sediments collected from mangroves of Guangxi Beibu Gulf by using conventional culture-dependent method. The strains with antagonistic ability were screened by means of confrontation culture and metabolites plate culture, and then the salt resistance of screened strains was investigated. The phylogenetie status of marine fungi was identified based on morphological observation and molecular biology experiment. [Result]The results showed that a total of 58 strains were isolated from marine sediment. Both HZ02 strain and HZ05 strain showed obvious inhibitory effect on P. litchi and C. gloeosporiodes Penz., thus under effects of their zymotic fluid, the relative growth inhibition ratios of P. litchi hyphae were 94.27% and 96.44%, respectively, and the relative growth inhibition ratios of C. gloeosponodes Penz. hyphae were 56.31% and 73.43%, respectively. Moreover, the results of salt tolerance test showed that two strains of marine fungi could be cultivated under the condition of no salt and low salt. In addition, based on morphological and molecular characteristics, the HZ02 and HZ05 strains were identified as P. oxalicum and P. adametzii, respectively. [Conclusion ]The 2 strains of marine fungi obtained from mangrove show obvious antagonistic effect on P. litchi and C. gloeosporiodes, which have potential for becoming bioantimierobial agents.