The AP2/ERF transcription factor MdDREB2A regulates nitrogen utilisation and sucrose transport under drought stress.

Drought stress is one of the main environmental factors limiting plant growth and development. Plants adapt to changing soil moisture by modifying root architecture, inducing stomatal closure, and inhibiting shoot growth. The AP2/ERF transcription factor DREB2A plays a key role in maintaining plant growth in response to drought stress, but the molecular mechanism underlying this process remains to be elucidated. Here, it was found that overexpression of MdDREB2A positively regulated nitrogen utilisation by interacting with DRE cis-elements of the MdNIR1 promoter. Meanwhile, MdDREB2A could also directly bind to the promoter of MdSWEET12, which may enhance root development and nitrogen assimilation, ultimately promoting plant growth. Overall, this regulatory mechanism provides an idea for plants in coordinating with drought tolerance and nitrogen assimilation to maintain optimal plant growth and development under drought stress.

Genome-wide analysis of the 6B-INTERACTING PROTEIN1 gene family with functional characterization of MdSIP1-2 in Malus domestica.

Trihelix transcription factors consist of five subfamilies, including GT-1, GT-2, SH4, GTγ, and SIP1, which play important roles in the responses to biotic and abiotic stresses, however, seldom is known about the role of the SIP1 genes in apples. In this study, 12 MdSIP1 genes were first identified in apples by genome-wide analysis, and contained conserved MYB/SANT-like domains. Expression patterns analyses showed that the MdSIP1 genes had different tissue expression patterns, and different transcription levels in response to abiotic stresses, indicating that MdSIP1s may play multiple roles under various abiotic stresses. Among them, the MdSIP1-2 gene was cloned and ectopic transformed into Arabidopsis, and its biology function was identified. The subcellular localization showed that MdSIP1-2 protein was specifically localized in the nucleus, and that overexpression of MdSIP1-2 promoted the development of lateral roots, increased abscisic acid (ABA) sensitivity, and improved salt and drought tolerance. These findings suggested that MdSIP1-2 plays an important role in root development, ABA synthesis, and salt and drought stress tolerance. In conclusion, these results lay a solid foundation for determining the role of MdSIP1 in the growth and development and abiotic stress tolerance of apples.

Functional characterization of MdERF113 in apple.

The AP2/ERF family is an important class of transcription factors involved in plant growth and various biological processes. One of the AP2/ERF transcription factors, RAP2.6L, participates in various stresses responses. However, the function of RAP2.6L is largely unknown in apples (Malus domestica). In this study, an apple gene homologous to Arabidopsis AtRAP2.6L, MdERF113, was analyzed by bioinformatic characterization, gene expression analysis and subcellular localization assessment. MdERF113 was highly expressed in the sarcocarp and was responsive to hormonal signals and abiotic stresses. MdERF113-overexpression apple calli were less sensitive to low temperature, drought, salinity, and abscisic acid than wild-type. Subcellular localization revealed that MdERF113 was a nuclear-localized transcription factor, and yeast experiments confirmed that MdERF113 has no autonomous activation activity. Overall, this study indicated that MdERF113 plays a role in regulating plant growth under abiotic conditions.

MdMYB10 affects nitrogen uptake and reallocation by regulating the nitrate transporter MdNRT2.4-1 in the red flesh apple.

Nitrate is the major nitrogen sources for higher plants. In addition to serving not only as a nutrient, it is also a signaling molecule that regulates plant growth and development. Although membrane-bound nitrate transporter/peptide transporters (NRT/PTR) have been extensively studied and shown to regulate nitrate uptake and movement, little is known about how these factors are regulated by the external nitrogen environment. Red flesh apple, the coloration of which is determined by the transcription factor MdMYB10, had higher nitrate uptake efficiency than non-red flesh apple. Nitrate assimilation and utilization were increased in red flesh apple cultivar, and comparative transcriptome analysis showed that the expression of genes encoding the NRT2s was increased in red flesh apple. In vitro and in vivo experiments showed that MdMYB10 directly bound to the MdNRT2.4-1 promoter to transcriptionally activate its expression, resulting in enhanced nitrate uptake. MdMYB10 also controlled nitrate reallocation from old leaves to new leaves through MdNRT2.4-1. Overall, our findings provide novel insights into the mechanism by which MdMYB10 controls nitrate uptake and reallocation in apple, which facilitates adaptation to low nitrogen environment.

Overexpression of MdZAT5, an C2H2-Type Zinc Finger Protein, Regulates Anthocyanin Accumulation and Salt Stress Response in Apple Calli and Arabidopsis.

Zinc finger proteins are widely involved and play an important role in plant growth and abiotic stress. In this research, MdZAT5, a gene encoding C2H2-type zinc finger protein, was cloned and investigated. The MdZAT5 was highly expressed in flower tissues by qRT-PCR analyses and GUS staining. Promoter analysis showed that MdZAT5 contained multiple response elements, and the expression levels of MdZAT5 were induced by various abiotic stress treatments. Overexpression of MdZAT5 in apple calli positively regulated anthocyanin accumulation by activating the expressions of anthocyanin biosynthesis-related genes. Overexpression of MdZAT5 in Arabidopsis also enhanced the accumulation of anthocyanin. In addition, MdZAT5 increased the sensitivity to salt stress in apple calli. Ectopic expression of MdZAT5 in Arabidopsis reduced the expression of salt-stress-related genes (AtNHX1 and AtABI1) and improved the sensitivity to salt stress. In conclusion, these results suggest that MdZAT5 plays a positive regulatory role in anthocyanin accumulation and negatively regulates salt resistance.

[Regulatory effect of the pannexin1 channel on invasion and migration of testicular cancer Tcam-2 cells and its possible mechanism].

OBJECTIVE: To investigate the role of the pannexin-1 (Panx1) protein in the invasion and migration of testicular cancer Tcam-2 cells and its possible action mechanism. METHODS: Tcam-2 cells were treated with carbenoxolone (CBX) at 100 µmol/L and probenecid (PBN) 200 µmol/L. Then the intercellular fluorescence transmission was assessed by real-time fluorescence assay, the extracellular ATP concentration measured by chemi-luminescence immunoassay, the invasive and migratory abilities of the Tcam-2 cells detected by Transwell assay, and the expressions of the proteins Panx1, p-ERK1/2, ERK1/2, vimentin, MMP-9 and E-cadherin in the TM3 Leydig cells and testicular cancer Tcam-2 cells determined by Western blot. RESULTS: Western blot showed that the expression of the Panx1 protein was significantly higher in the testicular cancer Tcam-2 cells than in the TM3 Leydig cells (2.79 ± 0.17 vs 1.00 ± 0.06, P<0.05). The rates of intercellular fluorescence transmission in the Tcam-2 cells treated with CBX and PBN were markedly decreased as compared with the blank control group (ï¼»61.54 ± 3.30ï¼½% and ï¼»68.06 ± 4.03ï¼½% vs ï¼»99.50 ± 3.12ï¼½%, P<0.01), and so were the extracellular ATP concentrations (ï¼»57.06 ± 5.80ï¼½% and ï¼»56.42 ± 7.70ï¼½% vs ï¼»110 ± 8.16ï¼½%, P<0.01). The numbers of migrated Tcam-2 cells in the CBX and PBN groups were significantly reduced in comparison with that in the control (11.5 ± 1.11 and 8.25 ± 1.23 vs 331.00 ± 30.80, P<0.05), and so were those of the invaded ones (11.75 ± 3.77 and 11.5 ± 3.5 vs 89.00 ± 13.09, P<0.01). CBX and PBN significantly down-regulated the expression of p-ERK1/2 as compared with that in the blank control group (0.538 ± 0.05 and 0.476 ± 0.02 vs 0.98 ± 0.03, P<0.05), as well as those of vimentin (0.541 ± 0.09 and 0.705 ± 0.07, P<0.01) and MMP-9 (0.439 ± 0.08 and 0.557 ± 0.065, P<0.01) but up-regulated that of E-cadherin (3.896 ± 0.06 and 3.551 ± 0.04, P<0.01). CONCLUSIONS: The Panx1 protein is highly expressed in testicular cancer Tcam-2 cells. CBX and PBN can inhibit the function of the panneixn1 channel and reduce the invasive and migratory abilities of the Tcam-2 cells, which is associated with the decreased expression of the p-ERK1/2 protein.

[Expressions of pannexin proteins in I-10 Leydig tumor cells and TM3 Leydig cells and their regulatory effect on the channel function in mice].

OBJECTIVE: To investigate the expressions of the pannexin (Panx) proteins in I-10 Leydig tumor cells and TM3 Leydig cells and their regulatory effect on the Panx channel function in mice. METHODS: The expressions of the Panx-1 and Panx-2 proteins in the mouse Leydig tumor cells were determined by Western blot. The I-10 Leydig tumor cells were treated with carbenoxolone (CBX) at 100 µmol/L or probenecid (PBN) at 200 µmol/L, the fluorescence resonance energy transfer (FRET) detected by time-lapse fluorescence imaging, and the extracellular adenosine 5'-triphosphate (eATP) level measured with the commercial detection kit. Molecular biological methods were used to interfere with shRNA and overexpress mPanx-1 the Panx-1 gene and regulate the expression and function of the Panx-1 protein. RESULTS: The expressions of Panx-1 (ï¼»289.5 ± 55.8ï¼½%) and Panx-2 (ï¼»264.5 ± 24.6ï¼½%) were significantly increased in the I-10 Leydig tumor cells as compared with those in the normal TM3 Leydig cells (both P < 0.05). FRET was remarkably reduced after treated with CBX (ï¼»87.5 ± 17.7ï¼½%) and PBN (ï¼»89.3 ± 14.3ï¼½%) in comparison with that in the control group (both P < 0.01). At 8, 16 and 24 hours, the eATP level was decreased by (57.3 ± 7.2)%, (56.4 ± 9.6)% and (63.4 ± 6.4)% in the CBX group (P < 0.01) and (61.7 ± 2.5)%, (35.8 ± 1.6)% and (13.5 ± 8.3)% in the PBN group (P < 0.01). Molecular biological treatment down-regulated the expression of Panx-1 by (38.3 ± 5.2)% and (31.8 ± 5.1)% in the shRNA1 and shRNA2 groups, respectively (both P < 0.01), but up-regulated that of Panx-1 by (128.4 ± 7.5)% in the mPanx-1 group (P < 0.01) as compared with the negative control. FRET was reduced by (72.4 ± 39.4)% in the shRNA group (P < 0.01) and the eATP level by (14.7 ± 0.1)%, (13.7 ± 0.3)% and (13.1 ± 0.3)% at 8, 16 and 24 hours, respectively (P < 0.01) while FRET elevated by (122.5 ± 17.1)% in the mPanx-1 group (P < 0.01) and the eATP level by (886.1 ± 82.1)%, (885.8 ± 83.3)% and (841.5 ± 21.8)% at 8, 16 and 24 hours, respectively (P < 0.01). CONCLUSIONS: The expressions of Panx-1 and Panx-2 are increased in I-10 mouse Leydig tumor cells, and inhibiting the Panx channel with CBX, PBN and shRNA reduces FRET and the eATP level in the I-10 cells.

[Distribution of PGEs contents and its factors in snowfall and snow cover over the arid region in Changji City].

This paper was to select a small-medium sized City, Changji city, over the arid region, study the distribution of platinum group metals(PGEs) contents and influencing factors in snowfall and snow cover. Samples were analysed by ICP-MS. The results revealed that the annual contents of Rh, Pd and Pt in snowfall were on the average value of 0.43 ng.L-1 ranging from not detected to 2.24 ng.L-1 , 60.07 ng.L-1 ranging from 46.66 to 84.25 ng.L-1 and 4.54 ng.L-1 ranging from 3.02 ng.L-1 to 6.38 ng.L-1 respectively. The difference of PGEs levels was found in different occurrences of snowfall, tended to increase before snowfall due to the longer arid days. PGEs contents maybe influenced by the amount of snowfall, the less snowfall, the higher PGEs contents reflected. The annual levels of Rh, Pd and Pt in snow cover were in the range of 2.50-18.80 ng.L-1 (av. 6.65 ng.L-1), 46.83-199.20 ng.L-1 (av. 83.45 ng.L-1) ,4. 27-13.78 ng.L-1 (av. 8.17 ng.L-1) respectively. PGEs content in snow cover were far higher than that of snowfall, PGEs in snowfall were only obtained from atmospheric PGEs rinsed by single time of snowfall, while PGEs were not only from the accumulation of PGEs in frequent times of snowfall and the snow cover under the long time exposure, but also continuously accepted the PGEs from atmospheric dry deposition. PGEs content of snow cover in all sampling sites were demonstrated as follows: traffic area > residential-culture-education district > square of park > suburban farmland. the input way of PGEs in snow cover was found a remarkable difference with the amount of input within different function areas, which was the main reason caused that PGEs content of snow cover in each function area varied and had a certain regularity.