Metabolic profiling for identification of potential biomarkers in potato tuber extracts associated with tolerance to Spongospora subterranea f. sp. subterranea infection

Abstract

Potatoes are popular and reliable crops all over the world. Unfortunately, its production is threatened by detrimental factors such as fungi, bacteria and viruses that attack potatoes during growth and storage. Among all the factors infecting the potato crops, the fungal disease is the most important diseases that cause severe damage in potatoes. Spongospora subterranea f. sp. subterranea (Sss) is one of the fungal pathogens of economic importance in potato production, causing a significant reduction in yield and quality of potato tubers globally. Currently, there are no effective control methods available for this pathogen, partly due to the longevity of the highly resistant sporosori surviving in the soil. The use of cultivars resistant to Sss is the most efficient and long-term strategy for preventing the build-up of field inoculum and the spread of the pathogen. However, classical breeding and selection methods are laborious, costly and time-consuming processes. Metabolomics, as a new advanced technology, was used to better understand the biochemical mechanisms of tolerance and to identify metabolic biomarkers that could distinguish between tolerant and susceptible cultivars with statistical significance at p≤ 0.05. Four susceptible and six tolerant cultivars of five biological repeats were each grown in the greenhouse inoculated with Sss pathogen-suspension and mock-solution. Based on the results, multivariate data analysis revealed different responses to Sss infection when comparing tolerant with susceptible cultivars. Most of the metabolites identified in the Sss-inoculated samples were abundant in tolerant compared to susceptible cultivars such as amino acids, phenylpropanoids, fatty acids, organic acids and alkaloids. These metabolites are known for their antimicrobial properties as well as cell wall thickening, used to suppress pathogen development in plants, leading to reduced susceptibility. In conclusion, palmitic acid, 3-indole acrylic acid and cuscohygrine were found as possible biomarkers for tolerance against Sss infection in potato tuber extracts. These biomarkers may play an important role in potato tolerance to Sss.