Bioactive potential of fungus induced Silybum marianum seedlings and isolation of antimicrobial genes

Abstract

Living organisms are equipped with sophisticated mechanisms to minimize the hazards and threats offered by the nature and maximize their survival potential against strain imposed by environmental forces. Growing concern about the frequent use of analogous antibiotics leading to resistant pathogens and their harmful impacts on crop yield worldwide has fuelled an explosion in the field of plant defense response by coupling biotechnology to the medicinal plants. Increasing knowledge of the mechanisms underlying plant defense response has also encouraged the idea that sensitizing a plant towards microbial elicitors increases plant resistance to the potential pathogens. Considering the same thought of knowledge, this study was entailed to examine the bioactive potential of Silybum marianum under control and fungal stress. Peptide based multidimensional studied of the plant with reference to antimicrobial, antioxidant, antitumor, cytotoxic and mutagenic potential were undertaken. A time course study of the extracts prepared under fungal stress strongly revealed the increased accumulation of proteins/peptides upto 8 hours post inoculation with a drop in the expression level at subsequent hours. Encouraging results regarding antibacterial potential towards gram negative species and highly significant antifungal potential were also observed. In addition to antimicrobial potential, plant also showed beneficial traits as antitumor and nonmutagenic against Agrobacterium tumefaciens and human cell lines respectively. As far as antioxidant and cytotoxic potential is concerned, all the extracts had excellent antioxidant capacity whereas among all, 8 h control and its treated time points showed slight cytotoxicity. Rewarding bioactive potential of Silybum marianum eventually led to the identification of peptides involved in cellular metabolism, plant growth and development, signal transduction and exclusively to the peptides involved in defense response. Antimicrobial gene isolation with subsequent cloning and heterologous expression has proved substantial pharmaceutical importance of the plant which may open novel avenues for biotechnological applications in agriculture.