Cloning,Expression And Functional Analysis Of Cold Induced Mybs In Prunus Mume 'Xue Mei'

Plants encounter a wide range of environmental stresses during a typical life cycle.To counteract the adverse effects of abiotic stresses,plants have evolved a set of efficient defensive mechanisms,such as the highly sensitive perception of stress signals and their transducers.Transcriptional factors(TFs)play an important role in the regulators of abiotic stress responses in plants.MYB transcription factors,one of the largest families of transcriptional regulators in plants,participate in multiple biological processes,such as development,metabolism and responses to stresses.Mei flower is an important ornamental plant,but weaker resistance at low temperature limits its flourish in the north China.In this study,Prunus mume 'Xue Mei' is used as tested material.The expression pattern of PmMYBs is detected under cold stress using qRT-PCR.12 PmMYBs genes are selected to construct over-expression vector.The stress tolerance of Arabidopsis plants that overexpress the PmMYBs is identified.The main results are obtained as follow.1.Seventeen of the 27 R2R3-MYB genes were induced quickly within 12h cold treatment.Among 1R-MYB genes,only the transcriptional abundance of Pm000420 was restrained at the early stage of cold treatment(3h),while other ones were not responsive to low temperature.The expression pattern of PmMYBs in different cultivars of P.mume was similar,but the up-regulation degree of PmMYBs in 'Xiao Yudie' and 'Feng Hou'with higher cold tolerance was lower than one in 'Xue Mei' with cold sensitivity.2.Twelve PmMYBs genes were cloned and their over-expression vector were constructed.Eleven PmMYBs genes were transformed into Arabidopsis via floral dip.After screening and 2 generation of inbreeding,over-expression plants of eight PmMYBs with 14 T3 homozygous lines have been acquired.3.The identification of abiotic stress resistance about transgenic Arabidopsis plants showed that the overexpression of Pm025177 in Arabidopsis decrease cold resistance,but the cold tolerance difference between transgenic plants overexpressing other PmMYBs and wild type was not significant;Arabidopsis transgenic plants that overexpress Pm004199,Pm014372 and Pm005332 improved the germination rate of seeds under high-salinity stress,while the seeds germination rate of Pm023786 and Pm015880-overexpressing lines was lower than WT;Arabidopsis plants that overexpress Pm015880,Pm013277,Pm023 786,Pm004199 and Pm014372 enhanced the germination capability under oxidative stress.