Genome-Wide Metatranscriptomics Crosswalk of Diseased Common Beans (Phaseolus vulgaris L.) Unravels Critical Metabolic Pathways Involved in Plant Defense Mechanisms

The common bean (Phaseolus vulgaris L.) is a vital food crop worldwide, particularly in Latin America, Asia, and Sub-Saharan Africa, due to its high levels of protein, fiber, and essential nutrients. However, it is susceptible to viral infections, especially from the Bean common mosaic virus and Bean common mosaic necrosis virus. While previous research has primarily focused on specific resistance genes, a broader understanding of the plant’s overall immune response remains limited. To investigate this, a study was conducted involving 51 infected leaf samples. RNA was extracted, and deep metatranscriptomic sequencing was performed using the Illumina MiSeq platform. The results indicated that several genes related to stress response, nitrogen metabolism, and biosynthesis pathways were activated during infection. Key defense mechanisms included pathogen recognition, the production of antimicrobial peptides, and changes in metabolic activity. The Mitogen-Activated Protein Kinase (MAPK) signaling pathway and enzymes like glycosyl transferases, which aid in building protective structures, played a significant role. These findings suggest that the bean’s defense system is complex and involves not only direct attacks on pathogens but also metabolic shifts and microbial interactions. Understanding these processes provides valuable insights for breeding stronger, disease-resistant, and climate-resilient bean varieties.