07 March 2022
German research team makes genome breakthrough
SCIENTISTS at Germany's Max Planck Institute for Plant Breeding in Cologne and the the Ludwig-Maximilians-Universität München have announced the completion of whole genome sequencing of the potato, an advancement that paves the way for the breeding of new varieties.
The potato has a highly complex genome which made the study technically demanding.
Humans are diploid, inheriting one set of chromosomes from each parent, while potatoes are tetraploid, inheriting two sets of chromosomes from each parent. As there are four chromosomes, there are four copies of each gene, making it highly challenging and time-consuming to generate new varieties of potatoes, with all the desirable characteristics such as resilience to diseases and high yields. Multiple copies of each gene makes reconstruction of potato genomes a harder technical challenge than say the reconstruction of the human genome. Researchers have announced assembly of the complete potato genome for the first time, by using a clever trick.
Instead of attempting to differentiate the four, often very similar chromosomes from one another, the researchers circumvented the problem by sequencing the DNAs of a long number of individual pollen cells. Each pollen contains only two random copies of the chromosome, facilitating the sequencing of the entire genome. For many years, a complete DNA sequence of the cultivated potato has been an ambition for scientists and plant breeders alike. With the information on hand, it is possible to more easily identify gene variants responsible for desirable or undesirable characteristics. While there have been successful breeding programs for other staples, potatoes have not had the same benefit so far.
The research has been carried out at the computational genetics lab of Korbinian Schneeberger, who said: "The potato is becoming more and more integral to diets worldwide including even Asian countries like China where rice is the traditional staple food. Building on this work, we can now implement genome-assisted breeding of new potato varieties that will be more productive and also resistant to climate change – this could have a huge impact on delivering food security in the decades to come."
Source: Max Planck
Photo: Ulrich Pollmann