Terezie Mandakova and her colleagues, Milan Pouch and Martin Lysak, from the Martin Lysak Research Group at CEITEC MU, deciphered the ancestors and closest relatives of the crop species Camelina sativa. Terezie Mandakova and her colleagues aimed to identify the most probable parental genomes of the hexaploid Camelina to reconstruct the genome structure and evolution of all known Camelina species and to identify mechanisms responsible for the present-day genome structures. New pieces of Camelina genome history now provide fresh insights needed to explore possibilities for the future improvement of this ancient and economically important crop.
Originating back to the Neolithic age, Camelina sativa – an ancient oilseed crop – was re-discovered recently for its unique characteristics. Grown in Europe as early as 4 000 BC but ignored as a crop, Camelina received its evolutionary glories back.
Thanks to Mandakova and Lysak, they decided to study the genome evolution of Camelina sativa (also known as false flax or gold of pleasure) – a commercially important crop closely related to the plant model species, Arabidopsis thaliana (Brassicaceae).
Camelina oil, extracted from seeds, has a very high content of omega-3 fatty acids (39%). Most of the fats in Camelina oil are polyunsaturated. These “good fats” are essential for healthy cell functioning in the human body, such as for reducing the risk of heart disease.
Camelina oil is also excellent for skin and hair due to its ample amounts of vitamin E and omega fatty acids. Last but not least, Camelina oil is known for its antioxidant and anti-inflammatory properties, which make it perfect for aiding human immune systems.
Camelina oil can be used as cooking oil, pure oil, a food supplement, or biofuel, and has become increasingly popular for its potential as a renewable industrial feedstock.
Camelina is also known for its excellent drought resistance and can be grown almost anywhere, which makes this plant even more valuable, considering climate change. The research was also done to develop its oil for jet fuel and other high-value chemicals. Presently, Camelina is grown mainly in the United States, Canada, Slovenia, Ukraine, China, Finland, Germany, and Austria.
Thanks to the combination of several advanced cytogenetic methods such as comparative chromosome painting, genomic in situ hybridization (a technique that identifies parental genomes within the genome of putative hybrid), and multi-gene phylogenetic analyses, Mandakova and her colleagues revealed the entire genome structure of the known diploid, tetraploid, and hexaploid Camelina species, including false flax.
Genomes of diploid Camelina species (C. hispida, n = 7 chromosomes; C. laxa, n = 6; and C. neglecta, n = 6) originated from an ancestral n = 7 genome. The allotetraploid C. rumelica genome (n = 13, N6H genome) arose from hybridization between diploids C. neglecta (n = 6, N6) and C. hispida (n = 7, H). The allohexaploid genomes of C. sativa (n = 20, N6N7H) originated through hybridization between an auto-allotetraploid C. neglecta-like genome (n = 13, N6N7) and C. hispida (n = 7, H), and the three subgenomes remained stable overall, after the genome merger.
The cytogenetic methods used are explicit, and as a result, other well-known institutes use the cytogenetic maps developed by Martin Lysak´s group as a basis for whole-genome assembly or the characterization of specific chromosome regions.
Mandakova managed to reconstruct the parental genomes of Camelina sativa and to discover the evolutionary history of the hexaploid genome, as well as the mechanisms responsible for the current structure of genomes studied.
She successfully traced the Camelina genome to millions of years into the past and observed all of the naturally occurring genetic crossings of this unique plant that took place with the absence of human intervention.
Remarkably, the ancestral and diploid Camelina genomes were shaped by complex chromosomal rearrangements – the so-called chromothripsis.
Chromothripsis can be explained as a catastrophic event in the cell´s history that causes the clustering of up to a thousand cells in one location.
This event is commonly associated with human diseases and can lead to the development of genome-specific shattered chromosomes. Chromothripsis is very rare in plants, but very common in diseases such as leukemia.
This unique discovery was possible thanks to a standard three-year GACR grant titled, Missing Links: Genome Evolution in Camelina Species (GA17-13029S), which was awarded to Terezie Mandakova by the Czech Science Foundation (GACR).
Further Research and Expected Impact
There are multiple implications for the ground-breaking discovery by Mandakova and Lysak.
Breeders like to improve the seed yield, oil content, and other agronomic traits of the Camelina crop. This is possible if new Camelina lines are produced by crossing the now identified parental Camelina species.
Furthermore, the diploid and tetraploid Camelina genomes should be more amenable to genome sequencing and uncovering the essential genes that influence yield and other desired agronomic traits.
Written by Ester Jarour
Edited by Somsuvro Basu and Jill Batdorf
Publication date: 23.01.2020