Microbial Mechanisms Suppressing Invasive Weeds for Sustainable Agriculture: A Review

Abstract

Invasive weeds are serious problems in crop production. They affect the production of vital crops, such as wheat, rice, sorghum, maize, and legumes. Weeds are major biotic stressors that reduce biomass and yield in many crops. Parthenium hysterophorus, Lantana camara, Chromolaena odorata, and Ageratum conyzoides are the predominant weed species that threaten agricultural fields in India. These aggressive weed species compete with other crop plants for vital resources such as growth factors, water, essential nutrients, and space, and ultimately cause a remarkable loss of agricultural yield. Furthermore, weed plants release allelopathic compounds in soil that inhibit seed germination and crop growth, and also alter soil pH. Farmers traditionally rely on weed management practices that demand excessive labour and high costs while delivering low efficiency. Although chemical herbicides are effective in controlling weeds, excessive application poses severe environmental risks, and repeated long-term use may cause weed resistance. Considering the secondary effects of chemical herbicides, rhizobacterial biological weed control is an efficacious alternative to control these weed plants. Increasing agricultural yields is essential to meet the food needs of a rapidly growing global population. Numerous rhizobacteria have been identified for their ability to suppress weed growth. The use of rhizobacteria is a new and upcoming approach for the biocontrol of invasive weeds. Certain rhizobacterial strains suppress weed growth, providing crop plants with a competitive advantage for essential growth factors. Various mechanisms have been studied by which rhizobacteria can suppress weed growth, production of plant growth regulators (indole-3-acetic acid and 5-aminolevulinic acid), antibiotics, VOCs (hydrogen cyanide), exopolysaccharides (biofilm), and phytotoxins. Inoculation of potent rhizobacterial strains, which show the property of biocontrol of weeds, can be used for the management of weeds and can be implemented in sustainable agriculture practices. Use of rhizobacteria is an environment friendly approach for the management of invasive weeds and is highly compatible with sustainable agriculture.