Abstract:
Rice is an important food crop. Its grain serves as a staple food for a large part of the
world's human population especially in urban areas. An endophyte is an endosymbiont,
often a bacterium or fungus, that lives within a plant for at least part of its life without
causing apparent disease. In this study, a survey of bacterial root endophytes was
carried out. 73 bacterial pure isolates were obtained from the root samples collected
from farmers’ and research fields in Mwea and Ahero. They were morphologically
characterized and screened for biological activities. The biochemical tests were used to
characterize all the isolates. 10 isolates produced indoleacetic acid (IAA) implying
potential to enhance plant growth. 67 isolates were positive for phosphate solubilisation.
These 73 isolates were further grouped according to morphological and biochemical
similarity and 37 were selected for molecular characterization. All the 37 selected
isolates were confirmed to have the potential to fix nitrogen based on acetylene
reduction assay (ARA). The phylogenetic analysis of 28 potential isolates clustered
them into four different genera namely Pseudomonas, Bacillus, Enterobacter, and
Micrococcus. Results of the phylogenetic analysis of the potential isolates were
supported by the outcome on morphological and biochemical characteristics. Isolates
M31 and M32 obtained from Mwea Basmati 370 rice were shown to promote plant
growth. Endophytes are useful in agriculture for enhancement of growth and production
which would consequently enhance affordable production of Kenyan basmati rice. This
will not only eradicate poverty and increase food security, but also help conserve
microbial diversity.
