松树蜂与其共生真菌的互利共生关系

松树蜂Sirex noctilio Fabricius是一种重要的国际林业检疫性害虫,主要危害针叶树,原产欧亚大陆和北非。近100多年来,先后入侵大洋洲(新西兰和澳大利亚)、南美洲(乌拉圭、阿根廷、巴西和智利)、北美洲(加拿大和美国),以及南非。2013年8月,在中国黑龙江省内首次发现松树蜂,目前发现其主要危害樟子松。松树蜂能与一种淀粉韧革菌属Amylostereum的真菌Amylostereum areolatum(Fr.)Boidin形成严格的互利共生关系,该虫除直接钻蛀树木外,还能通过产卵行为将自身毒素腺体分泌的毒素和体内共生真菌随同虫卵一起注入寄主树木体内,形成"虫-毒-菌"3个致害因子相互协作的特殊危害方式,加速树势的衰弱并造成寄主树木死亡。本文就国内外松树蜂与其共生菌互利共生关系的研究进行了综述,分别从结构与功能的层次上对其互利共生关系进行了梳理和总结,重点阐释了松树蜂与共生菌的营养共生关系,松树蜂携带传播共生菌的机制,共生菌的种群遗传学以及松树蜂毒素和共生菌在危害寄主树木时的协同关系等。以期为开展关于松树蜂的专项研究提供一些合理的建议,同时为积极有效地防控该害虫提供科学依据。

Mutualism between the Eurasian woodwasp,Sirex noctilio (Hymenoptera:Siricidae) and its fungal symbiont Amylostereum areolatum (Russulales:Amylostereaceae)

The Eurasian woodwasp, Sirex noctilio Fabricius is an important forestry quarantine pest in the world, which prefers to attack conifer. It is native to Eurasia and North Africa. However, over the last one hundred years, S. noctilio has been gradually introduced to New Zealand and Austria in Oceania, then to South American countries including Uruguay, Argentina, Brazil, and Chile and later to Canada, the US and South Africa. The woodwasp was first detected in Heilongjiang Province, in the northeast region of China in August, 2013, where it mainly attacked Pinus sylvestris. A very strict mutualistic relationship exists between S. noctilio and the white rot fungus Amylostereum areolatum (Fr.) Boidin. S. noctilio’s terrible attacks on host tree are in fact the act of its distinctive oviposition: female insects drill 1-5 small holes in the host tree through the bark to the cambium, injecting phytotoxic venom together with the arthrospores of A. areolatum, and sometimes an egg, into the holes. Together, the three pathogenic factors, Sirex larvae, symbiotic fungus and phytotoxic venom, act to weaken or even kill the tree. Particular attention should be paid to this important forest invading pest to China on account of its potential economic and ecological importance to Chinese forest ecosystem. In this article we reviewed the current researches on the symbiotic relationship between the woodwasp S. noctilio and its fungal symbiont A. areolatum. A great number of research findings on this subject were compared and summarized, in which the trophobiosis between Sirex larvae and the fungus, the spread of the fungus by woodwasps, the population structure of the fungus and the collaborative damage effect of the Sirex venom and the fungus on host tree were discussed in details. We attempted to provide some reasonable suggestions for the future study and open new insight into the control on this pest effectively.