AsE246 and AsIB259 were two root nodule-specific expressed nodulin genes encoding nsLTP1 (non-specific lipid transfer protein 1).The temporal-spatial expression characteristics of two target genes during root nodule development and nitrogen fixation process were investigated with real-time quantitative PCR.Meanwhile,the dynamic changes of expression level of target genes under heavy metal cadmium stress condition were also examined.The results showed that two target genes were strictly expressed in symbiotic organ-root nodules,and reached the peak level at about 22 days after inoculation of Mesorhizobium huakuii 7653R.It was also found that the expression levels of AsE246 and AsIB259 were significantly increased during the early stage as a response to low-level-cadmium stress.However,either at low- or high-level-cadmium stress conditions,their expression were significantly suppressed during the interim stage of Cd2+ stress treatment comparied with those in normal nodules,and continued to maintain a relative lower level until the final stage.These indicated the two nsLTP1 genes could play a fundamental role in the response mechanism of A.sinicus to cadmium stress.In this work,some convincing data were obtained to confirm that AsE246 and AsIB259 were specific expressed nsLTP1 genes in A.sinicus root nodules. 