Biology subjects

Polturak, G.

Publications and source records attributed to Polturak, G..

4 recordsLinked to original sources

bioRxiv2026

Diverse Diterpenoid Phytoalexins Shape Wheat Chemical Defenses

Cereal crops rely on a wide array of specialized metabolites to defend themselves against microbial pathogens. Here, using a combination of genome-wide analysis, heterologous pathway reconstruction, structural elucidation and in planta validation, we identify two pathogen-induced diterpenoid pathways in wheat that produce diterpenoids: the new glycosylated diterpenes aspisoside A and aspisoside B, and the diterpene alcohols scutenol A and scutenol B. The pathogen-responsive nature of these pathways, together with their antimicrobial activity are consistent with a likely defensive role in wheat. These compounds are produced by two biosynthetic gene clusters, each encoding a discrete pathway, so revealing organizational separation of wheat diterpenoid-based chemical defenses. The aspisoside-producing gene cluster is syntenic with diterpenoid phytoalexin-producing clusters in rice and barley, for momilactone and hordedane biosynthesis, respectively, yet gives rise to structurally distinct phytoalexins in wheat. The scutenol cluster is syntenic with currently uncharacterized predicted biosynthetic gene clusters in barley, oat, and Brachypodium. These findings establish diterpene glycosides as a previously unrecognized component of wheat defense chemistry and provide new insights into the chemical diversification of defense-related biosynthetic gene clusters within the Poaceae.

plant biology↗

bioRxiv2025

plantiSMASH 2.0: improvements to detection, annotation, and prioritization of plant biosynthetic gene clusters

Plants produce bioactive compounds as part of their specialized metabolism, with applications in medicine, agriculture, and nutrition. The biosynthesis of a growing number of these specialized metabolites has been found to be encoded in biosynthetic gene clusters (BGCs), creating increasing demand for genome mining tools to automate their detection. plantiSMASH enables the identification of putative plant BGCs through a rule-based approach, available via both command-line and web interfaces. Here, we present plantiSMASH 2.0 (https://plantismash.bioinformatics.nl/), a major update that expands and improves the original framework with revised and additional BGC detection rules (now supporting 12 BGC types), substrate prediction for selected enzyme families, and regulatory analysis through transcription factor binding site detection. The updated plantiSMASH 2.0 database includes 30,423 putative BGCs across 430 genomes. Together, these improvements make plantiSMASH 2.0 a powerful and comprehensive platform for the detection and characterization of plant biosynthetic pathways, supporting and accelerating research in plant specialized metabolism and plant natural product discovery.

bioinformatics↗

bioRxiv2024

Discovery of lydiamycin A biosynthetic gene cluster in the plant pathogen Rhodococcus fascians guides structural revision and identification of molecular target

The natural products actinonin and matlystatin feature an N-hydroxy-2-pentyl-succinamyl (HPS) chemophore that facilitates metal chelation and confers their metalloproteinase inhibitory activity. Actinonin is the most potent natural inhibitor of peptide deformylase (PDF) and exerts antimicrobial and herbicidal bioactivity by disrupting protein synthesis. Here, we used a genomics-led approach to identify candidate biosynthetic gene clusters (BGCs) hypothesised to produce novel HPS-containing natural products. We show that one of these BGCs is on the pathogenicity megaplasmid of the plant pathogen Rhodococcus fascians and produces lydiamycin A, a macrocyclic pentapeptide. The presence of genes predicted to make a HPS-like chemophore informed the structural recharacterisation of lydiamycin via NMR and crystallography to show it features a rare 2-pentyl-succinyl chemophore. We demonstrate that lydiamycin A inhibits bacterial PDF in vitro and show that a cluster-situated PDF gene confers resistance to lydiamycin A, representing a novel self-immunity mechanism associated with the production of a PDF inhibitor. In planta competition assays showed that lydiamycin enhances the fitness of R. fascians during plant colonisation. This study highlights how a BGC can inform the structure, biochemical target and ecological function of a natural product.

microbiology↗

bioRxiv2021

Genome Mining Uncovers Clustered Biosynthetic Pathways for Defense-Related Molecules in Bread Wheat

Wheat is one of the most widely grown food crops in the world. However, it succumbs to numerous pests and pathogens that cause substantial yield losses. A better understanding of biotic stress responses in wheat is thus of major importance. Here we identify previously unknown pathogen-induced biosynthetic pathways that produce a diverse set of molecules, including flavonoids, diterpenes and triterpenes. These pathways are encoded by six biosynthetic gene clusters and share a common regulatory network. We further identify associations with known or novel phytoalexin clusters in other cereals and grasses. Our results significantly advance the understanding of chemical defenses in wheat and open up new avenues for enhancing disease resistance in this agriculturally important crop.

plant biology↗