The isoelectric point of proteins influences their translocation to the extrahaustorial matrix of the barley powdery mildew fungus

Abstract

Many biotrophic fungal plant pathogens develop feeding structures, haustoria, inside living plant cells, which are essential for their success. Extrahaustorial membranes (EHMs) surround haustoria and delimit the extrahaustorial matrices (EHMxs). Little is known about transport mechanisms across EHMs and what properties proteins and nutrients need in order to cross these membranes. To investigate this further, we expressed fluorescent proteins in the cytosol of infected barley leaf epidermal cells after particle bombardment and investigated properties that influenced their localisation in the powdery mildew EHMx. We showed that this translocation is favoured by a neutral isoelectric point (pI) between 6.0 and 8.4. However, for proteins larger than 50 kDa, pI alone does not explain their localisation, hinting towards a more complex interplay between pI, size, and sequence properties. We discuss the possibility that an EHM translocon is involved in protein uptake into the EHMx.

Thinopyrum intermediumTiAP1 interacts with a chitin deacetylase fromBlumeria graminisf. sp.triticiand increases the resistance toBgtin wheat

“…The two recombinant plasmids, TiAP1-mYFP and mCherry-TaSYP51, were co-bombarded onto the leaves of the 7-day-old barley by particle bombardment at a helium pressure of 1,100 psi and placed on the 1% Phytagel TM petri dishes containing 40mg ml -1 of benzimidazole (Sigma-Aldrich, USA) to culture for 24 h, and then inoculated with Bgh spores. After additional 24 h of inoculation, the expression of TiAP1 and TaSYP51 proteins were observed and analysed using a confocal laser-scanning microscope (Leica SP5 - X, Germany) according to the methodology of Smigielski et al . (2019).…”

“…The copyright holder for this this version posted February 9, 2021. ; https://doi.org/10.1101/2021.02.08.430348 doi: bioRxiv preprint according to the methodology of Smigielski et al (2019). And three biological replicates were conducted per co-bombarded with six leaves.…”

“…according to the methodology of Smigielski et al (2019). And three biological replicates were conducted per co-bombarded with six leaves.…”

Proteome-wide screening for the analysis of protein targeting of Chlamydia pneumoniae in endoplasmic reticulum of host cells and their possible implication in lung cancer development

“…The previous report demonstrated that pathogen protein translocation is supported through a neutral isoelectric point (pI) between 6.0 to 8.4. Nevertheless, for proteins >50 kDa in size, pI alone does not clarify their localisation (Smigielski et al, 2019). The results were showed that the value of isoelectric point (pI) was not showing any constant pattern for protein targeting in ER of host cells (Fig.…”

A holistic view on plant effector-triggered immunity presented as an iceberg model

“…Other aspects of susceptibility concern the accommodation of the pathogen in the host tissue, for instance how niches are established for haustoria inside plant cells. Haustoria are surrounded by plant-derived extrahaustorial membranes (EHM), and it has recently been uncovered that the barley powdery mildew EHM has ER-like properties [102] and data suggest that it has a translocon that allows the passage of proteins [103]. This is different from plants attacked by the oomycetes, H. arabidopsidis and Phytophthora infestans.…”