植物寄生性線蟲之演變

The development of plant-parasitic nematodes

蔡東纂(T. T. Tasy)

《植物病理學會刊》 7卷1期 (1998/03) Pp. 1-9

https://doi.org/10.6649/PPB.199803_7(1).0001

摘要

自六億年前寒武紀時期即存在的線蟲，經漫長歲月演變後棲身於海水、淡水、土壤及動植物等環境中。由寄生習性及寄主種類判斷，最早的植物寄生性線蟲爲Tylenchida，而Dorylaimida之演化應在雙子葉被子植物出現之後。包括Aphelenchida之植物寄生性線蟲在攝食及生殖兩方面之器官及方式上皆有長足的演化，且與寄主植物間達到共同演化程度。種間遺傳變異産生的生理小種有race、pathotype及biotype等不同名詞，如Globodera pallida、G. rostochiensis及Heterodera avenae分別有6、4及8個pathotype；Ditylenchus dipsaci、H. glycines及Meloidogyne incognita分別有20、16及4個race；Tylenchulus semipenetrans 、Bursaphelenchus xylophilus及Radopholus similis分別有4、2及多個biotype。

關鍵字

植物寄生性線蟲 ； 演化 ； 變異

並列摘要

From the fossil record of the Cambrian, we can assume that nematodes evolved at least 600 x 10^6 years ago. The diversity of parasitic habit and the wide host range suggest that the first appearance of plant parasitism among Nematoda was in the Tylenchida. According the reported hosts on the Filicineae, Gymnospermae, and cycadofilicales, lenchida is almost a old as the origin of higher terrestrial plants, while Dorylaimida did not evolve before the appearance of dicotylendonous angiosperms. A large number of Tylenchida, Aphelenchida and Dorylaimida show a close adaptive morphological and physiological association with plant hosts, from commensalism to highly evolved parasitism. For recognizing infraspecific variation between species or sibling species, the terms race, biotype, pathotype and strain would be applied to those nematode population respectively. Adaptation to resistant varieties, ecological and temporal isolation would lead a nematode race to be a new species. More commonly patho- type has been used to refer to populations with differing pathogenic capabilities, Globodera pallida has 6, G. rostochiensis has 4 and Heterodera avenae has 8 pathotypes. Nematode races are separated by cultivars or lines whereas Ditylenchus dipsaci has over 20, H. glycines has 16 and Meloidogyne incognita has 4 races. Based on the relative parasitism of host range Tylenchulus semipenetrans has 4, Bursaphelenchus xylophilus has 2 and Radopholus similis has several biotypes.

並列關鍵字

Plant-parasitic nematode ； evolution ； variation