关键词: 烟草, 愈伤组织, 细胞程序性死亡（PCD）, Beclin1基因

Abstract: We induced the ten different stages callus from the leaves of Nicotiana benthamiana (tobacco) cultured in the MS medium. The morphologic varieties of nucleolus was observed through the fluorescence microscope and DNA Ladder was tested during ten different stages of the induced callus tissue of tobacco leaves, which correlated with PCD by RT-PCR method in the nine different stages, leaf segments cultured at 3,5,7,9,11,13,15,17,19 days. Northern blotting result showed that the expression of Beclin1-like gene at stage six, the leaf segments cultured 13 days was showed Programmed cell death (PCD) happened in the process of callus inducement, and stage six, the leaf segments cultured 13 days was the active period of PCD occurred. Then we cloned fragment of Beclin1 gene (678 bp) cDNA which was higher than those of the other eight stages, Furthermore the content of endogenous hormones ABA in leaf segments was measured by ELISA method, ABA reach to peak at stage six, All these results proved that PCD certainly happened during the tobacco leaves callus induced, ABA and Beclin1 gene had regulated function in this process.

Key words: Nicotiana benthamiana, callus, programmed cell death(PCD), Beclin1 gene