Identification of Antimicrobial Metabolites Isolated from Bryophytes and Vascular Plants as an Alternative for the Control of Phytopathogens of Agricultural Interest
Resumen
Huanglongbing (HLB), also known as citrus greening disease, is a devastating plant disease reported since the last century. It is primarily caused by the bacterium Candidatus Liberibacter asiaticus (CLas), transmitted by the Asian citrus psyllid (Diaphorina citri). This disease affects fruit quality and significantly reduces yield, leading to considerable agricultural losses and global economic impact.
Current control methods, based on insecticide use and phytosanitary management, have proven insufficient to eradicate the disease and often have adverse effects on the environment and human health. Additionally, CLas is a non-culturable microorganism under standard laboratory conditions, complicating efforts to replicate experiments under controlled settings. Therefore, Candidatus Liberibacter crescens, isolated from papaya in Puerto Rico and culturable in vitro, has been adopted as a model organism for CLas studies. Due to the high cost of C. crescens culture media, initial antimicrobial screenings of essential oils and plant extracts are being conducted on Rhizobium strains CIAT 899 and CE3, which also belong to the Rhizobiaceae family. Pseudomonas aeruginosa is included as an additional test organism.
Antimicrobial evaluation using the poisoned food technique demonstrated inhibitory effects of Cinnamomum verum essential oil against Rhizobium CIAT 899, CE3, and Pseudomonas aeruginosa on solid media. Moreover, liquid media assays assessed via OD600 readings showed a significant reduction in growth of CIAT 899.
Extracts from the moss Pseudocrossidium replicatum will be obtained following induction with biotic stress-related phytohormones such as salicylic acid and jasmonic acid. Subsequent assays will evaluate their antimicrobial activity as previously described. Metabolites present in active fractions will be identified using HPLC analytical techniques.