Discovering Potato Genes Linked to Boosted Pollen Production

Jenn Hoskins
14th March, 2024

Discovering Potato Genes Linked to Boosted Pollen Production

Image Source: Natural Science News, 2024

Key Findings

  • Researchers found key genetic areas affecting pollen production in potatoes
  • These areas include two major and two minor genetic regions linked to pollen traits
  • The discovery aids breeding by allowing selection of potatoes with desired genetics
Potatoes are a staple food for billions of people worldwide. However, breeding new varieties of potatoes that are both productive and resistant to diseases is a complex task, particularly because the commercial potato plants we eat are typically tetraploids—meaning they have four sets of chromosomes. This genetic complexity makes traditional breeding methods challenging. A promising approach to simplify potato breeding is the use of diploid potatoes, which have only two sets of chromosomes, much like humans. Diploid potatoes can be bred using true seeds rather than tubers, potentially streamlining the breeding process and enabling the development of new varieties with desirable traits more quickly[2]. Researchers at Wageningen University and Research have made a significant discovery that could aid in bridging the genetic gap between diploid and tetraploid potatoes. In their study[1], they investigated the genetic basis of the production of unreduced gametes—sex cells that contain a full set of chromosomes instead of the half-set typically found in gametes. This phenomenon is crucial for the process of sexual polyploidization, where diploid and tetraploid potatoes can cross-breed, allowing for the transfer of beneficial traits between them. The study identified multiple quantitative trait loci (QTLs), which are sections of the genome that correlate with particular traits—in this case, the production of unreduced pollen. Early research suggested that the ability to produce unreduced gametes was controlled by a single gene[3], but the Wageningen team discovered that it is far more complex. They found two minor-effect and three major-effect QTLs that regulate this trait. Notably, two of these QTLs had a large impact and were associated with genes similar to AtJAS, a gene in the model plant Arabidopsis thaliana known for regulating the orientation of cells during meiosis II, a key stage in gamete formation. The study's findings are consistent with previous research showing that the potato genome is highly diverse and contains a wealth of genetic variation[4]. The potato's complex tetraploid genome includes numerous structural variations and mutations which can hinder breeding efforts. The discovery of the QTLs related to unreduced pollen production offers a new tool to navigate this genetic complexity. The alleles, or different forms of a gene, linked with increased levels of unreduced pollen had mutations that were considered deleterious, meaning they could potentially disrupt the normal function of the proteins they encode. One had a transposon, a type of genetic element, inserted within it, leading to a premature stop in the reading of the genetic code. The other had a mutation in a critical region of the protein that is normally conserved across different species, indicating its importance. The identification of these QTLs and the associated mutant alleles is a breakthrough because it allows for marker-assisted selection—a technique where breeders can select plants with desirable genetic traits based on markers rather than waiting for the physical traits to be expressed. This could significantly speed up the breeding process and help in the development of new potato varieties that can be produced from seeds, are more genetically uniform, and could potentially exhibit better disease resistance and higher nutritional value[2]. Moreover, the discovery of these QTLs fits into a larger body of work aimed at understanding the potato genome and its evolution. For instance, the expansion of disease-resistance genes in potatoes, likely a result of their tuber-based propagation, has been previously noted[2]. The findings from Wageningen contribute to this understanding by revealing how the orientation of meiotic spindles—a part of the cell that helps in the distribution of chromosomes during cell division—can influence the production of unreduced gametes and thus the genetic makeup of future generations of potatoes. This research provides valuable insights that could be used to improve the breeding of inbred lines and avoid potential linkage drag, where undesirable traits are passed along with desirable ones due to their close proximity within the genome[2]. By understanding the genetic mechanisms behind unreduced pollen production, breeders can more effectively combine the genetic material of diploid and tetraploid potatoes, leveraging the natural diversity of wild and cultivated potato species to enhance the crop's resilience and yield. In conclusion, the study from Wageningen University and Research sheds light on the genetic underpinnings of an important trait in potato breeding. By elucidating the complex genetic factors that control the production of unreduced gametes, this research paves the way for more efficient and precise breeding strategies, potentially revolutionizing how we develop new potato varieties for a growing world.

AgricultureGeneticsPlant Science

References

Main Study

1) Identification of two mutant JASON-RELATED genes associated with unreduced pollen production in potato.

Published 12th March, 2024

https://doi.org/10.1007/s00122-024-04563-7

Related Studies

2) Genome evolution and diversity of wild and cultivated potatoes.

https://doi.org/10.1038/s41586-022-04822-x

3) Gametes with the somatic chromosome number: mechanisms of their formation and role in the evolution of autopolyploid plants.

https://doi.org/10.1111/j.1469-8137.1995.tb03005.x

4) Phased, chromosome-scale genome assemblies of tetraploid potato reveal a complex genome, transcriptome, and predicted proteome landscape underpinning genetic diversity.

https://doi.org/10.1016/j.molp.2022.01.003


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