Biology subjects

Wenig, M.

Publications and source records attributed to Wenig, M..

4 recordsLinked to original sources

bioRxiv2026

Pseudomonas simiae-induced resistance in barley is associated with compromised JA signaling and phyllosphere microbiome responses

Interactions of plant growth-promoting rhizobacteria with plant roots can trigger induced resistance (IR) protecting above-ground tissues from disease, a process that is increasingly recognized for its potential to support sustainable crop protection strategies. Although the molecular basis of IR has been extensively studied in Arabidopsis thaliana, considerably less is known about the underlying mechanisms in cereal crops. Here, we show that Pseudomonas simae WCS417r triggers IR in barley (Hordeum vulgare), reducing the propagation of Blumeria graminis f. sp. hordei, the causative agent of barley powdery mildew. Analysis of defense-associated marker genes revealed pathogen-dependent transcriptional responses during IR: HvPATHOGENESIS-RELATED1 (HvPR1) was induced by powdery mildew but not by the bacterial pathogen Xanthomonas translucens pathovar cerealis, whereas HvPR5 responded to both pathogens, with its induction by X. translucens depending on WCS417r-IR. To improve our molecular understanding of IR, transcriptomic responses to methyl jasmonate, salicylic acid and abscisic acid were characterized and used to identify hormone-responsive genes. Notably, several jasmonate-responsive genes were suppressed during powdery mildew infection, and this suppression was more pronounced in plants undergoing IR, indicative of priming. Finally, metabarcoding of the phyllosphere microbiome demonstrated that IR was not associated with major shifts in bacterial community composition. Alpha and beta diversity remained largely unchanged, while a limited number of amplicon sequence variants differed in abundance between treatments. Together, these results show that P. simiae WCS417r induces resistance against powdery mildew in barley through priming pathogen-dependent transcriptional changes while leaving the overall phyllosphere microbiome structure largely intact.

plant biology↗

bioRxiv2021

Local jasmonic acid cues drive systemic acquired resistance signal generation

The phytohormones salicylic acid (SA) and jasmonic acid (JA) promote two, mutually antagonistic immune pathways respectively protecting plants from biotrophic pathogens and necrotrophic pathogens or insects. This trade-off largely precludes the exploitation of SA and JA immune components for crop protection, raising the interest in immune signalling components that disrupt SA-JA antagonism. A local pathogen infection primes SA-dependent immunity in systemic tissues. This so-called systemic acquired resistance (SAR) ensures a long-lasting, broad-spectrum disease resistance that is not subject to SA-JA antagonism. Here, we show that two sequence-related LEGUME LECTIN-LIKE PROTEINs (LLPs) promote SAR through spatially separated functions with JA promoting local SAR signal generation through LLP3. In concert with LLP1, which is important for systemic recognition and propagation of SAR signals, LLP3 promotes both SA-dependent SAR and JA-mediated immunity. Thus, exploitation of LLP-associated signalling cues might allow application of plant innate immune signals to promote (crop) plant health.

plant biology↗

bioRxiv2021

Induced systemic resistance impacts the phyllosphere microbiome through plant-microbe-microbe interactions

Both above- and below-ground parts of plants are constantly confronted with microbes, which are main drivers for the development of plant-microbe interactions. Plant growth-promoting rhizobacteria enhance the immunity of above-ground tissues, which is known as induced systemic resistance (ISR). We show here that ISR also influences the leaf microbiome. We compared ISR triggered by the model strain Pseudomonas simiae WCS417r (WCS417) to that triggered by Bacillus thuringiensis israelensis (Bti) in Arabidopsis thaliana. In contrast to earlier findings, immunity elicited by both strains depended on salicylic acid. Both strains further relied on MYC2 for signal transduction in the plant, while WCS417-elicited ISR additionally depended on SAR-associated metabolites, including pipecolic acid. A metabarcoding approach applied to the leaf microbiome revealed a significant ISR-associated enrichment of amplicon sequence variants with predicted plant growth-promoting properties. WCS417 caused a particularly dramatic shift in the leaf microbiota with more than 50% of amplicon reads representing two bacterial species: WCS417 and Flavobacterium sp.. Co-inoculation experiments using WCS417 and At-LSPHERE Flavobacterium sp. Leaf82, suggest that the proliferation of these bacteria is influenced by both microbial and plant-derived factors. Together, our data connect systemic immunity with leaf microbiome dynamics and highlight the importance of plant- microbe-microbe interactions for plant health.

plant biology↗

bioRxiv2019

The cell-wall-localised BETA-XYLOSIDASE 4 contributes to immunity of Arabidopsis against Botrytis cinerea

Plant cell walls constitute physical barriers that restrict access of microbial pathogens to the contents of plant cells. The primary cell wall of multicellular plants predominantly consists of cellulose, hemicellulose and pectin. In Arabidopsis, a cell wall-localised protein, BETA-XYLOSIDASE 4 (BXL4) that belongs to a seven-member BETA-XYLOSIDASE (BXL) gene family was induced upon infection with the necrotrophic fungal pathogen Botrytis cinerea and mechanical wounding in a jasmonoyl isoleucine (JA-Ile) dependent manner. Ectopic expression of the BXL4 gene in Arabidopsis seed coat epidermal cells was able to rescue a bxl1 mutant phenotype suggesting that like BXL1, BXL4, had both xylosidase and arabinosidase activity and acts in mura on cell wall polysaccharides. bxl4 mutants show a compromised resistance to B. cinerea. Upon infection, bxl4 mutants accumulated reduced levels of JA-Ile and camalexin. Conditional overexpression of BXL4 resulted in enhanced expression of PDF1.2 and PAD3 transcripts both before and after B. cinerea infection. This was associated with reduced susceptibility of the transgenic lines to B. cinerea. These data suggest that remodelling or degradation of one or more cell wall polysaccharides is important for plant immunity against B. cinerea and plays a role in pathogen-induced JA-Ile and camalexin accumulation. One-sentence summaryBXL4 is a putative bifunctional xylosidase/arabinofuranisodase localising to the apoplast, important for immunity against the necrotrphic pathogen B. cinerea.

plant biology↗