Identification of hypo-osmotically induced genes in Kappaphycus alvarezii (Solieriaceae, Rhodophyta) through expressed sequence tag analysis

Abstract

Hypo-osmotic conditions are among the most stressful environmental factors that affect seaweed physiology and productivity. To improve understanding of hypo-osmotic adaptation and to find genes involved in low salinity stress, we conducted an analysis of expressed sequence tags (ESTs) on the κ-carrageenan-producing red algae, Kappaphycus alvarezii. Of 454 tentatively unique genes (TUGs), 281 matched protein sequences by BlastX analysis (e value≤10 -3), 112 TUGs matched ESTs from other agar- or carrageenan-producing red algae, and 98 TUGs were annotated. The transcriptional profiles of six functional genes from K. alvarezii ESTs were examined. An ATP-binding cassette transporter gene and a sodium phosphate symporter gene were significantly up-regulated, indicating the importance of membrane transport proteins in coping with hypo-osmotic stress conditions. © 2011 by Walter de Gruyter Berlin Boston.