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Title: Development of Salt Tolerant Alfalfa (Medicago Sativa) and Identification of Associated Change in mRNA Expression Levels

item Mott, Ivan
item Peel, Michael
item Bushman, Shaun
item WYLER, S - Case Western Reserve University (CWRU)

Submitted to: Molecular Breeding of Forage and Turf Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/2009
Publication Date: 3/15/2010
Citation: Mott, I.W., Peel, M., Bushman, B.S., Wyler, S. 2010. Development of Salt Tolerant Alfalfa (Medicago Sativa) and Identification of Associated Change in mRNA Expression Levels. Molecular Breeding of Forage and Turf Conference.

Interpretive Summary:

Technical Abstract: Soil salinity limits agricultural production worldwide. Nearly 50% of the world's irrigated land is affected by salinity which increases with improper management of irrigation and drainage, and irrigation with secondary water. In semiarid regions, limited water and hot, dry climates frequently cause salinity concentrations that limit or prevent crop production. Alfalfa is an important forage crop in the US and has been characterized as a moderately salt sensitive species with a threshold of 2.0 dS m-1 electrical conductivity (EC). To improve the tolerance to saline conditions, we have completed three cycles of recurrent selection for relative salt tolerance in alfalfa using a greenhouse selection protocol wherein plants were subjected to saline irrigation up to EC of 21.0 dS m-1. The selected alfalfa populations were field tested under high saline conditions. In comparisions of selected alfalfa for relative forage production, preliminary results showed that the top lines from one of the selected populations averaged 36% higher forage production than the cultivars Malne, Mesa Sirsa, Rambler, and Salado. To identify genetic changes in the selected alfalfas, we used Suppression Subtration Hybridization (SSH) to identify genes that are differentially expressed in salt-selected and non-selected alfalfa genotypes under salt stress. Eighty-eight out of 384 colony hybridization spots were identified as being differentially expressed. cDNA-plasmid clones representing the spots were isolated and sequenced followed by BLAST searches against the NCBI nucleotide database. The 88 clones represented 47 different genes of which only 10 had significant similarity to genes with known function. The remaining 37 genes had no known gene function, with 10 of those having no significant similarities to any nucleotide sequences in the NCBI database.