IDENTIFICATION AND EXPRESSION OF NOVEL COLD-INDUCED GENES IN POTATO (SOLANUM-SOGARANDINUM)

Twelve cold induced cDNA clones have been isolated by differential scr eening of a cDNA library prepared with mRNA from cold resistant potato (Solanum sogarandinum). Accumulation of mRNA corresponding to each of the clones was analyzed by Northern blot hybridization. The isolated cDNA clones were named Ssci (S. sogarandinum cold induced). All of the clones clearly respond to cold and accumulation of the corresponding transcripts was observed after one day of cold hardening, however, the y varied with regard to the timing of mRNA accumulation. Maximum accum ulation of mRNA corresponding to the crones Ssci1, Ssci2, Ssci6 and Ss ci8 was observed at the first day of cold hardening, while for the cro nes Ssci3, Ssci4, Ssci5, Ssci7, Ssci9, Ssci10, Ssci11 and Ssci12 after 8 days. Partial DNA sequence was determined from the 5' and 3' ends o f the clones and was examined for homology with sequences in database. The results showed that the isolated cDNP; clones correspond to known genes in the database. They encode mRNAs for the following proteins; mRNA for two different S-adenosyl-L-methionine decarboxylases (Ssci1 a nd 2), two chloroplasts chaperonins (Ssci3, Ssci4), a cell division cy cle protein CDC48 (Ssci5), malate dehydrogenase (Ssci6), myo-InositoI- 1-phosphate synthase (Ssci7), protoporphyrin IX: Mg chelatase (Ssci8), elongation factor EF-1 alpha (Ssci9), chloroplast translation elongat ion factor EF-G (Ssci10), ribosomal L-3 protein (Ssci11), and mRNA for TAS14 protein, an ABA. inducible protein in tomato. The identified ge nes may be involved in two different functions referring to cold resis tance. One group may protect chloroplasts and cell functions under the stress, while the other may be involved in metabolic adjustment to co ld. (C) 1997 Elsevier Science Ireland Ltd.