Maternal drought stress induces abiotic stress tolerance to the progeny at the germination stage in sunflower

Climate change produces more frequent and intense drought events during seed development that can affect seed quality. Germination is critical to ensure plant growth and reproductive success but it can be impacted by various abiotic stresses. Here, we studied the effect of drought stress during sunflower seed development on the germination of the progeny. We applied different scenarios of drought stress during seed development in sunflower inbred lines and hybrids and assessed seed germination of the progeny. Drought stress during seed development provided tolerance to water, hypoxic, cold and salt stresses during seed germination and also induced lower dormancy. We established that the induction of these traits was not transgenerational but maternally transmitted and could be reproduced in sunflower hybrids. Drought stress during seed development decreased pericarp thickness and induced higher leakage of soluble electrolytes from pericarp but it also modified embryo metabolism. A metabolomics analysis showed that ABA, oligosaccharides and polyphenols accumulated differently in drought stress seeds and could also participate in the seed tolerance to abiotic stress conditions during germination. Altogether our results reveal an adaptative process that allows sunflower plants exposed to drought stress during their reproductive stage to produce seeds with higher fitness. Besides bringing novel insight on natural adaption of plant populations to climate change, these results may have implications for the seed industry through the production of seeds resilient to higher climatic variability during the establishment of sunflower crop.