Biology subjects

Goncalves, A. P.

Publications and source records attributed to Goncalves, A. P..

3 recordsLinked to original sources

bioRxiv2026

Nutrient and prey-sensing signaling pathways converge on the sphingolipid methyltransferase SMT1 to regulate trap formation in a predatory fungus

The nematode trapping fungus Arthrobotrys oligospora transitions from saprophytic growth to a predatory lifestyle by forming adhesive traps in response to nutrient limitation and nematode derived cues. How nutrient availability integrates with prey sensing to control trap formation remains unclear. The presence of glucose can suppress trap formation and we found that Cre1, a conserved transcription factor that regulates the carbon catabolite repression pathway in fungi is essential for trap formation. Comparative transcriptomics and functional studies identified SMT1, which encodes a sphingolipid C9 methyltransferase, as a Cre1-dependent target that is sufficient to restore trap formation defect in the cre1 mutant. Smt1 contributes to the formation of sterol-enriched membrane domain at the tip of a growing trap hyphae and thus affects trap morphogenesis. We further discovered that the expression of SMT1 depends on both Cre1 and another transcription factor Ste12 that acts downstream of the pheromone response MAPK pathway critical for prey-sensing. These findings reveal functional crosstalk between Cre1 and Ste12 where both transcription factors are required for the expression of SMT1 and demonstrate that a predatory fungus integrates nutrient and prey-derived signals to regulate predatory lifestyle switching.

microbiology↗

bioRxiv2022

A moonlighting function of a chitin polysaccharide monooxygenase, CWR-1, in allorecognition in Neurospora crassa

Organisms require the ability to differentiate themselves from organisms of different or even the same species. Allorecognition processes in filamentous fungi are essential to ensure identity of an interconnected syncytial colony to protect it from exploitation and disease. Neurospora crassa has three cell fusion checkpoints controlling formation of an interconnected mycelial network. The locus that controls the second checkpoint, which allows for cell wall dissolution and subsequent fusion between cells/hyphae, cwr, encodes two linked genes, cwr-1 and cwr-2. Previously, it was shown that cwr-1 and cwr-2 show severe linkage disequilibrium with six different haplogroups present in N. crassa populations. Isolates from an identical cwr haplogroup show robust fusion, while somatic cell fusion between isolates of different haplogroups is significantly blocked in cell wall dissolution. The cwr-1 gene encodes a putative polysaccharide monooxygenase (PMO). Herein we confirm that CWR-1 is a C1-oxidizing chitin PMO. We show that the PMO domain of CWR-1 was sufficient for checkpoint function and cell fusion blockage; however, through analysis of active-site, histidine-brace mutants, the catalytic activity of CWR-1 was ruled out as a major factor for allorecognition. Swapping a portion of the PMO domain (V86 to T130) did not switch cwr haplogroup specificity, but rather cells containing this chimera exhibited a novel haplogroup specificity. Allorecognition to mediate cell fusion blockage is likely occurring through a protein-protein interaction between CWR-1 with CWR-2. These data highlight a moonlighting role in allorecognition of the CWR1 PMO domain.

genetics↗

bioRxiv2019

Natural diversity in the predatory behavior facilitates the establishment of a new robust model strain for nematode-trapping fungi

Nematode-trapping fungi (NTF) are a group of specialized microbial predators that consume nematodes when food sources are limited. Predation is initiated when conserved nematode ascaroside pheromones are sensed, followed by the development of complex trapping devices. To gain insights into the co-evolution of this inter-kingdom predator-prey relationship, we investigated natural populations of nematodes and NTF, that we found to be ubiquitous in soils. Arthrobotrys species were sympatric with various nematode species and behaved as generalist predators. The ability to sense prey amongst wild isolates of A. oligospora varied greatly, as determined by the number of traps after exposure to Caenorhabditis elegans. While some strains were highly sensitive to C. elegans and the nematode pheromone ascarosides, others responded only weakly. Furthermore, strains that were highly sensitive to the nematode prey also developed traps faster. The polymorphic nature of trap formation correlated with competency in prey killing, as well as with the phylogeny of A. oligospora natural strains, calculated after assembly and annotation of the genomes of twenty isolates. A chromosome level genome assembly and annotation was established for one of the most sensitive wild isolate, and deletion of the only G protein {beta} subunit-encoding gene of A. oligospora nearly abolished trap formation, implicating G protein signaling in predation. In summary, our study establishes a highly responsive A. oligospora wild isolate as a novel model strain for the study of fungal-nematode interactions and demonstrates that trap formation is a fitness character in generalist predators of the NTF family. Significance statementNematode-trapping fungi (NTF) are carnivorous microbes that hold potential to be used as biological control agents due to their ability to consume nematodes. In this work we show that NTF are ubiquitous generalist predators found in sympatry with their prey in soil samples. Wild isolates of NTF displayed a naturally diverse ability to execute their predatory lifestyle. We generated a large whole genome sequencing dataset for many of the fungal isolates that will serve as the basis of future projects isolates. In particular, we establish TWF154, a highly responsive strain of Arthrobotrys oligospora, as a model strain to study the genetics of NTF. Lastly, we provide evidence that G-protein signaling is necessary for trap induction in NTF.

molecular biology↗