Genes conserved for arbuscular mycorrhizal symbiosis identified through phylogenomics
Genes conserved for arbuscular mycorrhizal symbiosis identified through phylogenomics
复制标题
DOI：
10.1038/nplants.2015.208
复制
发表时间：
2016-02-01
期刊：
影响因子：
18
通讯作者：
Harrison, Maria J.
中科院分区：
文献类型：
--
作者：
Bravo, Armando;York, Thomas;Harrison, Maria J.
丛枝菌根共生(AMS)是一种广泛存在的陆地植物和真菌的互惠共生关系(1)，据预测在陆地植物进化的早期曾出现过一次(2-4)。与这一概念一致的是，AMS所需的几个基因在整个进化过程中都是保守的(5)，它们的共生功能也得到了保存，至少在单子叶植物和双子叶植物之间是如此(6，7)。尽管它意义重大，但对植物对AMS的遗传程序的了解是有限的。到目前为止，AMS所需的大多数基因都是通过与进化上较年轻的固氮豆类根瘤菌共生(RLS)(8)或通过对差异表达的候选基因进行反向遗传分析(9)而发现的。大规模的序列索引插入突变体集合和最新的基因组编辑技术极大地增加了反向遗传学的力量，但从AMS期间改变表达的数千个基因中选择候选基因仍然是一个随意的过程。在这里，我们描述了一种系统基因组学方法来识别其进化历史预测AMS保守性的基因，并通过反向遗传学分析证明了预测的准确性。对50个植物基因组进行了系统基因组学分析，得到了138个预测在AMS中起作用的基因。这包括15个在AMS中具有已知作用的基因。此外，我们还证明了在AMS中，六个先前未被描述的AMS保守基因中的突变都受到了损害。我们的结果表明，系统基因组学是识别AMS所需的一组进化上保守的基因的有效策略。
Arbuscular mycorrhizal symbiosis (AMS), a widespread mutualistic association of land plants and fungi(1), is predicted to have arisen once, early in the evolution of land plants(2-4). Consistent with this notion, several genes required for AMS have been conserved throughout evolution(5) and their symbiotic functions preserved, at least between monocot and dicot plants(6,7). Despite its significance, knowledge of the plants' genetic programme for AMS is limited. To date, most genes required for AMS have been found through commonalities with the evolutionarily younger nitrogen-fixing Rhizobium legume symbiosis (RLS)(8) or by reverse genetic analyses of differentially expressed candidate genes(9). Large sequence-indexed insertion mutant collections and recent genome editing technologies have vastly increased the power of reverse genetics but selection of candidate genes, from the thousands of genes that change expression during AMS, remains an arbitrary process. Here, we describe a phylogenomics approach to identify genes whose evolutionary history predicts conservation for AMS and we demonstrate the accuracy of the predictions through reverse genetics analysis. Phylogenomics analysis of 50 plant genomes resulted in 138 genes from Medicago truncatula predicted to function in AMS. This includes 15 genes with known roles in AMS. Additionally, we demonstrate that mutants in six previously uncharacterized AMS-conserved genes are all impaired in AMS. Our results demonstrate that phylogenomics is an effective strategy to identify a set of evolutionarily conserved genes required for AMS.