Brassinosteroids(BRs)and abscisic acid(ABA)are essential regulators of plant growth and stress tolerance.Although the antagonistic interaction of BRs and ABA is proposed to ensure the balance between growth and defens...Brassinosteroids(BRs)and abscisic acid(ABA)are essential regulators of plant growth and stress tolerance.Although the antagonistic interaction of BRs and ABA is proposed to ensure the balance between growth and defense in model plants,the crosstalk between BRs and ABA in response to chilling in tomato(Solanum lycopersicum),a warmclimate horticultural crop,is unclear.Here,we determined that overexpression of the BR biosynthesis gene DWARF(DWF)or the key BR signaling gene BRASSINAZOLE-RESISTANT1(BZR1)increases ABA levels in response to chilling stress via positively regulating the expression of the ABA biosynthesis gene 9-CIS-EPOXYCAROTENOID DIOXYGENASE1(NCED1).BR-induced chilling tolerance was mostly dependent on ABA biosynthesis.Chilling stress or high BR levels decreased the abundance of BRASSINOSTEROID-INSENSITIVE2(BIN2),a negative regulator of BR signaling.Moreover,we observed that chilling stress increases BR levels and results in the accumulation of BZR1.BIN2negatively regulated both the accumulation of BZR1protein and chilling tolerance by suppressing ABA biosynthesis.Our results demonstrate that BR signaling positively regulates chilling tolerance via ABA biosynthesis in tomato.The study has implications in production of warm-climate crops in horticulture.展开更多
基金supported by the National Key Research and Development Program (2019YFD1001900)the National Natural Science Foundation of China (31872153,U21A20233)the Fundamental Research Funds for the Central Universities (2021FZZX001-30)。
文摘Brassinosteroids(BRs)and abscisic acid(ABA)are essential regulators of plant growth and stress tolerance.Although the antagonistic interaction of BRs and ABA is proposed to ensure the balance between growth and defense in model plants,the crosstalk between BRs and ABA in response to chilling in tomato(Solanum lycopersicum),a warmclimate horticultural crop,is unclear.Here,we determined that overexpression of the BR biosynthesis gene DWARF(DWF)or the key BR signaling gene BRASSINAZOLE-RESISTANT1(BZR1)increases ABA levels in response to chilling stress via positively regulating the expression of the ABA biosynthesis gene 9-CIS-EPOXYCAROTENOID DIOXYGENASE1(NCED1).BR-induced chilling tolerance was mostly dependent on ABA biosynthesis.Chilling stress or high BR levels decreased the abundance of BRASSINOSTEROID-INSENSITIVE2(BIN2),a negative regulator of BR signaling.Moreover,we observed that chilling stress increases BR levels and results in the accumulation of BZR1.BIN2negatively regulated both the accumulation of BZR1protein and chilling tolerance by suppressing ABA biosynthesis.Our results demonstrate that BR signaling positively regulates chilling tolerance via ABA biosynthesis in tomato.The study has implications in production of warm-climate crops in horticulture.
