Symbiosis: The Art of Living

Detection and Identification of Novel Intracellular Bacteria Hosted in Strains CBS 648.67 and CFCC 80795 of Biocontrol Fungi Metarhizium

"Endosymbiosis" is a cohesive form of a symbiotic association. Endobacteria exist in many fungi and play important roles in fungal host biology. Metarhizium spp. are important entomopathogenic fungi for insect pest control. In the present study, we performed comprehensive ana-lyses of strains of Metarhizium bibionidarum and M. anisopliae using PCR, phylogenetics, and fluorescent electron microscopy to identify endobacteria within hyphae and conidia. The results of the phylogenetic ana-lysis based on 16S rRNA gene sequences indicated that these endobacteria were the most closely related to Pelomonas puraquae and affiliated with Betaproteobacteria. Ultrastructural observations indicated that endobacteria were coccoid and less than 500‍ ‍nm in diameter. The basic characteristics of endobacteria in M. bibionidarum and M. anisopliae were elucidated, and biological questions were raised regarding their biological functions in the Metarhizium hosts.

Metagenomic profiling of the community structure, diversity, and nutrient pathways of bacterial endophytes in maize plant

This study investigated the diversity, structure and nutrient pathways of the root-associated bacterial endophytes of maize plant cultivated using different fertilizers to verify the claim that inorganic fertilizers have some toxic effects on plant microbiome and not are ecofriendly. Whole DNA was extracted from the roots of maize plants cultivated with organic fertilizer, inorganic fertilizer and maize planted without any fertilizer at different planting sites in an experimental field and sequenced using shotgun metagenomics. Our results using the Subsystem database revealed a total of 28 phyla and different nutrient pathways in all the samples. The major phyla observed were Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, Verrucomicrobia, Tenericutes, Planctomycetes, Cyanobacteria, and Chlorobi. Bacteroidetes dominated maize from organic fertilizer sites, Firmicutes dominated the no fertilizers site while Proteobacteria dominated Inorganic fertilizer. The diversity analysis showed that the abundance of endophytic bacteria in all the sites is in the order organic fertilizer (FK) > no fertilizer (CK) > inorganic fertilizer (NK). Furthermore, the major nutrient cycling pathways identified are linked with nitrogen and phosphorus metabolism which were higher in FK samples. Going by the results obtained, this study suggests that organic fertilizer could be a boost to sustainable agricultural practices and should be encouraged. Also, a lot of novel endophytic bacteria groups were identified in maize. Mapping out strategies to isolate and purify this novel endophytic bacteria could help in promoting sustainable agriculture alongside biotechnological applications in future.

Exploring the potentialities of beneficial endophytes for improved plant growth

Pathogen affects plant growth, host health and productivity. Endophytes, presumed to live inside the plant tissues, might be helpful in sustaining the future of agriculture. Although recent studies have proven that endophytes can be pathogenic, commensal, non-pathogenic, and/or beneficial, this review will focus on the beneficial category only. Beneficial endophytes produce a number of compounds which are useful for protecting plants from environmental conditions, enhancing plant growth and sustainability, while living conveniently inside the hosts. The population of endophytes is majorly controlled by location, and climatic conditions where the host plant grows. Often the most frequently isolated endophytes from the tissues of the plant are fungi, but sometimes greater numbers of bacteria are isolated. Beneficial endophytes stand a chance to replace the synthetic chemicals currently being used for plant growth promotion if carefully explored by researchers and embraced by policymakers. However, the roles of endophytes in plant growth improvement and their behavior in the host plant have not been fully understood. This review presents the current development of research into beneficial endophytes and their effect in improving plant growth.