Morphological and metabolic profiling of a tropical adapted potato association panel subjected to a water recovery treatment reveals new insights into plant vigor.

Potato - Solanum tuberosum L. - is one of the world's most important crops, facing major challenges due to climatic changes. To investigate the effects of intermittent drought on the natural variability of plant morphology and tuber metabolism in a novel potato association panel, composed of 258 varieties, an augmented block design field study was carried out under normal irrigation and under water-deficit and recovery conditions in Ica, Peru. All potato genotypes were profiled for 45 morphological traits and 42 central metabolites via Nuclear Magnetic Resonance. Statistical tests and norm of reaction analysis revealed that the observed variations were trait specific, i.e. genotypic vs. environmental. Principal component analysis showed a separation of samples as a result of conditional changes. To explore relational ties between morphological traits and metabolites, correlation-based network analysis was employed, constructing one network for normal irrigation and one network for water-recovery samples. Community detection and difference network analysis highlighted the differences between the two networks, revealing a significant correlational link between fumarate and plant vigor. A genome wide association study was performed for each metabolic trait. Eleven single nucleotide polymorphism (SNP) markers were associated with fumarate. Gene ontology analysis of QTL regions associated with fumarate revealed an enrichment of genes regulating metabolic processes. Three of the eleven SNPs were located within genes, coding for a protein of unknown function, a RING domain protein, and a zinc finger protein ZAT2. Our findings have important implications for future potato breeding regimes, especially in countries suffering from climate change.