Construction of genetic linkage map and identification of a novel major locus for resistance to pine wood nematode in Japanese black pine (Pinus thunbergii)

Tomonori Hirao; Koji Matsunaga; Hideki Hirakawa; Kenta Shirasawa; Keiya Isoda; Kentaro Mishima; Miho Tamura; Atsushi Watanabe

doi:10.1186/s12870-019-2045-y

Construction of genetic linkage map and identification of a novel major locus for resistance to pine wood nematode in Japanese black pine (Pinus thunbergii)

BMC Plant Biol. 2019 Oct 15;19(1):424. doi: 10.1186/s12870-019-2045-y.

Authors

Tomonori Hirao¹, Koji Matsunaga², Hideki Hirakawa³, Kenta Shirasawa³, Keiya Isoda⁴, Kentaro Mishima⁴, Miho Tamura⁵, Atsushi Watanabe⁶

Affiliations

¹ Forest Bio-research Center, Forestry and Forest Products Research Institute, 3809-1 Ishi, Juo, Hitachi, Ibaraki, 319-1301, Japan. hiratomo@affrc.go.jp.
² Kyushu Regional Breeding Office, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, 2320-5 Suya, Goshi, Kumamoto, 860-0081, Japan.
³ Department of Frontier Research, Kazusa DNA Research Institute, Chiba, 292-0818, Japan.
⁴ Forest Tree Breeding Center, Forestry and Forest Products Research Institute, 3809-1 Ishi, Juo, Hitachi, Ibaraki, 319-1301, Japan.
⁵ Department of Forest Environmental Sciences, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
⁶ Department of Forest Environmental Sciences, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan. nabeatsu@agr.kyushu-u.ac.jp.

Abstract

Background: Pine wilt disease (PWD), which is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus, is currently the greatest threat to pine forests in Europe and East Asian countries including Japan. Constructing a detailed linkage map of DNA markers and identifying PWD resistance genes/loci lead to improved resistance in Pinus thunbergii, as well as other Pinus species that are also susceptible to PWD.

Results: A total F₁ mapping population of 188 individuals derived from a cross between the PWD-resistant P. thunbergii varieties 'Tanabe 54' (resistant rank 2 to PWD) and 'Tosashimizu 63' (resistant rank 4 to PWD) was inoculated with PWN, and was evaluated for disease symptoms. To perform linkage analysis for PWN resistance, a set of three maps was constructed; two parental maps generated using the integrated two-way pseudo-testcross method, and a consensus map with population-type cross-pollination. The linkage map of 'Tanabe 54' consisted of 167 loci, and covered 14 linkage groups (LGs), with a total genetic distance of 1214.6 cM. The linkage map of 'Tosashimizu 63' consisted of 252 loci, and covered 14 LGs, with a total genetic distance of 1422.1 cM. The integrated consensus map comprised 12 LGs with the basic chromosome number of P. thunbergii, and a total genetic distance of 1403.6 cM. Results from quantitative trait loci (QTL) analysis using phenotype data and linkage maps indicated that PWN resistance is controlled by a single dominant allele, which was derived from the 'Tanabe 54' female parent. This major QTL was located on linkage group 3 and was designated PWD1 for PINE WILT DISEASE 1.

Conclusions: The PWD1 locus is a major resistance QTL located on the Pinus consensus LG03 that acts in a dominant manner to confer pine wood nematode resistance. Information from the present study will be useful for P. thunbergii breeding programs to improve resistance to PWD, and also to help identify susceptibility genes in Pinus species.

Keywords: Genetic linkage map; Pine wood disease; Pine wood nematode; Pinus thunbergii; Resistance.

MeSH terms

Animals
Chromosome Mapping
Genetic Linkage*
Pinus / genetics*
Pinus / parasitology
Plant Diseases / genetics*
Plant Diseases / parasitology
Tylenchida / physiology*