Live cell imaging reveals extensive intracellular cytoplasmic colonization of banana by normally non-cultivable endophytic bacteria

It is generally believed that endophytic microorganisms are intercellular inhabitants present in either cultivable or non-cultivable form primarily as root colonizers. In a new study in AoB PLANTS, Thomas and Sekhar report extensive cytoplasmic colonization by endophytic bacteria in banana shoot-tissue which prima-facie displayed ‘Brownian movement’. Live cell imaging on tissue sections, callus, cell suspensions and protoplasts directly and after vital / SYTO-9 staining revealed two intracellular niches, namely cytoplasmic and periplasmic. Designated as ‘Cytobacts’ and ‘Peribacts’, these organisms were rarely amenable to cultivation and thus may have escaped the attention of biologists. This article, supported largely by live cell video-imaging, opens the way to studying these intracellular entities.