Drought stress memory in a germplasm of synthetic and common wheat: antioxidant system, physiological and morphological consequences

Abstract

Plants have evolved mechanisms of adaptation to fluctuations in their environmental conditions that have been given the term “stress memory”. Synthetic wheat offers new hope for breeders to restore useful genes lost during the genetic bottleneck. We aimed to test whether drought priming and seed priming could improve drought tolerance in a diverse germplasm of synthetic and common wheat under field conditions. In this research, 27 wheat genotypes (including 20 synthetics, 4 common local and 3 common exotic bread wheat) were field evaluated under four water environments. These treatments included: 1) normal condition (N), plants were irrigated when 40% of the total available soil water was depleted from the root-zone, 2) seed priming-secondary stress (SD2), only water stress was applied at anthesis when 90% of the total available soil water was depleted and seeds were planted for evaluating, 3) primary stress- secondary stress (D1D2), primary water stress was applied at jointing stage when 70% of the total available soil water was depleted then secondary water stress was applied at the anthesis stage when 90% of the total available soil water was depleted, and 4) secondary stress (D2) only water stress was applied at the anthesis when 90% of the total available soil water was depleted. Our results indicated that improved efficient enzymatic antioxidant system leads to less yield reduction in D1D2 treatment. However, the positive effects of drought priming were more pronounced in drought primed (D1D2) than seed primed treatment (SD2). Synthetic wheat genotypes had a significant superiority in terms of yield, yield components and drought tolerance compared to common wheat genotypes. Nevertheless, the response of genotypes to stress memory was very different. Drought sensitive genotypes had better response to stress memory. Superior genotypes were identified as high yield and drought tolerant genotypes which can be used for future studies.

The role of priming and memory in rice environmental stress adaptation: Current knowledge and perspectives

“…Whether an enhanced response is indicative of a previous absence of priming in lowland rice remains to be demonstrated. Better response of sensitive varieties than their tolerant counterparts to stress priming has also been reported in wheat (Amini et al, 2023). The difference in the ability to be primed in contrasting rice genotypes could be attributed to 'memory loss' or lack of priming from stress (Charng et al, 2023).…”