A multifactorial pathobiome model of factors affecting the germination of <i>Plasmodiophora brassicae</i> resting spores.

Root exudates collected under sterile conditions cannot stimulate the germination of resting spores, while they may serve as a carbon source to modulate the microbial community under non-sterile conditions. The initial microbial community is reshaped by environmental factors (e.g. carbon sources, nutrients and soil moisture) to a community stimulating the germination of P. brassicae resting spores.</p

Report of bacterial functional annotations using FAPROTAX.

Report of bacterial functional annotations using FAPROTAX.</p

Germination rates (G%) of sterile resting spores of <i>P</i>. <i>brassicae</i> incubated with different bacterial suspensions or filtrate with Hoagland solution or sdH₂O after 7 days.

Germination rates (G%) of sterile resting spores of P. brassicae incubated with different bacterial suspensions or filtrate with Hoagland solution or sdH2O after 7 days.</p

Germination rates of non-sterile resting spores of <i>P</i>. <i>brassicae</i> incubated with Iso4 bacterial suspension in various solutions after 7 days.

The positive control of 1/10 strength Hoagland solution (H) is indicated in yellow. The negative control of sdH2O (sd) is indicated in green. Error bars represent standard deviation s. Different letters represent significant differences among the treatments (Wilcoxon rank sum test. P < 0.05, n = 3).</p

Number of reads for the individual samples, abundance table and taxonomy annotation.

Number of reads for the individual samples, abundance table and taxonomy annotation.</p

Taxonomic and functional characteristics of differential bacteria in ‘high’ and ‘low’ germination rate groups.

(A) Relative abundance of the corresponding ASVs enriched in ‘high’ and ‘low’ germination rate groups (Wilcoxon rank sum test, FDR adjusted P P < 0.05).</p

Germinated and non-germinated spores in soil samples as observed under the microscope.

Germinated spores (GS, red arrows) and non-germinated spores (NS, black arrows) in soil samples as observed under the microscope. (TIF)</p

Germination rates of <i>P</i>. <i>brassicae</i> resting spores incubated in non-sterile and sterile soil suspensions from an oilseed rape field after 5 and 7 days of incubation.

Rhizosphere soil was collected from the roots of field-grown oilseed rape cv. Bender at BBCH 18 (eight-leaf stage). Bulk soil was collected from a neighbouring field without plants. Error bars represent standard deviations. Different letters represent significant differences among the treatments (Tukey test. P < 0.05, n = 3).</p

Fig 8 -

Germination rates of P. brassicae resting spores incubated with various sugars (A) and L-amino acids (B) in the presence of nitrate. Non-sterile spores were incubated with 50 mM potassium nitrate for 14 days. The germination rate in the water control was 0%. Error bars indicate standard deviations. Different letters indicate significant differences among samples (Tukey test, P < 0.05, n = 3).</p

A hydrophobic root exudate trapping system (HTS) based on perlite substrate to collect root exudates under sterile conditions.

The root exudates (red arrows) released from undisturbed living roots are selectively captured by the columns containing XAD8 and XAD4 resin. Hoagland solution (blue arrows) is continuously circulated through the entire system to sustain plant growth. The container is covered with a plastic membrane with micro-porous filter strips allowing gas exchange under sterile conditions (right). (TIF)</p