2026年9月1日，四川大学生命科学学院张阳教授等科学家在《遗传学报》（Journal of Genetics and Genomics）发表研究，揭示了蒺藜苜蓿中复制VIH基因的调控分化如何将磷酸盐信号与根瘤发育联系起来。

初级代谢物及其衍生物通常作为细胞内信号发挥作用。焦磷酸肌醇是磷酸盐信号的核心调控因子，但其在豆科植物结瘤中的作用仍知之甚少。在此，研究人员在蒺藜苜蓿中鉴定出两个保守的Vip1同源/二磷酸肌醇五磷酸激酶基因——MtVIH1和MtVIH2。生化分析表明，MtVIH1和MtVIH2的激酶结构域均保留PP-InsP激酶活性。然而，转录组和表达分析揭示了复制基因之间的调控分化，其中MtVIH2在结瘤过程中被优先诱导，并与磷酸盐饥饿标志物Mt4共表达。沉默MtVIH2会减少根瘤形成、固氮酶活性和成熟根瘤标志物表达，并改变根瘤中可提取的无机Pi积累。与此一致，CRISPR/Cas9介导的MtVIH2编辑重现了这些缺陷，而Mtvih1-cas9则表现出弱得多的效应，Mtvih1/2-cas9编辑的根则表现出与Mtvih2-cas9相当的表型。这些结果表明，复制VIH基因之间的调控分化与MtVIH2在根瘤发育中的主导作用相关。启动子分析和荧光素酶实验揭示，P1BS元件参与了MtPHR1介导的MtVIH2启动子激活。综上所述，这些发现揭示了复制VIH基因的调控分化，并提示保守的磷酸盐响应机制有助于蒺藜苜蓿的根瘤发育和氮固定。

附：英文原文

Title: Regulatory divergence of duplicated VIH genes links phosphate signaling to nodule development in Medicago truncatula

Author: anonymous

Issue&Volume: 2026/09/01

Abstract: Primary metabolites and their derivatives often serve as intracellular signals. Inositol pyrophosphates are central regulators of phosphate signaling, but their roles in legume nodulation remain poorly understood. Here, we identify two conserved Vip1 Homolog/Diphosphoinositol Pentakisphosphate Kinase genes, MtVIH1 and MtVIH2, in Medicago truncatula. Biochemical analyses show that the kinase domains of both MtVIH1 and MtVIH2 retain PP-InsP kinase activity. However, transcriptomic and expression analyses reveal regulatory divergence between the duplicated genes, with MtVIH2 being preferentially induced during nodulation and co-expressed with the phosphate starvation marker Mt4. Silencing MtVIH2 reduces nodule formation, nitrogenase activity, and mature nodule marker expression, and alters extractable inorganic Pi accumulation in nodules. Consistently, CRISPR/Cas9-mediated editing of MtVIH2 reproduces these defects, whereas Mtvih1-cas9 shows much weaker effects and Mtvih1/2-cas9 edited roots display phenotypes comparable to Mtvih2-cas9. These results demonstrate that regulatory divergence between duplicated VIH genes is associated with a predominant role of MtVIH2 in nodule development. Promoter analysis and luciferase assays reveal that a P1BS element contributes to MtPHR1-mediated activation of the MtVIH2 promoter. Together, these findings reveal regulatory divergence of duplicated VIH genes and suggest that conserved phosphate-responsive mechanisms contribute to nodule development and nitrogen fixation in M. truncatula.

DOI: 10.1016/j.jgg.2026.08.008

Source:https://www.sciencedirect.com/science/article/abs/pii/S1673852726002730