百脉根中Lj5NG4与结瘤因子受体LjNFR1互作调控根瘤菌侵染

The interaction of Lj5NG4 and LjNFR1 in Lotus japonicus regulates the infection of Rhizobium

以百脉根结瘤因子受体激酶LjNFR1为诱饵,通过建立百脉根根瘤共生不同时期的酵母膜双杂文库筛选获得了一个与之互作的生长素相关转运蛋白Lj5NG4。通过酵母双杂交和烟草Split-Luc等试验进一步证实了Lj5NG4与LjNFR1的蛋白互作。利用CRISPR-Cas9基因敲除及超表达技术创建相关转基因材料,研究发现Lj5NG4可能在根瘤菌侵染前期起负调控作用,但对结瘤过程没有显著影响。同时启动子表达也证实了Lj5NG4在侵染前期根毛中强烈表达,成熟根瘤内部不表达。外源施加生长素试验发现低浓度的生长素会减弱Lj5NG4突变体的早期侵染表型,这表明生长素在共生结瘤发育中通过Lj5NG4发挥功能。

Using the Lotus japonicus nodule factor receptor kinase Lj NFR1 as a bait and a yeast membrane two hybrid library constructed with transcripts harvested at different stages of nodule symbiosis, we identified an auxin related transporter protein Lj5 NG4. The interaction between Lj5 NG4 and Lj NFR1 was further confirmed by yeast two hybrid and Split-Luc experiments. Using CRISPR-Cas9 and overexpression technology, we conclude that Lj5 NG4 may play a negative regulatory role in the early stage of rhizobial infection, but had no significant effect on nodule formation. Meanwhile, promoter expression also confirmed that Lj5 NG4 was strongly expressed in root hairs at the early stage of infection, but not in inner mature nodules. Exogenously applied auxin treatment showed that low concentration of auxin weakened the phenotype of Lj5 NG4 mutant, indicating that auxin plays a role in the development of symbiotic nodules.