Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China.
Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China; and Corresponding author. Email:
Funct Plant Biol. 2021 Jul;48(8):827-838. doi: 10.1071/FP20303.
The responses of plants to recurrent stress may differ from their responses to a single stress event. In this study, we investigated whether clonal plants can remember past environments. Parental ramets of Glechoma longituba (Nakai) Kuprian were exposed to UV-B stress treatments either once or repeatedly (20 and 40 repetitions). Differences in DNA methylation levels and growth parameters among parents, offspring ramets and genets were analysed. Our results showed that UV-B stress reduced the DNA methylation level of parental ramets, and the reduction was enhanced by increasing the number of UV-B treatments. The epigenetic variation exhibited by recurrently stressed parents was maintained for a long time, but that of singly stressed parents was only short-term. Moreover, clonal plants responded to different UV-B stress treatments with different growth strategies. The one-time stress was a eustress that increased genet biomass by increasing offspring leaf allocation and defensive allocation in comparison to the older offspring. In contrast, recurring stress was a distress that reduced genet biomass, increased the biomass of storage stolons, and allocated more defensive substances to the younger ramets. This study demonstrated that the growth of offspring and genets was clearly affected by parental experience, and parental epigenetic memory and the transgenerational effect may play important roles in this effect.
植物对反复胁迫的反应可能与它们对单一胁迫事件的反应不同。在这项研究中，我们调查了克隆植物是否能记住过去的环境。垂序商陆（Glechoma longituba (Nakai) Kuprian）的亲本分株分别接受了一次或多次（20 次和 40 次）UV-B 胁迫处理。分析了亲本、后代分株和基株之间的 DNA 甲基化水平和生长参数的差异。我们的结果表明，UV-B 胁迫降低了亲本分株的 DNA 甲基化水平，且随着 UV-B 处理次数的增加，这种降低作用增强。反复受到胁迫的亲本表现出的表观遗传变异能长时间维持，但单次受到胁迫的亲本的变异只能维持短期。此外，克隆植物对不同的 UV-B 胁迫处理表现出不同的生长策略。一次性胁迫是一种正胁迫，与较老的后代相比，它通过增加后代叶片分配和防御性分配来增加基株的生物量。相比之下，反复胁迫是一种逆境胁迫，它降低了基株的生物量，增加了贮藏匍匐茎的生物量，并向较年轻的分株分配更多的防御物质。本研究表明，后代和基株的生长明显受到亲本经验的影响，而亲本的表观遗传记忆和跨代效应可能在这种影响中发挥重要作用。
