Metal trace elements, such as Fe, Zn, and Mn, are necessary micronutrients required by all plants. In this study, the MxNAS3 gene was cloned from Malus xiaojinensis and MxNAS3 was localized in the cytoplasmic membrane. The expression level of MxNAS3 in root and new leaf was higher than in mature leaf and phloem, which was greatly influenced by high and low Fe stresses, IAA and ABA treatments in M. xiaojinensis. Over-expression of MxNAS3 in transgenic Arabidopsis thaliana contributed to enhanced Fe stress tolerance, as well as higher levels of root length, fresh weight, concentrations of chlorophyll, nicotianamine, Fe, Zn, and Mn, especially under high and low Fe stresses. More importantly, it was the first time for us to find that higher expression of MxNAS3 in transgenic A. thaliana contributed to misshappen flowers. Moreover, the MxNAS5-OE A. thaliana had increased expression levels of flowering-related genes (AtYSL1, AtYSL3, AtAFDL, AtAP1, ATMYB21, and AtSAP).
ARTICLE HISTORY
Plant-specific WRKY transcription factors are widely involved in abiotic stress responses. In this study, a WRKY gene was isolated from Malus baccata (L.) Borkh and designated it as MbWRKY2. Subcellular localization showed that MbWRKY2 was localized in the nucleus. The expression levels of MbWRKY2 were up-regulated by abiotic stresses in M. baccata. When MbWRKY2 was introduced into tobacco, it improved drought stress tolerance in transgenic plants. The transgenic tobaccos had the higher contents of chlorophyl, proline, relative water content, AsA, and GSH, increased activities of CAT, APX, SOD, and POD, and decreased levels of MDA, H 2 O 2 , and electrolyte leakage than wild-type, especially when dealt with dehydration treatment. Moreover, the MbWRKY2-OE plants enhanced the expression of oxidative stress response and stress-related genes involved in osmotic adjustment and membrane protection. These results suggest that MbWRKY2 gene plays a positive regulatory role in drought stress response.
ARTICLE HISTORY
Long noncoding RNAs (lncRNAs) are important regulators for a variety of biological processes. Chondrogenic differentiation of mesenchymal stem cells (MSCs) is a crucial stage in chondrogenesis while chondrocyte hypertrophy is related to endochondral ossification and osteoarthritis. However, the effects of lncRNAs on chondrogenic and hypertrophic differentiation of mouse MSCs are unclear. To explore the potential mechanisms of lncRNAs during chondrogenesis and chondrocyte hypertrophy, microarray was performed to investigate the expression profiles of lncRNA and mRNA in MSCs, pre-chondrocytes, and hypertrophic chondrocytes. Then, we validated microarray data by RT-PCR and screened three lncRNAs from upregulating groups during chondrogenesis and chondrocyte hypertrophy respectively. After downregulating any of the above lncRNAs, we found that the expression of chondrogenesis-related genes such as Sox9 and Col2a1 and hypertrophy-related genes including Runx2 and Col10a1 was inhibited, respectively. Furthermore, the target genes of above lncRNAs were predicted by bioinformatics approaches. Gene ontology and Kyoto encyclopedia of genes and genome biological pathway analysis were also made to speculate the functions of above lncRNAs. In conclusion, the study first revealed the expression profile of lncRNAs in chondrogenic and hypertrophic differentiations of mouse MSCs and presented a new prospect for the underlying mechanisms of chondrogenesis and endochondral ossification.
WRKY transcription factors are involved in stress responses in plants; however, their roles in abiotic stresses are still not well known in Malus plants. In the present study, a WRKY gene was isolated from Malus baccata (L.) Borkh and designated as MbWRKY1. Subcellular localization revealed that MbWRKY1 was localized in the nucleus. The expression levels of MbWRKY1 were up-regulated by dehydration, salinity, and ABA treatments in M. baccata seedlings. When MbWRKY1 was introduced into tobacco, it improved drought stress tolerance in transgenic plants. Under the drought treatment, transgenic plants had higher contents of chlorophyll, proline, relative water, AsA, and GSH than wild-type (WT) plants. Compared with WT plants, the overexpression of MbWRKY1 in transgenic tobacco also led to decreased levels of H2O2, MDA, and elecrolyte leakage when dealing with drought stress. There were increased activities of POD, CAT, SOD, and APX in transgenic tobaccos, especially when dealing with drought treatment. Moreover, the MbWRKY1 transgenic plants enhanced the expressions of oxidative stress response (NtPOD, NtCAT, NtSOD, and NtAPX) and stress-related genes (NtP5CS and NtLEA5) when dealing with drought stress. These results suggest that the MbWRKY1 gene plays a positive regulatory role in drought stress response.
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