LAUSR

In the present investigation, emphasis was placed on the efficacy of lipopolysaccharide (LPS) extracted from the plant beneficial rhizobacterium Alcaligenes faecalis MSS8 for the induction of disease resistance by enhancing immune response in plants against phytopathogen Fusarium oxysporum f. sp. lycopersici (FOL). Characterization and proficiency of the rhizobacterial LPS for the induced defense response in plant against FOL was revealed by the gel activity staining of Peroxidase (PO) and Polyphenol oxidase (PPO) isoforms as compared to the untreated and only FOL treated plants. It has been observed that after 48 h of FOL challenge inoculation, in the LPS pretreated plant there was significant induction of PO and PPO isoforms. Furthermore, RT-PCR analysis for the study of relative gene expression of pathogenesis related (PR) proteins confirms the result of gel activity staining. It has been observed that expression level of LeChi9, LeGluB, LePR1a was significantly upregulated in LPS treated plants 24 h after FOL inoculation and maximum level was observed at 48 h as compared to the control and FOL treated plants. This clearly indicates the role of LPS extracted from A. faecalis as a potential biocontrol agent against fusarium wilt.