Pepper gene encoding a basic beta-1,3-glucanase is differentially expressed in pepper tissues upon pathogen infection...

A basic beta-1,3-glucanase cDNA clone (CABGLU) was isolated from the cDNA library constructed from hypersensitive response lesions of pepper leaves infected with avirulent strain of Xanthomonas campestris pv. vesicatoria. The deduced polypeptide of CABGLU which contains a C-terminal extension N-glycosylated at a single site characterized as typical structure of class I beta-1,3-glucanase has a high level of identity with tobacco basic beta-1,3-glucanase (77.4%), but only a moderate level of identity with tomato acidic beta-1,3-glucanase (42.6%). Genomic DNA gel blot analysis indicates that the pepper genome contains one or two beta-1,3-glucanase copy genes. Transcripts of the CABGLU gene were more induced in incompatible interactions than in compatible interactions, when inoculated with X. campestris pv. vesicatoria or Phytophthora capsici. Accumulation of CABGLU mRNA was strongly induced in pepper leaves by both ethephon and methyl jasmonate. The CABGLU mRNA was constitutively expressed only in the roots of all the plant organs. These data indicate that the basic beta-1,3-glucanase gene may be induced by pathogen attack and abiotic stresses.