Evidence for structurally specific negative feedback in the Nod factor signal transduction pathway

Citation
Ged. Oldroyd et al., Evidence for structurally specific negative feedback in the Nod factor signal transduction pathway, PLANT J, 28(2), 2001, pp. 191-199
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT JOURNAL
ISSN journal
0960-7412 → ACNP
Volume
28
Issue
2
Year of publication
2001
Pages
191 - 199
Database
ISI
SICI code
0960-7412(200110)28:2<191:EFSSNF>2.0.ZU;2-8
Abstract
Nod factor is a critical signalling molecule in the establishment of the le gume/rhizobial symbiosis. The Nod factor of Sinorhizobium meliloti carries O-sulphate, O-acetate and C-16:2 N-acyl attachments that define its activit y and host specificity. Here we assess the relative importance of these mod ifications for the induction of calcium spiking in Medicago truncatula. We find that Nod factor structures lacking the O-sulphate, structures lacking the O-acetate and N-acyl groups, and structures lacking the O-acetate combi ned with a C-18:1 N-acyl group all show calcium spiking when applied at hig h concentrations. These calcium responses are blocked in dmi1 and dmi2 muta nts, suggesting that they function through the Nod factor signal transducti on pathway. The dmi3 mutant, which is proposed to function in the Nod facto r signal transduction pathway downstream of calcium spiking, shows increase d sensitivity to Nod factor. This increased sensitivity is only active with wild-type Nod factor and was not present when the plants were treated with mutant Nod factor structures. We propose that the Nod factor signal transd uction pathway is under negative feedback regulation that is activated at o r downstream of DMI3 and requires structural components of the Nod factor m olecule for activity.