Epigenetic responses to heat stress at differenttime scales and the involvement of small RNAs

摘要

Epigenetic responses to heat stress at differenttime scales and the involvement of small RNAsAnna Stief, Krzysztof Brzezinka, J?orn L?amke, and Isabel B?aurle*Institute for Biochemistry and Biology; University of Potsdam; Potsdam, GermanyKeywords:development, epigenetic silencing, heat stress, miRNA, priming, stress memory, thermotolerance, transposonAbbreviations:HSP, heat shock protein; HSF, heat shock transcription factor; HS memory, heat stress, memory;miRNA, microRNA; siRNA, small interfering RNAThe hypothesis that plants can benefit from a memory ofpast stress exposure has recently attracted a lot of attention.Here, we discuss two different examples of heat stressmemory to elucidate the potential benefits that epigeneticresponses may provide at both the level of acclimation of theindividual plant and adaptation at a species-wide level.Specifically, we discuss how microRNAs regulate the heatstress memory and thereby increase survival upon a recurringheat stress. Secondly, we review how a prolonged heat stressin a small interfering RNA-deficient background inducesretrotransposition that is transmitted to the next generation,thus creating genetic variation for natural selection to act on.Collectively, these studies reveal a crucial role of short RNAsin heat stress memory across different time scales.