Tripartite plant microbe and nutrients interaction in the below ground soil ecosystems

Abstract

Plants are the sole producers that support all the trophic levels and sustain life on earth. In their growth and development, plants interact with both biotic and abiotic factors. The major biotic factors are the below ground microbes though there also above grown microbes and other herbivores. The abiotic factors are mainly the soil nutrients, soil temperature, moisture and light intensity. This paper therefore aimed at reviewing the various interactions within the soil rhizosphere especially between the plant roots interaction with soil microbes and how they are affected by the soil nutrient availability. The review focussed on identifying the major soil microbes in the soil rhizosphere, interaction of the plant roots with these microbes and how the interactions bring about nutrient cycling as well as dynamics in the trophic levels. From the review it came out clearly that plants interact with both pathogenic and non-pathogenic microbes resulting to varied results. Symbiotic relationship among plant roots and nitrogen fixing bacteria and mycorrhizal fungi results in improved plant growth and yields while interaction with pathogenic soil microbes resulted in disease development and reduced yield. Plants react to soil microbes by producing defensive secondary metabolites like phenolics. From the interaction some of the pathogenic microbes have developed mechanisms of evading the effects of plant defensive compounds by modifying them into forms that are less toxic. The review also shows that plant microbe interaction affects nutrient cycling and is also affected by the nutrients availability. The tripartite interaction of soil microbes, soil abiotic factors and plant root affects the general trophic levels in almost the entire ecosystems.

Symbiotic efficiency and genetic characterization of rhizobia and non rhizobial endophytes associated with cowpea grown in semi-arid tropics of Kenya

“…Inoculation of cowpea with rhizobia is a viable alternative that can improve nitrogen fixation, soil fertility, and increase legume yields [ 7 ]. The practice is especially necessary in soils where the native rhizobia are incompatible with the host plants, the population is low or is inefficient in N fixation [ 8 ].…”