Expression Analysis of Ethylene-synthesis Related Genes aco and sams During the Rooting Process of Mulberry Softwood Cuttings

Plant endogenous ethylene has an important influence on induction and proliferation of callus,formation of adventitious bud and adventitious root,and induction of somatic embryo.Transcriptional levels of two ethylene-synthesis related genes,aminocyclopropane-1-carboxylate oxidase gene(aco) and S-adenosyl-L-methionine systhetase gene(sams),in basal cortex of mulberry softwood cuttings during the rooting process were measured by real-time fluorescent quantitative PCR.The results indicated that the expressions of aco and sams were both down-regulated during the rooting process of cuttings.The transcriptional levels of these two genes in cuttings of the control group with low rooting rate showed a first decreasing slightly and then increasing tendency.Those in the treatment group with high rooting rate were expressed continuously at low level.Especially at the late developmental stage of rooting,transcriptional level variation of the two genes showed a nearly opposite pattern.It was preliminarily illustrated that the mRNA transcriptional levels of ethylene-synthesis related genes aco and sams are negatively correlated with rooting rate of mulberry softwood cuttings.