Recent studies have shown that the R2R3-MYB transcription factor MdMYB73 is involved in salt stress response in apple. However, no research was done whether MdMYB73 mediated cold tolerance in apple or not. In this stu...Recent studies have shown that the R2R3-MYB transcription factor MdMYB73 is involved in salt stress response in apple. However, no research was done whether MdMYB73 mediated cold tolerance in apple or not. In this study, we found that the expression of MdMYB73 was obviously induced by cold stress. Functional analysis showed that MdMYB73 significantly increased cold tolerance in transgenic apple calli and Arabidopsis. Quantitative real-time PCR （qRT-PCR） assay indicated that the expression levels of cold-responsive genes including MdCBF2, MdCBF3, MdCBF4, and MdCBF5 were obviously enhanced in MdMYB73 transgenic calli, suggesting that MdMYB73 increased cold tolerance via C-repeat binding factor （CBF） cold response pathway. Finally, we found that soluble sugar, which provides an osmoticum for cells, was increased in MdMYB73 transgenic calli compared to that in the wild type control. These findings provide a new insights into how MdMYB73 is involved in cold stress response.展开更多
Auxin response factors(ARFs)play key roles throughout the whole process of plant growth and development,and mediate auxin response gene transcription by directly binding with auxin response elements(AuxREs).However,th...Auxin response factors(ARFs)play key roles throughout the whole process of plant growth and development,and mediate auxin response gene transcription by directly binding with auxin response elements(AuxREs).However,their functions in abiotic stresses are largely limited,especially in apples.Here,the auxin response factor gene MdARF2(HF41569)was cloned from apple cultivar‘Royal Gala’(Malus×domestica Borkh.).Phylogenetic analysis showed that ARF2 proteins are highly conserved among different species and MdARF2 is the closest relative to PpARF2 of Prunus persica,but they differ at the DNA level.MdARF2 contains three typical conserved domains including the B3 DNAbinding domain,Auxin_resp domain and AUX_IAA domain.The subcellular localization demonstrated that MdARF2 is localized in the nucleus.The three-dimensional structure prediction of the proteins showed that MdARF2 is highly similar with AtARF2,and they contain helices,folds,and random coils.The promoter of MdARF2 contains cis-acting elements which respond to various stresses,as well as environmental and hormonal signals.Expression analysis showed that MdARF2 is widely expressed in all tissues of apple,with the highest expression of MdARF2 in root.Functional analysis with a series of MdARF2 transgenic apple calli indicated that MdARF2 can reduce the sensitivity to ABA signaling and enhance salt tolerance in apple.In summary,the results of this research provide a new basis for studying the regulation of abiotic stresses by ARFs.展开更多
基金supported by the National Natural Science Foundation of China (31601728,31272142,31325024)the Natural Science Foundation of Shandong Province,China (ZR2016CQ13)the Youth Science and Technology Innovation Fund of Shandong Agricultural University,China (24024)
文摘Recent studies have shown that the R2R3-MYB transcription factor MdMYB73 is involved in salt stress response in apple. However, no research was done whether MdMYB73 mediated cold tolerance in apple or not. In this study, we found that the expression of MdMYB73 was obviously induced by cold stress. Functional analysis showed that MdMYB73 significantly increased cold tolerance in transgenic apple calli and Arabidopsis. Quantitative real-time PCR （qRT-PCR） assay indicated that the expression levels of cold-responsive genes including MdCBF2, MdCBF3, MdCBF4, and MdCBF5 were obviously enhanced in MdMYB73 transgenic calli, suggesting that MdMYB73 increased cold tolerance via C-repeat binding factor （CBF） cold response pathway. Finally, we found that soluble sugar, which provides an osmoticum for cells, was increased in MdMYB73 transgenic calli compared to that in the wild type control. These findings provide a new insights into how MdMYB73 is involved in cold stress response.
基金supported by the National Key Research and Development Program of China(2018YFD1000200)the National Natural Science Foundation of China(31972375 and 31801330)the Outstanding Youth Fund of Shandong Province,China(ZR2020YQ25 and SDAIT-06-03)。
文摘Auxin response factors(ARFs)play key roles throughout the whole process of plant growth and development,and mediate auxin response gene transcription by directly binding with auxin response elements(AuxREs).However,their functions in abiotic stresses are largely limited,especially in apples.Here,the auxin response factor gene MdARF2(HF41569)was cloned from apple cultivar‘Royal Gala’(Malus×domestica Borkh.).Phylogenetic analysis showed that ARF2 proteins are highly conserved among different species and MdARF2 is the closest relative to PpARF2 of Prunus persica,but they differ at the DNA level.MdARF2 contains three typical conserved domains including the B3 DNAbinding domain,Auxin_resp domain and AUX_IAA domain.The subcellular localization demonstrated that MdARF2 is localized in the nucleus.The three-dimensional structure prediction of the proteins showed that MdARF2 is highly similar with AtARF2,and they contain helices,folds,and random coils.The promoter of MdARF2 contains cis-acting elements which respond to various stresses,as well as environmental and hormonal signals.Expression analysis showed that MdARF2 is widely expressed in all tissues of apple,with the highest expression of MdARF2 in root.Functional analysis with a series of MdARF2 transgenic apple calli indicated that MdARF2 can reduce the sensitivity to ABA signaling and enhance salt tolerance in apple.In summary,the results of this research provide a new basis for studying the regulation of abiotic stresses by ARFs.
