Two cDNA clones (FsDhn1 and FsClo1) up-regulated by ABA are involved in drought responses in Fagus sylvatica L. seeds.

Two abscisic acid (ABA)-responsive clones (FsDhn1 and FsClo1) were isolated from a cDNA library of ABA-treated seeds of Fagus sylvatica L. FsDhn1 codes for type-II late embryogenesis abundant (LEA) proteins, also known as dehydrins. The corresponding transcripts were ABA-induced and expressed when seeds were artificially dried. FsClo1 codes for a caleosin, a calcium-binding protein. By expressing FsCLO1 as a fusion protein in Escherichia coli, we obtained biochemical evidence of its ability to bind calcium, a second messenger involved in ABA signaling. This cDNA clone is seed specific, shows a LEA expression pattern and is also induced by ABA and dehydration treatments. The relationship of both genes with seed responses to ABA is discussed.