title: Comparative analysis of the tubulin cytoskeleton organization in nodules of Medicago truncatula and Pisum sativum: bacterial release and bacteroid positioning correlate with characteristic microtubule rearrangements.
abstract: In this study we analyzed and compared the organization of the tubulin cytoskeleton in nodules of Medicago truncatula and Pisum sativum. We combined antibody labeling and green fluorescent protein tagging with laser confocal microscopy to observe microtubules (MTs) in nodules of both wild-type (WT) plants and symbiotic plant mutants blocked at different steps of nodule development. The 3D MT organization of each histological nodule zone in both M. truncatula and P. sativum is correlated to specific developmental processes. Endoplasmic MTs appear to support infection thread growth, infection droplet formation and bacterial release into the host cytoplasm in nodules of both species. No differences in the organization of the MT cytoskeleton between WT and bacterial release mutants were apparent, suggesting both that the phenotype is not linked to a defect in MT organization and that the growth of hypertrophied infection threads is supported by MTs. Strikingly, bacterial release coincides with a change in the organization of cortical MTs from parallel arrays into an irregular, crisscross arrangement. After release, the organization of endoplasmic MTs is linked to the distribution of symbiosomes. The 3D MT organization of each nodule histological zone in M. truncatula and P. sativum was analyzed and linked to specific developmental processes.
authors.affiliation: Laboratory of Molecular and Cellular Biology, All-Russia Research Institute for Agricultural Microbiology, Podbelsky chaussee 3, Pushkin 8, 196608, Saint-Petersburg, Russia.
authors.forename: Anna B
authors.initials: AB
authors.lastname: Kitaeva
authors.affiliation: Laboratory of Molecular and Cellular Biology, All-Russia Research Institute for Agricultural Microbiology, Podbelsky chaussee 3, Pushkin 8, 196608, Saint-Petersburg, Russia.|Laboratory of Anatomy and Morphology, Komarov Botanical Institute, Russian Academy of Sciences, Prof. Popov street 2, 197376, Saint-Petersburg, Russia.
authors.forename: Kirill N
authors.initials: KN
authors.lastname: Demchenko
authors.affiliation: Laboratory of Molecular and Cellular Biology, All-Russia Research Institute for Agricultural Microbiology, Podbelsky chaussee 3, Pushkin 8, 196608, Saint-Petersburg, Russia.|Department of Genetics and Biotechnology, Saint-Petersburg State University, Universitetskaya Embankment 7-9, 199034, Saint-Petersburg, Russia.
authors.forename: Igor A
authors.initials: IA
authors.lastname: Tikhonovich
authors.affiliation: Laboratoire des Interactions Plantes-Microorganismes (LIPM), INRA, UMR441, F-31326, Castanet-Tolosan, France.|Laboratoire des Interactions Plantes-Microorganismes (LIPM), CNRS, UMR2594, F-31326, Castanet-Tolosan, France.
authors.forename: Antonius C J
authors.initials: AC
authors.lastname: Timmers
authors.affiliation: Laboratory of Molecular and Cellular Biology, All-Russia Research Institute for Agricultural Microbiology, Podbelsky chaussee 3, Pushkin 8, 196608, Saint-Petersburg, Russia.
authors.forename: Viktor E
authors.initials: VE
authors.lastname: Tsyganov
mesh_terms: D004721:Endoplasmic Reticulum / Q000378:metabolism; D046913:Medicago truncatula / Q000378:metabolism* / Q000382:microbiology*; D018519:Meristem / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D009586:Nitrogen Fixation; D018532:Pisum sativum / Q000378:metabolism* / Q000382:microbiology*; D058105:Polymerization; D053204:Root Nodules, Plant / Q000378:metabolism / Q000382:microbiology*; D020579:Sinorhizobium / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism*
chemical_list: D014404:Tubulin
keywords: Medicago truncatula (barrel medic); Pisum sativum (pea); cell differentiation; microtubules (MTs); nodulation; symbiosis; tubulin cytoskeleton