Plant Transcription Factors as Novel Molecular Markers for Legumes.

Legumes are considered highly important due to their nutritional value and their ability to fix atmospheric nitrogen through symbiotic relationships with rhizobia.  Transcription factors are regulators of gene networks that play a vital role in many cellular processes and represent excellent targets for developing molecular markers.  The goals of this research are to develop a comprehensive resource of plant transcription factors and utilize them to facilitate the transfer of information from model to crop legumes.  Primers designed from M. truncatula transcription factors and producing PCR amplicons in alfalfa (M. sativa L.) were used to further evaluate amplification in a panel consisting of plant model legumes (M. truncatula, Lotus japonicus) and crop legumes (Glycine max L., M. sativa L., Pisum sativum L., Phaseolus vulgaris L., Trifolium repens L., T. pratense L., Vigna radiata L., V. unguiculata L., and Lupinus albus L.) that included parents of existing mapping populations.  Amplification, size polymorphism, and sequence variation were evaluated using capillary sequencers.  From the total number of primers producing amplicons, 90%, 78%, 38% and 34% of them amplified in M. truncatula, M. sativa L., Glycine max L. and Lotus japonicus, respectively.  In general, the likelihood of successful amplification decreased with increased phylogenetic distance among species.  Sequencing of PCR products confirmed amplification of the target sequence and enabled identification of SNP sites both within and among the multiple legume species evaluated.  These polymorphic SNP markers can be used as anchor markers to facilitate the transfer of information from models to crops.  These resources represent valuable tools for comparative genomics and can be used to improve complex traits in multiple legume species including those with limited genetic and genomic resources.