Abstract:Quantitative reverse transcription-polymerase chain reaction(Quantitative RT-PCR) is based on the reverse transcription and PCR.It can be applied for the quantification of mRNA expressed from endogenous genes,and transfected genes of either stable or transient transfection in both relative and absolute terms.In particular,it is the most sensitive and reproducible method for the detection of low-abundance mRNA,often obtained from limited tissue samples.In fact,this technique is sensitive enough to enable quantitation of RNA from a single cell.There are four kinds of quantitative RT-PCR: relative quantitative RTPCR,competitive quantitative RT-PCR,comparative quantitative RT-PCR and real time quantitative RT-PCR.Quantitative RT-PCR is available for botany research including plant nutrition,plant development,plant stress study,genetically modified organism assay,diagnosis of pathogen,relation between the plant and microorganism,disease resistance assay and so on.This article reviews the principle and application of the quantitative RT-PCR in botany research.