Potato genome decoded
The complete sequencing of the genetic material facilitates the breeding
of new varieties

Date:
March 3, 2022
Source:
Max Planck Institute for Plant Breeding Research
Summary:
More than 20 years after the first release of the human genome,
scientists have for the first time deciphered the highly complex
genome of the potato. Their impressive technical feat will
accelerate efforts to breed superior varieties.



FULL STORY ==========================================================================
More than 20 years after the first releasse of the human genome,
scientists at the Ludwig-Maximilians-Universita"t Mu"nchen and the
Max Planck Institute for Plant Breeding Research in Cologne, have for
the first time decoded the highly complex genome of the potato. This technically demanding study lays the biotechnological foundation to
accelerate the breeding of more robust varieties -- a goal in plant
breeding for many years and an important step for global food security.


==========================================================================
When shopping for potatoes on a market today, buyers may well be going
home with a variety that was already available more than 100 years
ago. Traditional potato varieties are popular. And yet this example
also highlights a lack of diversity among the predominant potato
varieties. However, that could soon change: researchers in the group
of geneticist Korbinian Schneeberger were able to generate the first
full assembly of a potato genome. This paves the way for breeding new,
robust varieties: "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." Especially the low diversity makes
potato plants susceptible to diseases. This can have stark consequences,
most dramatically during the Irish famine of the 1840s, where for
several years nearly the entire potato crop rotted in the ground, and
millions of people in Europe suffered from starvation simply because the
single variety that was grown was not resistant to newly emerging tuber
blight. During the Green Revolution of the 1950s and 1960s, scientists
and plant breeders succeeded in achieving large increases in the yields
of many of our major crop staples like rice or wheat. However, the potato
has seen no comparable boost, and efforts to breed new varieties with
higher yields have remained largely unsuccessful to the current day.

The reason for this is simple but has proven difficult to tackle --
instead of inheriting one copy of every chromosome from both the father
and from the mother (as in humans) potatoes inherit two copies of each chromosome from each parent, making them a species with four copies of
each chromosome (tetraploid).

Four copies of each chromosome also mean four copies of each gene,
and this makes it highly challenging and time-consuming to generate
new varieties that harbour a desired combination of individual
properties; what's more, multiple copies of each chromosome also make
the reconstruction of the potato genome a far greater technical challenge
than was the case for the human genome.

The researchers have overcome this longstanding hurdle using a simple
yet elegant trick. Instead of trying to differentiate the four, often
very similar, chromosome copies from each other, Korbinian Schneeberger together with his colleague Hequan Sun and other co-workers circumvented
this problem by sequencing the DNA of large numbers of individual pollen
cells. In contrast to all other cells, each pollen cell contains only
two random copies of each chromosome; this facilitated the reconstruction
of the sequence of the entire genome.

An overview of the complete DNA sequence of cultivated potato has the
potential of greatly facilitating breeding and has been an ambition
of scientists and plant breeders alike for many years already. With
this information in hand, scientists can now more easily identify gene
variants responsible for desirable or undesirable.

========================================================================== Story Source: Materials provided by Max_Planck_Institute_for_Plant_Breeding_Research. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Hequan Sun, Wen-Biao Jiao, Kristin Krause, Jose' A. Campoy,
Manish Goel,
Kat Folz-Donahue, Christian Kukat, Bruno Huettel, Korbinian
Schneeberger.

Chromosome-scale and haplotype-resolved genome assembly of
a tetraploid potato cultivar. Nature Genetics, 2022; DOI:
10.1038/s41588-022-01015-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220303112155.htm

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