Universität zu Köln

Kumar, Manoj (2011). Analysis of cell proliferation and growth control during seed development in Arabidopsis thaliana. PhD thesis, Universität zu Köln.

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Abstract

Endosperm supports the development of embryos and thus, is crucial for the life cycle and reproductive success of flowering plants. In addition, the endosperm of especially grass species is of key importance for human nutrition. Endosperm development relies on rapid free nuclear divisions resulting in formation of large syncytium with many hundred nuclei. Despite of its importance, not much is known about the cell cycle machinery that drives divisions during endosperm development. In the present study, two approaches were followed to get insights into the molecular machinery that controls endosperm proliferation and growth. In the first part, one subfamily of mitotic cyclins, the B1-group comprising five members, was analysed. Expression and localisation studies revealed that B1-type cyclins accumulate during G2/M phase and localise to chromatin and the spindle during mitosis. B1-type cyclins were found to redundantly control mitosis throughout plant development and in particular the nuclear divisions of endosperm were affected in double and triple mutants. This work revealed that B1 type cyclins are responsible to maintain the spindle architecture thereby regulating cell division. To complement the reverse genetics approach, I exploited the existing natural variation in Arabidopsis to identify important regulators of seed growth and nuclear proliferation. The analysis of seed mass trait in three recombinant inbred line populations having one common parent discovered 12 QTLs, 10 main and 2 complex loci influencing seed mass in Arabidopsis. In addition, by using Est-Col RIL population 2 QTLS, 1 main and 1 complex locus that influence the development of autonomous endosperm upon cdka;1 pollination were found. The loci did not co-localise with B1-type cyclins and thus, represent additional regulators of endosperm proliferation and growth.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Kumar, Manoj kmanojt@gmail.com UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-530826
Date:	11 September 2011
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Biology > Botanical Institute
Subjects:	Natural sciences and mathematics Life sciences
Uncontrolled Keywords:	Keywords Language Arabidopsis, Cell cycle, cyclinB1 UNSPECIFIED Mitosis UNSPECIFIED Microtubule UNSPECIFIED
Date of oral exam:	22 June 2011
Referee:	Name Academic Title Huelskamp, Martin Prof. Dr. Koornneef, Maarten Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/53082