Perception of conserved pathogen elicitors at the plasma membrane leads to relocalization of the Arabidopsis PEN3 transporter

Abstract

The Arabidopsis PENETRATION RESISTANCE 3 (PEN3) ATP binding cassette transporter participates in nonhost resistance to fungal and oomycete pathogens and is required for full penetration resistance to the barley powdery mildew Blumeria graminis f. sp. hordei. PEN3 resides in the plasma membrane and is recruited to sites of attempted penetration by invading fungal appressoria, where the transporter shows strong focal accumulation. We report that recruitment of PEN3 to sites of pathogen detection is triggered by perception of pathogen-associated molecular patterns, such as flagellin and chitin. PEN3 recruitment requires the corresponding pattern recognition receptors but does not require the BAK1 coreceptor. Pathogen-and pathogen-associated molecular pattern-induced focal accumulation of PEN3 and the PENETRATION RESISTANCE 1 (PEN1) syntaxin show differential sensitivity to specific pharmacological inhibitors, indicating distinct mechanisms for recruitment of these defense-associated proteins to the host-pathogen interface. Focal accumulation of PEN3 requires actin but is not affected by inhibitors of microtubule polymerization, secretory trafficking, or protein synthesis, and plasmolysis experiments indicate that accumulation of PEN3 occurs outside of the plasma membrane within papillae. Our results implicate pattern recognition receptors in the recruitment of defense-related proteins to sites of pathogen detection. Additionally, the process through which PEN3 is recruited to the host-pathogen interface is independent of new protein synthesis and BFA-sensitive secretory trafficking events, suggesting that existing PEN3 is redirected through an unknown trafficking pathway to sites of pathogen detection for export into papillae.plant | PAMP-triggered immunity | focal protein accumulation | vesicle

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

“…3G). Previous studies of AtABCG36/PEN3 and NbABCG1/2 showed that these transporters are preferentially localized at the pathogen penetration sites (5,11). However, we did not observe such preferential accumulation of AtABCG34 at the penetration site.…”

“…PDR8/ ABCG36/PEN3, which is localized at the plasma membrane, recruited to infection sites (11), and involved in glucosinolatedependent pathogen defense at the contact site (12), blocks the penetration of nonhost fungal pathogens (13). Recently, a report suggested that this protein transports 4-O-β-D-glucosyl-indol-3-yl formamide (4OGlcI3F) (14); however, this possibility remains to be proven.…”

Myosins XI modulate host cellular responses and penetration resistance to fungal pathogens

“…All three PEN proteins are also recruited to attempted fungal penetration sites (6)(7)(8)(9)(10)(11). Intriguing findings show that the focal accumulation of PEN1 and PEN3 occurs outside the plasma membrane and within papillae or haustorial encasements (3,11,12).…”

“…All three PEN proteins are also recruited to attempted fungal penetration sites (6)(7)(8)(9)(10)(11). Intriguing findings show that the focal accumulation of PEN1 and PEN3 occurs outside the plasma membrane and within papillae or haustorial encasements (3,11,12). Disruption of actin cytoskeleton by pharmacological inhibitors blocks PEN3-GFP accumulation at most penetration sites, but has a lesser effect on the recruitment of GFP-PEN1 to these sites (11), suggesting that transport pathways mediating PEN1 and PEN3 recruitment and export to the apoplastic papillae are distinct.…”

“…The secretory vesicles and organelles, including peroxisomes, Golgi, mitochondria, and the nucleus, also move toward penetration sites (7,13). In addition to the deposition of cell wall reinforcements and focal accumulation of penetration-related proteins such as PEN3, the accretion of cytoplasm and organelles at sites of attempted fungal penetration involves reorganization of actin cytoskeleton, which forms a radial array focused on penetration site (10,11,(14)(15)(16)(17)(18). Consistent with this finding, disruption of AFs hampers penetration resistance, leading to increased penetration frequency by various fungal and oomycete pathogens (15)(16)(17)19).…”