Triticum aestivum cDNAs homologous to nuclear-encoded mitochondrion-localized small heat shock proteins

Two cDNAs, TaHSP23.5 and TaHSP23.6, encoding proteins with homology to mito chondrion-localized (MT) small heat shock proteins (sHSPs) were isolated fr om a heat shock cDNA library from Triticum aestivum (wheat). TaHSP23.5 spec ified a 214 amino acid protein and TaHSP23.6 specified a 216 amino acid pro tein. Amino acid sequence identity was only 45.7% between the two proteins. However, both proteins showed greater identity to MT sHSPs of other plant species than to any other sHSPs from wheat. Amino acid sequence alignments with other MT sHSPs identified the putative amino terminus of the mature pr oteins and consensus regions specific to this class of sHSPs. Transcripts o f both genes were absent from control tissues, but strongly induced by heat stress. Phylogenetic analysis indicates that these two wheat genes arose b y duplication after the divergence of monocots and dicots. (C) 1999 Elsevie r Science Ireland Ltd. All rights reserved.