Scientists highlight recent advances, new prospects, and a roadmap for the future in pear genetics

The release of the pear genome sequence has greatly aided in the identification of genes and markers associated with important economic traits. With the availability of new genomic tools and genetic approaches, a wide variety of valuable technologies and resources have been successfully developed in pear, including genetic transformation, genome sequencing, molecular markers, genetic and physical mapping, and comparative genomic analyses. Furthermore, the availability of tools and data resources offers new opportunities for the efficient and robust discovery of genes that control desirable traits related to fruit quality, productivity, and postharvest storage life, as well as traits that markedly shorten the pear breeding cycle.

Recent work by scientists from Nanjing Agricultural University in China and other teams, published in Horticulture Research on Jan. 5, highlights the key advances in pear genetics, genomics, and breeding driven by the availability of whole-genome sequences, including whole-genome resequencing efforts and studies of pear domestication and evolution.

First, the researchers provided an overview of the genome sequences of Asian and European pears, which have a basic chromosome number of 17 (2n = 34). Different pear species have distinctly different genome sizes, ranging from 500 to 650 Mb, and possess large numbers of repeats and transposable elements (TEs), as well as high levels of heterozygosity. The team reviewed pear domestication and improvement, genome-wide variation, and genetic linkage maps, including the construction and mapping of trait-linked loci. As genome-wide association studies (GWAS) are an effective approach for exploring genome-level genetic architecture and have been widely used to identify genetic variants associated with human-related diseases, GWAS in pear were also discussed. Marker-assisted selection (MAS), marker-assisted breeding (MAB), genomic selection (GS), and the use of multi-omics to identify genes related to important traits in pear were highlighted. Finally, the researchers pointed out that some specific topics should be given priority in future research; these include genome development, resequencing and phylogenetic studies, whole-genome association studies, integrated omics technologies, and gene editing.

“This roadmap for the pear genome will serve as a useful guide for pursuing genetic improvement efforts toward developing new high-quality and well-adapted pear cultivars,” said the researchers. “And it is also critical for addressing issues of the pear response to climate change, as well as of ever-changing consumer demands and preferences.”

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Reference

Authors

Jiaming Li 1, Mingyue Zhang 2, Xiaolong Li 1, Awais Khan 3, Satish Kumar 4, Andrew Charles Allan 5, Kui Lin-Wang 5, Richard Victor Espley 5, Caihong Wang 6, Runze Wang 1, Cheng Xue 2, Gaifang Yao 7, Mengfan Qin 1, Manyi Sun 1, Richard Tegtmeier 3, Hainan Liu 1, Weilin Wei 1, Meiling Ming 1, Shaoling Zhang 1, Kejiao Zhao 1, Bobo Song 1, Jiangping Ni 1, Jianping An 2, Schuyler S. Korban 8 and Jun Wu 1

Affiliations

1 Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China

2 State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China

3 Plant Pathology & Plant-Microbe Biology Section, Cornell University, Geneva, NY 14456, USA

4 Hawke’s Bay Research Centre, The New Zealand Institute for Plant and Food Research Limited, Havelock North 4157, New Zealand

5 The New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand

6 College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China

7 School of Food and Biological Engineering, Hefei University of Technology, 230009 Hefei, China

8 Department of Natural Resources & Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA

About Dr. Jun Wu and Dr. Schuyler S. Korban

Dr. Jun Wu is a professor in the State Key Laboratory of Crop Genetics and Germplasm Enhancement at Nanjing Agricultural University. She studies the mining and utilization of elite genetic resources in pear. She is also interested in genomics and genetic variation, molecular breeding technology, and germplasm innovation, in pear.

Dr. Schuyler S. Korban is a professor in the Department of Natural Resources & Environmental Sciences at University of Illinois at Urbana-Champaign. His research interests include adding novel, high-value traits to plants for biopharmaceuticals; improving food quality and the safety of food and food products by reducing chemical sprays; improving the composition of healthy components in various food crops; and exploring the use of plants for pollutant removal from soils.