First Report: Metabolic and Molecular Evidence for the Detection of the Pathogenic Pseudomonas aeruginosa on Common Bean Seeds and Its Control Via Chitosan-silver Nanocomposite

Abstract

T HE CURRENT study stated the novel pathogenic action of Pseudomonas aeruginosa MA1 on common bean, causing the soft rot of seeds as the infection route. The pathogenic bacterium was molecularly identified and deposited in NCBI GenBank with an accession number of ON000399. Enzymatic activities of xylanase, cellulase, pectinase, proteinase and protease were observed to be 13.054, 11.09, 9.28, 20.90, and 1.47U respectively, indicating the ability of MA1 to invade the plant tissue, recording a disease incidence of 63.25% with a severity of 42.52%. The physiological features showed a remarkable decrease in chlorophyll content with an increase in proline and phenolic contents in the infected plant. Both peroxidase and phenylalanine ammonia-lyase (PAL) activities increased, reaching their maximum value after 72h of infection with a significant overexpression of the PAL gene after 24h. that proves the pathogenic role of P. aeruginosa on common bean. However, seed transmission is paramount in further pathological studies since the current pathogenic bacterium was detected on seeds. In-vitro evaluation of the chitosan-silver nanocomposite (Ch-Ag NC) reveals the first management protocol for the bacterial pathogen MA1 that was confirmed by applying (Ch-Ag NC) in the greenhouse. Furthermore, in-situ application of Ch-Ag NC (50 and 100mg/L) suppressed bacterial infection with a significant increase in seedling growth properties.