Novel Strategy to Unlock Transgenerational Stress Memory in Clonal Plants

Abstract

Being sessile organisms, plants are exposed to a wide range of environmental stress conditions. Recent studies have shown that plants can store information about environmental stresses and access this associated memory to mount a primed response that offers protection from subsequent stress events. This ‘stress memory’ is thought to be mediated by epigenetic modifications, which in turn modulate gene expression, phenotype, and metabolism. However, these environmentally directed epigenetic changes although they are integrated into somatic cells, they are short-lived and/or actively reset during sexual reproduction. Notably, using Arabidopsis as a model system we have recently found that clonal plants generated using zygotic transcription factors display epigenetic and transcriptional features present in the founder cells used for regeneration. Moreover, these molecular signatures are stably transmitted over multiple generations of sexual reproduction, creating distinct phenotypic variants. Therefore, we hypothesised that cloning from somatic cells exposed to distinct environmental stimuli could be used to engineer specific primed responses in plants. To test this hypothesis, we have generated clonal lines from tissues exposed to a short abiotic stress pulses that were propagated sexually over three generations in stress free conditions. Our data shows clonal plants derived from primed tissues display a transgenerational stress memory response, which is associated with specific transcriptional states, and enhanced tolerance under stress. Our study also aiming to identify the molecular mechanisms implicated in the integration, storage and retrieval of the acquired stress memory with the aim of engineering specific primed responses in plants. Our data shows that the transcriptional activity of DREB2A genes is necessary and partly sufficient for a salt-induced transgenerational salt memory in clonal plants