Investigation of the Demographic and Selective Forces Shaping the Nucleotide Diversity of Genes Involved in Nod Factor Signaling in Medicago truncatula

• DOI: 10.1534/genetics.107.076943
• Publication Date: 2007-12-12T04:46:15Z
• Authors: Stéphane De Mita; Joëlle Ronfort; Heather I McKhann; Charles Poncet; Redouane El Malki; Thomas Bataillon
• Keywords: Medicago truncatula; Nod factor; Nucleotide diversity

Abstract Symbiotic nitrogen-fixing rhizobia are able to trigger root deformation in their Fabaceae host plants, allowing intracellular accommodation. They do so by delivering molecules called Nod factors. We analyzed the patterns of nucleotide polymorphism five genes controlling early factor perception and signaling Medicago truncatula understand selective forces shaping evolution these genes. used 30 M. genotypes sampled a genetically homogeneous region species distribution range. first sequenced 24 independent loci detected genomewide departure from hypothesis neutrality demographic equilibrium that suggests population expansion. These data were estimate parameters simple model incorporating The was then examined using combination two complementary tests, Tajima's D Fay Wu's standardized H. joint H expected under obtained fitted expansion model. Only gene DMI1, which is regulate downstream signal, shows pattern consistent with putative event. In contrast, receptor-encoding NFP NORK show no significant signatures selection. Among we analyzed, only DMI1 should be viewed as candidate for adaptation recent history truncatula.