Transcript Profiling of Cold Responsive Genes in Medicago faicata

摘要

A cold-induced cDNA library containing 2,016 cDNA clones was constructed using suppression subtractive hybridization (SSH) from cold hardy Medicago sativa L. ssp. faicata (L.) Arcang. A total of 928 plasmids were initially screened using reverse Northern blot analysis, and 523 clones were sequenced. We identified 238 unique gene transcripts (84 repeats and 154 singlets). The EST sequences were deposited into GenBank and annotated. Eight representative clones, which encode a EREBP, phosphoinositide-specific phospholipase C (PLC), FtsH, sucrose phosphate synthase (SPS), sucrose synthase (SS), L-myo-inositol-1-phosphate synthase (MIPS), dehydrin-like protein, and a protein of unknown function, were selected as probes for Northern blot analysis. They were all induced at low temperature. The data indicate that SSH is an effective tool for identification of cold responsive genes and suggest that M. faicata rely on typical stress-inducible molecular mechanisms for cold acclimation.