Why are momilactones always associated with biosynthetic gene clusters in plants?
Why are momilactones always associated with biosynthetic gene clusters in plants?
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DOI：
10.1073/pnas.2007934117
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发表时间：
2020-06
期刊：
影响因子：
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通讯作者：
Juan Zhang;R. Peters
中科院分区：
文献类型：
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作者：
Juan Zhang;R. Peters
人们逐渐认识到，植物基因组包含生物合成基因簇 (BGC)，在某些情况下可进行更专门的代谢 (1)。然而，虽然水平基因转移似乎驱动微生物中自给自足的 BGC 组装，但严格的垂直基因传递的局限性使得植物中 BGC 的组装需要独特的驱动力。微生物中 BGC 水平基因转移的证据源自同源此类基因座的出现，导致在系统发育不同的物种中生物合成相同（或非常密切相关）的天然产物。相比之下，对植物中此类事件的研究要少得多。这是由于 BGC 的例子少得多，以及该王国中跳过系统发育距离的天然产物的例子。幸运的是，莫米内酯提供了一个信息丰富的例外。这些二萜类化合物最初是在水稻 (Oryza sativa) 中发现的，其中相关的 BGC 是最早在植物中发现的少数化合物之一 (2)，并且它们充当化感物质和/或植物抗毒素 (3, 4)。值得注意的是，莫米内酯不仅由稻属内的其他野生稻物种产生，还由稗草（稗草）产生，稗草属于禾本科的一个单独分支。有趣的是，除了在稻 (5) 中预期的直系同源莫米内酯 BGC 之外，在系统发育上更遥远的 E. crus-galli (6) 中也发现了同源 BGC。更有趣的是苔藓植物 Calohypnum plumiforme（以前称为 Hypnum pocketeforme）产生的莫米内酯，代表了陆地植物非常早期的分化谱系 (7)。在 PNAS 中，Mao 等人。 (8)报道C. plumiforme基因组含有用于momilactone生物合成的BGC。引人注目的是，这不仅代表了苔藓植物中 BGC 的鉴定，而且在系统发育上与禾本科中与莫米内酯生物合成相关的 BGC 明显不同。然而，尽管他们明确…… [↵][1]1应向谁发送信件。电子邮件：rjpeters{at}iastate.edu。 [1]：#xref-corresp-1-1
There is an emerging realization that plant genomes contain biosynthetic gene clusters (BGCs) for more specialized metabolism in certain cases (1). However, while horizontal gene transfer seems to drive the assembly of self-sufficient BGCs in microbes, the limitations of strict vertical gene transmission necessitate a distinct driving force for the assembly of BGCs in plants. The evidence for horizontal gene transfer of BGCs in microbes is derived from the appearance of homologous such loci, leading to biosynthesis of the same (or very closely related) natural products, in phylogenetically distinct species. By contrast, there has been much less investigation of such occurrences in plants. This is a result of many fewer examples of BGCs, as well as instances of natural products that skip across phylogenetic distances in this kingdom. Fortunately, the momilactones provide a strikingly informative exception. These diterpenoids were originally found in rice ( Oryza sativa ), where the associated BGC was among the first few identified in plants (2), and where they serve as allelochemicals and/or phytoalexins (3, 4). Notably, momilactones are produced by not only other wild rice species within the Oryza genus but also barnyard grass ( Echinochloa crus-galli ), which falls within a separate clade of the Poaceae family. Intriguingly, beyond the expected orthologous momilactone BGCs in Oryza (5), a homologous BGC also was found in the phylogenetically more distant E. crus-galli (6). Even more interesting is the production of momilactones by the bryophyte Calohypnum plumiforme (formerly Hypnum plumaeforme ), representing a very early diverging lineage of land plants (7). In PNAS, Mao et al. (8) report that the C. plumiforme genome contains a BGC for momilactone biosynthesis. Strikingly, this not only represents identification of a BGC in a bryophyte but, further, is clearly phylogenetically distinct from the BGCs associated with momilactone biosynthesis in the Poaceae. Nevertheless, despite their clearly … [↵][1]1To whom correspondence should be addressed. Email: rjpeters{at}iastate.edu. [1]: #xref-corresp-1-1