ORCID Profile
0000-0001-5213-0905
Current Organisation
University of Aveiro
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Publisher: Springer Science and Business Media LLC
Date: 03-10-2018
DOI: 10.1038/S41598-018-33146-Y
Abstract: Photosystem II (PSII) reaction centre D1 protein of oxygenic phototrophs is pivotal for sustaining photosynthesis. Also, it is targeted by herbicides and herbicide-resistant weeds harbour single amino acid substitutions in D1. Conservation of D1 primary structure is seminal in the photosynthetic performance in many erse species. In this study, we analysed built-in and environmentally-induced (high temperature and high photon fluency – HT/HL) phenotypes of two D1 mutants of C hlamydomonas reinhardtii with Ala250Arg (A250R) and Ser264Lys (S264K) substitutions. Both mutations differentially affected efficiency of electron transport and oxygen production. In addition, targeted metabolomics revealed that the mutants undergo specific differences in primary and secondary metabolism, namely, amino acids, organic acids, pigments, NAD, xanthophylls and carotenes. Levels of lutein, β-carotene and zeaxanthin were in sync with their corresponding gene transcripts in response to HT/HL stress treatment in the parental (IL) and A250R strains. D1 structure analysis indicated that, among other effects, remodelling of H-bond network at the Q B site might underpin the observed phenotypes. Thus, the D1 protein, in addition to being pivotal for efficient photosynthesis, may have a moonlighting role in rewiring of specific metabolic pathways, possibly involving retrograde signalling.
Publisher: Oxford University Press (OUP)
Date: 15-05-2021
DOI: 10.1093/JXB/ERAB216
Abstract: The kleptoplastic sea slug Elysia chlorotica consumes Vaucheria litorea, stealing its plastids, which then photosynthesize inside the animal cells for months. We investigated the properties of V. litorea plastids to understand how they withstand the rigors of photosynthesis in isolation. Transcription of specific genes in laboratory-isolated V. litorea plastids was monitored for 7 days. The involvement of plastid-encoded FtsH, a key plastid maintenance protease, in recovery from photoinhibition in V. litorea was estimated in cycloheximide-treated cells. In vitro comparison of V. litorea and spinach thylakoids was applied to investigate reactive oxygen species formation in V. litorea. In comparison to other tested genes, the transcripts of ftsH and translation elongation factor EF-Tu (tufA) decreased slowly in isolated V. litorea plastids. Higher levels of FtsH were also evident in cycloheximide-treated cells during recovery from photoinhibition. Charge recombination in PSII of V. litorea was found to be fine-tuned to produce only small quantities of singlet oxygen, and the plastids also contained reactive oxygen species-protective compounds. Our results support the view that the genetic characteristics of the plastids are crucial in creating a photosynthetic sea slug. The plastid’s autonomous repair machinery is likely enhanced by low singlet oxygen production and elevated expression of FtsH.
Publisher: Cold Spring Harbor Laboratory
Date: 02-02-2021
DOI: 10.1101/2021.02.02.429324
Abstract: Elysia chlorotica is a kleptoplastic sea slug that preys on Vaucheria litorea , stealing its plastids which then continue to photosynthesize for months inside the animal cells. We investigated the native properties of V. litorea plastids to understand how they withstand the rigors of photosynthesis in isolation. Transcription of specific genes in laboratory-isolated V. litorea plastids was monitored up to seven days. The involvement of plastid-encoded FtsH, a key plastid maintenance protease, in recovery from photoinhibition in V. litorea was estimated in cycloheximide-treated cells. In vitro comparison of V. litorea and spinach thylakoids was applied to investigate ROS formation in V. litorea . Isolating V. litorea plastids triggered upregulation of ftsH and translation elongation factor EF-Tu ( tufA ). Upregulation of FtsH was also evident in cycloheximide-treated cells during recovery from photoinhibition. Charge recombination in PSII of V. litorea was found to be fine-tuned to produce only small quantities of singlet oxygen ( 1 O 2 ). Our results support the view that the genetic characteristics of the plastids themselves are crucial in creating a photosynthetic sea slug. The plastid’s autonomous repair machinery is likely enhanced by low 1 O 2 production and by upregulation of FtsH in the plastids. Isolated Vaucheria litorea plastids exhibit upregulation of tufA and ftsH , key plastid maintenance genes, and produce only little singlet oxygen. These factors likely contribute to plastid longevity in kleptoplastic slugs.
No related grants have been discovered for Vesa Havurinne.