Burkholderia bacteria recruit a prophage tail-like protein to feed on fungi.
Across the world, fungal infections are emerging as a major problem for sustainable agriculture and farming. They are also responsible for death and disability in humans, and extinctions of wildlife. Currently, worldwide researchers have been trying to find various measures to control the fungal infections.
A research group at National Institute of Plant Genome Research (NIPGR), New Delhi (An autonomous institute of Department of Biotechnology, Govt. of India) -led by Dr. Gopaljee Jha, has recently identified a novel broad spectrum antifungal protein. The study was published in the journal Nature Communications.
Group of researchers from Dr. Jha's lab has quarantined a novel bacterium Burkholderia gladioli strain NGJ1 from healthy rice seedling which demonstrates fungal eating property, a phenomenon known as mycophagy.
When the researchers allowed bacterium to grow on the plates containing fungal cells, dramatically bacterium killed fungal cells to utilize fungal metabolites for its own growth.
"On this observation, we expected that NGJ1 would prove to be a better biocontrol agent than other antifungal bacteria. Due to its mycophagous property, the bacterium can not only prevent fungal growth but can eradicate fungal biomass as it utilizes them as a source of nutrients," said Dr. Jha.
According to this study, it was found that treatment of NGJ1 was able to prevent the disease causing ability of Rhizoctonia solani, which is responsible for sheath blight disease of rice. It is certainly a unique observation that a small size bacterium killing relatively large size fungi.
From previous studies, it is believed that phages are bacterial predators and upon induction they can kill bacterial cells. Through series of experimentation, Dr. Jha's group has reported that NGJ1 has made its phage inactive (prophage) and appoint one of the prophage tail-like proteins (Bg_9562) to forage over fungi.
They also observed that the purified Bg_9562 protein demonstrates broad spectrum anti-fungal activity against several economically important pathogens, such as Rhizoctonia solani (rice sheath blight pathogen), Fusarium oxysporum (pathogenic to various plants), Chickpea blight pathogen, Apple scab pathogen and Candida albicans (causes Candidiasis in humans) and others.
This Bg_9562 gene could be new perspective for further research against fungal infections. It can be used as a transgene to develop broad spectrum fungal disease resistant plants, which is need of the hour.
"Considering broad-spectrum antifungal activity of this protein, it is being proposed that the protein could be utilized to control fungal diseases of plants as well as humans/animals. Moreover, the current study opens up various translational applications in controlling fungal diseases," said Dr. Durga Madhab Swain, research fellow and one of the first authors.
Dr. Jha appreciates his team members (Durga, Sunil, Isha, Rahul, Rajeev, Srayan, Joyati) for this accomplishment. He says that all team members have worked day and night to find the molecular basis of bacterial mycophagy.