Role of Serratia sp. as Biocontrol Agent and Plant Growth Stimulator, with Prospects of Biotic Stress Management in Plant

Abstract

Serratia species is a member of the Enterobacteriaceae family and found to be ubiquitous in the environment. There are several plants associated with Serratia sp. that are reported as endophytes or thriving in the rhizosphere of host plants. Many such isolates are known to have plant growth-promoting (PGP) abilities and/or biocontrol potential based on the antibiosis (production of prodigiosin and pyrrolnitrin) and production of lytic enzymes (chitinases and β-1,3-glucanases) against soilborne fungal pathogens that infect various crops. Serratia sp. colonized plant roots and within the plant tissues and induced plant growth. Among the mechanisms by which the genus Serratia exerts beneficial effects on plants are facilitating the uptake of nutrients such as phosphorus via phosphate solubilization and siderophore production (secretes catecholate siderophore enterobactin) and synthesizing stimulatory phytohormones like indole-3-acetic acid (IAA) (both auxin-dependent and auxin-independent signaling pathways) that are involved in plant growth promotion. Serratia sp. also elicits induced systemic resistance (ISR) where enhancement of the plant's defensive capacity against diverse plant pathogens and pests is acquired after appropriate stimulation. Bacteria of the genus Serratia have created tremendous interest in researchers as such strains showed high potential for biofertilization and plant growth promotion, contributing better yield of the diverse field and agricultural crops. Some of the species such as S. plymuthica, S. liquefaciens, S. proteamaculans, S. grimesii, S. nematodiphila, and S. rubidaea had acquired the attention of researchers due to their benefits to plants. Some other uncommon species of Serratia, like S. ficaria, S. fonticola, S. odorifera, S. entomophila, and S. quinivorans, have been recognized for their role in plant growth stimulation. With the continuation of interest and research on Serratia as PGPR and biocontrol agents, the formulations based on Serratia sp. will be instrumental for sustainable agriculture.