Identification of the High-Temperature Response Genes From Porphyra Seriata (Rhodophyta) Expression Sequence Tags and Enhancement of Heat Tolerance of Chlamydomonas (Chlorophyta) by Expression of the Porphyra Htr2 Gene1

Abstract

Temperature is one of the major environmental factors that affect the distribution, growth rate, and life cycle of intertidal organisms, including red algae. In an effort to identify the genes involved in the high-temperature tolerance of Porphyra, we generated 3,979 expression sequence tags (ESTs) from gametophyte thalli of P. seriata Kjellm. under normal growth conditions and high-temperature conditions. A comparison of the ESTs from two cDNA libraries allowed us to identify the high temperature response (HTR) genes, which are induced or up-regulated as the result of high-temperature treatment. Among the HTRs, HTR2 encodes for a small polypeptide consisting of 144 amino acids, which is a noble nuclear protein. Chlamydomonas expressing the Porphyra HTR2 gene shows higher survival and growth rates than the wild-type strain after high-temperature treatment. These results suggest that HTR2 may be relevant to the tolerance of high-temperature stress conditions, and this Porphyra EST data set will provide important genetic information for studies of the molecular basis of high-temperature tolerance in marine algae, as well as in Porphyra.

Heat Shock Protein Gene Family of the Porphyra seriata and Enhancement of Heat Stress Tolerance by PsHSP70 in Chlamydomonas

“…In a previous work, we generated 3,989 ESTs from two cDNA libraries constructed from P. seriata thalli under normal growth conditions and heat stress (Kim et al 2011). EST analysis via keyword allowed us to identify the cDNAs encoding for putative heat shock protein (HSP).…”

“…In a previous study, we generated 3,979 ESTs from two P. seriata cDNA libraries constructed from the gametophyte thalli at 10°C (control) and under high-temperature (25°C) conditions, respectively (Kim et al 2011). The ESTs were analyzed for Porphyra heat shock protein gene resources.…”

Effects of Climate Change on Global Seaweed Communities

“…, Kim et al. ). Relevant genomic, transcriptomic, and proteomic studies are only just beginning to scratch the surface and most links from gene expression to organismal performance are far from well established.…”

“…In response, seaweeds can produce heat shock proteins that repair or remove damaged proteins (e.g., Vayda CLIMATE CHANGE AND SEAWEEDS 1065 and Yuan 1994, Lewis et al 2001). However, protein thermal physiology is not well understood in macroalgae (Eggert et al 2012) and the upregulation of heat shock protein production is only one of many transcriptional changes that occur in seaweeds during periods of thermal stress (Collén et al 2007, Kim et al 2011. Relevant genomic, transcriptomic, and proteomic studies are only just beginning to scratch the surface and most links from gene expression to organismal performance are far from well established.…”

De novo assembly of transcriptome from the gametophyte of the marine red algae Pyropia seriata and identification of abiotic stress response genes

“…Expression sequence tag (EST) analyses have been successfully applied to identify genes involved in abiotic stress tolerance in plants, including in marine algae (Houde et al 2006;Kim et al 2011;Roeder et al 2005;Zhang et al 2005). With the advent of next-generation sequencing (NGS) methods such as Roche/454 and Illumina/Hi-seq, large-scale transcriptome sequences can be generated economically from a wider range of organisms (Cheung et al 2008;Huang et al 2012;Lister et al 2008;Qin et al 2008).…”