Identification and fine-mapping of a new resistance gene, Xa40, conferring resistance to bacterial blight races in rice (Oryza sativa L.)
Identification and fine-mapping of a new resistance gene, Xa40, conferring resistance to bacterial blight races in rice (Oryza sativa L.)
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DOI：
10.1007/s00122-015-2557-2
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发表时间：
2015-10-01
影响因子：
5.4
通讯作者：
Jena, Kshirod K.
中科院分区：
文献类型：
--
作者：
Kim, Suk-Man;Suh, Jung-Pil;Jena, Kshirod K.
一个新的白叶枯病抗性基因已被确定，通过精细定位，赋予高水平的抗性，所有韩国黄单胞菌pv。水稻白叶枯病（BB）是由黄单胞菌白叶枯病致病变种（Xanthomonaspv.）Xoo是亚洲和非洲水稻生产的严重制约因素。以籼稻IR 65482 -7-216-1-2为母本，以Junam为父本，通过回交选育出的粳稻高代回交育种系，对韩国BB小种（包括K3 a）均表现抗性。为了鉴定参与对韩国Xoo小种的抗性的基因，在来自11325（IR 83261 -3-7-23-6-2-1-1-2-1-2）/Anmi和11325/Ilpum之间的杂交的两个F-2群体中检查基因型和表型变异的关联。11325/Anmi和11325/Ilpum组合F-2的分离比分别为578：209和555：241，与3：1的等位基因频率一致。利用作图法进行的遗传分析表明，抗性（R）受一个新的抗性基因控制，该基因与第11号染色体上28.14和28.22 Mbp之间的约80 kb区域内的侧翼标记RM 27320和ID55.WA18-5连锁。功能预测的8个候选基因包含在目标区域中。通过RT-PCR分析的候选基因的检查仅证实了在存在或不存在病原体感染的情况下WAK 3基因的转录水平的显著差异。用其他已知的BB R基因进行的等位性测试显示，该等位基因与具有相似染色体位置的其他等位基因不同。
A new bacterial blight resistance gene has been identified through fine-mapping, which confers high levels of resistance to all Korean Xanthomonas oryzae pv. oryzae ( Xoo ) races, including the new Xoo race K3a.Rice bacterial leaf blight (BB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is a serious constraint to rice production in Asia and Africa. The japonica advanced backcross breeding lines derived from the indica line IR65482-7-216-1-2 in the background of cultivar Junam are resistant to all Korean BB races, including K3a. To identify the gene(s) involved in resistance to Korean Xoo races, the association of genotypic and phenotypic variations was examined in two F-2 populations derived from the crosses between 11325 (IR83261-3-7-23-6-2-1-1-2-1-2)/Anmi and 11325/Ilpum. The segregation ratios of F-2 individuals from the crosses of 11325/Anmi and 11325/Ilpum were 578 resistant:209 susceptible and 555 resistant:241 susceptible, respectively, which is consistent with the expected allelic frequency of a 3:1 ratio. Genetic analysis using graphical mapping indicated that resistance (R) was controlled by a new resistance gene linked with the flanking markers RM27320 and ID55.WA18-5 within an approximately 80-kb region between 28.14 and 28.22 Mbp on chromosome 11. The eight candidate genes functionally predicted were included in the target region. Examination of the candidate genes by RT-PCR analysis only corroborated with the significant difference in transcript levels of the WAK3 gene in the presence or absence of pathogen infection. Allelism tests performed with other known BB R-genes revealed that the allele was distinct from others having a similar chromosomal location.