The protein encoded by BPH26 was a CC-NBS-LRR protein. The sequence of BPH26 derived from ADR52 was completely identical to one from ASD7, which carried the resistance allele of BPH2. On the other hand, there was a nonsense mutation in the sequence of the susceptible cultivar Taichung 65. The aphid resistance gene Mi from tomato23,24 and BPH resistance gene BPH14 from wild rice25 have been reported to encode a CC-NBS-LRR-receptor kinase-like protein. Although only a few resistance genes against sap-sucking insects have been cloned, genes belonging to the NBS-LRR family might confer resistance to sap-sucking insects, in addition to conferring disease resistance.