Quantitative Morphological Profiling and Isolate-Specific Insensitivity of Cacao Pathogens to Novel Bio-Based...

Area of Science:

• Agricultural Science
• Mycology
• Biochemistry

Background:

• Fungal pathogens such as Colletotrichum gloeosporioides and Pestalotiopsis spp. pose significant risks to global cacao production.
• Developing sustainable strategies requires understanding pathogen responses to new antifungal agents.

Purpose of the Study:

• To investigate the isolate-specific sensitivity and morphological responses of cacao pathogens to novel bio-based phenolic-branched fatty acids and amides.
• To evaluate the potential of these compounds as sustainable antifungal agents for crop protection.

Main Methods:

• Tested four novel bio-based phenolic-branched fatty acids and amides against three cacao pathogen isolates (one Pestalotiopsis sp., two C. gloeosporioides).
• Utilized quantitative image analysis to assess morphological changes in fungal colonies.
• Employed multivariate analyses and machine learning models for response classification and prediction.

Main Results:

• Observed high isolate-specific susceptibility, with one compound (PhSOAM) showing potent inhibition against two isolates.
• Identified significant intraspecific variation, as one C. gloeosporioides isolate was insensitive to all tested compounds.
• PhSOAM uniquely increased the length-to-width ratio of fungal colonies, suggesting disruption of polarized growth.
• Machine learning models achieved R² up to 0.74 in classifying pathogen-compound interaction outcomes.

Conclusions:

• Bio-based amides, particularly PhSOAM, demonstrate potential as effective antifungal agents against specific cacao pathogens.
• The study highlights significant intraspecific variation in pathogen response, crucial for targeted control strategies.
• A combined approach of morphological profiling and predictive modeling offers a powerful framework for studying complex fungal-antifungal interactions.