Abiotic stress tolerance in plants

Abstract

Plants regulate expression of a set of genes in response to environmental stresses. Hence, it is important to decipher the information on comprehensive expression analysis under stress condition. We have studied salt-inducible genes in barley by differential display and the function of some candidates using heterologous expression system. Total 218 and 102 cDNA clones were identified as a salt-inducible gene in barley roots and leaves under salt stress, respectively. Among these, transgenic Arabidopsis overexpressing peroxisomal ascorbate peroxidase or proline transporter showed tolerance toward heat or salt stress. Using barley salt-responsive genes, we have also fabricated barley custom cDNA microarray system to monitor the transcriptomes in barley and rice. Comparative analysis reveals the differences in gene expression pattern between the two plants during the initial phase of salt stress. Especially, divergent responses were observed in expression profiles involving in osmoregulation and ion homeostasis. Furthermore, transcript of methionine synthase is increased in barley, but not in rice. This is identical to abundance of methionine synthase protein that examined by Western blot analysis. Thus, direct comparison in transcriptome is useful to narrow the differences in the two plants, and give information on genetic improving of plant stress tolerance. © 2006 Springer. All Rights Reserved.