Differential expression of a senescence‐enhanced metallothionein gene inArabidopsisin response to isolates ofPeronospora parasiticaandPseudomonas syringae

Abstract

SummaryThe metallothionein gene, LSC54, shows increased expression during leaf senescence in Brassica napus and Arabidopsis thaliana. A number of abiotic and biotic stresses have been shown to induce senescence-like symptoms in plants and, to investigate this further, the promoter of the LSC54 gene was cloned and fused to the GUS gene and transformed into Arabidopsis. The promoter was highly induced during leaf senescence and also in response to wounding; histochemical analysis indicated that this induction was localised to a few cells close to the wound site. The transgenic Arabidopsis tissue was infected with compatible and incompatible isolates of both the fungal biotroph, Peronospora parasitica and the bacterial necrotroph, Pseudomonas syringae. Incompatible isolates induced rapid cell death (the hypersensitive response) at the site of infection and, with both pathogens, early, localised expression of the GUS gene was observed. In contrast, relatively slow induction of the GUS gene was seen in the compatible interaction and this was correlated with the appearance of senescence-like symptoms in the biotrophic interaction and cell death by necrosis that occurred in response to the necrotrophic pathogen. These results suggest that there are common steps in the signalling pathways that lead to cell death in the hypersensitive response, pathogen induced necrosis and senescence.

Identification of genes expressed during the compatible interaction of grapevine with Plasmopara viticola through suppression subtractive hybridization (SSH)

“…Although the majority of expressed MT genes belong to type 2, type 1, 3 and 4 MT have also been reported to be involved in various plant processes. Transcript accumulation of type 1 MT was shown in various organs and also in response to pathogen attack (Butt et al 1998). In this study, induction of a type 1 MT was observed 12 hpi followed by a decline at 24 hpi.…”

Salicylic Acid Regulates Arabidopsis Microbial Pattern Receptor Kinase Levels and Signaling

“…Double mutants acd6-1 fls2, acd6-1 bak1-4, and acd6-1 mpk3 were obtained by doing crosses and screening the F2 generation for plants homozygous for acd6-1 by PCR using derived cleaved-amplified polymorphic sequence markers (Rate et al, 1999) and using the respective gene-specific primers (fls2, 59-AGGGCTTCTTACAAACCTTCG-39 and 59-CGTTGATGTTTTTGAACACCC-39; bak1-4, 59-CCTCCTATCTCTCCTA-GACCGCCATC-39 and 59-CTCTTAAACAGGAGGCAACACTTCCA-39; mpk3, 59-TGCGCTTATTGACAGAGGTAA-39 and 59-CCGTATGTTGGATTGAGT-GCT-39) and the left border primer of the T-DNA (59-ATTTTGCCGATTTCGG-AAC-39) for the second mutation. Plants were grown as described (Greenberg et al, 1994;Butt et al, 1998) in 16-h-light/8-h-dark conditions for 19 to 21 d and then harvested for various assays.…”

The Gain-of-Function Arabidopsis acd6 Mutant Reveals Novel Regulation and Function of the Salicylic Acid Signaling Pathway in Controlling Cell Death, Defenses, and Cell Growth

“…Plants (Arabidopsis thaliana) were grown in growth rooms or aseptically, as described elsewhere (Greenberg et al, 1994;Butt et al, 1998), in a 16-hr-light and 8-hr-dark cycle. Pseudomonas syringae pv maculicola ES4326 and P. s. pv tomato DC3000 and its derivatives were obtained from F.M.…”