KIN3 impacts arbuscular mycorrhizal symbiosis and promotes fungal colonisation in Medicago truncatula
KIN3 impacts arbuscular mycorrhizal symbiosis and promotes fungal colonisation in Medicago truncatula
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DOI：
10.1111/tpj.15685
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发表时间：
2022-03-05
期刊：
影响因子：
7.2
通讯作者：
Ane, Jean-Michel
中科院分区：
文献类型：
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作者：
Irving, Thomas B.;Chakraborty, Sanhita;Ane, Jean-Michel
丛枝菌根真菌帮助寄主植物获得养分，而这种联系本身受到土壤养分水平的影响。高磷水平抑制共生，而高氮水平促进共生。调控共生反应土壤养分的遗传机制还知之甚少。在这里，我们表征了四个插入突变体Tnt1的紫花苜蓿在丛枝菌根定植中的共生表型。我们定位了它们的Tnt1插入，并确定了两个已知参与菌丝化的基因Ram1和KIN3的等位基因。我们比较了Kin3-2和Ram1-4突变对基因表达的影响，发现这两个基因改变了重叠但不相同的基因集的表达，表明Ram1作用于KIN3的上游。此外，KIN3似乎参与了对真菌共生体的植物防御反应的抑制。KIN3位于含有丛枝的皮层细胞的内质网上，KIN3-2突变株的丛枝数量明显少于野生型。KIN3在对土壤氮素水平的共生反应中起着至关重要的作用，因为与野生型植物相反，KIN3-2突变体在高氮条件下没有表现出更多的根定植。
Arbuscular mycorrhizal fungi help their host plant in the acquisition of nutrients, and this association is itself impacted by soil nutrient levels. High phosphorus levels inhibit the symbiosis, whereas high nitrogen levels enhance it. The genetic mechanisms regulating the symbiosis in response to soil nutrients are poorly understood. Here, we characterised the symbiotic phenotypes in four Medicago truncatula Tnt1-insertion mutants affected in arbuscular mycorrhizal colonisation. We located their Tnt1 insertions and identified alleles for two genes known to be involved in mycorrhization, RAM1 and KIN3. We compared the effects of the kin3-2 and ram1-4 mutations on gene expression, revealing that the two genes alter the expression of overlapping but not identical gene sets, suggesting that RAM1 acts upstream of KIN3. Additionally, KIN3 appears to be involved in the suppression of plant defences in response to the fungal symbiont. KIN3 is located on the endoplasmic reticulum of arbuscule-containing cortical cells, and kin3-2 mutants plants hosted significantly fewer arbuscules than the wild type. KIN3 plays an essential role in the symbiotic response to soil nitrogen levels, as, contrary to wild-type plants, the kin3-2 mutant did not exhibit increased root colonisation under high nitrogen.