Abstract: NLP gene family is a special transcription factor, the initiation of nodule development is dependent on the function of this gene family, in other species plant it has the function of regulating plant nitrate absorption and assimilation. Genome-wide analysis in Populus trichocarpa had identified 14 NLP gene family members. These members have the characteristics of low hydrophilic, the conservative gene structure and contain RWP-RK and PB1 two conservative domain. The localization of all members of NLP genes in P.trichocarpa was predicted in the nucleus. Evolution analysis showed that NLP gene family members experience strict filter. Chromosome localization analysis showed that the members of P.trichocarpa NLP genes were located on 9 chromosomes, the expanding of NLPs in P.trichocarpa was caused by Salicaceae duplication events. Microarray data analysis showed that NLPs had a high transcript accumulation in leaf, root and male catkins, some genes were expressed in xylem, seed and female catkins, but no gene was detected in the mature leaf.

Key words: Populus trichocarpa, NLP, gene family, expression pattern