Identification of a novel major locus for gray leaf spot resistance in Italian ryegrass (Lolium multiflorumLam.)

BMC Plant Biology

Research Article

Tadashi Takamizo¹  Wataru Takahashi¹  Tohru Sasaki²  Yuichi Miura³ 

[1] Forage Crop Research Division, NARO Institute of Livestock and Grassland Science, 768 Senbonmatsu, 329-2793, Nasushiobara, Tochigi, Japan;Forage Crop Research Institute, Japan Grassland Agriculture and Forage Seed Association, 388-5 Higashiakada, 329-2742, Nasushiobara, Tochigi, Japan;Hokkaido Branch, Japan Grassland Agriculture and Forage Seed Association, 406 Higashi-Nopporo, 069-0822, Ebetsu, Hokkaido, Japan;Kyushu Experiment Station, Japan Grassland Agriculture and Forage Seed Association, 1740 Takaba, 861-1114, Koshi, Kumamoto, Japan;Snow Brand Seed Co., Ltd, Hokkaido Research Station, 1066 Horonai, Naganuma-cho, 069-1464, Yubari-gun, Hokkaido, Japan;

关键词: Blast;    Comparative genomics;    Expressed sequence tag;    Lolium multiflorum;    Magnaporthe oryzae;    Single-strand conformation polymorphism;   

DOI  :  10.1186/s12870-014-0303-6

 received in 2014-05-07, accepted in 2014-10-23,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundGray leaf spot (GLS), caused by Magnaporthe oryzae (anamorph Pyricularia oryzae), in ryegrasses is a very serious problem. Heavily infected small seedlings die within a matter of days, and stands of the grasses are seriously damaged by the disease. Thus, the development of GLS-resistant cultivars has become a concern in ryegrass breeding.ResultsPhenotypic segregations in a single cross-derived F1 population of Italian ryegrass (Lolium multiflorum Lam.) indicated that the GLS resistance in the population was possibly controlled by one or two dominant genes with 66.5-77.9% of broad-sense heritability. In bulked segregant analyses, two simple sequence repeat (SSR) markers, which have so far been reported to locate on linkage group (LG) 3 of Italian ryegrass, showed specific signals in the resistant parent and resistant bulk, indicating that the resistance gene locus was possibly in the LG 3. We thus constructed a genetic linkage map of the LG 3 covering 133.6 centimorgan with other SSR markers of the LG 3 of Italian ryegrass and grass anchor probes that have previously been assigned to LG 3 of ryegrasses, and with rice expressed sequence tag (EST)-derived markers selected from a rice EST map of chromosome (Chr) 1 since LG 3 of ryegrasses are syntenic to rice Chr 1. Quantitative trait locus (QTL) analysis with the genetic linkage map and phenotypic data of the F1 population detected a major locus for GLS resistance. Proportions of phenotypic variance explained by the QTL at the highest logarithm of odds scores were 61.0-69.5%.ConclusionsA resistance locus was confirmed as novel for GLS resistance, because its genetic position was different from other known loci for GLS resistance. Broad-sense heritability and the proportion of phenotypic variance explained by the QTL were similar, suggesting that most of the genetic factors for the resistance phenotype against GLS in the F1 population can be explained by a function of the single resistance locus. We designated the putative gene for the novel resistance locus as LmPi2. LmPi2 will be useful for future development of GLS-resistant cultivars in combination with other resistance genes.

【 授权许可】

CC BY   
© Takahashi et al.; licensee BioMed Central Ltd. 2014