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Short Title Microsystems
Title BioSystemanalyse von Mikrosporen zur Verbesserung der industriellen Embryoproduktion in Pflanzen
Founded by German Ministry for Education and Research (BMBF FKz.: 0316185) as part of the collaborative research initiative e:Bio
Principal Investigators Dr. Jens Weyen, SAATEN-UNION BIOTEC GmbH, Leopoldshöhe, Germany (coordinator)
Prof. Dr. Klaus Palme, Institute of Biology I, University of Freiburg, Germany (coordinator Freiburg)
Prof. Dr. Rainer Uhl, TILL I.D. GmbH, Gräfelfing, Germany
Dr. Alexander Dovzhenko, Center for Applied Bio-Sciences & Institute of Biology, University of Freiburg, Germany
Prof. Dr. Olaf Ronneberger, Computer Science Department, University of Freiburg, Germany
Prof. Dr. Robert F. Murphy, Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Germany
Dr. Hauke Busch, Zentrum für Biosystemanalyse (ZBSA), University of Freiburg, Germany
Duration April 2013 - December 2016
Image analysis Thorsten Falk, Dominic Mai, Robert Bensch

Microsystems

Goals

According to current estimates, 9.5 billion people which have to be supplied with food will inhabit our planet till the year 2050. Besides this population increase, hunger in many regions is already a problem today, therefore there is a huge need for improved food supply. The required agriculturally usable area shrinks and erosion reduces soil quality. In the long run agriculture is particularly affected by the on-going climate change. The importance of plant sciences, especially in breeding new plants with optimal features, grows. Modern plant breeding generates homogeneous breeds which, as extreme case, consists of only one genotype. Nowadays, biotechnology is routinely employed in plant breeding. Typically, line-breeding is applied to generate highly homozygous lines of cereals like barley or corn with continued fertilization. This process requires 5-7 years.

Double-haploid plants (DHs) open a way to drastically reduce breeding time. They originate in in-vitro cultivated haploid parts of the plant, most often isolated microspores or full anthers. With addition of hormones, microspores develop into haploid sprouts. The genome of these sprouts then doubles either spontaneously or by addition of colchicine resulting in complete homozygous DH plants yielding a purity not achievable by repetitive reproduction. Homozygous plants can already be generated from microspores of F1-hybrids and therefore are already available in the first year of breeding. Besides culturing of microspores, DH plants can also result from pollination with species-foreign pollen or from pollination with so-called inductor-plants. DH plants not only play a role in line breeding, but also in hybrid breeeding. Many breeds on the market are DH plants or DH plants were used in their production.

The mechanism of haploid induction and the generation of haploid embroys is up-to-now unclear in many aspects. To employ microspores as tool for breeding in-depth knowledge of the mechanisms leading to embryo induction is required. Goal of the collaborative research project Microsystems is the exploration of mechanisms for reprogramming and totipotence in plants and to employ the systems-biological findings to improve the production of double-haploid plants.

Without knowledge of the molecular processes underlying re-programming and re-differentiation of single plant cells, reliable cultivation and transformation of microspores into embryonic cells is impossible. A deep understanding of these processes is therefore the prerequisite to make new species and varyities accessible for microspore embryogenesis. Unfortunately, only few plants allow effective microspore embryogenesis; many others, even closely related varieties, show recalcitrant behavior, i.e. microspores do not develop into embryos under normal conditions, they only develop into pollen.

The planned analytical approaches and models will reveal key switches and regulatory elements to also apply microspore embryogenesis to recalcitrant plants and therefore lay the foundations for efficient breeding. Our results are based on a combination of transcriptome and 4D image data which are fed into a mathematical model which allows to predict the spatio-temporal distribution of key components and their effect on morphometrical cell features in cells of various species (Bracaceae, Nicotiana, Triticeae). The obtained models for Brassicaceae will be used to analyse recalcitrant genotypes.