Abstract
This study investigates how Phacidium infestans acquires nutrients on Pinus sylvestris needles, which possess antimicrobial properties. P. infestans was evaluated for its growth and enzyme production on various substrates, alongside genomic and metabolomic analysis. Direct-infusion high-resolution mass spectrometry (DI-HRMS) was performed on methanol extracts obtained from P. infestans cultivated on needles and malt extract media. DI-HRMS analysis identified 21 compounds from the malt extract and 112 from the needle samples. The resin components increased in the needle samples post-cultivation, suggesting terpenoid release from resin ducts due to fungal degradation of plant cell walls. P. infestans fully consumed sugars and antifungal compounds, including taxiresinol and salicylic acid, with control-to-sample ratios (CTR/SA) of 289.76 and 47.24, respectively. Moreover, lariciresinol and pinoresinol were reduced to undetectable levels. The genomic analysis identified 421 secreted proteins, including 128 carbohydrate-active enzymes, 3 cutinases, and 49 lipases that aid host penetration and wax degradation. Several multi-drug efflux pumps and two acyclic terpene utilisation proteins were identified as well. These proteins support the cellular integrity of P. infestans by expelling toxic compounds. Our findings provide valuable insights into the metabolic strategies of P. infestans for nutrient assimilation on pine needles.