Memory of environmental conditions across generations affects the acclimation potential of scots pine

Abstract

Long generation times have been suggested to hamper rapid genetic adaptation of organisms to changing environmental conditions. We examined if environmental memory of the parental Scots pines (Pinus sylvestris L.) drive offspring survival and growth. We used seeds from trees growing under naturally dry conditions (control), irrigated trees (irrigated from 2003 to 2016), and formerly irrigated trees ("irrigation stop"; irrigated from 2003-2013; control condition since 2014). We performed two experiments, one under controlled greenhouse conditions and one at the experimental field site. In the greenhouse, the offspring from control trees exposed regularly to drought were more tolerant to hot-drought conditions than the offspring from irrigated trees and showed lower mortality even though there was no genetic difference. However, under optimal conditions (high water supply and full sunlight), these offspring showed lower growth and were outperformed by the offspring of the irrigated trees. This different offspring growth, with the offspring of the "irrigation-stop" trees showing intermediate responses, points to the important role of transgenerational memory for the long-term acclimation of trees. Such memory effects, however, may be overridden by climatic extremes during germination and early growth stages such as the European 2018 mega-drought that impacted our field experiment. K E Y W O R D S climate change, drought, maternal environment, transgenerational acclimation, trees

Small DNA Methylation, Big Player in Plant Abiotic Stress Responses and Memory

“…Increased trichome density Unknown (Scoville et al, 2011) Oryza sativa Hg 2+ (50 µM/L) for 7 days Transgenerational Gene expression changes DNA methylation (Ou et al, 2012;Cong et al, 2019) Oryza sativa Successive generations of drought stress Transgenerational Improved drought adaptability DNA methylation (Zheng et al, 2017) Picea abies Daylength and temperature during seed production Intergenerational Adaptive plasticity Unknown (Johnsen et al, 2005;Kvaalen and Johnsen, 2008) Pinus sylvestris L. Drought stress Intergenerational Tolerant to hot-drought conditions Unknown (Bose et al, 2020) Polygonum persicaria Drought stress Intergenerational Improved drought tolerance Unknown (Sultan et al, 2009) Taraxacum officinale Drought and salicylic acid (SA) treatment…”

“…The intergenerational stress memory can be triggered by multiple biotic and abiotic stresses, such as flagellin (an elicitor of plant defense), ultraviolet-C, salt, cold, heat and drought stress, β-aminobutyric acid (BABA), methyl jasmonate and the bacteria Pseudomonas syringae pv tomato ( PstavrRpt2 ) ( Table 1 ; Johnsen et al, 2005 ; Kvaalen and Johnsen, 2008 ; Sultan et al, 2009 ; Boyko et al, 2010 ; Ito et al, 2011 ; Scoville et al, 2011 ; Slaughter et al, 2012 ; Iwasaki and Paszkowski, 2014 ; Migicovsky et al, 2014 ; Bilichak et al, 2015 ; Wibowo et al, 2016 ; Ganguly et al, 2017 ; Bose et al, 2020 ). Interestingly, in perennial Scots pines ( Pinus sylvestris L.), environmental memory of naturally dry conditions in the parental trees drive offspring survival and growth under hot-drought conditions ( Bose et al, 2020 ). The stress memory may protect the immediate offspring against recurring stress or offer them the potential for local acclimation to changing environments, while the resetting in the next generation may maximize growth under favorable circumstances ( Crisp et al, 2016 ).…”

Determinants of legacy effects in pine trees – implications from an irrigation‐stop experiment

“…Here we test this idea of linking past and present environmental conditions to current physiological and morphological responses via organ and reserve turnover rates with field data from mature Scots pine trees which were experimentally irrigated since 2003 and cut off from the treatment after 11 yr at the end of 2013 (Dobbertin et al , 2010; Schönbeck et al , 2018; Brunner et al , 2019). The setup of the Pfynwald irrigation experiment allows comparing control trees that were never irrigated with trees that received continued irrigation treatment until present, with trees for which irrigation was recently stopped (Bose et al , 2020).…”

Priming Maritime Pine Megagametophytes during Somatic Embryogenesis Improved Plant Adaptation to Heat Stress

“…Plants can store information from stressful conditions at early embryogenic stages, and then acquire memory to respond more efficiently to future environmental constraints [4,5]. This memory is mediated by epigenetic mechanisms, such as sustained alterations in gene expression, changes in hormonal profiles, and accumulation of signaling proteins and transcription factors [6].…”