Nod factors potentiate auxin signaling for transcriptional regulation and lateral root formation in Medicago truncatula.
J Exp Bot, 2017/01/01;68(3):569-583.
Herrbach V[1], Chirinos X[1], Rengel D[1], Agbevenou K[1], Vincent R[1], Pateyron S[2, 3], Huguet S[2, 3], Balzergue S[2, 3], Pasha A[4], Provart N[4], Gough C[1], Bensmihen S[1]
Affiliations
PMID: 28073951DOI: 10.1093/jxb/erw474
Impact factor: 7.298
Abstract
Nodulation (Nod) factors (NFs) are symbiotic molecules produced by rhizobia that are essential for establishment of the rhizobium-legume endosymbiosis. Purified NFs can stimulate lateral root formation (LRF) in Medicago truncatula, but little is known about the molecular mechanisms involved. Using a combination of reporter constructs, pharmacological and genetic approaches, we show that NFs act on early steps of LRF in M. truncatula, independently of the ethylene signaling pathway and of the cytokinin receptor MtCRE1, but in interaction with auxin. We conducted a whole-genome transcriptomic study upon NF and/or auxin treatments, using a lateral root inducible system adapted for M. truncatula. This revealed a large overlap between NF and auxin signaling and, more interestingly, synergistic interactions between these molecules. Three groups showing interaction effects were defined: group 1 contained more than 1500 genes responding specifically to the combinatorial treatment of NFs and auxin; group 2 comprised auxin-regulated genes whose expression was enhanced or antagonized by NFs; and in group 3 the expression of NF regulated genes was antagonized by auxin. Groups 1 and 2 were enriched in signaling and metabolic functions, which highlights important crosstalk between NF and auxin signaling for both developmental and symbiotic processes.
Keywords: Auxin; NimbleGen arrays; Nod factors; ethylene; lateral root; lateral root inducible system (LRIS); lipo-chitooligosaccharides (LCOs); symbiosis; transcriptome
MeSH terms
Gene Expression Regulation, Plant; Indoleacetic Acids; Lipopolysaccharides; Medicago truncatula; Plant Growth Regulators; Plant Roots; Sinorhizobium meliloti
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