A natural short pathway synthesizes roquefortine C but not meleagrin in three different Penicillium roqueforti strains
A natural short pathway synthesizes roquefortine C but not meleagrin in three different Penicillium roqueforti strains
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DOI：
10.1007/s00253-015-6676-0
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发表时间：
2015-09-01
影响因子：
5
通讯作者：
Martin, J. F.
中科院分区：
文献类型：
--
作者：
Kosalkova, K.;Dominguez-Santos, R.;Martin, J. F.
由于其在蓝纹干酪生产中的悠久历史，罗克福青霉的真菌毒素和其他次生代谢物的产生引起了人们的极大兴趣。在这篇文章中，我们报道了从美国(模式菌株)、法国和英国(柴郡奶酪)分离的三个不同的Roqueforti菌株中roquefortin基因簇的克隆和特征。这三株毒株在整个16.6kb的簇区显示出完全相同的roquefortin基因簇组织和几乎相同的(98-99%)基因核苷酸序列。与产黄青霉/meleagrin 7基因簇相比，roqueforti roquefortin簇仅含有4个基因(rds、rdh、rpt和gmt)，分别编码罗奎福廷二肽合成酶、罗奎福廷D脱氢酶、罗奎福廷戊烯基转移酶和甲基转移酶。通过RNAi策略沉默rds或rpt基因，使罗奎福汀C的产量减少50%，证实了这两个关键基因参与了罗奎福汀的生物合成。另外一个假定的基因是MFS转运蛋白roqT的同源基因，在所有三个菌株中都以假基因的形式重新排列。同样的四个基因和一个完整的(未重排)roqT，编码一个包含12个TMS结构域的MFS转运蛋白，在产黄P.chrysgenum的七个基因簇中存在，尽管组织不同。有趣的是，罗氏产黄杆菌/meleagrin基因簇中将roquefortin C转化为腺苷B和meleagrin的两个“晚期”基因在roqueforti四基因簇中缺失。在YES培养条件下，罗氏假单胞菌不产生多聚集素，而产黄假单胞菌在此条件下产生多聚集素。在最近公布的罗氏假单胞菌基因组的其他地方，没有发现这两个缺失的聚集素合成基因的同源基因。我们的数据表明，在进化过程中，存在于产黄链霉菌中的七个基因簇，可能也存在于其他产生腺苷/去甲肾上腺素的真菌中，已经被削减为罗奎福尔蒂菌中的一个短簇，导致合成罗奎福汀C而不是去合成去甲肾上腺素作为最终产物。
The production of mycotoxins and other secondary metabolites in Penicillium roqueforti is of great interest because of its long history of use in blue-veined cheese manufacture. In this article, we report the cloning and characterization of the roquefortine gene cluster in three different P. roqueforti strains isolated from blue cheese in the USA (the type strain), France, and the UK (Cheshire cheese). All three strains showed an identical roquefortine gene cluster organization and almost identical (98-99 %) gene nucleotide sequences in the entire 16.6-kb cluster region. When compared with the Penicillium chrysogenum roquefortine/meleagrin seven-gene cluster, the P. roqueforti roquefortine cluster contains only four genes (rds, rdh, rpt, and gmt) encoding the roquefortine dipeptide synthetase, roquefortine D dehydrogenase, roquefortine prenyltransferase, and a methyltransferase, respectively. Silencing of the rds or rpt genes by the RNAi strategy reduced roquefortine C production by 50 % confirming the involvement of these two key genes in roquefortine biosynthesis. An additional putative gene, orthologous of the MFS transporter roqT, is rearranged in all three strains as a pseudogene. The same four genes and a complete (not rearranged) roqT, encoding a MFS transporter containing 12 TMS domains, occur in the seven-gene cluster in P. chrysogenum although organized differently. Interestingly, the two "late" genes of the P. chrysogenum roquefortine/meleagrin gene cluster that convert roquefortine C to glandicoline B and meleagrin are absent in the P. roqueforti four-gene cluster. No meleagrin production was detected in P. roqueforti cultures grown in YES medium, while P. chrysogenum produces meleagrin in these conditions. No orthologous genes of the two missing meleagrin synthesizing genes were found elsewhere in the recently released P. roqueforti genome. Our data suggest that during evolution, the seven-gene cluster present in P. chrysogenum, and probably also in other glandicoline/meleagrin producing fungi, has been trimmed down to a short cluster in P. roqueforti leading to the synthesis of roquefortine C rather than meleagrin as a final product.