Li Shi-Dong, Miao Zuo-Qing, Zhang Yong-Hua, Liu Xing-Zhong
Systematic Mycology and Lichenology Laboratory, Institute of Microbiology, Chinese Academy of Sciences, P.O. Box 2714, Beijing 100080, People's Republic of China.
Mycol Res. 2003 Jul;107(Pt 7):888-94. doi: 10.1017/s0953756203008165.
During an investigation of mycoparasitic fungi on sclerotia of Sclerotinia sclerotiorum in China, a new fungal species was consistently encountered and isolated from natural soils taken from soybean fields of Shandong and Jiangsu Provinces. The fungus is featured by its sphaeroid conidia with 1-2 transverse septa, but mostly (>65%) with only one septum at the base. It resembles Monacrosporium indicum, M. sphaeroides and M. sinense, but can be distinguished from the first two species by lack of basal hila and large vacuoles on its conidia, respectively, and from M. sinense by its typically two-celled and broadly turbinate to napiform conidia. Colonization frequencies on S. sclerotiorum sclerotia by the new species were 10% and 33.3% in the two field soils, respectively, when the sclerotia were introduced into soils and coincubated at 22-24 degrees C for 4 wk. Reinoculation tests by placing surface-sterilized sclerotia onto the tested isolate colony for 2 wk and then surface-sterilized again resulted in 23.3% sclerotia colonized. Microscopic observations indicated that the fungus coiled around hyphae of Rhizoctonia solani and grew along and appressed to hyphae of Fusarium solani f.sp. pisi, S. sclerotiorum and Phytophthora cactorum when dual-cultured in slides. Tests on agar plates demonstrated that the fungus formed adhesive networks and was an active predator of Panagrellus redivivus. This study indicated the diverse mechanisms for the fungus to survive in soil. For expression of its mycoparasitic and nematode-trapping capacities, the fungus is named as Monacrosporium janus.
在中国对核盘菌菌核上的真菌寄生真菌进行调查期间，一种新的真菌物种不断地从山东省和江苏省大豆田的天然土壤中被发现并分离出来。该真菌的特征是其球形分生孢子具1-2个横向隔膜，但大部分（>65%）基部仅有一个隔膜。它与印度单顶孢、球形单顶孢和中华单顶孢相似，但分别可通过分生孢子缺乏基部脐点和大液泡与前两个物种区分开来，通过其典型的双细胞且宽陀螺形至梨形的分生孢子与中华单顶孢区分开来。当将菌核引入土壤并在22-24℃下共培养4周时，该新物种在两种田间土壤中对核盘菌菌核的定殖频率分别为10%和33.3%。通过将表面灭菌的菌核放置在测试分离物菌落上2周，然后再次进行表面灭菌的再接种试验，结果有23.3%的菌核被定殖。显微镜观察表明，在载玻片上进行双培养时，该真菌缠绕在立枯丝核菌的菌丝周围，并沿着豌豆专化型尖孢镰刀菌、核盘菌和恶疫霉的菌丝生长并紧贴其上。在琼脂平板上的试验表明，该真菌形成粘性网络，是复活线虫的活跃捕食者。本研究表明了该真菌在土壤中生存的多种机制。为了表达其真菌寄生和捕食线虫的能力，该真菌被命名为双面单顶孢。
