Tomato

Tomato Microbiome Project

Galapagos 

 Introduction

The wild tomato species from the Galapagos Islands can be found in harsh environments. Unlike their domesticated relatives, endemic tomatoes can persist in arid, saline, and/or volcanic soils. These factors can influence the composition of the tomato microbiome, which provides the plants with numerous life-support functions such as tolerance to abiotic and biotic stresses. However, little is known about the microbial diversity recruited or activated in both endemic and introduced tomatoes growing in diverse niches at the Galápagos. 

In this project, we aim to profile tomato wild microbiomes and functions in soils from their centers of origin and the Galapagos Islands, as well as to study how common biotic pressures (e.g. nematode infections and psyllid infestations) on various tomato species influence their microbiome.

To date, we have executed two expeditions to the Galapagos Islands in 2022 and 2024 to sample (bulk) soil, rhizosphere and phyllosphere of four tomato species: The 2 endemic tomatoes S. galapagense, S. cheesmaniae, the introduced S. pimpinellifolium which is found in the center of origin on the mainland in the South of Ecuador, and cultivated tomato S. lycopersicum varieties. We have samples these tomato species and varieties on six inhabited and uninhabited islands: Isabela, Santa Cruz, San Cristobal, Floreana, Santiago, and Fernandina. Preliminary findings of this work were presented at the 5th Plant Microbiome Symposium in Amsterdam in June 2024 with the poster "The tomato fungal partners: Mycobiome composition associated with endemic and introduced tomato species at the Galapagos Islands". The 16S rRNA and ITS sequences of the samples collected in 2022 are currently under analysis, whereas the 2024 specimens will be processed with shotgun metagenomics.