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Host‐specific N od‐factors associated with M edicago truncatula nodule infection differentially induce calcium influx and calcium spiking in root hairs
Author(s) -
Morieri Giulia,
Martinez Eduardo A.,
Jarynowski Andrzej,
Driguez Hugues,
Morris Richard,
Oldroyd Giles E. D.,
Downie J. Allan
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12475
Subject(s) - medicago truncatula , nod factor , calcium , nod , root hair , biology , microbiology and biotechnology , calcium signaling , biochemistry , chemistry , signal transduction , root nodule , symbiosis , genetics , bacteria , organic chemistry , gene
Summary Rhizobial nodulation ( N od) factors activate both nodule morphogenesis and infection thread development during legume nodulation. Nod factors induce two different calcium responses: intra‐nuclear calcium oscillations and a calcium influx at the root hair tip. Calcium oscillations activate nodule development; we wanted to test if the calcium influx is associated with infection. S inorhizobium meliloti nod L and nod F mutations additively reduce infection of Medicago truncatula . Nod‐factors made by the nod L mutant lack an acetyl group; mutation of nod F causes the nitrogen ( N )‐linked C16:2 acyl chain to be replaced by C18:1. We tested whether these Nod‐factors differentially induced calcium influx and calcium spiking. The absence of the NodL‐determined acetyl group greatly reduced the induction of calcium influx without affecting calcium spiking. The calcium influx was even further reduced if the N‐linked C16:2 acyl group was replaced by C18:1. These additive effects on calcium influx correlate with the additive effects of mutations in nodF and nodL on legume infection. Infection thread development is inhibited by ethylene, which also inhibited Nod‐factor‐induced calcium influx. We conclude that N od‐factor perception differentially activates the two developmental pathways required for nodulation and that activation of the pathway involving the calcium influx is important for efficient infection.