Molecular Mechanism of GmSNE3 Ubiquitin Ligase-Mediated Inhibition of Soybean Nodulation by Halosulfuron Methyl

In this study, the role of E3 ubiquitin ligase GmSNE3
in halosulfuron
methyl (HSM) inhibiting soybean nodulation was investigated. GmSNE3 was strongly induced by HSM stress, and the overexpression
of GmSNE3 significantly reduced the number of soybean
nodules. Further investigation found that GmSNE3 could interact with
a nodulation signaling pathway 1 protein (GmNSP1a) and GmSNE3 could
mediate the degradation of GmNSP1a. Importantly, GmSNE3-mediated degradation
of GmNSP1a could be promoted by HSM stress. Moreover, HSM stress and
the overexpression of GmSNE3 resulted in a substantial decrease in
the expression of the downstream target genes of GmNSP1a. These results revealed that HSM promotes the ubiquitin-mediated
degradation of GmNSP1a by inducing GmSNE3, thereby inhibiting the
regulatory effect of GmNSP1a on its downstream target
genes and ultimately leading to a reduction in nodulation. Our findings
will promote a better understanding of the toxic mechanism of herbicides
on the symbiotic nodulation between legumes and rhizobia.

在本项研究中，对E3泛素连接酶GmSNE3在抑制豆科植物根瘤形成过程中所扮演的角色进行了探讨。GmSNE3在环嘧磺隆甲基（HSM）胁迫下显著诱导表达，而GmSNE3的过表达显著降低了大豆根瘤的数量。进一步研究发现，GmSNE3能够与根瘤信号通路1蛋白（GmNSP1a）相互作用，并介导GmNSP1a的降解。值得注意的是，GmSNE3介导的GmNSP1a降解过程可被HSM胁迫所促进。此外，HSM胁迫及GmSNE3的过表达导致GmNSP1a下游靶基因的表达显著下降。这些结果揭示了HSM通过诱导GmSNE3，进而促进泛素介导的GmNSP1a降解，从而抑制GmNSP1a对其下游靶基因的调控作用，最终导致根瘤形成减少。本研究成果将有助于更深入地理解除草剂对豆科植物与根瘤菌共生根瘤形成过程中毒机理的认识。