Poster: Plant Pathogen/Symbiont Interactions

Abs # 714: Isolation and characterization of an Arabidopsis len3 mutant

Presenter:	Ishikawa, Atsushi , ishikawa@fpu.ac.jp
Authors	Ishikawa, Atsushi  (A)   Asahi, Tadashi  (A)
Affiliations:	(A): Fukui Prefectural University

We have screened approximately 4,000 T-DNA tagged lines for lesion@initiation (len) mutants which spontaneously develop small patches of necrotic tissue and constitutively express SAR. Here we describe the isolation and characterization of a dominant len3 mutant. The lesions in len3 plants develop under short day and long day conditions. The len3 plants were smaller than wild-type plants and expressed cytological and biochemical markers that associated with disease resistance response. The len3 plants constitutively expressed the PR genes and PDF1.2 gene and showed enhanced resistance to virulent pathogens. Disease resistance in Arabidopsis is regulated by multiple signal transduction pathways in which salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) function as key signaling molecules. Expression of PR genes are mediated by SA-dependent pathway and PDF1.2 gene induction is mediated by JA/ET-dependent pathways. Thus, the LEN3 may participate in signal communication between SA- and JA/ET-dependent pathways. So far, many Arabidopsis mutants that display altered SA- or JA/ET-dependent signaling have been isolated. We are making double mutants between mutants that disrupt these pathways and len3 plants. This will allow us to explore the relationship between the SA-and JA/ET-mediated resistance responses in len3 plants.