Cellular localization of the Arabidopsis class 2 phytoglobin influences somatic embryogenesis

Godee, Cara; Mira, Mohamed M.; Wally, Owen; Hill, Robert D.; Stasolla, Claudio

doi:10.1093/jxb/erx003

Cited by 13 publications

(10 citation statements)

References 59 publications

(105 reference statements)

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“…In addition, we found that both of these genes were expressed on the adaxial side of the cotyledons, which are the explant areas that are involved in the embryogenic response. Relevant to TSA-induced SE, the function of YUC1 and YUC10 has also been observed during zygotic embryogenesis ( Cheng et al, 2007 ) and in SE that was induced as a result of LEC2 overexpression and a phytoglobin 2 ( pgb2 ) mutation ( Wójcikowska et al, 2013 ; Godee et al, 2017 ). In addition, it was suggested that YUC1 marks the future somatic embryo initiation sites in the Arabidopsis callus ( Bai et al, 2013 ).…”

Section: Discussionmentioning

confidence: 99%

“…It is noteworthy that ROS accumulation was not observed in the TSA-treated roots of Populus ( Ma et al, 2016 ) and this finding strengthens the assumption that ROS are produced in relation to the auxin accumulation rather than in response to the TSA treatment per se . The role of ROS in plant development and stress responses has been widely demonstrated reviewed in Choudhury et al (2017) and Mittler (2017) and among the different free radicals, nitrate oxide (NO) has been found to control auxin biosynthesis during SE induction through the inhibition of the MYC2 repressor of IAA biosynthesis ( Elhiti et al, 2013 ; Godee et al, 2017 ). Moreover, a link between NO and histone acetylation-mediated regulation of gene expression in stress response has recently been demonstrated ( Mengel et al, 2017 ).…”

Section: Discussionmentioning

confidence: 99%

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Trichostatin A Triggers an Embryogenic Transition in Arabidopsis Explants via an Auxin-Related Pathway

et al. 2018

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Auxin is an important regulator of plant ontogenies including embryo development and the exogenous application of this phytohormone has been found to be necessary for the induction of the embryogenic response in plant explants that have been cultured in vitro. However, in the present study, we show that treatment of Arabidopsis explants with trichostatin A (TSA), which is a chemical inhibitor of histone deacetylases, induces somatic embryogenesis (SE) without the exogenous application of auxin. We found that the TSA-treated explants generated somatic embryos that developed efficiently on the adaxial side of the cotyledons, which are the parts of an explant that are involved in auxin-induced SE. A substantial reduction in the activity of histone deacetylase (HDAC) was observed in the TSA-treated explants, thus confirming a histone acetylation-related mechanism of the TSA-promoted embryogenic response. Unexpectedly, the embryogenic effect of TSA was lower on the auxin-supplemented media and this finding further suggests an auxin-related mechanism of TSA-induced SE. Congruently, we found a significantly increased content of indolic compounds, which is indicative of IAA and an enhanced DR5::GUS signal in the TSA-treated explants. In line with these results, two of the YUCCA genes (YUC1 and YUC10), which are involved in auxin biosynthesis, were found to be distinctly up-regulated during TSA-induced SE and their expression was colocalised with the explant sites that are involved in SE. Beside auxin, ROS were extensively accumulated in response to TSA, thereby indicating that a stress-response is involved in TSA-triggered SE. Relevantly, we showed that the genes encoding the transcription factors (TFs) that have a regulatory function in auxin biosynthesis including LEC1, LEC2, BBM, and stress responses (MYB118) were highly up-regulated in the TSA-treated explants. Collectively, the results provide several pieces of evidence about the similarities between the molecular pathways of SE induction that are triggered by TSA and 2,4-D that involve the activation of the auxin-responsive TF genes that have a regulatory function in auxin biosynthesis and stress responses. The study suggests the involvement of histone acetylation in the auxin-mediated release of the embryogenic program of development in the somatic cells of Arabidopsis.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Trichostatin A Triggers an Embryogenic Transition in Arabidopsis Explants via an Auxin-Related Pathway

et al. 2018

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“…By relieving the inhibition on auxin synthesis, as well as by redirecting auxin flow through a relocation of PIN1, a required step for the induction of dedifferentiation related genes (Su et al, 2009 ), suppression of Pgb2 favored embryogenic competence (Elhiti et al, 2013 ). These events can be replicated by targeting Pgb2 in the cytoplasm (Godee et al, 2017 ). A further elaboration of this model, reinforcing the link between Pgb and stress response factors in the somatic-embryogenic transition includes the suppression of MYC2 by jasmonic acid (JA) in cells enriched in NO as a result of Pgb2 suppression (Mira et al, 2017 ).…”

Section: Regulation Of Somatic-embryogenic Transition By Pgbsmentioning

confidence: 99%

Redirecting Cell Fate During in vitro Embryogenesis: Phytoglobins as Molecular Switches

Elhiti¹,

Mira²,

Hill³

et al. 2018

Front. Plant Sci.

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“…The presence of class 1 nsHbs in growing tissues such as root tips of germinating seeds is correlated with the hypoxic stress as well 7 . Class 2 nsHbs (including AtHb2) have lower oxygen affinity 10 – 12 and appear to play a role in young and developing plant tissues 13 , 14 . Apparently, the difference in oxygen affinity between class 1 and class 2 nsHbs is correlated to the Fe coordination sphere.…”

Section: Introductionmentioning

confidence: 99%

Redox control and autoxidation of class 1, 2 and 3 phytoglobins from Arabidopsis thaliana

Moţ

Pușcaș

Miclea

et al. 2018

Sci Rep

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Despite a recent increase in interest towards phytoglobins and their importance in plants, much is still unknown regarding their biochemical/biophysical properties and physiological roles. The present study presents data on three recombinant Arabidopsis phytoglobins in terms of their UV-vis and Raman spectroscopic characteristics, redox state control, redox potentials and autoxidation rates. The latter are strongly influenced by pH for all three hemoglobins – (with a fundamental involvement of the distal histidine), as well as by added anion concentrations – suggesting either a process dominated by nucleophilic displacement of superoxide for AtHb2 or an inhibitory effect for AtHb1 and AtHb3. Reducing agents, such as ascorbate and glutathione, are found to either enhance– (presumably via direct electron transfer or via allosteric regulation) or prevent autoxidation. HbFe3+ reduction was possible in the presence of high (presumably not physiologically relevant) concentrations of NADH, glutathione and ascorbate, with differing behaviors for the three globins. The iron coordination sphere is found to affect the autoxidation, redox state interconversion and redox potentials in these three phytoglobins.

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Cellular localization of the Arabidopsis class 2 phytoglobin influences somatic embryogenesis

Abstract: HighlightDuring Arabidopsis somatic embryogenesis phytoglobin 2 exercises its effects only when targeted to the nucleus, while when cytoplasmic it mimics the effects of its mutant form.

Cited by 13 publications

References 59 publications

Trichostatin A Triggers an Embryogenic Transition in Arabidopsis Explants via an Auxin-Related Pathway

Trichostatin A Triggers an Embryogenic Transition in Arabidopsis Explants via an Auxin-Related Pathway

Redirecting Cell Fate During in vitro Embryogenesis: Phytoglobins as Molecular Switches

Redox control and autoxidation of class 1, 2 and 3 phytoglobins from Arabidopsis thaliana

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