Isolation of bacteria from the leaf gland of Dioscoreae sansibarensis

Abstract

This study aims to find bacteria that could colonise the leaf glands of Dioscoreae sansibarensis, a Yam species. D. sansibarensis lives in a mutualistic type of symbiosis with the bacterium Orrella dioscoreae and in an exclusive interaction together. O. dioscoreae occupies a niche in glands located at the tips of the leaves and excludes all other bacterial colonisers by a mechanism still unknown to this day. In this work the microbe-free plants were created in the laboratory and its leaf glands were naturally colonized by bacteria other than O. dioscoreae. Once colonised, the bacteria were extracted, plated out, isolated, and identified and the bacteria with the highest potential to colonize the leaf gland were selected. The results serve as the basis for the further study, in which the isolated bacteria will be put in competition with O. dioscoreae to study the latter’s mechanisms of defence.

The results show that the leaf gland can host diverse kinds of bacteria and that the bacteria can fully colonise the gland, remain inside the leaf gland and survive. 13 bacteria have been identified as having the best potential to be colonisers of the leaf gland niche. Results show as well that the original symbiont and the found bacteria can be put in competition for the leaf gland niche, which will provide a better understanding of the defence mechanisms of O. dioscoreae.