ABSTRACT
Adventitious root (AR) formation is a critical factor in the vegetative propagation of forestry and horticultural plants. Competence for AR formation declines in many species during the miR156/SPL-mediated vegetative phase change. Auxin also plays a regulatory role in AR formation. In apple rootstock, both high miR156 expression and exogenous auxin application are prerequisites for AR formation. However, the mechanism by which the miR156/SPL module interacts with auxin in controlling AR formation is unclear. In this paper, leafy cuttings of juvenile (Mx-J) and adult (Mx-A) phase Malus xiaojinensis were used in an RNA-sequencing experiment. The results revealed that numerous genes involved in phytohormone signaling, carbohydrate metabolism, cell dedifferentiation, and reactivation were downregulated in Mx-A cuttings in response to indole butyric acid treatment. Among the differentially expressed genes, an HD-ZIP transcription factor gene, MxHB13, was found to be under negative regulation of MdSPL26 by directly binding to MxHB13 promoter. MxTIFY9 interacts with MxSPL26 and may play a role in co-repressing the expression of MxHB13. The expression of MxTIFY9 was induced by exogenous indole butyric acid. MxHB13 binds to the promoter of MxABCB19-2 and positively affects the expression. A model is proposed in which MxHB13 links juvenility-limited and auxin-limited AR recalcitrance mechanisms in Mx-A.
Subject(s)
Malus/growth & development , Plant Proteins/metabolism , Plant Roots/growth & development , Transcription Factors/metabolism , Cell Differentiation , Gene Expression Regulation, Plant/drug effects , Indoleacetic Acids/metabolism , Indoles/metabolism , Indoles/pharmacology , Malus/drug effects , Malus/genetics , Malus/metabolism , Plant Cells , Plant Growth Regulators/metabolism , Plant Proteins/genetics , Plant Roots/genetics , Plant Stems/cytology , Plant Stems/genetics , Plant Stems/growth & development , Plants, Genetically Modified , Nicotiana/genetics , Transcription Factors/geneticsABSTRACT
Low water availability is the major environmental factor limiting growth and productivity of plants and crops and is therefore considered of high importance for agriculture affected by climate change. Identifying regulatory components controlling the response and tolerance to drought stress is thus of major importance. The NAC transcription factor (TF) JUNGBRUNNEN1 (JUB1) from Arabidopsis thaliana extends leaf longevity under non-stress growth conditions, lowers cellular hydrogen peroxide (H2O2) level, and enhances tolerance against heat stress and salinity. Here, we additionally find that JUB1 strongly increases tolerance to drought stress in Arabidopsis when expressed from both, a constitutive (CaMV 35S) and an abiotic stress-induced (RD29A) promoter. Employing a yeast one-hybrid screen we identified HD-Zip class I TF AtHB13 as an upstream regulator of JUB1. AtHB13 has previously been reported to act as a positive regulator of drought tolerance. AtHB13 and JUB1 thereby establish a joint drought stress control module.
ABSTRACT
Objective To evaluate the in vitro antiviral activity of HB-13,a compound derivant from berberine and its prodrug berberine,against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). Methods Vero cells were cultured in vitro and infected with HSV.Then,various concentrations of HB-13, berberine,and aciclovir were used to treat these infected cells.The cytopathic effect was observed to deter- mine the antiviral effects and cytotoxicity of HB-13 and berberine.Results For HB-13,berberine and acy- clovir,the half toxicity concentration (TC_(50)) to Vero cells was 31.99,380 and more than 800?g/mL, respectively;the average half inhibitory concentration (IC_(50)) against HSV-1 was 1.328,more than 100,and 0.443?g/mL,respectively,the treatment index (TI) against HSV-1 was 24.09,less than 3.80,and more than 1805.87,respectively;the IC_(50) against HSV-2 was 1.344,more than 100,and 0.679?g/mL,respectively,the TI against HSV-2 was 23.80,less than 3.80 and more than 1178.20,respectively.Conclusion HB-13 possesses marked antiviral activity against HSV-1 and HSV-2 in vitro,while berberine does not.