Search

The rhizosphere is a dynamic region influenced by complex interactions between plants and microbes that are closely linked to the metabolically active hotspots of the roots below the soil and participate in below-ground interactions. We must consider the roles of the rhizosphere to improve above-ground productivity and hence regulate the environment. Initially, the soil was measured to be stable only based on nutrient abundance, but the healthy soil is now seen with large microbial communities after rhizosphere evolution. In this regard, numerous strategies for manipulating the rhizosphere for better ecological functioning need to be developed. Based on current ecological evidence, we propose a new sketch in which future comparative research through sustainable agriculture and an environment is required to uncover the underlying mechanisms. Plant roots manage below-ground diversity by releasing exudates into the rhizosphere, due to their microbial growth capability. The microbes are attracted to the exudates, and in the rhizosphere, they developed communities. Roots play an important role in the microbial community establishment, having a major and primary energy channel in the ecosystem of the rhizosphere. Via the roots channel, the energy release then transfers to the microbial channel, eventually converted into microbial biomolecules, which are then returned to the above-ground in the form of volatile compounds and productivity. This review discusses the different energy channels in the rhizosphere that facilitate the development of the microbial community and the transfer of energy in a sequence in the form of productivity from above-ground to below-ground to above-ground. Importantly, such awareness may result in strategies for improving plant health and development in the context of future agricultural demand.

Arbuscular mycorrhiza (AM), plant growth promoting rhizobacteria (PGPRs) and root-knot nematode survive in the rhizosphere and perform the same niche. AM and PGPRs play positive role in roots while nematode oppose it. Nematode damages the root system, which reduces the nutrient uptake specially phosphorus (P) while AM help to uptake. PGPRs are another symbiotic micro-organism helpful to mycorrhizal survival and colonization. AM and PGPRs can defeat the soil borne diseases like root-knot disease which lead to increasing mycorrhizal colonization and nutrient uptake. On this basis current work emphasizes the effects on mycorrhizal colonization and P uptake in presence of PGPRs along with root-knot nematode infection in tomato plants.

Arbuscular mycorrhizal fungi (AMF) and plant growth promoting rhizobacteria (PGPR) have potential to control soil-borne diseases including plant-parasitic nematodes. First, the effects of dual inoculation of mycorrhiza (Rhizophagus irregularis) and two stains of pseudomonads (Pseudomonas jessenii strain R62 and Pseudomonas synxantha strain R81) on tomato (Solanum lycopersicum cv. PT-3) growth were tested. Further, the physiological and biochemical changes caused by these beneficial organisms during infection by the root-knot nematode Meloidogyne incognita were studied. The experiment was conducted under glass house conditions and carried out up to one month after nematode inoculation. Plants treated with dual or individual inoculation of AMF and PGPR showed significantly enhanced plant growth and reduced nematode infection. In addition, they exhibited potent activity of phenolics (28 %) and defensive enzymes i.e. peroxidase (PO; 1.26 fold), polyphenyloxidase (PPO; 1.35 fold) and superoxide dismutase (SOD; 1.09 fold) while a significant reduction in malondialdehyde (MDA; 1.63 fold) and hydrogen peroxide (H2O2; 1.30 fold) content was recorded when compared to the nematode-infected plants. These findings indicate the feasibility of AMF and PGPR individually or in combinations as potential biocontrol agents for the management of root-knot nematodes.

The article Mycorrhizal colonization and phosphorus uptake in presence of PGPRs along with nematode infection, written by Ishwar Prakash Sharma and A. K. Sharma, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 20 September 2018 with open access.