Desiccation tolerance in <scp><i>Physcomitrella patens</i></scp>: Rate of dehydration and the involvement of endogenous abscisic acid (ABA)

Xiao, Li; Yobi, Abou; Koster, Karen L.; He, Yulong; Oliver, Melvin J.

doi:10.1111/pce.13096

Cited by 38 publications

(42 citation statements)

References 47 publications

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“…ABA plays key roles in mosses' stress tolerance (Beckett, 1999;Beckett, Csintalan, & Tuba, 2000;Bhyan et al, 2012;Mayaba, Beckett, Csintalan, & Tuba, 2001;Nagao et al, 2005;Xiao, Yobi, Koster, He, & Oliver, 2018). Our results show that stresses induced sharp increases in ABA contents in both species, in accordance with previous studies (Kohli et al, 2013;Xiao et al, 2018).…”

Section: Phytohormone Regulationsupporting

confidence: 91%

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

Liu

et al. 2019

Ecology and Evolution

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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.

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Section: Phytohormone Regulationsupporting

confidence: 91%

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

Liu

et al. 2019

Ecology and Evolution

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“…Physcomitrella patens is classified as inducibly desiccation tolerant, as exogenous ABA induces DT in protonemata (Oldenhof et al ) and gametophores (Koster et al ). Recent studies have also shown that very slow dehydration of P. patens gametophores, but not protonemata, can induce DT (Greenwood and Stark , Xiao et al ).…”

Section: Discussionmentioning

confidence: 99%

“…Greenwood and Stark () determined that slow drying over a 150‐h period at high humidity could induce DT in gametophores of P. patens , as measured by improved survival and photosynthetic capacity. A recent study by Xiao et al () also demonstrated that gametophores, but not filamentous protonemata, can survive equilibration to water potentials below −100 MPa following a drying regime that features an initial phase with a slow rate of water loss.…”

Section: Introductionmentioning

confidence: 96%

“…For example, Shinde et al () measured a rapid increase in the ABA content of protonemata during dehydration at 75% RH, but they did not report whether the moss survived the stress. Xiao et al () recently reported that although ABA accumulated during dehydration of P. patens gametophores and protonemata, elevated ABA amounts did not always correspond with DT in those tissues. Gametophores accumulated equal amounts of ABA during a gradual drying regime that led to DT and also during an equilibrium drying regime that did not induce DT, while protonemata accumulated significant amounts of ABA during gradual dehydration, but did not become desiccation tolerant (Xiao et al ).…”

Section: Introductionmentioning

confidence: 99%

“…Xiao et al () recently reported that although ABA accumulated during dehydration of P. patens gametophores and protonemata, elevated ABA amounts did not always correspond with DT in those tissues. Gametophores accumulated equal amounts of ABA during a gradual drying regime that led to DT and also during an equilibrium drying regime that did not induce DT, while protonemata accumulated significant amounts of ABA during gradual dehydration, but did not become desiccation tolerant (Xiao et al ). It was suggested that factors in addition to ABA accumulation contribute to DT in P. patens and that the initial drying rate may be particularly important.…”

Section: Introductionmentioning

confidence: 99%

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Acclimation and endogenous abscisic acid in the moss Physcomitrella patens during acquisition of desiccation tolerance

Rathnayake

Nelson

Seeve

et al. 2019

Physiologia Plantarum

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The moss Physcomitrella patens has been used as a model organism to study the induction of desiccation tolerance (DT), but links between dehydration rate, the accumulation of endogenous abscisic acid (ABA) and DT remain unclear. In this study, we show that prolonged acclimation of P. patens at 89% relative humidity (RH) [−16 MPa] can induce tolerance of desiccation at 33% RH (−153 MPa) in both protonema and gametophore stages. During acclimation, significant endogenous ABA accumulation occurred after 1 day in gametophores and after 2 days in protonemata. Physcomitrella patens expressing the ABA‐inducible EARLY METHIONINE promoter fused to a cyan fluorescent protein (CFP) reporter gene revealed a mostly uniform distribution of the CFP increasing throughout the tissues during acclimation. DT was measured by day 6 of acclimation in gametophores, but not until 9 days of acclimation for protonemata. These results suggest that endogenous ABA accumulating when moss cells experience moderate water loss requires sufficient time to induce the changes that permit cells to survive more severe desiccation. These results provide insight for ongoing studies of how acclimation induces metabolic changes to enable DT in P. patens.

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Strategies of desiccation tolerance vary across life phases in the moss Syntrichia caninervis

Coe

Greenwood

Slate

et al. 2020

American J of Botany

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PREMISE Desiccation tolerance (DT) is a widespread phenomenon among land plants, and variable ecological strategies for DT are likely to exist. Using Syntrichia caninervis, a dryland moss and model system used in DT studies, we hypothesized that DT is lowest in juvenile (protonemal) tissues, highest in asexual reproductive propagules (gemmae), and intermediate in adults (shoots). We tested the long‐standing hypothesis of an inherent constitutive strategy of DT in this species. METHODS Plants were rapidly dried to levels of equilibrating relative humidity (RHeq) ranging from 0 to 93%. Postrehydration recovery was assessed using chlorophyll fluorescence, regeneration rates, and visual tissue damage. For each life phase, we estimated the minimum rate of drying (RoDmin) at RHeq = 42% that did not elicit damage 24 h postrehydration. RESULTS DT strategy varied with life phase, with adult shoots having the lowest RoDmin (10‒25 min), followed by gemmae (3‒10 h) and protonema (14‒20 h). Adult shoots exhibited no detectable damage 24 h postrehydration following a rapid‐dry only at the highest RHeq used (93%), but when dried to lower RHs the response declined to <50% of control fluorescence values. Notably, immediately following rehydration (0 h postrehydration), shoots were damaged below control levels of fluorescence regardless of the RHeq, thus implicating damage. CONCLUSIONS Life phases of the moss S. caninervis had a range of strategies from near constitutive (adult shoots) to demonstrably inducible (protonema). A new response variable for assessing degree of DT is introduced as the minimum rate of drying from which full recovery occurs.

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Desiccation tolerance in Physcomitrella patens: Rate of dehydration and the involvement of endogenous abscisic acid (ABA)

Cited by 38 publications

References 47 publications

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

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

Acclimation and endogenous abscisic acid in the moss Physcomitrella patens during acquisition of desiccation tolerance

Strategies of desiccation tolerance vary across life phases in the moss Syntrichia caninervis

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