title: CRYPTOCHROME 1 is implicated in promoting R protein-mediated plant resistance to Pseudomonas syringae in Arabidopsis.
abstract: Plants have evolved complex mechanisms to defend themselves against pathogens. It has been shown that several defense responses are influenced by light, and the red/far-red light photoreceptor phytochromes (PHY) modulate plant defense responses in Arabidopsis. Blue light receptor cryptochromes (CRY) work together with PHY to regulate many light-controlled responses, including photomorphogenesis, floral induction, and entrainment of the circadian clock. We report here that the Arabidopsis blue light photoreceptor CRY1 positively regulates inducible resistance to Pseudomonas syringae under continuous light conditions. By challenging plants with P. syringae pv. tomato (Pst.) DC3000 carrying avrRpt2, we demonstrate that effector-triggered local resistance is down-regulated in the cry1 mutant, leading to more pathogen multiplication. In plants overexpressing CRY1 (CRY1-ovx), however, local resistance is significantly up-regulated. We also show that systemic acquired resistance (SAR) is positively regulated by CRY1, and that salicylic acid (SA)-induced pathogenesis-related gene PR-1 expression is reduced in the cry1 mutant, but enhanced in CRY1-ovx plants. However, our results indicate that CRY1 only modestly influences SA accumulation and has no effect on hypersensitive cell death. These results suggest that CRY1 may positively regulate R protein-mediated resistance to P. syringae with increased PR gene expression.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Graduate School of Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Wu
authors.forename: Hong-Quan
authors.initials: HQ
authors.lastname: Yang
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D056931:Cryptochromes / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D044224:Pseudomonas syringae / Q000472:pathogenicity*; D020156:Salicylic Acid / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; C538962:CRY1 protein, Arabidopsis; D056931:Cryptochromes; C077262:PR-1 protein, Arabidopsis; D020156:Salicylic Acid