Rapid dehydration induces long-term water deficit memory in sorghum seedlings: advantages and consequences

Studies on water deficit follow methodologies with short recovery intervals, which makes it difficult to determine whether a long-lasting memory is imprinted. There is a paucity of information on the dehydration level and time needed to form memory. This study aimed to evaluate whether rapid dehydration in the early stages of sorghum life induces changes in the epigenetic mechanisms, antioxidant activities, photosynthesis, total stomatal density, dry mass and leaf area of this species subjected to water deficit in a later growth stage. Four treatments were assessed: irrigated plants, plants subjected to rapid dehydration for 2:30 h at the beginning of their life, plants subjected to water deficit by withholding irrigation in adulthood, and plants subjected to rapid dehydration with a subsequent water deficit in adulthood. The antioxidant and photosynthesis results showed that the latter treatment was the more tolerant to water deficit and also led to a reduction in total stomatal density to avoid water loss; however, under this treatment shoot dry mass decreased. Moreover, plants subjected to two water stress events presented high occurrence and maintenance of the epigenetic memory marker H3K4me3. Therefore, rapid stimulation of early-life dehydration can induce long-term water deficit memory.