野生二粒小麦NBS-LRR类抗病基因家族的鉴定及其表达分析

野生二粒小麦(Triticum dicoccoides L,2n=4x=28,AABB)是普通小麦遗传改良的重要种质和基因库。抗病基因(resistance gene,R基因)是植物体内广泛存在的抗性基因,通常具有NBS(nucleotide-binding site)和LRR(leucine-rich-repeat)结构域,属于NBS-LRR家族,在植物抗病和免疫过程中具有重要作用。为挖掘和利用野生二粒小麦基因组中的R基因,基于最新发布的野生二粒小麦参考基因组数据,利用生物信息分析手段,在全基因组水平上对其NBS-LRR类R基因家族进行鉴定。结果共鉴定到429个可信度较高的NBS-LRR类R基因,其中N亚家族66个,CNL亚家族205个,NL亚家族76个,CN亚家族79个,PN亚家族3个;进一步对NL亚家族R基因进行分析,发现76个NL亚家族基因在所有染色体上均有分布,并且以成簇方式存在,包含20个保守域,且在N端高度保守;表达模式分析发现,它们在花、叶片和根中的表达量较高;最后,随机选择4个NL类R基因,发现在白粉菌诱导后均上调表达。本研究为进一步挖掘和利用野生二粒小麦NBS-LRR类抗病基因奠定了基础。

Identification and Expression Profile Analysis of NBS-LRR Gene Family in Wild Emmer Wheat(Triticum dicoccoides L.)

Wild emmer wheat(Triticum dicoccoides L.) has always been considered as an essential germplasm and gene resource for genetic improvement of the cultivated wheat.Resistance(r) gene is a group of disease resistance genes with the NBS and LRR conserved domains,which is widely found in plants,and plays an important role in plant disease resistance and immune response. In order to explore and utilize r genes in the wild emmer wheat,this study used the genome-search method based on the updated wild emmer wheat reference genome to identify its r gene family at the genome level. A total of 429 putative high confidence r genes were identified,of which 66 belong to N subfamily,205 belong to CNL subfamily,76 belong to NL subfamily,79 belong to CN subfamily and 3 belong to PN subfamily.Furthermore,we investigated the genomic distribution,phylogenetic relationship and expression profiles of NL subfamily. Results showed that NL subfamily members distribute in clusters on all of the 14 chromosomes. They contain 20 conserved domains and show high conserved domain compositions in N terminal. These gene were highly expressed in the flower,leaf and root. Finally,the expression of 4 randomly selected NBS-LR r genes under Blumeria graminis f. sp. tritici(Bgt) infection were investigated using qRT-PCR analysis and the results showed that their expression were induced by Bgt,suggesting that they might be involved in resistance to powdery mildew.This study laid the foundation for further research on the function of r genes in wild emmer wheat.