Acta Univ Latv (2008) 745: 87–101

Cloning and characterization of barley homologues of the Arabidopsis LSD1 gene: putative regulators of hypersensitive response

Abstract

Plant hypersensitive response (HR) is a highly controlled reaction to prevent spread of biotroph pathogens. Understanding the mechanisms of HR could potentially allow development of crop plant varieties with improved resistance to pathogens. HR and its molecular control mechanisms have been extensively studied in model organisms, such as Arabidopsis thaliana, allowing to identify numerous necrotic or lesion-mimic mutants that constitutively express the HR even in absence of pathogen. Arabidopsis LSD1 gene encodes a zinc finger protein characterized as a central regulator of HR. Here we identified three genes homologous to the LSD1 in barley and compared them to LSD1 homologues in other grass species. Barley gene CBC04043 appeared to be more similar to the Arabidopsis LOL1 gene, however, the two other genes originating from gene duplication after the monocot - dicot divergence represented candidate genes for the LSD1 orthologue. As the sequence analysis alone did not allow identification of the LSD1 orthologue in barley, expression of the three genes was studied in barley necrotic mutants nec1 and nec3.