Infection of Arabidopsis thaliana leaves with Albugo candida (white blister rust) causes a reprogramming of host metabolism

• DOI: 10.1046/j.1364-3703.2000.00013.x
• Publication Date: 2003-03-12T14:37:05Z
• Authors: Hsueh‐Mei Chou; Nicholas Bundock; Stephen A. Rolfe; Julie D. Scholes
• Keywords: Rust (programming language); White (mutation)

Abstract Albugo candida (Pers.) (O.) Kunze is a biotrophic pathogen which infects the crucifer Arabidopsis thaliana (L.) Heynh forming discrete areas of infection. Eight days after inoculation leaves, white blisters became visible on under surface leaf although no symptoms were apparent upper surface. By day 14, region invaded by fungal mycelium had become chlorotic. Recently it has been hypothesized that an accumulation soluble carbohydrates, following increase in invertase activity, may trigger sugar signal transduction pathways leading to repression photosynthetic gene expression and induction defence proteins. This hypothesis was investigated quantifying localized changes carbohydrate metabolism genes encoding Quantitative imaging chlorophyll fluorescence revealed rate photosynthesis declined progressively regions leaf. However, uninfected infected similar measured control until late during infection cycle when declined. Images nonphotochemical quenching (NPQ) suggested capacity Calvin reduced there complex metabolic heterogeneity within A. also caused leaf; carbohydrates accumulated whereas amount starch The reverse seen did not accumulate increased as progressed. There activity invertases confined mycelium. apoplastic host origin, mRNA levels ATβFRUCT1 (measured semiquantitative RT‐PCR) 40‐fold region. resulted from appearance new isoform Current evidence suggests this origin. Northern blot analysis cab rbcS showed repressed 6 (DAI) compared leaves. In contrast, detectable proteins These data are discussed context sugar‐sensing presented above.