ArabidopsisPEN3/PDR8, an ATP Binding Cassette Transporter, Contributes to Nonhost Resistance to Inappropriate Pathogens That Enter by Direct Penetration

Abstract

Arabidopsis thaliana is a host to the powdery mildew Erysiphe cichoracearum and nonhost to Blumeria graminis f. sp hordei, the powdery mildew pathogenic on barley (Hordeum vulgare). Screening for Arabidopsis mutants deficient in resistance to barley powdery mildew identified PENETRATION3 (PEN3). pen3 plants permitted both increased invasion into epidermal cells and initiation of hyphae by B. g. hordei, suggesting that PEN3 contributes to defenses at the cell wall and intracellularly. pen3 mutants were compromised in resistance to the necrotroph Plectosphaerella cucumerina and to two additional inappropriate biotrophs, pea powdery mildew (Erysiphe pisi) and potato late blight (Phytophthora infestans). Unexpectedly, pen3 mutants were resistant to E. cichoracearum. This resistance was salicylic acid–dependent and correlated with chlorotic patches. Consistent with this observation, salicylic acid pathway genes were hyperinduced in pen3 relative to the wild type. The phenotypes conferred by pen3 result from the loss of function of PLEIOTROPIC DRUG RESISTANCE8 (PDR8), a highly expressed putative ATP binding cassette transporter. PEN3/PDR8 tagged with green fluorescent protein localized to the plasma membrane in uninfected cells. In infected leaves, the protein concentrated at infection sites. PEN3/PDR8 may be involved in exporting toxic materials to attempted invasion sites, and intracellular accumulation of these toxins in pen3 may secondarily activate the salicylic acid pathway.

Quantitative detection of changes in the leaf‐mesophyll tonoplast proteome in dependency of a cadmium exposure of barley (Hordeum vulgare L.) plants

“…Although, the abundance of most proteins was not altered by Cd 2+ treatment, peptides 5 corresponding to AtPDR8, an ABC transporter shown to be implicated in pathogen defence [26,27] and heavy metal resistance [28] and the ammonium transporter AtAMT1.1 [29] were present in 3-to 5-fold higher amounts in Cd 2+ treated cell cultures. Despite the fact that the vacuole is the major Cd 2+ store no study has so far investigated whether the abundance of vacuolar membrane proteins changes in response to Cd 2+ stress.…”

Requirement of Vesicle-Associated Membrane Protein 721 and 722 for Sustained Growth during Immune Responses in Arabidopsis

“…One pathway consists of the P450 monooxygenase CYP81F2, the myrosinase PEN2, and the ABC transporter PEN3. CYP81F2 is necessary for the generation of substrates of PEN2, which in turn initiates the metabolism of a group of tryptophan-derived compounds, known as indole glucosinolates, to release potential antimicrobial products by the PEN3 transporter into the extracellular space (Bednarek et al, 2009;Lipka et al, 2005;Stein et al, 2006). The other consists of the PM-anchored syntaxin PEN1, the PM-bound adaptor SNAP33, and the vesicle-associated membrane proteins (VAMPs) 721 and 722 that share 96% identical amino acid sequences (Collins et al, 2003;Kwon et al, 2008c;Pajonk et al, 2008).…”

The Brassica juncea BjCdR15, an ortholog of Arabidopsis TGA3, is a regulator of cadmium uptake, transport and accumulation in shoots and confers cadmium tolerance in transgenic plants

“…It is noteworthy that AtPDR8, a member of the pleiotropic drug resistance subfamily of ABC transporters, is involved in both cadmium resistance and pathogen resistance (Kobae et al, 2006;Stein et al, 2006), even though no direct link between pathogen resistance and heavy metals has yet been found (Kim et al, 2007). It has been suggested that AtPDR8 can recognize a very wide range of compounds that may be toxic to the plant cell when accumulated at high concentration, and transport them out of the plasma membrane (Kim et al, 2007).…”