No abstract

NAC (NAM, ATAF1/2, and CUC2) transcription factors are ubiquitously distributed in eukaryotes and play significant roles in stress response. However, the functional verifications of NACs in Picea (P.) wilsonii remain largely uncharacterized. Here, we identified the NAC transcription factor PwNAC11 as a mediator of drought stress, which was significantly upregulated in P. wilsonii under drought and abscisic acid (ABA) treatments. Yeast two-hybrid assays showed that both the full length and C-terminal of PwNAC11 had transcriptional activation activity and PwNAC11 protein cannot form a homodimer by itself. Subcellular observation demonstrated that PwNAC11 protein was located in nucleus. The overexpression of PwNAC11 in Arabidopsis obviously improved the tolerance to drought stress but delayed flowering time under nonstress conditions. The steady-state level of antioxidant enzymes’ activities and light energy conversion efficiency were significantly increased in PwNAC11 transgenic lines under dehydration compared to wild plants. PwNAC11 transgenic lines showed hypersensitivity to ABA and PwNAC11 activated the expression of the downstream gene ERD1 by binding to ABA-responsive elements (ABREs) instead of drought-responsive elements (DREs). Genetic evidence demonstrated that PwNAC11 physically interacted with an ABA-induced protein—ABRE Binding Factor3 (ABF3)—and promoted the activation of ERD1 promoter, which implied an ABA-dependent signaling cascade controlled by PwNAC11. In addition, qRT-PCR and yeast assays showed that an ABA-independent gene—DREB2A—was also probably involved in PwNAC11-mediated drought stress response. Taken together, our results provide the evidence that PwNAC11 plays a dominant role in plants positively responding to early drought stress and ABF3 and DREB2A synergistically regulate the expression of ERD1.

Research Highlights: Phenotypic changes and expression profiles, phylogeny, conserved motifs, and expression correlations of NAC (NAM, ATAF1, ATAF2 and CUC2) transcription factors (TFs) in blueberry genome were detected under drought stress, and the expression patterns and functions of 12 NACs were analyzed. Background and Objectives: Blueberry is an important shrub species with a high level of flavonoids in fruit, which are implicated in a broad range of health benefits. However, the molecular mechanism of this shrub species in response to drought stress still remains elusive. NAC TFs widely participate in stress tolerance in many plant species. The characterization and expression profiles of NAC TFs were analyzed on the basis of genome data in blueberry when subjected to drought stress. Materials and Methods: Combined with the analysis of chlorophyll a fluorescence and endogenous phytohormones, the phenotypic changes of blueberry under drought stress were observed. The phylogenetic tree, conserved motifs, differently expressed genes, and expression correlation were determined by means of multiple bioinformatics analysis. The expression profiles of NACs in different organs were examined and compared through RNA-seq and qRT-PCR assay. Results: The chlorophyll a fluorescence parameters φPo, φEo, φRo, and PIabs of leaves were significantly inhibited under drought stress. ABA (abscisic acid) content noticeably increased over the duration of drought, whereas GA3 (gibberellic acid) and IAA (indole acetic acid) content decreased continuously. A total of 158 NACs were identified in blueberry genome and 62 NACs were differently expressed in leaf and root of blueberry under drought stress. Among them, 14 NACs were significantly correlated with the expression of other NAC genes. Conclusions: Our results revealed the phenotypic changes of this shrub under drought stress and linked them with NAC TFs, which are potentially involved in the process of response to drought stress.

This study was aimed to verify whether there existed any associations between long noncoding RNA MEG3/miR‐219a‐5p/EGFR axis and the development of ovarian cancer (OC). As a whole, we gathered 317 pairs of OC tissues and surgical marginal normal tissues and simultaneously acquired four OC cell lines (ie, A2780, Caov‐3, OVCAR‐3, and SKOV‐3) and human normal ovarian surface epithelial cell line. Moreover, pcDNA3.1‐MEG3, si‐MEG3, miR‐219a‐5p mimic, miR‐219a‐5p inhibitor, pcDNA3.1‐EGFR, and si‐EGFR were, respectively, transfected into the OC cells, and their impacts on viability, proliferation, apoptosis, invasion, and migration of OC cells were assessed via conduction of MTT assay, colony formation assay, flow cytometry assay, transwell assay, and scratch assay. Ultimately, dual‐luciferase reporter gene assay was performed to testify the targeted relationships among maternally expressed gene 3 (MEG3), miR‐219a‐5p, and estimated glomerular filtration rate (EGFR). It was indicated that underexpressed MEG3 and miR‐219a‐5p were significantly associated with unfavorable prognosis of patients with OC when compared with overexpressed MEG3 and miR‐219a‐5p (P < .05). In addition, the OC cells transfected with si‐MEG3 or miR‐219a‐5p inhibitor exhibited stronger viability, proliferation, invasion, and migration than untreated cells (P < .05). Correspondingly, the apoptotic percentage of OC cells was reduced observably under treatments of si‐MEG3 and miR‐219a‐5p inhibitor (P < .05). Moreover, MEG3 exerted modulatory effects on the expression of miR‐219a‐5p (P < .05), and there was a sponging relationship between them (P < .05). Finally, EGFR expression was modified by both MEG3 and miR‐219a‐5p significantly (P < .05), and raising EGFR expression could changeover the impacts of MEG3 and miR‐219a‐5p on the above‐mentioned activity of OC cells (P < .05). Conclusively, MEG3 could serve as a promising biomarker for diagnosis and treatment of OC, considering its involvement with OC etiology via regulation of miR‐219a‐5p/EGFR axis.