Gene discovery in potatoes: A step forward in improving yield and sugar content

Potatoes are one of the world's most important food crops, yet genetic improvements to increase tuber yield and quality have been constrained by the lack of a high-quality reference genome. Recent research provides a breakthrough by assembling a chromosome-scale haplotype-resolved genome for the tetraploid potato variety Ningshu 15, which is known for its high starch content and drought resistance. This genome has enabled the identification of 53 loci related to sugar content and tuber yield, with a key focus on the StTST2 gene, which directly affects glucose levels and biomass production. This discovery offers new prospects for molecular breeding in potatoes.

Despite the significant importance of potatoes, breeding for enhanced yield and sugar content has been hindered by challenges such as complex genetic inheritance and the lack of a high-quality reference genome. Although several potato genomes have been sequenced in recent years, comprehensive understanding of the genetic factors behind crucial agricultural traits remained limited. Based on these challenges, there is a pressing need for in-depth genomic research to identify genes regulating sugar metabolism and tuber yield in potatoes.

In a new study published (DOI: 10.1093/hr/uhaf075) in Horticulture Research, researchers from Nanjing Agricultural University and other institutions present the first chromosome-scale genome assembly of the tetraploid potato variety Ningshu 15. This reference genome not only advances our understanding of potato genetics but also uncovers the role of the StTST2 gene in regulating sugar content and enhancing yield. The findings provide essential insights for future potato breeding programs aimed at improving crop productivity and quality.

The assembled genome of Ningshu 15 spans 1.653 Gb, with high-quality assemblies of two haplotypes. The team performed a genome-wide association study (GWAS) on 141 potato accessions to identify loci associated with sugar content and yield. The most significant discovery was the identification of the StTST2 gene, which encodes a tonoplast sugar transporter. Overexpression of StTST2 in potato and Arabidopsis plants led to a marked increase in sugar content and tuber yield. The gene also enhanced photosynthetic efficiency and chlorophyll content, which further boosted plant growth and biomass. These findings suggest that StTST2 plays a crucial role in regulating sugar metabolism and could be a valuable target for genetic improvement in potatoes.

“This genome assembly represents a significant step forward in potato genomics,” said Dr. Hongxia Zhang, one of the leading researchers. “The identification of the StTST2 gene not only provides insights into sugar regulation but also opens up new avenues for breeding more productive and resilient potato varieties. This work will pave the way for the development of high-yield potato cultivars with improved quality.”

The discovery of StTST2 as a regulator of sugar content and tuber yield has profound implications for potato breeding. By targeting this gene, breeders could develop potato varieties with enhanced sugar content and higher yield, improving both nutritional quality and agricultural productivity. This research also underscores the potential of genome-wide association studies in identifying key traits in crops, making it a valuable resource for the broader agricultural community. The newly assembled genome of Ningshu 15 will serve as a critical tool for future research and breeding programs aimed at addressing global food security challenges.

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References

DOI

10.1093/hr/uhaf075

Original Source URL

https://doi.org/10.1093/hr/uhaf075

Funding information

This work has been jointly supported by the following grants: the National Natural Science Foundation of China (32260504, 32070344, 32071733, 32371915), the Innovation Foundation of NingXia Academy of Agriculture and Forestry Sciences (NKYG-24–14) and the Mega Crop Breeding Project of Ningxia District-Engineering of New Potato Cultivars.

About Horticulture Research

Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.