Fig. 4

BcNoxB has its predominant role outside the ER. ΔbcnoxB was complemented with an ER locked allele of bcnoxB. The construct was integrated into the bcniaD locus (Additional file 1: Table S1). a, b The ER retained version of BcNoxB is not able to infect bean leaves as good as the wild type. Primary bean leaves were inoculated with 7.5 µl of conidial suspension (10⁵ conidia/ml). Lesion diameters were measured and statistically evaluated (3 bean plants/strain). Replicates showed similar results. c ΔbcnoxB and ΔbcnoxB:bcnoxB_HDEL are not able to form functional appressoria for the penetration of onion epidermal layers. Onion epidermal layers were infected with drops of a conidial suspension (10⁵ conidia/ml). Just before microscopy the fungal hyphae were stained with lactophenol blue. d The ER locked allele of BcNoxB is able to produced wild type like levels of conidiospores. The different strains were incubated on CM medium for at least 3 weeks. Conidia were harvested, diluted and quantified. Replicates showed similar results. e Stress resistance is mediated by the ER retained version of BcNoxB. Agar plugs were placed on CM agar and selective media supplemented with H₂O₂ (10 mM) or menadione (500 µM) and monitored for 7 days (here depicted: 3 dpi). f BcNoxB_HDEL is not sufficient for restoration of wild type like ROS levels. Spores were grown in a microtiter plate overnight. Just before microscopy the detection agent for the visualization of ROS was added. Monitoring took place in a Tecan Saphire with 3 × 3 reads. Replicates displayed similar results