Transcript profiling in M. truncatula lss and sunn-1 mutants reveals different expression profiles despite disrupted SUNN gene function in both mutants.

A novel autoregulation of nodulation locus in Medicago truncatula, lss, silences the SUNN gene thorough a cis-acting mechanism. Microarray analysis was performed on the Affymetrix Gene Chip® Medicago Genome Array with cDNA isolated from seven-day-old seedlings of wild type, sunn-1 and lss plants. The results suggest that in lss plants expression of only a few dozen genes differs significantly from wild type while in sunn-1 plants expression of several hundred genes represented by over 800 probe sets is altered. These results suggest that the kinase domain modification caused by the sunn-1 mutation alters the receptor's influence on gene expression and that these differences are present even in the absence of nodulation.