Evidence of stress imprinting with population‐level differences in two moss species

Abstract

Plants are often repeatedly exposed to stresses during their lives and have a mechanism called stress imprinting that provides “memories” of stresses they experience and increases their ability to cope with later stresses. To test hypotheses that primed bryophytes can preserve their stress imprinting after 6 days of recovery and induce higher levels of osmolytes and ROS‐scavenging activities upon later stress exposure, and there exist population‐level differentiation in their desiccation defenses, we transplanted samples of two populations of each of two moss species, Hypnum plumaeforme and Pogonatum cirratum, in a nature reserve in southern China. After 16 months of acclimation, sets of each population were subjected to control, one‐time desiccation stress, duplicated desiccation stress and cross‐stress (low temperature stress followed by desiccation stress) treatments. Levels of oxidant enzymes, osmolytes, and phytohormones in the samples were then determined. The desiccation stress generally led to increases in activities or contents of superoxide dismutase, guaiacol peroxidase, catalase, proline, soluble sugars, soluble proteins, and stress hormones including abscisic acid (ABA), jasmonates (JA), and salicylic acid (SA), with differences between both species and populations. After a 6‐day recovery period, contents of phytohormones (including ABA, JA, SA, and cytokinins) in stressed H. plumaeforme had substantially fallen toward control levels. The duplicated and cross‐stress treatments generally led to further accumulation of proline, soluble sugars, and soluble proteins, with further increases in activities of antioxidant enzymes in some cases. Furthermore, significant differences between allochthonous and native populations were found in contents of malondialdehyde and osmolytes, as well as antioxidant enzyme activities. Our results confirm the hypotheses and highlight the importance of osmolytes in mosses' stress responses.

Proteomic and Metabolic Analysis of Pinus halepensis Mill. Embryonal Masses Induced under Heat Stress

“…The histone H4 variant TH091 and histone H2A.2.2 (core components of nucleosomes), and the 40S ribosomal protein S15a-1 and 60S ribosomal protein L18-3 (structural components of ribosomes) had increased amounts in samples from heat stress conditions. This agrees with previous studies on the temperature stress response, where ribosomal proteins, translation regulator factors and translation regulatory proteins played a significant role [ 39 , 64 , 65 , 66 ]. This data, combined with the fact that proteins´ abundance variations are not always correlated with changes in the corresponding transcriptome [ 67 ], can explain the lack of significant differences found in the transcription assay performed here.…”

Embryonal Masses Induced at High Temperatures in Aleppo Pine: Cytokinin Profile and Cytological Characterization

“…Kinetin showed to be the most abundant cytokinin in our samples which might be related to its exogenous application in the culture media. Despite the fact that the majority of naturally occurring CKs in plants are the N 6 -isopentenyl conjugated adenine derivatives, in addition to a small amount of N 6 -aromatic CK species [64,70], exogenous addition of CKs to culture media is known to have an effect by altering and increasing the endogenous CKs pool [66,71]. Similarly, reports in Solanum tuberosum [72], Pinus pinea [73], and Pinus radiata [66] found that aromatic CKs accounted for more than 90% of the total endogenous CK pool although isoprenoid forms are generally the most abundant CKs in plant materials that have not been hormonally treated.…”

Metabolism of carbohydrates and activity of the antioxidant system in mosses on a post-technogenic salinized territory

“…The increase of proline synthesis under the influence of drying in mosses Hypnum plumaeforme Wilson and Pogonatum cirratum (Sw.) Brid. as well as its participation in cross-adaptation to low temperatures was revealed (Liu et al, 2019). Thus, analysis of the current literature data has shown that there are significant differences in the ability to accumulate proline in different moss species in the case of the same stress influence and in the same species under various types of stress, which requires further investigation.…”

“…The resistance of plants to stressors is determined by the functioning of constitutive and induced protective systems (Lobachevska et al, 2005;Liu et al, 2019;Hasanuzzaman et al, 2020;Oke et al, 2020).Their fundamental difference is that constitutive systems are constantly in a functionally active state and are detected immediately under short-term stress, and induced -are not normally present and are detected only in response to prolonged stress (Boots & Best, 2018;He et al, 2018;Venegas-Molina et al, 2020).…”