Symbiotic incompatibility between soybean and Bradyrhizobium arises from one amino acid determinant in soybean Rj2 protein
Symbiotic incompatibility between soybean and Bradyrhizobium arises from one amino acid determinant in soybean Rj2 protein
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DOI：
10.1371/journal.pone.0222469
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发表时间：
2019-09
期刊：
影响因子：
3.7
通讯作者：
Masayuki Sugawara;Y. Umehara;A. Kaga;M. Hayashi;M. Ishimoto;Shusei Sato;H. Mitsui;K. Minamisawa
中科院分区：
文献类型：
--
作者：
Masayuki Sugawara;Y. Umehara;A. Kaga;M. Hayashi;M. Ishimoto;Shusei Sato;H. Mitsui;K. Minamisawa
携带Rj 2等位基因的栽培大豆（Glycine max）通过由根瘤菌III型分泌蛋白NopP和宿主抗性蛋白Rj 2介导的宿主免疫来限制与特异性慢生根瘤菌菌株的结合。在这里，我们发现，单一的异亮氨酸残基I490在Rj 2是诱导共生不相容性所必需的。此外，我们调查了地理分布的Rj 2基因型大豆种质的单核苷酸多态性（SNP）基因分型，使用单核苷酸多态性标记I490。通过对日本大豆微核心种质中79份材料的等位基因比较，我们认为Rj 2中的单个氨基酸残基（R490至I490）的取代会诱导与Bradyrhizobium diazoefficiens USDA 122的共生不亲和性。I490的重要性通过编码含I490残基的Rj 2蛋白的显性等位基因与rj 2-大豆的互补来验证。Rj 2等位基因也存在于野生大豆中。max，其单氨基酸多态性与Rj 2表达表型相关。对1583份大豆材料进行SNP分型，发现5.4%的大豆材料存在Rj 2-基因型。max和G.大豆种质Rj 2基因型大豆植株的分布相对集中在温带亚洲地区。这些结果提供了重要的信息，宿主免疫介导的寄主基因型特异性共生不亲和性的机制，并建议在大豆驯化过程中的环境条件下，Rj 2基因一直保持。
Cultivated soybean (Glycine max) carrying the Rj2 allele restricts nodulation with specific Bradyrhizobium strains via host immunity, mediated by rhizobial type III secretory protein NopP and the host resistance protein Rj2. Here we found that the single isoleucine residue I490 in Rj2 is required for induction of symbiotic incompatibility. Furthermore, we investigated the geographical distribution of the Rj2-genotype soybean in a large set of germplasm by single nucleotide polymorphism (SNP) genotyping using a SNP marker for I490. By allelic comparison of 79 accessions in the Japanese soybean mini-core collection, we suggest substitution of a single amino acid residue (R490 to I490) in Rj2 induces symbiotic incompatibility with Bradyrhizobium diazoefficiens USDA 122. The importance of I490 was verified by complementation of rj2-soybean by the dominant allele encoding the Rj2 protein containing I490 residue. The Rj2 allele was also found in Glycine soja, the wild progenitor of G. max, and their single amino acid polymorphisms were associated with the Rj2-nodulation phenotype. By SNP genotyping against 1583 soybean accessions, we detected the Rj2-genotype in 5.4% of G. max and 7.7% of G. soja accessions. Distribution of the Rj2-genotype soybean plants was relatively concentrated in the temperate Asian region. These results provide important information about the mechanism of host genotype-specific symbiotic incompatibility mediated by host immunity and suggest that the Rj2 gene has been maintained by environmental conditions during the process of soybean domestication.