ASL/LBD Phylogeny Suggests that Genetic Mechanisms of Root Initiation Downstream of Auxin Are Distinct in Lycophytes and Euphyllophytes
ASL/LBD Phylogeny Suggests that Genetic Mechanisms of Root Initiation Downstream of Auxin Are Distinct in Lycophytes and Euphyllophytes
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DOI：
10.1093/molbev/mss250
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发表时间：
2013-03-01
影响因子：
10.7
通讯作者：
Gantet, Pascal
中科院分区：
文献类型：
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作者：
Coudert, Yoan;Dievart, Anne;Gantet, Pascal
古植物学研究表明，在陆地植物多样化过程中，根至少两次独立进化，一次是在石松植物中，一次是在幼嫩植物中。生长素在两组中促进胚胎后根的形成，但来自不同的细胞类型。在拟南芥、水稻和玉米等几种幼芽植物中，AS2/ lob结构域（ASL/LBD）蛋白直接作用于生长素的下游，是根形成所必需的保守元件。目前尚不清楚生长素在石松植物和胡杨植物中对根形成的下游是否有相似或不同的遗传机制。我们在横跨生命之树的基因组序列中寻找ASL/LBD蛋白，以追溯其进化史。我们对ASL/LBD蛋白进行了系统发育分析，并将所有特征ASL/LBD的功能映射到系统发育树上。我们确定了一个与根发育特别相关的分支，它不包括石松序列。这表明在生长素下游的生长素对石松植物和幼嫩植物的根形成有不同的遗传机制。
Paleobotanical studies suggest that roots evolved at least twice independently during land plant diversification, once in lycophytes and once in euphyllophytes. Auxin promotes postembryonic root initiation in both groups but from different cell types. In several euphyllophytes, such as Arabidopsis, rice, and maize, AS2/LOB-domain (ASL/LBD) proteins act directly downstream of auxin and are conserved elements necessary for root initiation. It is currently unknown whether similar or different genetic mechanisms act downstream of auxin for root initiation in lycophytes and euphyllophytes. We searched for ASL/LBD proteins in genome sequences spanning the tree of life to retrace their evolutionary history. We performed a phylogenetic analysis of ASL/LBD proteins and mapped the functions of all characterized ASL/LBD onto the phylogenetic trees. We identified a clade specifically associated with root development, which includes no lycophyte sequence. This points toward the existence of distinct genetic mechanisms downstream of auxin for root initiation in lycophytes and euphyllophytes.