Phylogenetic analysis of the deduced sHsps of Arabidopsis , rice and P. patens. Full-length amino acid sequences were aligned by the CLUSTAL W and a phylogenetic tree was constructed by the neighbor-joining method using MEGA version 5. Accession numbers of the genes from Arabidopsis and rice are listed in Methods. P. patens sHsps are listed in Table 1. Numbers at branch nodes represent the confidence level of 1000 bootstrap replications. The abbreviations of species are as follows: At: Arabidopsis thaliana, Os: Oryza sativa and Pp: Physcomitrella patens. Arabidopsis and rice sHsps are separated into different subclasses which are highlighted in grey squares. ER (endoplasmic reticulum). Arrow shows PpHsp16.4a and PpHsp16.4b from P. patens.