EXO70C2 is a key regulatory factor for optimal tip growth of pollen

Handle URI:
http://hdl.handle.net/10754/623085
Title:
EXO70C2 is a key regulatory factor for optimal tip growth of pollen
Authors:
Synek, Lukas; Vukasinovic, Nemanja; Kulich, Ivan; Hala, Michal; Aldorfova, Klara; Fendrych, Matyas; Zarsky, Viktor
Abstract:
The exocyst, an eukaryotic tethering complex, co-regulates targeted exocytosis as an effector of small GTPases in polarized cell growth. In land plants, several exocyst subunits are encoded by double or triple paralogs, culminating in tens of EXO70 paralogs. Out of 23 Arabidopsis EXO70 isoforms, we analyzed seven isoforms expressed in pollen. Genetic and microscopic analyses of single mutants in EXO70A2, C1, C2, F1, H3, H5, and H6 genes revealed that only a loss-of-function EXO70C2 allele resulted in a significant male-specific transmission defect (segregation 40%:51%:9%) due to aberrant pollen tube growth. Mutant pollen tubes grown in vitro exhibited enhanced growth rate and a decreased thickness of the tip cell wall, causing tip bursts. However, exo70C2 pollen tubes could frequently recover and restart their speedy elongation, resulting in a repetitive stop-and-go growth dynamics. A pollen-specific depletion of the closest paralog, EXO70C1, using ami-RNA in the exo70C2 mutant background resulted in a complete pollen-specific transmission defect, suggesting redundant functions of EXO70C1 and EXO70C2. Both EXO70C1 and EXO70C2, GFP-tagged and expressed under their native promoters, localized in the cytoplasm of pollen grains, pollen tubes, and also root trichoblast cells. Expression of EXO70C2-GFP complemented aberrant growth of exo70C2 pollen tubes. The absent EXO70C2 interactions with core exocyst subunits in the yeast two-hybrid assay, cytoplasmic localization, and genetic effect suggest an unconventional EXO70 function possibly as a regulator of exocytosis outside the exocyst complex. In conclusion, EXO70C2 is a novel factor contributing to the regulation of optimal tip growth of Arabidopsis pollen tubes.
KAUST Department:
Center for Desert Agriculture
Citation:
Synek L, Vukasinovic N, Kulich I, Hala M, Aldorfova K, et al. (2017) EXO70C2 is a key regulatory factor for optimal tip growth of pollen. Plant Physiology: pp.01282.2016. Available: http://dx.doi.org/10.1104/pp.16.01282.
Publisher:
American Society of Plant Biologists (ASPB)
Journal:
Plant Physiology
Issue Date:
30-Mar-2017
DOI:
10.1104/pp.16.01282
Type:
Article
ISSN:
0032-0889; 1532-2548
Sponsors:
This work was supported by the Czech Science Foundation (grant no. 15-24711S). Part of the V.Z. and I.K. income is covered by the Ministry of Education of the Czech Republic (project no. NPUI LO1417).
Additional Links:
http://www.plantphysiol.org/content/early/2017/03/30/pp.16.01282
Appears in Collections:
Articles; Center for Desert Agriculture

Full metadata record

DC FieldValue Language
dc.contributor.authorSynek, Lukasen
dc.contributor.authorVukasinovic, Nemanjaen
dc.contributor.authorKulich, Ivanen
dc.contributor.authorHala, Michalen
dc.contributor.authorAldorfova, Klaraen
dc.contributor.authorFendrych, Matyasen
dc.contributor.authorZarsky, Viktoren
dc.date.accessioned2017-04-10T07:49:50Z-
dc.date.available2017-04-10T07:49:50Z-
dc.date.issued2017-03-30en
dc.identifier.citationSynek L, Vukasinovic N, Kulich I, Hala M, Aldorfova K, et al. (2017) EXO70C2 is a key regulatory factor for optimal tip growth of pollen. Plant Physiology: pp.01282.2016. Available: http://dx.doi.org/10.1104/pp.16.01282.en
dc.identifier.issn0032-0889en
dc.identifier.issn1532-2548en
dc.identifier.doi10.1104/pp.16.01282en
dc.identifier.urihttp://hdl.handle.net/10754/623085-
dc.description.abstractThe exocyst, an eukaryotic tethering complex, co-regulates targeted exocytosis as an effector of small GTPases in polarized cell growth. In land plants, several exocyst subunits are encoded by double or triple paralogs, culminating in tens of EXO70 paralogs. Out of 23 Arabidopsis EXO70 isoforms, we analyzed seven isoforms expressed in pollen. Genetic and microscopic analyses of single mutants in EXO70A2, C1, C2, F1, H3, H5, and H6 genes revealed that only a loss-of-function EXO70C2 allele resulted in a significant male-specific transmission defect (segregation 40%:51%:9%) due to aberrant pollen tube growth. Mutant pollen tubes grown in vitro exhibited enhanced growth rate and a decreased thickness of the tip cell wall, causing tip bursts. However, exo70C2 pollen tubes could frequently recover and restart their speedy elongation, resulting in a repetitive stop-and-go growth dynamics. A pollen-specific depletion of the closest paralog, EXO70C1, using ami-RNA in the exo70C2 mutant background resulted in a complete pollen-specific transmission defect, suggesting redundant functions of EXO70C1 and EXO70C2. Both EXO70C1 and EXO70C2, GFP-tagged and expressed under their native promoters, localized in the cytoplasm of pollen grains, pollen tubes, and also root trichoblast cells. Expression of EXO70C2-GFP complemented aberrant growth of exo70C2 pollen tubes. The absent EXO70C2 interactions with core exocyst subunits in the yeast two-hybrid assay, cytoplasmic localization, and genetic effect suggest an unconventional EXO70 function possibly as a regulator of exocytosis outside the exocyst complex. In conclusion, EXO70C2 is a novel factor contributing to the regulation of optimal tip growth of Arabidopsis pollen tubes.en
dc.description.sponsorshipThis work was supported by the Czech Science Foundation (grant no. 15-24711S). Part of the V.Z. and I.K. income is covered by the Ministry of Education of the Czech Republic (project no. NPUI LO1417).en
dc.publisherAmerican Society of Plant Biologists (ASPB)en
dc.relation.urlhttp://www.plantphysiol.org/content/early/2017/03/30/pp.16.01282en
dc.rightsArchived with thanks to Plant Physiologyen
dc.titleEXO70C2 is a key regulatory factor for optimal tip growth of pollenen
dc.typeArticleen
dc.contributor.departmentCenter for Desert Agricultureen
dc.identifier.journalPlant Physiologyen
dc.eprint.versionPost-printen
dc.contributor.institutionInstitute of Experimental Botany, Czech Academy of Sciences CITY: Prague Czech Republic [CZ].en
dc.contributor.institutionDepartment of Experimental Botany, Charles University CITY: Prague Czech Republic [CZ].en
dc.contributor.institutionInstitute of Science and Technology CITY: Klosterneuburg Austria [AT].en
kaust.authorSynek, Lukasen
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