Identification and Fine Mapping of rhm1 Locus for Resistance to Southern Corn Leaf Blight in Maize

Authors

  • Yuanzeng Zhao,

    1. State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
    2. Department of Life Science and Technology, Henan Institute of Science and Technology, Xinxiang 453003, China
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    • These two authors contributed equally to this study.

  • Xiaomin Lu,

    1. State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
    2. Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
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    • These two authors contributed equally to this study.

  • Chaoxian Liu,

    1. State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
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  • Haiying Guan,

    1. State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
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  • Mei Zhang,

    1. State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
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  • Zhongfeng Li,

    1. State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
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  • Hongwei Cai,

    Corresponding author
    1. State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
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  • Jinsheng Lai

    Corresponding author
    1. State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
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Tel: +86 10 6273 1405; Fax: +86 10 6273 1416; E-mail: caihw@cau.edu.cn; jlai@cau.edu.cn

Abstract

rhm1 is a major recessive disease resistance locus for Southern corn leaf blight (SCLB). To further narrow down its genetic position, F2 population and BC1F1 population derived from the cross between resistant (H95rhm) and susceptible parents (H95) of maize (Zea mays) were constructed. Using newly developed markers, rhm1 was initially delimited within an interval of 2.5 Mb, and then finally mapped to a 8.56 kb interval between InDel marker IDP961–503 and simple sequence repeat (SSR) marker A194149–1. Three polymorphic markers IDP961–504, IDP B2–3 and A194149–2 were shown to be co-segregated with the rhm1 locus. Sequence analysis of the 8.56 kb DNA fragment revealed that it contained only one putative gene with a predicted amino acid sequence identical to lysine histidine transporter 1 (LHT1). Comparative sequence analysis indicated that the LHT1 in H95rhm harbors a 354 bp insertion in its third exon as compared with that of susceptible alleles in B73, H95 and Mo17. The 354 bp insertion resulted in a truncation of the predicted protein of candidate resistance allele (LHT1-H95rhm). Our results strongly suggest LHT1 as the candidate gene for rhm1 against SCLB. The tightly linked molecular markers developed in this study can be directly used for molecular breeding of resistance to Southern corn leaf blight in maize.

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