Root nodulation is controlled by sensing the R/ FR ratio through phytochrome signaling

通过光敏色素信号检测 R/FR 比率来控制根结瘤

• 批准号: 21657017
• 负责人: SUZUKI Akihiro
• 金额: $ 2.18万
• 依托单位: Saga University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Challenging Exploratory Research
• 财政年份: 2009
• 资助国家: 日本
• 起止时间: 2009 至 2011
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21657017/
• 关键词: 根粒; 共生; フィトクロム; 光形態形成; 植物微生物相互作用; ジャスモン酸; ミヤコグサ; 光質; 変異体; 赤色光; シグナル伝達; スクリーニング; 根粒; 共生; フィトクロム; 光形態形成; 植物微生物相互作用; ジャスモン酸; ミヤコグサ; 光質; 変異体; 赤色光; シグナル伝達; スクリーニング

Light is critical for supplying carbon to the energetically expensive, nitrogen-fixing symbiosis between legumes and rhizobia. In this study, I show that Phytochrome B(phyB) is part of the monitoring system to detect suboptimal light conditions, which normally suppress Lotus japonicus nodule development following Mesorhizobium loti inoculation. I found that the number of nodules produced by L. japonicus phyB mutants is significantly reduced compared to that of wild-type MG20. To explore causes other than photoassimilate production, the possibility that local control by the root genotype occurred was investigated by grafting experiments. The results showed that the shoot and not the root genotype is responsible for root nodule formation. To explore systemic control mechanisms exclusive of photoassimilation, we moved wild-type MG20 plants from white light to conditions that differed in their ratios of low or high red(R)/ far-red(FR) light. In low R/ FR light, the number of MG20 root nodules dramatically decreased compared to plants grown in high R/ FR even though photoassimilate content was higher for plants grown under low R/ FR. Also, the expression of jasmonic acid(JA)-responsive genes decreased in both low R/ FR light-grown wild-type and in white light-grown phyB mutant plants, and correlated with decreased JA-Ile content in the phyB mutant. Moreover, both infection thread formation and root nodule formation were positively influenced by JA treatment of wild-type plants grown in low

光对于向豆类和根瘤菌之间的能量昂贵，固定氮共生的碳供应至关重要。在这项研究中，我表明植物色素B（Phyb）是检测次优光条件的监测系统的一部分，通常会抑制Mesorhizobium loti接种后的莲花japonicus结节发育。我发现，与野生型Mg20相比，Japonicus Phyb突变体产生的结节数量显着减少。为了探索除光剂量生产以外的其他原因，通过嫁接实验研究了根基因型局部控制的可能性。结果表明，芽而不是根基因型是根结节形成的原因。为了探索不包括光照明的系统控制机制，我们将野生型MG20植物从白光移动到其低红色或高红色或高红色（R）/远红色（FR）光的比率。在低R/ FR的光中，与在低R/ FR下生长的植物相比，MG20根结节的数量急剧下降，而在低R/ Fr下生长的植物含量较高。同样，在低R/ FR的野生型野生型和白光生长的Phyb突变植物中，茉莉酸（JA）反应基因的表达均降低，并且与phyb突变体中JA-EIL含量降低相关。此外，感染螺纹形成和根结节形成都受到低野生型植物的JA处理的积极影响