Miao V P, Covert S F, VanEtten H D
Department of Plant Pathology, Cornell University, Ithaca, NY 14853.
Science. 1991 Dec 20;254(5039):1773-6. doi: 10.1126/science.1763326.
A family of cytochrome P-450 (Pda) genes in the pathogenic fungus Nectria haematococca is responsible for the detoxification of the phytoalexin pisatin, an antimicrobial compound produced by garden pea (Pisum sativum L.). The Pda6 gene was mapped by electrophoretic karyotype analysis to a small meiotically unstable chromosome that is dispensable for normal growth. Such traits are typical of B chromosomes. The strains of Nectria studied here have no sequences that are homologous to the Pda family other than Pda6 and therefore demonstrate that unique, functional genes can be found on B chromosomes. Unstable B chromosomes may be one mechanism for generating pathogenic variation in fungi.
致病真菌血座壳菌中的细胞色素P - 450（Pda）基因家族负责对植保素豌豆素进行解毒，豌豆素是由豌豆（Pisum sativum L.）产生的一种抗菌化合物。通过电泳核型分析将Pda6基因定位到一条减数分裂不稳定的小染色体上，该染色体对于正常生长是可有可无的。这些特征是B染色体的典型特征。此处研究的血座壳菌菌株除了Pda6之外没有与Pda家族同源的序列，因此证明在B染色体上可以发现独特的功能基因。不稳定的B染色体可能是真菌产生致病变异的一种机制。
