CENH3-dependent induction of haploidity in plants and its application

Šijanski, Filip (2016) CENH3-dependent induction of haploidity in plants and its application. Bachelor's thesis, Faculty of Science > Department of Biology.

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Abstract

The term haploid in plants is generally used to designate sporophytes having the gametic chromosome number. They can occur either spontaneously or can be induced by modified pollination methods in vivo, or by in vitro culture of immature male or female gametophytes. Haploid plants and so-called doubled haploids (DH) are applied in wide extent in various aspects of botany and genetics. The newest strategy for haploid induction introduced in A. thaliana is based on crossing with a kinetochore protein mutated plant, more precisely a CENH3 mutant. Centromeres are loci that nucleate kinetochores, the protein complexes that bind to spindle microtubules and mediate chromosome segregation during cell division. In this novel method, centromeres are subtly disabled by altering the kinetochore protein CENH3 in such a manner that mutants still maintain chromosome segregation function. Crossing this centromere mutant to wild-type plants mixes two sets of chromosomes in the fertilized zygote. Chromosomes from the CENH3 mutant (the ‘‘haploid inducer’’) have defective kinetochores and can be lost by missegregation during zygotic mitosis. Resulting adult plants are haploids with only chromosomes from their wild-type parent. The exact mechanism of chromosome elimination in the hybrid zygote is unknown yet, altough it is considered that during early embrio development unequally rates of CENH3 loading on mutant and wild-type centromeres lead to the situation that at a certain moment chromosomes of the mutant have less CENH3 loaded on their centromeres than chromosomes of the wild-type. Finally, many technologies and methods in genetics, botany and their related industries have expirienced significant advantages (simplification, rapidity, etc.) from CENH3-dependent haploid production. Some of these methods are synthetic clonal reproduction, reverse breeding used for generating homozygous parental lines from a heterozygous plant and quantitative trait locus mapping (QTL).

Item Type: Thesis (Bachelor's thesis)
Supervisor: Malenica, Nenad
Date: 2016
Number of Pages: 24
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Palma Dizdarevic
Date Deposited: 05 May 2017 08:08
Last Modified: 05 May 2017 08:08
URI: http://digre.pmf.unizg.hr/id/eprint/5507

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