Role of auxin during intercellular infection of Discaria trinervis by Frankia

Frontiers in Plant Science

卷:5

Genevieve eConejero¹  Francine Manuella Perrine-Walker²  Alice eVayssieres²  Mikael eLucas²  Sergio eSVISTOONOFF³  Laurent eLaplaze³  Adama eNdour³  Antony eChampion³  Leandro eImanishi⁴  Luis eWall⁴ 

[1] Inatitut National de la Recherche Agronomique;

[2] Institut de Recherche pour le Développement;

[3] Laboratoire Commun de Microbiologie IRD/ISRA/UCAD;

[4] Universidad Nacional de Quilmes;

关键词: Nitrogen Fixation;    Systems Biology;    Model;    auxin;    endosymbiosis;    PIN;   

DOI  :  10.3389/fpls.2014.00399

来源: DOAJ

【 摘 要 】

Nitrogen-fixing nodules induced by Frankia in the actinorhizal plant Discaria trinervis result from a primitive intercellular root invasion pathway that does not involve root hair deformation and infection threads. Here, we analyzed the role of auxin in this intercellular infection pathway at the molecular level and compared it with our previous work in the intracellular infected actinorhizal plant Casuarina glauca. Immunolocalisation experiments showed that auxin accumulated in Frankia-infected cells in both systems. We then characterized the expression of auxin transporters in D. trinervis nodules. No activation of the heterologous CgAUX1 promoter was detected in infected cells in D. trinervis. These results were confirmed with the endogenous D. trinervis gene, DtAUX1. However, DtAUX1 was expressed in the nodule meristem. Consistently, transgenic D. trinervis plants containing the auxin response marker DR5:VENUS showed expression of the reporter gene in the meristem. Immunolocalisation experiments using an antibody against the auxin efflux carrier PIN1, revealed the presence of this transporter in the plasma membrane of infected cells. Finally, we used in silico cellular models to analyse auxin fluxes in D. trinervis nodules. Our results point to the existence of divergent roles of auxin in intercellularly- and intracellularly-infected actinorhizal plants, an ancestral infection pathways leading to root nodule symbioses.

【 授权许可】

Unknown