Nitrogen Stress Memory in Quinoa: Maternal Effects on Seed Metabolism and Offspring Growth and Physiology

Plants have developed various strategies to deal with abiotic stresses throughout their lifetimes. However, environmental stresses can have long-lasting effects, positively modifying plant physiological responses to subsequent stress episodes, a phenomenon known as preconditioning or stress memory. Intriguingly, this memory can even be transmitted to offspring, referred to as "inter- or transgenerational memory". Chenopodium quinoa is a pseudocereal that can withstand several abiotic stresses, including nitrogen (N) limitation. This research highlights the critical role of maternal N conditions in shaping the physiological and metabolic responses of their offspring. Mother quinoa plants (F0) were grown under High N (HN) or Low N (LN) conditions. LN_F0 plants exhibited lower panicle biomass, net photosynthesis, and yield compared to HN_F0 plants. Seeds from LN_F0 retained proteins, reduced amino acids' levels, and increased lipids (such as PI 34:2), especially phosphatidylcholines, and their unsaturation level, which was associated with faster germination compared to HN_F0 seeds. Offsprings seedlings (F1) grown under either HN or LN had similar proteins and amino acid proportions of their seeds. However, LN_F0LN_F1 seedlings displayed significantly higher biomass and number of root tips. These changes were significantly correlated with transpiration, net photosynthesis, and stomatal conductance, as well as with starch content, suggesting higher CO₂ fixation at the whole plant level in LN_F0LN_F1 plants. Our findings suggest that quinoa transmits maternal environmental stress information to its offspring, modulating their resilience. This work underscores the potential of utilizing maternal environmental conditions as a natural priming tool to enhance crop resilience against nutritional stress.