Pears, as one of the oldest domesticated fruit trees, have undergone extensive genetic alterations to adapt to varying climatic conditions. While previous studies have identified deleterious mutations in annual crops, their patterns in perennial fruit trees, such as pears, are less understood. The study of genetic variations, including deleterious mutations, is crucial for improving the breeding and selection processes of pears. This research explores the genetic diversity and mutation patterns across different pear species, aiming to improve our understanding of their domestication and provide a framework for breeding more resilient and high-quality pear varieties. Based on these challenges, further research is necessary to uncover the genetic underpinnings of these mutations.
A research team from Shandong Agricultural University and Nanjing Agricultural University, in collaboration with the Zhongshan Biological Breeding Laboratory, has published (DOI: 10.1093/hr/uhaf140) a significant study in Horticulture Research (May 2025). By analyzing over 9 million SNPs across 232 pear accessions, the team uncovered the genetic impact of domestication on deleterious mutations in pears. Their findings have important implications for future pear breeding, revealing the mechanisms behind key traits like stone cell content and lignin biosynthesis.
The study employed genome-wide resequencing of 232 pear accessions, including major wild and cultivated varieties, to analyze the distribution and impact of deleterious mutations in the pear genome. A total of 9,909,773 SNPs were identified, with 139,335 being deleterious mutations. These mutations were concentrated in coding regions, with a higher frequency in Pyrus communis, the European pear, compared to other species. The research highlighted the selective sweep regions where domestication reduced deleterious mutations in P. pyrifolia and P. bretschneideri, while in P. communis, there was an increase in such mutations, likely due to genetic drift during domestication. Furthermore, the study revealed the key role of the PyMYC2 gene, linked to stone cell formation in pears. Overexpression of PyMYC2 in pear callus cultures increased lignin and stone cell content, marking it as a critical gene for breeding efforts aimed at improving pear texture. These insights contribute to understanding the genetic evolution of pears and offer new strategies for breeding high-quality, resilient fruit varieties.
According to Professor Jun Wu from Nanjing Agricultural University, "This research provides valuable genomic insights into pear domestication, particularly in understanding how deleterious mutations shape agronomic traits. The identification of PyMYC2 as a regulator of stone cell content is a breakthrough that could significantly inform future breeding strategies. Our findings not only enhance our understanding of pear genetics but also pave the way for improved pear varieties with better quality and adaptability to changing environmental conditions."
The discovery of deleterious mutations and their association with agronomic traits in pears offers important implications for breeding programs. By targeting genes like PyMYC2, breeders can develop new pear varieties with optimized traits, such as improved texture and disease resistance. The findings also suggest that modern molecular breeding techniques, including genome-wide selection, can help reduce the accumulation of harmful mutations in cultivated varieties, leading to healthier and more productive pear crops. These insights are crucial for meeting the growing global demand for high-quality pears and improving crop resilience in the face of climate change.
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References
DOI
10.1093/hr/uhaf140
Original Source URL
https://doi.org/10.1093/hr/uhaf140
Funding information
This work was supported by the National Science Foundation of China (nos 32230097 and 32172531), the National Key Research and Development Program of China (no. 2022YFD1200503), the Earmarked Fund for China Agriculture Research System (CARS-28), the Earmarked Fund for Jiangsu Agricultural Industry Technology System JATS [2023] 412, and the Natural Science Foundation of Jiangsu Province for Young Scholar (no. BK20221010).
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.