Induced instability of two Arabidopsis constitutive pathogen-response alleles

摘要

Paramutation is an example of a non-Mendelian-directed allelic interaction that results in the epigenetic alteration of one allele. We describe a paramutation-like interaction between two alleles, bal and cpr1-1 (constitutive expressor of PR genes 1), which map to a complex R-like gene cluster on Arabidopsis chromosome 4. Both alleles cause dwarfing and constitutive defense responses, similar to another dwarf variant, ssi1 (suppressor of SA-insensitivity 1). Previous work has demonstrated that the bal and ssi1 phenotypes are caused by overexpression of an R-like gene from the cluster, which activates an salicylic acid-dependent defense pathway.