Brown planthopper (BPH) is a phloem sap-sucking insect pest of rice which causes severe yield loss. We cloned the BPH18 gene from the BPH-resistant introgression line derived from the wild rice species Oryza australiensis. Map-based cloning and complementation test revealed that the BPH18 encodes CC-NBS-NBS-LRR protein. BPH18 has two NBS domains, unlike the typical NBS-LRR proteins. The BPH18 promoter::GUS transgenic plants exhibited strong GUS expression in the vascular bundles of the leaf sheath, especially in phloem cells where the BPH attacks. The BPH18 proteins were widely localized to the endo-membranes in a cell, including the endoplasmic reticulum, Golgi apparatus, trans-Golgi network, and prevacuolar compartments, suggesting that BPH18 may recognize the BPH invasion at endo-membranes in phloem cells. Whole genome sequencing of the near-isogenic lines (NILs), NIL-BPH18 and NIL-BPH26, revealed that BPH18 located at the same locus of BPH26. However, these two genes have remarkable sequence differences and the independent NILs showed differential BPH resistance with different expression patterns of plant defense-related genes, indicating that BPH18 and BPH26 are functionally different alleles. These findings would facilitate elucidation of the molecular mechanism of BPH resistance and the identified novel alleles to fast track breeding BPH resistant rice cultivars.
褐飛虱（BPH）是一種吸取水稻韌皮部汁液的害蟲，它會(huì)引起嚴(yán)重減產(chǎn)。我們從來源于野生稻種澳洲野生稻的BPH抗性滲入基因系克隆了BPH18基因。圖位克隆和互補(bǔ)實(shí)驗(yàn)表明，BPH18編碼一個(gè)CC-NBS-NBS-LRR蛋白。BPH18具有兩個(gè)NBS結(jié)構(gòu)域，與典型NBS-LRR蛋白不同。BPH18啟動(dòng)子驅(qū)動(dòng)GUS的轉(zhuǎn)基因植株在葉鞘的維管束中表現(xiàn)出較強(qiáng)的GUS表達(dá)，特別是韌皮部細(xì)胞，這是BPH入侵的地方。BPH18蛋白廣泛定位在細(xì)胞的內(nèi)膜上，包括內(nèi)質(zhì)網(wǎng)、高爾基體、反面高爾基復(fù)合體和液泡前體，表明BPH18可能識(shí)別BPH在韌皮部細(xì)胞內(nèi)膜上的入侵。近等基因系（NILs）NIL-BPH18和NIL-BPH26的全基因測(cè)序表明，BPH18和BPH26位于相同位點(diǎn)。但是，這兩個(gè)基因具有顯著的序列差異，獨(dú)立的NILs表現(xiàn)出不同BPH抗性，同時(shí)植物防衛(wèi)相關(guān)基因具有不同表達(dá)模式，表明BPH18和BPH26是功能不同的等位基因。這些結(jié)果能夠加速闡明BPH抗性的分子機(jī)制，新等位基因的鑒定有利于加快培育抗褐飛虱的水稻品種。