Endophytes are microorganisms—typically, fungi, bacteria, or cyanobacteria—that inhabit the living tissues of a host, often a plant. Hosts and endophytes likely coevolve to form a mutualistic relationship, in which the microorganism provides a service, such as releasing hormones to aid plant growth, and receives shelter or nutrients from the plant in return. The interactions between endophytes and their hosts still remain largely undetermined. The objective of this study was to determine if bacterial symbionts play a role in modulating seedling development of the beefsteak tomato (Solanum lycopersicum). Basic microbiological and genetic techniques were conducted to isolate and identify the intracellular bacteria.
Initial surface sterilization techniques suggested a relationship between root hair development and the presence of intracellular bacteria. This was further supported with a comparison between seeds containing indigenous bacteria and seeds with the bacteria removed through antibiotic treatments. Several cultivars displayed internal microorganisms after staining and analysis under a compound microscope. Bacteria were isolated and their distinct cuboidal packet morphologically identified the colonies as members of the Sarcina genus in the Clostridiaceae family. DNA sequencing will be conducted to reveal the taxonomic classification of the isolated bacterial 16s rRNA. Discovering a beneficial relationship between an endophyte and the beefsteak tomato may reveal insight on coevolution, mutualistic relationships, and improvements in agriculture.