作者： Geng J., Liu J. H.
摘要：CsbHLH18, a bHLH transcription factor ofCitrus sinensis,functions as a positive regulator of cold tolerance due to promoted ROS scavenging, and directly targets aPODgene. The basic helix–loop–helix (bHLH) transcription factors (TFs) comprise one of the largest gene families in plants, and participate in various physiological processes, but the physiological role and regulatory function of the majority of bHLHs remain poorly understood. Here, a total of 56 putativeCsbHLHgenes were identified in sweet orange (Citrus sinensis) based on a genome-wide analysis. TheCsbHLHgenes, except four members, were distributed throughout nine chromosomes and divided into 19 subgroups. Most of theCsbHLHgenes were responsive to cold stress, with the greatest up-regulation being observed inCsbHLH18. CsbHLH18 is localized in the nuclei and has transcriptional activation activity. Overexpression ofCsbHLH18 conferred enhanced cold tolerance in transgenic tobacco. The transgenic plants accumulated significantly less reactive oxygen species (ROS), concurrent with increased activities and transcript levels of antioxidant enzymes. In contrast, knockdown ofbHLH18by RNAi in trifoliate orange promoted cold susceptibility, accompanied by down-regulation of antioxidant genes and accumulation of more ROS. Protein–DNA interaction assays demonstrate that CsbHLH18 directly and specifically binds to and activates the promoter ofCsPOD. Taken together, these findings indicate thatCsbHLH18plays a positive role in cold tolerance through, at least partly, modulation of ROS homeostasis by directly regulating the antioxidant gene.
关键词：Basic helix–loop–helix transcription factors Citrus sinensis cold stress toleran
文献注录： Geng J., Liu J. H.. The transcription factor CsbHLH18 of sweet orange (Citrus sinensis) functions in modulation of cold tolerance and reactive oxygen species homeostasis by regulating the antioxidant gene [J]. . 2018, 10: 2677-2692.
报/刊名：《》，发表于2018 / 第 10 期。
文献类型： [J]
页码：第 2677-2692 页 / 共 页