ATP-Dependent Binding Cassette Transporter G Family Member 16 Increases Plant Tolerance to Abscisic Acid and Assists in Basal Resistance against Pseudomonas syringae DC3000    

Abstract

Plants have been shown previously to perceive bacteria on the leaf surface and respond by closing their stomata. The virulent bacterial pathogen Pseudomonas syringae pv tomato DC3000 (PstDC3000) responds by secreting a virulence factor, coronatine, which blocks the functioning of guard cells and forces stomata to reopen. After it is inside the leaf, PstDC3000 has been shown to up-regulate abscisic acid (ABA) signaling and thereby suppress salicylic acid-dependent resistance. Some wild plants exhibit resistance to PstDC3000, but the mechanisms by which they achieve this resistance remain unknown. Here, we used genome-wide association mapping to identify an ATP-dependent binding cassette transporter gene (ATP-dependent binding cassette transporter G family member16) in Arabidopsis (Arabidopsis thaliana) that contributes to wild plant resistance to PstDC3000. Through microarray analysis and b-glucuronidase reporter lines, we showed that the gene is up-regulated by ABA, bacterial infection, and coronatine. We also used a green fluorescent protein fusion protein and found that transporter is more likely to localize on plasma membranes than in cell walls. Transferred DNA insertion lines exhibited consistent defective tolerance of exogenous ABA and reduced resistance to infection by PstDC3000. Our conclusion is that ATP-dependent binding cassette transporter G family member16 is involved in ABA tolerance and contributes to plant resistance against PstDC3000. This is one of the first examples, to our knowledge, of ATPdependent binding cassette transporter involvement in plant resistance to infection by a bacterial pathogen. It also suggests a possible mechanism by which plants reduce the deleterious effects of ABA hijacking during pathogen attack. Collectively, these results improve our understanding of basal resistance in Arabidopsis and offer unique ABA-related targets for improving the innate resistance of plants to bacterial infection.

Learning from each other: ABC transporter regulation by protein phosphorylation in plant and mammalian systems

“…Recently, ABCG16 was reported to play a role in pathogen resistance against Pseudomonas syringae [96]. Furthermore, like for ABCG36, also for ABCG16 a second transport function was described that provides tolerance to the phytohormone, ABA (abscisic acid) [96].…”

“…Furthermore, like for ABCG36, also for ABCG16 a second transport function was described that provides tolerance to the phytohormone, ABA (abscisic acid) [96]. Previously, ABCG25 was reported to export ABA from the cell, whereas ABCG40/PDR12 seems to mediate the import into cells [76,97] Therefore the question arises whether the ABCG transporter class has a broader substrate specificity as described for its yeast orthologues [98][99][100].…”

Arabidopsis ABCG34 contributes to defense against necrotrophic pathogens by mediating the secretion of camalexin

“…We hypothesized that additional ABCG transporters are involved in pathogen defense, because (i) the transcript levels of many additional full-size ABCG transporters have been reported to be up-regulated in plants exposed to pathogens (16,17) and (ii) pathogen defense is often mediated by secondary metabolites, many of which are transported by ABC transporters (18). To identify such additional ABCG transporters involved in plant defense against pathogens, we screened A. thaliana transfer DNA (T-DNA) insertion mutants of full-size ABCG genes for altered sensitivity to the secondary metabolite sclareol, because sclareol hypersensitivity might provide a clue as to which ABCG proteins are involved in secondary metabolite transport.…”

Microbial Interactions in the Phyllosphere Increase Plant Performance under Herbivore Biotic Stress

“…Unless otherwise stated in the manuscript, we refer to these three species by their commonly used names, Pst DC3000, Xanthomonas , and Bacillus , respectively. The bacterial strains Bacillus , and Xanthomonas were originally isolated from the Arabidopsis phyllosphere in a previous study (Traw et al, 2007) whereas the Pst DC3000 is a model phytopathogen; all three bacterial species are widely used in studies of plant–microbe interactions (Kover and Schaal, 2002; Korves and Bergelson, 2003; Ji et al, 2014). …”

“…The appropriate dilutions of sample mixtures were then plated on KB agar plates without antibiotic for Bacillus and Xanthomonas whereas the Pst DC3000 plates contained 50 μg ml -1 of rifampicin. All plates were incubated at 28°C for 3 days before counting the number of colonies using a standard method (Ji et al, 2014). Meanwhile, we also recorded plant fitness data, such as days to flowering (DF), siliques per plant (SPP), seeds per silique (SPS), and plant biomass (aboveground only) depending on plant reproductive developmental stages.…”