ABSTRACT
Plant growth promoting rhizobacteria (PGPR) and Vesicular Arbuscular Mycorrhizal spores (VAM) are soil microorganisms that enhance the plant growth and suppress plant diseases. The current study was conducted at Ahmed Orabi Agricultural Cooperative Association, Ismailia, Egypt, to investigate the efficient antagonistic bacterial isolates and VAM against Fusarium wilt disease in pepper plant under greenhouse and filed experiments. A total of 49 bacterial isolates were isolated, out of which 4 (P1, P11, P19 and P42) were selected based on their antagonism of phytopathogens. Phylogenetic analysis of 16SrRNA sequences identified these isolates as new strains of Bacillus subtilis, Bacillus aerius, Achromobacter xylosoxidans and Lysinibacillus fusiformis. The selected isolates produced high levels siderophore and hydrogen cyanide. Disease symptoms, disease index percent, phytochemicals and Metabolic indicators of resistance in plant as response to induction of systemic resistance in pepper plants were recorded. The best time to applied inducers is at one week before infection with mixture of (PGPR + VAM) followed by PGPR and VAM with protection percent of 90.0, 87.5 and 86.3% and disease severity of 9.00, 11.25 and 12.25%, respectively. VAM and P42 were the best isolates and reduced percent disease indexes by 10 and 15% while, P11, and PGPR (P1, P11, P19, P42) gave the same result 17.5% followed by P19, (VAM+PGPR) and P1 which recorded 20.00, 22.5 and 30.00 %, respectively. The beneficial effects of the used elicitors were extended to increase not only total phenol, total soluble protein content but also the activities of peroxidase and polyphenoloxidase enzymes in comparison with control. Concerning the effect of tested elicitors on the challenged plants with fusarium, it was noticed that pre-treatment pepper seedlings with P42, P11, VAM and P19 were the best elicitors which recorded highly significant increase in fruit number and fruit weight in comparison with other tested elicitors.