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A team of researchers has successfully decoded the genomes of historic potato varieties and leveraged this knowledge to formulate an efficient method for analyzing numerous additional potato genomes.
Potatoes, a key food source for more than 1.3 billion people worldwide, play a vital role in global food security. However, advances in potato breeding have been relatively limited, with many of the prominent cultivars developed several decades ago. This stagnation can be attributed to the potato’s intricate genome, which is characterized by having four genome copies per cell, a complexity that complicates traditional hybridization techniques. Led by Professor Korbinian Schneeberger, who heads the Genome Plasticity and Computational Genetics research group at LMU and the Max Planck Institute for Plant Breeding Research, the research team has achieved a significant milestone in this area. Their findings, published in the journal Nature, detail the reconstruction of the genomes of ten historic potato cultivars. This foundational work has paved the way for a more rapid and simplified method to reconstruct additional potato genomes.
In partnership with experts from Wageningen University, the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) in Groß Lüsewitz, and Xi’an Jiaotong University in China, the research team focused on historical potato varieties, some of which date back to the 18th century. Professor Schneeberger highlighted the intention behind this selection, stating that understanding the genetic diversity of these early cultivars could reveal insights into the genetic potential of contemporary potatoes. The findings indicated a concerning reality: the genetic diversity of potatoes is alarmingly scarce. The examined ten varieties encompass approximately 85 percent of the genetic variability found in all modern European potato cultivars.
Genetic Bottleneck After Introduction from South America
The study results suggest significant genetic bottleneck effects stemming from the introduction of potatoes from South America starting in the 16th century. A limited number of potato varieties were brought over, many of which struggled to adapt to European agricultural conditions. This already restricted gene pool was further diminished by agricultural diseases, notably the potato late blight epidemic in the 1840s, which led to devastating crop failures and severe famines, particularly in Ireland and across Europe.
A surprising discovery made during the research was the extensive genetic differences observed between individual chromosome copies of the potatoes. “While the overall gene pool is limited, the chromosomes that do exist exhibit remarkable divergence, exceeding anything documented in domesticated plants before,” Schneeberger noted. The degree of variation is about twenty times greater than genetic differences seen in humans. These variations likely occurred before potatoes made their way to Europe, stemming from domestication practices of indigenous peoples in South America, who began cultivating potatoes approximately 10,000 years ago, likely leading to hybridization with wild species.
To advance potato genome analysis, the researchers introduced an innovative method that enables the examination of the roughly 2,000 potato varieties registered with the European Union. Instead of the traditional, labor-intensive genome reconstruction process, this new approach allows for comparing easily obtainable data with existing genome sequences to identify which known chromosome variations are present in a particular cultivar. This method was successfully tested on the Russet Burbank cultivar, a variety that has been prevalent since 1908 and remains a standard choice for French fries today. “Understanding genome sequences is crucial to modern plant breeding practices, encompassing everything from conventional techniques to cutting-edge genome engineering methods,” emphasized Schneeberger. “This knowledge will be indispensable for future endeavors in potato breeding.”
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