In order to clarify the mechanism of deficient phosphorus stress on phosphorus absorption of flue-cured tobacco,taking ‘Yuyan No.10’ as the material,we designed a pot experiment with two treatments,which were no phosphate fertilizer application and recommended amount of phosphate fertilizer.The expression differences of high-affinity phosphate transporter genes NtPht1;1(PT1) and NtPht1;2(PT2) between two treatments and the correlation of genes expression and phosphorus accumulation in leaves and roots at later growth stages were analyzed.The results showed that:(1)with the advancement of the growth stages,the relative expression of PT1 and PT2 genes,the dry matter weight and the phosphorus accumulation in leaves and roots of flue-cured tobacco increased gradually and the content of phosphorus in leaves decreased.Whereas,there was no significant pattern in roots.(2)The relative expression of PT1 and PT2 genes were up-regulated under deficient phosphorus stress.The relative expression of PT1 gene in leaves was higher than that in roots,while PT2 gene was the opposite,comparatively.(3)The accumulation of dry matter and phosphorus in flue-cured tobacco were limited under deficient phosphorus stress.At 90 days after transplanting,the dry matter weight and phosphorus accumulation in tobacco roots and leaves with no phosphate fertilizer application were less than half the values of the phosphorus application treatment.There were extremely significant differences among treatments at 0.01 probability levels.This might imply that the up-regulated expression of PT1 and PT2 genes under deficient phosphorus stress was due to the decrease of phosphorus accumulation in tobacco tissues rather than the low available phosphorus soil.