The comprehensive sequencing of genetic material makes breeding new types easier.
Scientists from Ludwig-Maximilians-Universität München and the Max Planck Institute for Plant Breeding Research in Cologne have decoded the very complicated genome of the potato for the first time, more than 20 years after the human genome was originally released. This technically challenging work sets the biotechnological basis for faster breeding of more robust cultivars, which has been a long-term objective in plant breeding and is a critical step toward global food security.
When purchasing potatoes at a market today, customers may find themselves with a variety that was accessible more than a century ago. Popular potato types are those that have been around for a long time. Nonetheless, this example demonstrates a paucity of variation among the most common potato cultivars. That may soon change, as researchers led by geneticist Korbinian Schneeberger were able to complete the first entire genome assembly of a potato. This lays the path for the development of new, hardy varieties:
“Even in Asian nations like China, where rice is the traditional staple meal, the potato is becoming more important in people’s diets. Building on this work, we may now use genome-assisted breeding to create new potato types that are both more productive and resistant to climate change, which might have a significant influence on food security in the coming decades.”
Potato plants are particularly sensitive to diseases due to their limited variety. This had serious effects during the Irish famine of the 1840s, when practically the entire potato crop rotted in the ground for many years, starving millions of people throughout Europe simply because the sole variety cultivated was not immune to newly emergent tuber blight. During the 1950s and 1960s Green Revolution, scientists and plant breeders were successful in increasing the yields of several of our key agricultural staples, such as rice and wheat. The potato, on the other hand, has not seen a similar surge, and attempts to develop new kinds with larger yields have mainly failed to date.
The explanation for this is straightforward, but it has proved difficult to address: instead of acquiring one copy of each chromosome from both parents (like humans do), potatoes receive two copies of each chromosome from each parent, giving them four copies of each chromosome (tetraploid). Four copies of each chromosome also means four copies of each gene, which makes developing new varieties with a desired combination of individual properties extremely difficult and time-consuming. Furthermore, multiple copies of each chromosome make reconstructing the potato genome a far more technical challenge than reconstructing the human genome.
The researchers used a simple yet straightforward method to circumvent this long-standing barrier. Rather of attempting to distinguish the four chromosomal copies from one another, Korbinian Schneeberger, his colleague Hequan Sun, and other coworkers solved the challenge by sequencing the DNA of a huge number of individual pollen cells. Pollen cells, unlike all other cells, have just two random copies of each chromosome, which aided in the reconstruction of the full genome sequence.
An overview of the whole DNA sequence of the cultivated potato has long been a goal of scientists and plant breeders alike, with the potential to considerably simplify breeding. Scientists may now more quickly discover gene variations that cause favorable or negative outcomes using this knowledge.
