Occurrence of Parasexual Cycle in Phytophthora parasitica Following Protoplast Fusion

Phytophthora parasitica之無性生殖週期發生於原生質體融合之後

古玉環(Y.H. Gu) ； 柯文雄(W.H. Ko)

《Botanical Bulletin of Academia Sinica》 41卷3期 (2000/07) Pp. 225-230

https://doi.org/10.7016/BBAS.200007.0225

摘要

Phytophthora parasitica之抗metalaxyl(M(上標 r)原生質體與同菌種之抗Chloroneb(Cn(上標 r)原生質體進行融合,其形成異核體的機率為2.6×10(^-3)-8.2×10(^-3)。在7個可能異核體中有6個可產生M(上標 r)游走子和Cn(上標 r)游走子和／或M(上標 r)+Cn(上標 r)游走子。另一個可能異核體僅產生Cn(上標 r)游走子，可能是在培養過程中失去M(上標 r)染色體。原生質體融合之異核體菌株可產生正常大小之游走子，同時產生比正常游走子大約兩倍之較大游走子。50%之正常游走子具有M(上標 r)和Cn(上標 r)基因。本研究結果表示變兩倍體現象發生於異核融合後，因此顯示原生質體融合可引起無性生殖週期之發生。

關鍵字

變兩倍體現象 ； Phytophthora parasitica ； 無性生殖週期 ； 原生質體融合

並列摘要

Metalaxyl-resistant (M(superscript r)) and chloroneb-resistant (Cn(superscript r)) protoplasts of Phytophthora parasitica were fused, with heterokaryon formation rates ranging from 2.6×l0((superscript -3) to 8.2×l0(superscript -3). The heterokaryosis was confirmed in six of seven putative heterokaryons by the production of both M(superscript r) zoospores and Cn(superscript r) zoospores. and/or M(superscript r)+Cn(superscript r) zoospores. The 7th putative heterokaryon produced only Cn(superscript r) zoospores, probably because of the loss of the M(superscript r) chromosome during subculture. The heterokaryons produced normal-sized zoospores as well as large zoospores that were almost twice the size of normal-sized zoospores. Fifty percent of the normal-sized zoospores contained M(superscript r) and Cn(superscript r) genes. The results suggested an occurrence of diploidization after karyogamy of the heterokaryon and thus demonstrated the completion of events leading to a parasexual cycle following protoplast fusion.

並列關鍵字

Diploidization ； Phytophthora parasitica ； Parasexual cycle ； Protoplast fusion.