W376 Neodiversification in the Paleotetraploid Soybean Genome: GmCLAVATA 1A, a GmNARK Paralogue Involved in the Control of Stem Nodal Identity But Not Root Nodulation

Date: Sunday, January 15, 2012
Time: 5:35 PM
Room: Golden Ballroom
Saeid Mirzaei , University of Queensland, St. Lucia, Australia
Brett J. Ferguson , University of Queensland, St. Lucia, Australia
Khalid Meksem , Southern Illinois University, Carbondale, IL
Jacqueline Batley , University of Queensland, St. Lucia, Australia
Peter M. Gresshoff , University of Queensland, St. Lucia, Australia
Duplicated genes may evolve in different directions. Neodiversification involves the development of a new gene function. Here we identified the paralogue of the LRR receptor kinase gene (GmNARK) in soybean. While GmNARK is directly involved in the systemic regulation of nodulation in soybean, its paralogue (GmCLV1A) has no apparent nodulation function. Analysis of gene structure, gene expression and genomic environment support the homeologous origins in the segmentally duplicated soybean genome. GmNARK mutants are not complemented by GmCLV1A. We isolated a TILLING mutant in GmCLV1A, which was characterised by a missense mutation in a putative S-glycosylation site (S562L). The mutant behaves a loss-of-function allele and causes severe nodal identity alterations in the younger parts of the emergent plant, as well as flower and pod abnormalities. All phenotypic responses in the mutant suggest altered regulation of cell division, consistent with the general mechanism illustrated in the Arabidopsis CLAVATA1 system and mimicked in the long distance regulation of nodule meristem proliferation controlled by GmNARK.