The members of the fourth subgroup of R2R3-MYB(Sg4 members)are well-known inhibitors of phenylpropanoid and lignin synthesis pathways.The C2 domain is closely related to the transcriptional inhibitory activity of Sg4 ...The members of the fourth subgroup of R2R3-MYB(Sg4 members)are well-known inhibitors of phenylpropanoid and lignin synthesis pathways.The C2 domain is closely related to the transcriptional inhibitory activity of Sg4 members.Phosphorylation modification enhances the transcriptional inhibitory activity of Sg4 members.Here,we identified a phosphorylation site on the C2 domain of Cs MYB4a from tea plants(Camellia sinensis).A mitogen-activated protein kinase(MAPK),named Cs MPK3-2,phosphorylated this site on the C2 domain of Cs MYB4a.Further experiments revealed that phosphorylation of Cs MYB4a weakened its ability to inhibit the gene expression of PAL,C4H,and 4CL in the phenylpropanoid pathway and activated the expression of transcription factor YABBY5,maintaining the adaxial-abaxial polarity of the leaf.Knocking out Nt YAB5 in Cs MYB4a transgenic tobacco partially repaired the leaf wrinkling phenotype caused by Cs MYB4a.The C1 domain exhibited an activation function when the C2 domain of Cs MYB4a was phosphorylated by Cs MPK3-2,causing this reversal phenomenon.These results enrich our understanding of the regulatory diversity of Sg4 members.展开更多
The MYB4 transcription factor family regulates plant traits.However,their overexpression often results in undesirable side effects like growth reduction.We have reported a green tea(Camellia sinensis)MYB4 transcriptio...The MYB4 transcription factor family regulates plant traits.However,their overexpression often results in undesirable side effects like growth reduction.We have reported a green tea(Camellia sinensis)MYB4 transcription factor(CsMYB4)that represses the phenylpropanoid and shikimate pathways and stunts plant growth and development.In the current study,we observed that in CsMYB4a transgenic tobacco(Nicotiana tabacum)plants,primary metabolism was altered,including sugar and amino acid metabolism,which demonstrated a pleiotropic regulation by CsMYB4a.The CsMYB4a transgenic tobacco plants had improved drought tolerance,which correlated to alterations in carbohydrate metabolism and an increase in proline content,as revealed by metabolic profiling and transcriptomic analysis.To mitigate the undesirable repressive side effects on plant traits,including dwarfism,shrunken leaves,and shorter roots of CsMYB4a transgenic plants,we deleted the C4 domain of CsMYB4a to obtain a CsMYB4a-DC4 variant and then overexpressed it in transgenic plants(CsMYB4a-DC4).These CsMYB4a-DC4 plants displayed a normal growth and had improved drought tolerance.Metabolite analysis demonstrated that the contents of carbohydrates and proline were increased in these transgenic plants.Our findings suggest that an approriate modification of TFs can generate novel crop traits,thus providing potential agricultural benefits and expanding its application to various crops.展开更多
基金supported by the joint funds of National Natural Science Foundation of China(Grant Nos.U21A20232,32372756,32072621)。
文摘The members of the fourth subgroup of R2R3-MYB(Sg4 members)are well-known inhibitors of phenylpropanoid and lignin synthesis pathways.The C2 domain is closely related to the transcriptional inhibitory activity of Sg4 members.Phosphorylation modification enhances the transcriptional inhibitory activity of Sg4 members.Here,we identified a phosphorylation site on the C2 domain of Cs MYB4a from tea plants(Camellia sinensis).A mitogen-activated protein kinase(MAPK),named Cs MPK3-2,phosphorylated this site on the C2 domain of Cs MYB4a.Further experiments revealed that phosphorylation of Cs MYB4a weakened its ability to inhibit the gene expression of PAL,C4H,and 4CL in the phenylpropanoid pathway and activated the expression of transcription factor YABBY5,maintaining the adaxial-abaxial polarity of the leaf.Knocking out Nt YAB5 in Cs MYB4a transgenic tobacco partially repaired the leaf wrinkling phenotype caused by Cs MYB4a.The C1 domain exhibited an activation function when the C2 domain of Cs MYB4a was phosphorylated by Cs MPK3-2,causing this reversal phenomenon.These results enrich our understanding of the regulatory diversity of Sg4 members.
基金Natural Science Foundation of China(Grant No.32372756,No 32072621)the National Science Basic Research Program of Shanxi(2022JQ-194)for supporting this research.
文摘The MYB4 transcription factor family regulates plant traits.However,their overexpression often results in undesirable side effects like growth reduction.We have reported a green tea(Camellia sinensis)MYB4 transcription factor(CsMYB4)that represses the phenylpropanoid and shikimate pathways and stunts plant growth and development.In the current study,we observed that in CsMYB4a transgenic tobacco(Nicotiana tabacum)plants,primary metabolism was altered,including sugar and amino acid metabolism,which demonstrated a pleiotropic regulation by CsMYB4a.The CsMYB4a transgenic tobacco plants had improved drought tolerance,which correlated to alterations in carbohydrate metabolism and an increase in proline content,as revealed by metabolic profiling and transcriptomic analysis.To mitigate the undesirable repressive side effects on plant traits,including dwarfism,shrunken leaves,and shorter roots of CsMYB4a transgenic plants,we deleted the C4 domain of CsMYB4a to obtain a CsMYB4a-DC4 variant and then overexpressed it in transgenic plants(CsMYB4a-DC4).These CsMYB4a-DC4 plants displayed a normal growth and had improved drought tolerance.Metabolite analysis demonstrated that the contents of carbohydrates and proline were increased in these transgenic plants.Our findings suggest that an approriate modification of TFs can generate novel crop traits,thus providing potential agricultural benefits and expanding its application to various crops.
