NIN interacts with NLPs to mediate nitrate inhibition of nodulation in Medicago truncatula
NIN interacts with NLPs to mediate nitrate inhibition of nodulation in Medicago truncatula
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NIN 与 NLP 相互作用介导硝酸盐抑制蒺藜苜蓿结瘤
DOI：
10.1038/s41477-018-0261-3
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发表时间：
2018-11-01
期刊：
影响因子：
18
通讯作者：
Xie, Fang
中科院分区：
文献类型：
--
作者：
Lin, Jie-shun;Li, Xiaolin;Xie, Fang
豆科植物可以同化无机氮，并通过与固氮菌（根瘤菌）的共生作用获得固定氮。共生固氮是一个耗能的过程，当有足够水平的固定氮时会受到强烈抑制，但这种调节的分子机制在很大程度上是未知的。转录因子nodule inception（NIN）是拟南芥生长所必需的转录因子，属于NIN样蛋白家族，参与拟南芥氮稳态的调控。在这里，我们表明，NLP基因的突变或下调阻止硝酸盐抑制感染，根瘤形成和固氮。我们发现NIN和NLP通过其羧基末端PB1结构域进行物理相互作用。此外，我们发现，NLP 1是必需的硝酸盐响应基因的表达和硝酸盐触发NLP 1重新定位从细胞质到细胞核。最后，我们表明NLP 1可以抑制NIN激活本塞姆氏烟草和蒺藜苜蓿中的CRE1表达。我们的研究结果强调了NLP在抑制硝酸盐引起的炎症中的核心作用。
Legume plants can assimilate inorganic nitrogen and have access to fixed nitrogen through symbiotic interaction with diazotrophic bacteria called rhizobia. Symbiotic nitrogen fixation is an energy-consuming process and is strongly inhibited when sufficient levels of fixed nitrogen are available, but the molecular mechanisms governing this regulation are largely unknown. The transcription factor nodule inception (NIN) is strictly required for nodulation and belongs to a family of NIN-like proteins (NLPs), which have been implicated in the regulation of nitrogen homeostasis in Arabidopsis. Here, we show that mutation or downregulation of NLP genes prevents nitrate inhibition of infection, nodule formation and nitrogen fixation. We find that NIN and NLPs physically interact through their carboxy-terminal PB1 domains. Furthermore, we find that NLP1 is required for the expression of nitrate-responsive genes and that nitrate triggers NLP1 re-localization from the cytosol to the nucleus. Finally, we show that NLP1 can suppress NIN activation of CRE1 expression in Nicotiana benthamiana and Medicago truncatula. Our findings highlight a central role for NLPs in the suppression of nodulation by nitrate.