Functional analysis of shikimate pathway gene duplicates

本应用着重于植物和微生物中莽草酸途径基因重复的功能注释。具体来说，我们将研究植物莽草酸激酶和微生物莽草酸脱氢酶基因复制的功能。我们在植物中发现了两个shikimate kinase基因的重复序列，我们将其标记为SKL1和SKL2。编码的蛋白质不具有莽草酸激酶活性，但在植物中进化出新的生物学功能。SKL1在质体发育中发挥作用，SKL2在种子萌发过程中具有耐盐性。我们将根据这些蛋白各自的生物学功能来研究它们催化的生化反应。SKL1是开发新型作物除草剂的理想靶点，因为我们已经证明它是植物生长所必需的。同样，SKL2基因的研究进展将加深我们对作物耐盐机制的理解。本建议的第二个方面涉及微生物莽草酸脱氢酶。我们鉴定出微生物中5个不同的莽草酸脱氢官能团：AroE、YdiB、shdhl、Rif1和Ael1。这些莽草酸脱氢酶基因重复参与多种生物化学活动。有趣的是，这五类细菌只存在于一些土壤传播的生物中，包括恶臭假单胞菌。其中一些蛋白质的基因存在于被称为操纵子的基因簇中。这些操纵子可能代表芳香化合物分解的代谢途径。因此，我们的研究结果可能对生物修复过程具有直接意义，特别是在这些芳香族化合物含量升高的地区。

This application focuses on the functional annotation of shikimate pathway gene duplicates in plants and microbes. Specifically, we will investigate the function of plant shikimate kinase and microbial shikimate dehydrogenase gene duplicates. We have identified two shikimate kinase gene duplicates in plants, which we annotated as SKL1 and SKL2. The encoded proteins do not have shikimate kinase activity, but have evolved novel biological functions in plants. SKL1 has evolved a function in plastid development and SKL2 confers salinity tolerance during seed germination. We will investigate the biochemical reaction catalyzed by these proteins in light of their respective biological function. SKL1 is an excellent target for the development of novel herbicides in crops because we have shown that it is absolutely required for plant growth. Similarly, progress on SKL2 will enhance our understanding of the mechanism of salinity tolerance in crop plants. The second aspect of this proposal deals with microbial shikimate dehydrogenases. We identified five distinct functional groups of shikimate dehydrogenses in microbes, AroE, YdiB, SDHL, Rif1, and Ael1. These shikimate dehydrogenase gene duplicates participate in diverse biochemical activities. Interestingly, all five classes are found only in some soil borne organisms, including Pseudomonas putida. The genes for some of these proteins are found in genetic clusters, called operons. These operons may represent metabolic pathways for the breakdown of aromatic compounds. As such findings from our studies may have direct implications on bioremediation processes especially for areas where these aromatic compounds are found in elevated levels.