title: Evaluation of Resistance to Phytophthora sojae in Soybean Mini Core Collections Using an Improved Assay System.
abstract: Stem and root rot disease caused by Phytophthora sojae is devastating to soybean crops worldwide. Developing host resistance to P. sojae, considered the most effective and stable means to control this disease, is partly hampered by limited germplasm resources. In this study, we first modified conventional methods for a P. sojae resistance assay to a simpler and more cost-effective version, in which the P. sojae inoculum was mixed into the soil and the resistance was evaluated by survival rate (%) of soybean seedlings. This rating had significant correlations (P < 0.01) with the reduction in root fresh weight and the visual root rot severity. Applying this method to evaluate P. sojae resistance in soybean mini core collections comprising either 79 accessions originating from Japan (JMC) or 80 accessions collected around the world (WMC) revealed a wide variation in resistance among the individual varieties. In total, 38 accessions from the JMC and 41 from the WMC exhibited resistance or moderate resistance to P. sojae isolate N1 (with virulence to Rps1b, 3c, 4, 5, and 6), with ≥50% survival. Of these, 26 from the JMC and 29 from the WMC showed at least moderate resistance to P. sojae isolate HR1 (vir Rps1a-c, 1k, 2, 3a-c, 4-6, and 8). Additionally, 24 WCS accessions, in contrast to only 6 from the JMC, exhibited 100% survival after being challenged with both the N1 and HR1 isolates, suggesting a biogeographical difference between the two collections. We further verified two JMC varieties, Daizu and Amagi zairai 90D, for their resistance to an additional four P. sojae isolates (60 to 100% survival), which may provide new and valuable genetic sources for P. sojae resistance breeding in soybean.
authors: First, second, third, fourth, and seventh authors: Institute of Agrobiological Sciences, NARO, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602 Japan; fifth author: Hyogo Agricultural Institute for Agriculture, Forestry and Fisheries, 1533 Minamino-oka, Befu, Kasai, Hyogo 679-0198, Japan; and sixth author: Central Region Agricultural Research Center, NARO, Inada1-2-1, Jyoetsu, Niigata 943-0193, Japan.
authors: Chang-Jie
authors: CJ
authors: Jiang
authors: First, second, third, fourth, and seventh authors: Institute of Agrobiological Sciences, NARO, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602 Japan; fifth author: Hyogo Agricultural Institute for Agriculture, Forestry and Fisheries, 1533 Minamino-oka, Befu, Kasai, Hyogo 679-0198, Japan; and sixth author: Central Region Agricultural Research Center, NARO, Inada1-2-1, Jyoetsu, Niigata 943-0193, Japan.
authors: Shoji
authors: S
authors: Sugano
authors: First, second, third, fourth, and seventh authors: Institute of Agrobiological Sciences, NARO, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602 Japan; fifth author: Hyogo Agricultural Institute for Agriculture, Forestry and Fisheries, 1533 Minamino-oka, Befu, Kasai, Hyogo 679-0198, Japan; and sixth author: Central Region Agricultural Research Center, NARO, Inada1-2-1, Jyoetsu, Niigata 943-0193, Japan.
authors: Akito
authors: A
authors: Kaga
authors: First, second, third, fourth, and seventh authors: Institute of Agrobiological Sciences, NARO, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602 Japan; fifth author: Hyogo Agricultural Institute for Agriculture, Forestry and Fisheries, 1533 Minamino-oka, Befu, Kasai, Hyogo 679-0198, Japan; and sixth author: Central Region Agricultural Research Center, NARO, Inada1-2-1, Jyoetsu, Niigata 943-0193, Japan.
authors: Sung Shin
authors: SS
authors: Lee
authors: First, second, third, fourth, and seventh authors: Institute of Agrobiological Sciences, NARO, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602 Japan; fifth author: Hyogo Agricultural Institute for Agriculture, Forestry and Fisheries, 1533 Minamino-oka, Befu, Kasai, Hyogo 679-0198, Japan; and sixth author: Central Region Agricultural Research Center, NARO, Inada1-2-1, Jyoetsu, Niigata 943-0193, Japan.
authors: Takuma
authors: T
authors: Sugimoto
authors: First, second, third, fourth, and seventh authors: Institute of Agrobiological Sciences, NARO, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602 Japan; fifth author: Hyogo Agricultural Institute for Agriculture, Forestry and Fisheries, 1533 Minamino-oka, Befu, Kasai, Hyogo 679-0198, Japan; and sixth author: Central Region Agricultural Research Center, NARO, Inada1-2-1, Jyoetsu, Niigata 943-0193, Japan.
authors: Mami
authors: M
authors: Takahashi
authors: First, second, third, fourth, and seventh authors: Institute of Agrobiological Sciences, NARO, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602 Japan; fifth author: Hyogo Agricultural Institute for Agriculture, Forestry and Fisheries, 1533 Minamino-oka, Befu, Kasai, Hyogo 679-0198, Japan; and sixth author: Central Region Agricultural Research Center, NARO, Inada1-2-1, Jyoetsu, Niigata 943-0193, Japan.
authors: Masao
authors: M
authors: Ishimoto
mesh_terms: D001947:Breeding; D007564:Japan; D010838:Phytophthora / Q000469:parasitology / Q000502:physiology*; D010935:Plant Diseases / Q000276:immunology* / Q000469:parasitology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000276:immunology / Q000469:parasitology; D018547:Plant Stems / Q000235:genetics / Q000276:immunology / Q000469:parasitology; D036226:Seedlings / Q000235:genetics / Q000276:immunology / Q000469:parasitology; D013025:Glycine max / Q000235:genetics / Q000276:immunology* / Q000469:parasitology; D014774:Virulence
chemical_list: D010940:Plant Proteins