Strigolactone Biosynthesis Genes of Rice are Required for the Punctual Entry of Arbuscular Mycorrhizal Fungi into the Roots
Strigolactone Biosynthesis Genes of Rice are Required for the Punctual Entry of Arbuscular Mycorrhizal Fungi into the Roots
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DOI：
10.1093/pcp/pcy001
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发表时间：
2018-03-01
影响因子：
4.9
通讯作者：
Kyozuka, Junko
中科院分区：
文献类型：
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作者：
Kobae, Yoshihiro;Kameoka, Hiromu;Kyozuka, Junko
丛枝菌根(AM)是大多数植物与根部古老的真菌类群球菌门之间的一种互惠共生关系，在植物从土壤中吸收养分方面起着关键作用。根合成类胡萝卜素的衍生物，并分泌它们来诱导AM真菌的能量代谢和菌丝分枝。尽管SLS在共生前阶段的作用已有很好的文献记载，但对SLS在根部定植过程中的作用知之甚少。在这里，我们发现水稻SL生物合成基因的突变体类胡萝卜素裂解双加氧酶D10抑制了根定植的扩大，在D17中抑制得更严重。有趣的是，大多数定殖过程是正常的，即AM真菌菌丝接近根部并附着在根部，D10和D17突变体的表皮穿透、丛枝大小、每下胚轴的丛枝数和茎内菌丝的代谢活性没有受到影响。相反，下胚轴的形成严重减弱。我们的观察确定了有效形成菌柄所需的SL生物合成基因，表明SLS在这一过程中是必需的。有效的菌丝形成是菌丝及时内化到根部和维持定殖扩张所必需的。
Arbuscular mycorrhiza (AM) is a mutualistic association between most plant species and the ancient fungal phylum Glomeromycota in roots, and it plays a key role in a plant's nutrient uptake from the soil. Roots synthesize strigolactones (SLs), derivatives of carotenoids, and exude them to induce energy metabolism and hyphal branching of AM fungi. Despite the well-documented roles of SLs in the pre-symbiotic phase, little is known about the role of SLs in the process of root colonization. Here we show that the expansion of root colonization is suppressed in the mutants of rice (Oryza sativa) SL biosynthesis genes, carotenoid cleavage dioxygenase D10 and more severely in D17. Interestingly, most of the colonization process is normal, i.e. AM fungal hyphae approach the roots and cling around them, and epidermal penetration, arbuscule size, arbuscule number per hyphopodium and metabolic activity of the intraradical mycelium are not affected in d10 and d17 mutants. In contrast, hyphopodium formation is severely attenuated. Our observations establish the requirement for SL biosynthesis genes for efficient hyphopodium formation, suggesting that SLs are required in this process. Efficient hyphopodium formation is required for the punctual internalization of hyphae into roots and maintaining the expansion of colonization.