Kimura M, Matsumoto G, Shingu Y, Yoneyama K, Yamaguchi I
Microbial Toxicology Laboratory, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama, Japan.
FEBS Lett. 1998 Sep 18;435(2-3):163-8. doi: 10.1016/s0014-5793(98)01061-8.
The trichothecene 3-O-acetyltransferase gene, Tri101, plays a pivotal role for the well-being of the type B trichothecene producer Fusarium graminearum. We have analyzed the cosmids containing Tri101 and found that this resistance gene is not in the biosynthetic gene cluster reported so far. It was located between the UTP-ammonia ligase gene and the phosphate permease gene which are not related to trichothecene biosynthesis. These two 'house-keeping' genes were also linked in Fusarium species that do not produce trichothecenes. The result suggests that the isolated occurrence of Tri101 is attributed to horizontal gene transfer and not to the reciprocal translocation of the chromosome containing the gene cluster. Interestingly, 3-O-acetylation was not always a primary self-defensive strategy for all the t-type trichothecene producers; i.e. the type A trichothecene producer Fusarium sporotrichioides did not acetylate T-2 toxin in vivo although the fungus possessed a functional 3-O-acetyltransferase gene. Thus Tri101 appears to be a defense option which the producers have independently acquired in addition to their original resistance mechanisms.
单端孢霉烯3 - O - 乙酰转移酶基因Tri101，对B型单端孢霉烯产生菌禾谷镰刀菌的生存起着关键作用。我们分析了含有Tri101的黏粒，发现这个抗性基因并不在目前报道的生物合成基因簇中。它位于与单端孢霉烯生物合成无关的尿苷三磷酸 - 氨连接酶基因和磷酸盐通透酶基因之间。这两个“管家”基因在不产生单端孢霉烯的镰刀菌属物种中也相互连锁。结果表明，Tri101的孤立存在归因于水平基因转移，而非含有该基因簇的染色体的相互易位。有趣的是，3 - O - 乙酰化并非对所有t型单端孢霉烯产生菌都是主要的自我防御策略；即A型单端孢霉烯产生菌拟分枝孢镰刀菌在体内并不乙酰化T - 2毒素，尽管该真菌拥有一个功能性的3 - O - 乙酰转移酶基因。因此，Tri101似乎是产生菌除了其原始抗性机制之外独立获得的一种防御选择。
