Biology subjects

Potocka, A.

Publications and source records attributed to Potocka, A..

3 recordsLinked to original sources

bioRxiv2026

Arabidopsis exocyst complex subunit EXO70E2 in defence against Pseudomonas syringae in conjunction with autophagy

Exocyst was initially uncovered in yeast genetic sec-screen as a tethering complex for exocytotic vesicles and this function was later found to be evolutionarily conserved in other eukaryotes including plants. Later however, a surprising engagement of the exocyst complex in autophagy was observed in animals, plants and recently also in yeast. Using the genetic approach we observed EXO70E2 exocyst complex subunit engagement in the defence response to Pseudomonas syringae attack linked to the autophagy pathway. CRISPR/CAS LOF mutant of EXO70E2 is more sensitive to Pseudomonas infection (both virulent as well as T3SS mutant) and autophagy flux monitored by NBR1 antibody is compromised in comparison to WT. We conclude that the plant exocyst complex linked to the EXO70E2 subunit participates in defence against Pseudomonas bacteria in conjunction with the autophagy pathway. HighlightArabidopsis exocyst subunit EXO70E2 affects selective autophagic flux monitored by NBR1 and is participating in defense against Pseudomonas syringae infection.

plant biology↗

bioRxiv2026

Loss of PR1 function enhances Arabidopsis resistance to Botrytis cinerea

PATHOGENESIS-RELATED 1 (PR1) is one of the most widely used markers of salicylic acid (SA)-dependent plant immunity, yet its direct functional contribution to pathogen defence remains poorly understood. Here, we investigated the role of PR1 in Arabidopsis thaliana by analyzing a pr1 loss-of-function mutant challenged with bacterial and fungal pathogens and fumonisin B1 (FB1)-induced cell death. Notably, loss of PR1 led to markedly different responses to distinct pathogens; while it moderately increased susceptibility to the pathogenic bacterium Pseudomonas syringae, it substantially enhanced resistance to the necrotrophic fungus Botrytis cinerea, and the responses to the necrotroph Sclerotinia sclerotiorum remained unaltered. The pr1 mutant also displayed reduced spread of FB1-induced cell death, linking PR1 function to the promotion of stress-associated cell death. In line with the susceptibility changes, we observed the strongest PR1 accumulation and cell wall enrichment during B. cinerea infection using mCherry-tagged PR1 expressed under its endogenous promoter. Complementation with full-length PR1 and with a C-terminally truncated PR1 variant lacking the CAPE peptide restored wild-type susceptibility, whereas a non-cleavable PR1 variant did not. These results indicate that proteolytic processing at the CAPE cleavage motif, rather than the CAPE peptide itself, is required for PR1 function. Our data thus strongly suggest that PR1 may act as a susceptibility factor for necrotrophic pathogens by promoting host cell death.

Plant Biology↗

bioRxiv2023

Chitosan stimulates root hair callose deposition and inhibits root hair growth

Although angiosperm plants have a general capacity to react after the immunity elicitor chitin or chitosan treatment by the cell wall callose deposition, this response in particular cell types and its evolutionary conservation is not understood. Here we show that also the growing root hairs (RHs) of Arabidopsis can respond to a mild (0.001%) chitosan treatment by the callose deposition and by a deceleration of the RH growth. We demonstrate that the glucan synthase-like 5 (GSL5)/PMR4 is vital for chitosan-induced callose deposition but not for RH growth inhibition. Upon the higher chitosan concentration (0.01%) treatment, RHs do not deposit callose, while growth inhibition is prominent. To understand the specificities of the low and high concentration chitosan treatments, we analysed the corresponding PTI signalling components, gene expression, and RH cellular endomembrane and cytoskeleton modifications. Importantly, chitosan-induced callose deposition is also present in the functionally analogous and evolutionarily only distantly related RH-like structures rhizophores (lycophytes) and rhizoids (bryophytes). Our results point to the RH callose deposition as a conserved strategy of soil-anchoring plant cells (rhizoids/rhizophores/RHs) to deal with mild biotic stress. At the same time, high chitosan concentration prominently disturbs intracellular dynamics, tip-localised endomembrane compartments and RH growth, precluding callose deposition.

plant biology↗