摘要
Non-damaging ultraviolet B(UV-B)light promotes photomorphogenic development and stress acclimation through UV-B-specific signal transduction in Arabidopsis.UV-B irradiation induces monomerization and nuclear translocation of the UV-B photoreceptor UV RESISTANCE LOCUS 8(UVR8).However,it is not clear how the nuclear localization of UVR8 leads to changes in global gene expression.Here,we reveal that nuclear UVR8 governs UV-B-responsive transcriptional networks in concert with several previously known transcription factors,including ELONGATED HYPOCOTYL 5(HY5)and PHYTOCHROME INTERACTING FACTOR 4(PIF4).Based on the transcriptomic analysis,we identify MYB13 as a novel positive regulator in UV-B-induced cotyledon expansion and stress acclimation.MYB13 is UV-B inducible and is predominantly expressed in the cotyledons.Our results demonstrate that MYB13 protein functions as a transcription factor to regulate the expression of genes involved in auxin response and flavonoid biosynthesis through direct binding with their promoters.In addition,photoactivated UVR8 interacts with MYB13 in a UV-B-dependent manner and differentially modulates the affinity of MYB13 with its targets.Taken together,our results elucidate the cooperative function of the UV-B photoreceptor UVR8 with various transcription factors in the nucleus to orchestrate the expression of specific sets of downstream genes and,ultimately,mediate plant responses to UV-B light.
基金
grants from the National Key R&D Program of China(2017YFA0506100 and 2016YFA0502900)
the National Natural Science Foundation of China(31771347 and 31671378)
the National Natural Science Foundation of Fujian(2018J06009)
the Fundamental Transcriptional Regulation by UVR8 and TFs Research Funds for the Central Universities(20720190085 and 20720170068).