Presence of three mycorrhizal genes in the common ancestor of land plants suggests a key role of mycorrhizas in the colonization of land by plants.
Presence of three mycorrhizal genes in the common ancestor of land plants suggests a key role of mycorrhizas in the colonization of land by plants.
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DOI：
10.1111/j.1469-8137.2009.03137.x
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发表时间：
2010-04
期刊：
影响因子：
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通讯作者：
Bin Wang;L. Yeun;J. Xue;Yang Liu;Jean-Michel Ané;Y. Qiu
中科院分区：
文献类型：
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作者：
Bin Wang;L. Yeun;J. Xue;Yang Liu;Jean-Michel Ané;Y. Qiu
*植物对土地的殖民从根本上改变了地球的环境条件。植物-菌根真菌共生可能在这一过程中发挥了关键作用，帮助植物从土壤中吸收水分和养分。 *在这里，我们在多种陆地植物中研究了豆科植物和水稻 (Oryza sativa) 菌根形成所需的三个基因 DMI1、DMI3 和 IPD3 的进化历史和功能保护。 *这些基因几乎是从所有主要植物谱系中分离出来的。系统发育分析表明，它们自陆地植物起源以来就一直垂直遗传。此外，跨物种突变拯救实验表明，来自地钱和金鱼藻的 DMI3 基因可以拯救蒺藜苜蓿 dmi3 突变体的菌根形成。酵母双杂交测定还表明，苔藓植物 DMI3 蛋白可以与下游作用的蒺藜 M. trunculata IPD3 蛋白结合。最后，分子进化分析表明，这些基因处于纯化选择之下，以维持其在所有菌根植物谱系中的祖先功能。 *这些结果表明，菌根基因存在于陆地植物的共同祖先中，并且它们的功能在陆地植物进化过程中很大程度上是保守的。这里提供的证据有力地表明，植物-菌根真菌共生是促进陆地植物群起源的关键过程之一。
*The colonization of land by plants fundamentally altered environmental conditions on earth. Plant-mycorrhizal fungus symbiosis likely played a key role in this process by assisting plants to absorb water and nutrients from soil. *Here, in a diverse set of land plants, we investigated the evolutionary histories and functional conservation of three genes required for mycorrhiza formation in legumes and rice (Oryza sativa), DMI1, DMI3 and IPD3. *The genes were isolated from nearly all major plant lineages. Phylogenetic analyses showed that they had been vertically inherited since the origin of land plants. Further, cross-species mutant rescue experiments demonstrated that DMI3 genes from liverworts and hornworts could rescue Medicago truncatula dmi3 mutants for mycorrhiza formation. Yeast two-hybrid assays also showed that bryophyte DMI3 proteins could bind to downstream-acting M. trunculata IPD3 protein. Finally, molecular evolutionary analyses revealed that these genes were under purifying selection for maintenance of their ancestral functions in all mycorrhizal plant lineages. *These results indicate that the mycorrhizal genes were present in the common ancestor of land plants, and that their functions were largely conserved during land plant evolution. The evidence presented here strongly suggests that plant-mycorrhizal fungus symbiosis was one of the key processes that contributed to the origin of land flora.