Chandra Saket, Kazmi Andaleeb Z, Ahmed Zainab, Roychowdhury Gargi, Kumari Veena, Kumar Manish, Mukhopadhyay Kunal
Department of Bio-Engineering, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India.
Plant Cell Rep. 2017 Jul;36(7):1097-1112. doi: 10.1007/s00299-017-2141-0. Epub 2017 Apr 11.
NB-ARC domain-containing resistance genes from the wheat genome were identified, characterized and localized on chromosome arms that displayed differential yet positive response during incompatible and compatible leaf rust interactions. Wheat (Triticum aestivum L.) is an important cereal crop; however, its production is affected severely by numerous diseases including rusts. An efficient, cost-effective and ecologically viable approach to control pathogens is through host resistance. In wheat, high numbers of resistance loci are present but only few have been identified and cloned. A comprehensive analysis of the NB-ARC-containing genes in complete wheat genome was accomplished in this study. Complete NB-ARC encoding genes were mined from the Ensembl Plants database to predict 604 NB-ARC containing sequences using the HMM approach. Genome-wide analysis of orthologous clusters in the NB-ARC-containing sequences of wheat and other members of the Poaceae family revealed maximum homology with Oryza sativa indica and Brachypodium distachyon. The identification of overlap between orthologous clusters enabled the elucidation of the function and evolution of resistance proteins. The distributions of the NB-ARC domain-containing sequences were found to be balanced among the three wheat sub-genomes. Wheat chromosome arms 4AL and 7BL had the most NB-ARC domain-containing contigs. The spatio-temporal expression profiling studies exemplified the positive role of these genes in resistant and susceptible wheat plants during incompatible and compatible interaction in response to the leaf rust pathogen Puccinia triticina. Two NB-ARC domain-containing sequences were modelled in silico, cloned and sequenced to analyze their fine structures. The data obtained in this study will augment isolation, characterization and application NB-ARC resistance genes in marker-assisted selection based breeding programs for improving rust resistance in wheat.
从小麦基因组中鉴定、表征了含NB-ARC结构域的抗性基因，并将其定位在染色体臂上，这些染色体臂在不亲和及亲和的叶锈菌互作过程中表现出不同但呈阳性的反应。小麦（Triticum aestivum L.）是一种重要的谷类作物；然而，其产量受到包括锈病在内的多种病害的严重影响。一种有效、经济且生态可行的控制病原体的方法是通过寄主抗性。在小麦中，存在大量的抗性位点，但只有少数已被鉴定和克隆。本研究完成了对完整小麦基因组中含NB-ARC基因的全面分析。利用隐马尔可夫模型（HMM）方法从Ensembl Plants数据库中挖掘完整的NB-ARC编码基因，以预测604个含NB-ARC的序列。对小麦和禾本科其他成员含NB-ARC序列中的直系同源簇进行全基因组分析，发现与籼稻和二穗短柄草的同源性最高。直系同源簇之间重叠区域的鉴定有助于阐明抗性蛋白的功能和进化。发现含NB-ARC结构域的序列在小麦的三个亚基因组中分布均衡。小麦染色体臂4AL和7BL含有最多的含NB-ARC结构域的重叠群。时空表达谱研究例证了这些基因在小麦对叶锈菌病原菌Puccinia triticina的不亲和及亲和互作过程中，在抗性和感病小麦植株中的积极作用。对两个含NB-ARC结构域的序列进行了计算机模拟建模、克隆和测序，以分析其精细结构。本研究获得的数据将有助于在基于标记辅助选择的育种计划中分离、表征和应用NB-ARC抗性基因，以提高小麦的抗锈性。
