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Zhang, Bo
Publications (5 of 5) Show all publications
Escamez, S., André, D., Zhang, B., Bollhöner, B., Pesquet, E. & Tuominen, H. (2016). METACASPASE9 modulates autophagy to confine cell death tothe target cells during Arabidopsis vascular xylem differentiation. Biology Open, 5(2), 122-129
Open this publication in new window or tab >>METACASPASE9 modulates autophagy to confine cell death tothe target cells during Arabidopsis vascular xylem differentiation
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2016 (English)In: Biology Open, ISSN 2046-6390, Vol. 5, no 2, p. 122-129Article in journal (Refereed) Published
Abstract [en]

We uncovered that the level of autophagy in plant cells undergoingprogrammed cell death determines the fate of the surrounding cells.Our approach consisted of using Arabidopsis thaliana cell culturescapable of differentiating into two different cell types: vasculartracheary elements (TEs) that undergo programmed cell death(PCD) and protoplast autolysis, and parenchymatic non-TEs thatremain alive. The TE cell type displayed higher levels of autophagywhen expression of the TE-specific METACASPASE9 (MC9) wasreduced using RNAi (MC9-RNAi). Misregulation of autophagy in theMC9-RNAi TEs coincided with ectopic death of the non-TEs, implyingthe existence of an autophagy-dependent intercellular signallingfrom within the TEs towards the non-TEs. Viability of the non-TEswas restored when AUTOPHAGY2 (ATG2) was downregulatedspecifically in MC9-RNAi TEs, demonstrating the importance ofautophagy in the spatial confinement of cell death. Our resultssuggest that other eukaryotic cells undergoing PCD might also needto tightly regulate their level of autophagy to avoid detrimentalconsequences for the surrounding cells.

Place, publisher, year, edition, pages
The Company of Biologists ltd, 2016
Keywords
Arabidopsis thaliana, Autophagy, Intercellular signalling, Metacaspase, Programmed cell death, Tracheary element
National Category
Botany
Identifiers
urn:nbn:se:umu:diva-115784 (URN)10.1242/bio.015529 (DOI)000370240300005 ()26740571 (PubMedID)
Projects
Bio4Energy
Available from: 2016-02-04 Created: 2016-02-04 Last updated: 2019-08-30Bibliographically approved
Zhang, B., Tremousaygue, D., Denancé, N., van Esse, H. P., Hörger, A. C., Dabos, P., . . . Tuominen, H. (2014). PIRIN2 stabilizes cysteine protease XCP2 and increases susceptibility to the vascular pathogen Ralstonia solanacearum in Arabidopsis. The Plant Journal, 79(6), 1009-1019
Open this publication in new window or tab >>PIRIN2 stabilizes cysteine protease XCP2 and increases susceptibility to the vascular pathogen Ralstonia solanacearum in Arabidopsis
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2014 (English)In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 79, no 6, p. 1009-1019Article in journal (Refereed) Published
Abstract [en]

PIRIN (PRN) is a member of the functionally diverse cupin protein superfamily. There are four members of the Arabidopsis thaliana PRN family, but the roles of these proteins are largely unknown. Here we describe a function of the Arabidopsis PIRIN2 (PRN2) that is related to susceptibility to the bacterial plant pathogen Ralstonia solanacearum. Two prn2 mutant alleles displayed decreased disease development and bacterial growth in response to R. solanacearum infection. We elucidated the underlying molecular mechanism by analyzing PRN2 interactions with the papain-like cysteine proteases (PLCPs) XCP2, RD21A, and RD21B, all of which bound to PRN2 in yeast two-hybrid assays and in Arabidopsis protoplast co-immunoprecipitation assays. We show that XCP2 is stabilized by PRN2 through inhibition of its autolysis on the basis of PLCP activity profiling assays and enzymatic assays with recombinant protein. The stabilization of XCP2 by PRN2 was also confirmed in planta. Like prn2 mutants, an xcp2 single knockout mutant and xcp2 prn2 double knockout mutant displayed decreased susceptibility to R.solanacearum, suggesting that stabilization of XCP2 by PRN2 underlies susceptibility to R.solanacearum in Arabidopsis.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2014
Keywords
PIRIN2, XCP2, papain-like cysteine protease, Arabidopsis thaliana, Ralstonia solanacearum, vascular pathogen
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-94152 (URN)10.1111/tpj.12602 (DOI)000341515600010 ()
Available from: 2014-10-08 Created: 2014-10-06 Last updated: 2018-06-07Bibliographically approved
Pesquet, E., Zhang, B., Gorzsas, A., Puhakainen, T., Serk, H., Escamez, S., . . . Tuominen, H. (2013). Non-Cell-Autonomous Postmortem Lignification of Tracheary Elements in Zinnia elegans. The Plant Cell, 25(4), 1314-1328
Open this publication in new window or tab >>Non-Cell-Autonomous Postmortem Lignification of Tracheary Elements in Zinnia elegans
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2013 (English)In: The Plant Cell, ISSN 1040-4651, E-ISSN 1532-298X, Vol. 25, no 4, p. 1314-1328Article in journal (Refereed) Published
Abstract [en]

Postmortem lignification of xylem tracheary elements (TEs) has been debated for decades. Here, we provide evidence in Zinnia elegans TE cell cultures, using pharmacological inhibitors and in intact Z. elegans plants using Fourier transform infrared microspectroscopy, that TE lignification occurs postmortem (i.e., after TE programmed cell death). In situ RT-PCR verified expression of the lignin monomer biosynthetic cinnamoyl CoA reductase and cinnamyl alcohol dehydrogenase in not only the lignifying TEs but also in the unlignified non-TE cells of Z. elegans TE cell cultures and in living, parenchymatic xylem cells that surround TEs in stems. These cells were also shown to have the capacity to synthesize and transport lignin monomers and reactive oxygen species to the cell walls of dead TEs. Differential gene expression analysis in Z. elegans TE cell cultures and concomitant functional analysis in Arabidopsis thaliana resulted in identification of several genes that were expressed in the non-TE cells and that affected lignin chemistry on the basis of pyrolysis-gas chromatography/mass spectrometry analysis. These data suggest that living, parenchymatic xylem cells contribute to TE lignification in a non-cellautonomous manner, thus enabling the postmortem lignification of TEs.

Place, publisher, year, edition, pages
American Society of Plant Biologists, 2013
National Category
Botany Cell Biology
Identifiers
urn:nbn:se:umu:diva-76275 (URN)10.1105/tpc.113.110593 (DOI)000319450500012 ()
Available from: 2013-07-08 Created: 2013-07-08 Last updated: 2018-06-08Bibliographically approved
Bollhöner, B., Zhang, B., Stael, S., Denancé, N., Overmyer, K., Goffner, D., . . . Tuominen, H. (2013). Post mortem function of AtMC9 in xylem vessel elements. New Phytologist, 200(2), 498-510
Open this publication in new window or tab >>Post mortem function of AtMC9 in xylem vessel elements
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2013 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 200, no 2, p. 498-510Article in journal (Refereed) Published
Abstract [en]

Cell death of xylem elements is manifested by rupture of the tonoplast and subsequent autolysis of the cellular contents. Metacaspases have been implicated in various forms of plant cell death but regulation and execution of xylem cell death by metacaspases remains unknown. Analysis of the type II metacaspase gene family in Arabidopsis thaliana supported the function of METACASPASE 9 (AtMC9) in xylem cell death. Progression of xylem cell death was analysed in protoxylem vessel elements of 3-d-old atmc9 mutant roots using reporter gene analysis and electron microscopy. Protoxylem cell death was normally initiated in atmc9 mutant lines, but detailed electron microscopic analyses revealed a role for AtMC9 in clearance of the cell contents post mortem, that is after tonoplast rupture. Subcellular localization of fluorescent AtMC9 reporter fusions supported a post mortem role for AtMC9. Further, probe-based activity profiling suggested a function of AtMC9 on activities of papain-like cysteine proteases. Our data demonstrate that the function of AtMC9 in xylem cell death is to degrade vessel cell contents after vacuolar rupture. We further provide evidence on a proteolytic cascade in post mortem autolysis of xylem vessel elements and suggest that AtMC9 is part of this cascade.

Place, publisher, year, edition, pages
John Wiley & Sons, 2013
Keywords
Arabidopsis thaliana, autolysis, metacaspase, protease, vessel element, xylem cell death
National Category
Botany
Identifiers
urn:nbn:se:umu:diva-81218 (URN)10.1111/nph.12387 (DOI)000324621600021 ()23834670 (PubMedID)
Available from: 2013-10-04 Created: 2013-10-04 Last updated: 2018-06-08Bibliographically approved
Nystedt, B., Street, N. R., Wetterbom, A., Zuccolo, A., Lin, Y.-C., Scofield, D. G., . . . Jansson, S. (2013). The Norway spruce genome sequence and conifer genome evolution. Nature, 497(7451), 579-584
Open this publication in new window or tab >>The Norway spruce genome sequence and conifer genome evolution
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2013 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 497, no 7451, p. 579-584Article in journal (Refereed) Published
Abstract [en]

Conifers have dominated forests for more than 200 million years and are of huge ecological and economic importance. Here we present the draft assembly of the 20-gigabase genome of Norway spruce (Picea abies), the first available for any gymnosperm. The number of well-supported genes (28,354) is similar to the >100 times smaller genome of Arabidopsis thaliana, and there is no evidence of a recent whole-genome duplication in the gymnosperm lineage. Instead, the large genome size seems to result from the slow and steady accumulation of a diverse set of long-terminal repeat transposable elements, possibly owing to the lack of an efficient elimination mechanism. Comparative sequencing of Pinus sylvestris, Abies sibirica, Juniperus communis, Taxus baccata and Gnetum gnemon reveals that the transposable element diversity is shared among extant conifers. Expression of 24-nucleotide small RNAs, previously implicated in transposable element silencing, is tissue-specific and much lower than in other plants. We further identify numerous long (>10,000 base pairs) introns, gene-like fragments, uncharacterized long non-coding RNAs and short RNAs. This opens up new genomic avenues for conifer forestry and breeding.

Place, publisher, year, edition, pages
Nature Publishing Group, 2013
National Category
Earth and Related Environmental Sciences Botany
Identifiers
urn:nbn:se:umu:diva-76264 (URN)10.1038/nature12211 (DOI)000319556100035 ()
Available from: 2013-07-08 Created: 2013-07-08 Last updated: 2019-07-05Bibliographically approved
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