Supn, a novel supernodulation mutant in Medicago truncatula

Abstract

Novel Medicago truncatula mutant line, supn, is confirmed as hyper-nodulating phenotype mutant. supn mutant is displaying short root phenotype with increasing nodule numbers approximately three folds compared to wild type phenotype. supn is Tnt1-retrotransposon mutant, more than ~40 Tnt1 insertion sites were identified and sequenced during molecular characterization of supn. About only 10% of insertions could be accountable for super-nodulation phenotype. The predicted M. truncatula GSO2-like locus was isolated, cloned, and sequenced through the Tnt1-insertion screening. The putative Mt GSO2-like is 3287bp in length with two exons and one intron, 1974bp, 1140bp, and 173bp lengths respectively and it is predicted to encode leucin rich-repeats receptor like protein, 999 amino acids in length. MtGS02:GFP is located at cell periphery and within the nucleus of onion epidermal cells while it is located along root cell boundaries of M. truncatula root. GFP localization sites within cell boundaries could be an evidence of cell to cell communication function of our predicted MtGSO2. Exogenous phytohormones were able to elucidate the differences in supn root phenotype from those of wild type and the previously characterized supernodulating, sunn mutant.