Bai Jianfa, Pennill Lourdes A, Ning Jianchang, Lee Se Weon, Ramalingam Jegadeesan, Webb Craig A, Zhao Bingyu, Sun Qing, Nelson James C, Leach Jan E, Hulbert Scot H
Department of Plant Pathology, Kansas State University, Manhattan, Kansas 66506-5502, USA.
Genome Res. 2002 Dec;12(12):1871-84. doi: 10.1101/gr.454902.
The diversity of the largest group of plant disease resistance genes, the nucleotide binding site-leucine-rich repeat (NBS-LRR) genes, was examined in cereals following polymerase chain reaction (PCR) cloning and database mining. NBS-LRR genes in rice are a large and diverse class with more than 600 genes, at least three to four times the complement of Arabidopsis. Most occur in small families containing one or a few cross-hybridizing members. Unlike in Arabidopsis and other dicots, the class of NBS-LRR genes coding for a Toll and mammalian interleukin-1 receptor (TIR) domain were not amplified during the evolution of the cereals. Genes coding for TIR domains are present in the rice genome, but have diverged from the NBS-LRR genes. Most cereal genes are similar in structure to the members of the non-TIR class of dicots, although many do not code for a coiled-coil domain in their amino termini. One unique class of cereal genes, with ~50 members, codes for proteins similar to the N-termini and NBS domains of resistance genes but does not code for LRR domains. The resistance gene repertoire of grasses has changed from that of dicots in their independent evolution since the two groups diverged. It is not clear whether this reflects a difference in downstream defense signaling pathways.
在通过聚合酶链反应（PCR）克隆和数据库挖掘研究谷物后，对最大的一组植物抗病基因——核苷酸结合位点富含亮氨酸重复序列（NBS-LRR）基因的多样性进行了检测。水稻中的NBS-LRR基因是一个庞大且多样的类别，有600多个基因，至少是拟南芥中此类基因数量的三到四倍。大多数NBS-LRR基因存在于包含一个或几个可交叉杂交成员的小家族中。与拟南芥和其他双子叶植物不同，编码Toll和哺乳动物白细胞介素-1受体（TIR）结构域的NBS-LRR基因类别在谷物进化过程中未被扩增。编码TIR结构域的基因存在于水稻基因组中，但已与NBS-LRR基因发生分化。大多数谷物基因在结构上与双子叶植物非TIR类别的成员相似，尽管许多基因在其氨基末端不编码卷曲螺旋结构域。一类独特的谷物基因，约有50个成员，编码的蛋白质与抗病基因的N末端和NBS结构域相似，但不编码LRR结构域。自双子叶植物和禾本科植物分化以来，它们在独立进化过程中，禾本科植物的抗病基因库已与双子叶植物不同。目前尚不清楚这是否反映了下游防御信号通路的差异。
