MolBar: The molecular basis of postzygotic hybridization barriers in plants

This project seeks to improve our understanding of how new plant species emerges and what are the barriers that stop hybrids from developing.

About the project

In this project we study the post-zygotic barriers and especially processes that prevent the embryo from developing normally when germ cells from two different species merge. In plants, the embryo develops inside the seed. In most plants, the seed contains in addition nutritive tissue (endosperm) that the new plant needs to grow big. We especially study the embryo and endosperm development in seeds resulting from crosses between different species. We will further investigate which genes are responsible and to what extent the result is affected most by the mother or the father. We will study whether the reproductive barriers are the same 1) in different plant genera, 2) between species pairs which have been separated over long evolutionary time and species pairs that have originated recently and 3) between species pairs having the same number of chromosomes and species pairs with unequal number of chromosomes.

a) Growth chamber with Arabidopsis plants, b) seed development – heart stage, c) young A. lyrata plants; d) A. arenosa plant. Photo: I. M. Johannessen and K. Stensland Hornslien

Outcomes

Our main focus is on basic research, improving our common knowledge on one of the core issues in evolution – the underlying causes of the evolution of reproduction barriers, promoting speciation which is a prerequisite for biological diversity. In addition, increased knowledge on this subject will pave the ground for designing genetic strategies to overcome interploidy hybridization barriers, holding great potential for plant breeding.

Background

New species originate in various ways. Often it happens by two populations of a species being isolated from each other and eventually becoming so different that they no longer are able to cross and have new offspring. When this takes place over a long time period, the two original populations often become different both genetically and in external traits, but in some cases the genetic differences happen so rapidly that the two new species still look the same even when they are genetically different - we are then talking about 'cryptic species'. New species can also originate as a result of changes in the number of chromosomes; this may occur either within a single species or as a result of two related species hybridizing with each other.

No matter how a new species originate, it will to a greater or lesser extent be genetically isolated from other species because of a 'reproductive barrier' which prevents them from having common offspring. Such barriers are divided into those that take place before the gametes fuse to form a fertilized egg (zygote) - we call them pre-zygotic barriers, and those occurring after the zygote is formed - post-zygotic barriers.

Financing

FRIMEDBIO - From the Norwegian Recearch Council (RCN).

The project runs from 01.08.2017 to 31.07.2021.

Cooperation

National collaborators

The Natural History Museum of Norway, Prof. Christian Brochman

International collaborators

The Swedish University of Agricultural Sciences, Sweden, Prof. Claudia Köhler

UC Davis Genome Centre, USA, Prof. Luca Comai

Shepherd University, USA, Ass. Prof. Jason R. Miller

The University of Hamburg, Germany, Prof. Arp Schnittger

The Czech Academy of Sciences, The Czech Republic, Dr. Roswitha Schmickl

 

Publications

Lafon-Placette C, Johannessen IM, Hornslien KS, Ali MF, Bjerkan KN, Bramsiepe J, Glöckle BM, Rebernig CA, Brysting AK, Grini PE, Köhler C. Endosperm-based hybridization barriers explain the pattern of gene flow between Arabidopsis lyrata and A. arenosa in Central Europe. 2017. PNAS 114: E1027-E1035.

Tags: Hybridization, Plant physiology, Plant research
Published Aug. 29, 2017 9:44 AM - Last modified Nov. 13, 2017 3:53 PM