Understanding the role of Streptomyces ASV 6c8e8 in potato vigor

Abstract

Potato is one of the most important food crops in the world with an annual production of over 300 million tons. In earlier studies, it was found that the field of production influences the growth potential and resistance of seed potatoes. It was also demonstrated that the microbiome of potatoes can influence their growth. In a previous research, a model was developed to predict the vigor of seed potatoes based on their microbial fingerprints. This model identified several key predictors for the potato vigor, one of which was Streptomyces amplicon sequence variant (ASV) 6c8e8. However, it remains unclear whether this ASV is a casual factor or merely an indicator of the observed vigor. Therefore, this project aimed to isolate and identify Streptomyces containing this ASV to investigate their potential direct effects. To test this, Streptomyces-like bacteria were isolated from potato seed tubers. Whole genome sequencing revealed several Streptomyces isolates that contained the ASV of interest. It was shown that this ASV is present in multiple genetically distinct isolates of Streptomyces, indicating that Streptomyces ASV 6c8e8 is wide spread across some phylogenetically and functionally diverse Streptomyces isolates. In addition, bioassays were developed and tested to establish a framework to test the effect of the isolated Streptomyces for their effect on potato plants. To this end , we performed bioassays in both soil-based and in vitro systems and tested the effect of some bacteria from which we expected a positive effect on potato growth, so they can be used as a benchmark later on. This project therefore isolated and characterized isolates of Streptomyces AVS 6c8e8, which can now be tested for their effect on potato. In addition, it established the conditions for the bioassays in which these isolates can be tested in the future of this project, to ultimately verify and further investigate the effect of Streptomyces ASV 6c8e8 on potato vigor.