To explore the genetic variety present in current breeding lines, we performed two stress-related field trials, each consisting of 54 potato varieties, selected based on previous projects for differential sensitivity to heat and drought stress. To obtain insights into molecular events during stress acclimation, glasshouse studies under controlled stress conditions were performed in the PlantScreenTM phenotyping platform at the PSI Research Center in Brno (CZ). This allowed us to define growth conditions, stress application, experimental design, and phenotyping protocols. We assessed the morpho-physiological traits by image-based sensors and harvested samples for downstream analyses of hormone, metabolite, marker gene and proteomics analyses by different partners. Understanding the dynamics of the stress response and the molecular pathways involved will be critical to screen selected potato cultivars out of the larger panel used in the field trials. Additionally, 30 different varieties were screened for their response to heat- and drought stress revealing genetic variance in the stress-response of different varieties and suitable parameters to rank them.
Most important for stability of potato yield under stress conditions is the amount and the quality of potato tubers generated. Thus, the overall aim was to unravel the complex relationship between the tuberisation signalling pathways and responses to abiotic stresses at the molecular level. A detailed transcriptomic analysis of transgenic potato lines revealed how SP6A expression is related to plant hormone signalling pathways. Transgenic reporter lines have been developed and demonstrated in detail the control of SP6A as major tuberization signal under environmental stress conditions.
Insights into early signalling (sensory) events in potato that regulate the molecular and physiological acclimation to stress were gained using two types of transgenic plants were generated: (i) sensor lines to measure secondary messengers (Ca2+ and ROS); and (ii) gene reporter lines to measure ROS, drought-stress responses, and stress-induced plant hormones as important regulators determining plant resistance to drought and water logging.
A key issue arising from large-scale and high-throughput studies is the analysis of large data sets. Therefore, we focused in the first period on setting up the methodological basis for the analysis and have developed the StressKnowledgeMap App, which allows both visualisation of current knowledge in network format, reproducible insertion of novel knowledge and easy linkage to mechanistic modelling. We compiled several data analysis protocols that are now available for use by ADAPT and the broader scientific community.
