Overexpression of phosphoenolpyruvate carboxylase kinase gene MsPPCK1 from Medicago sativa L. increased alkali tolerance of alfalfa by enhancing photosynthetic efficiency and promoting nodule development.

The phosphoenolpyruvate carboxylase kinase of Medicago sativa L. (MsPPCK1) modulates the phosphorylation status and activity of the C4 pathway phosphoenolpyruvate carboxylase enzyme, which is pivotal for photosynthetic carbon assimilation in plants. This study investigated the role of MsPPCK1 in alfalfa by creating transgenic plants overexpressing MsPPCK1 under the control of the CaMV35S promoter. The enhanced alkali tolerance of transgenic plants indicated an important role of MsPPCK1 gene in regulating plant alkali tolerance. Transgenic plants exhibited heightened antioxidant activity (SOD, POD, and CAT), reduced MDA, H2O2, OFR and REC% content, increased activity of key photosynthetic enzymes (PEPC, PPDK, NADP-ME, and NADP-MDH), and enhanced photosynthetic parameters (Pn, E, Gs, and Ci). Moreover, MsPPCK1 overexpression increased the content of organic acids (oxaloacetic, malic, citric, and succinic acids) in the plants. The upregulation of MsPPCK1 under rhizobial inoculation showcased its other role in nodule development. In transgenic plants, MsDMI2, MsEnod12, and MsNODL4 expression increased, facilitating root nodule development and augmenting plant nodulation. Accelerated root nodule growth positively influences plant growth and yield and enhances alfalfa resistance to alkali stress. This study highlights the pivotal role of MsPPCK1 in fortifying plant alkali stress tolerance and improving yield, underscoring its potential as a key genetic target for developing alkali-tolerant and high-yielding alfalfa varieties.

Can IMERG QPE product capture the heavy rain on urban flood scale?

Urban areas are increasingly vulnerable to sudden flooding disasters caused by intense rainfall and high imperviousness degree, resulting in great economic losses and human casualties. Interactions between rainfall data and urban catchment characteristics highlight the urgent need of accurate and effective precipitation data to apply in reliable hydrological simulations. However, it remains a challenge to obtain accurate rainfall datasets on such small scales in urban areas. As satellite remote sensing is the only method that can achieve global observation, it is important to evaluate satellite precipitation products in their ability to accurately capture intense precipitation on urban flood scales. This study evaluates the performance of the latest version 06B (V06B) Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) in North China Plain, with using the Radar-Gauge merged precipitation estimates as reference data. First, it could be concluded that IMERG fails to accurately estimate precipitation in the whole study area, having the problem of overestimating light precipitation and underestimating heavy precipitation. Second, results show that IMERG has poor ability to capture heavy precipitation on small scales, with the percentage of Hit nearly 0 and the percentage of Miss higher than 40 % for all the precipitation cases. Third, with the expansion of heavy precipitation centers' coverage, the problem of IMERG not to detect heavy precipitation gets mitigated, with the percentage of Miss decreasing by 14 % (19 %). However, the ability to capture both spatial location and precipitation intensity is still not good, the percentage of Hit ranging from 0.05 % to 7 %, without obvious improvement. When IMERG is able to capture the center of strong precipitation, it also tends to overestimate the weak precipitation around the center of strong precipitation. Results of this study provide an improved understanding of how well the V06B IMERG products capture the heavy precipitation center at small scales in urban areas, which will be useful for both developers and users of IMERG.

Vertical structures and microphysical characteristics of summer precipitation in North China detected by GPM-DPR.

The vertical structure and microphysical characteristics of stratiform precipitation (SP) and convective precipitation (CP) in North China are revealed based on the GPM-DPR product during boreal summer of 2014-2021 in this study. Additionally, the differences in precipitation features between the mountain and the plain are investigated. Under the combined influence of climatic factors and local topography, the precipitation amount is larger in the plain than in the mountain while precipitation frequency exhibits an opposite pattern. The proportions of the two precipitation types are similar in the mountain and the plain, with CP contributing to approximately a quarter of total precipitation frequency. In terms of mean intensity, both SP and CP are roughly 20 % more intense in the plain than in the mountain. The greater number of light SPs is a major contributor to higher precipitation frequency in the mountain, while more intense CPs result in larger precipitation amount in the plain. Compared to the mountain, the precipitation system is deeper in the plain, where higher storm top altitudes (STAs) and larger freezing level heights contribute to more intense CPs. Besides, it is observed that for the STA, more intense CPs occur in the plain compared to the mountain. In both the mountain and the plain, the coalescence process is dominant in the low-level layers for heavy (8-20 mm/h) to storm-level (>20 mm/h) CPs. Compared to the mountain, the low-level growth of hydrometeor size and radar reflectivity is more significant in the plain. These findings are important to quantitative precipitation estimation and precipitation prediction in the mountainous region, and can help understand the influence of local topography on precipitation.

Symbiotic System Establishment between Piriformospora indica and Glycine max and Its Effects on the Antioxidant Activity and Ion-Transporter-Related Gene Expression in Soybean under Salt Stress.

The utilization of symbiosis with beneficial microorganisms has considerable potential for increasing growth and resistance under abiotic stress. The endophytic root fungus Piriformospora indica has been shown to improve plant growth under salt and drought stress in diverse plant species, while there have been few reports of the interaction of P. indica with soybean under salt stress. In this study, the symbiotic system of P. indica and soybean (Glycine max L.) was established, and the effect of P. indica on soybean growth and salt tolerance was investigated. The colonized and non-colonized soybeans were subjected to salt stress (200 mmol/L NaCl), and the impairments in chlorophyll and increasing relative conductivity that can be caused by salt stress were alleviated in the P. indica-colonized plants. The accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2−) were lower than that in non-colonized plants under salt treatment, whereas the activities of antioxidant enzymes were significantly increased by P. indica colonization, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione reductase (GR). Importantly, without salt treatment, the Na+ concentration was lower, and the K+ concentration was higher in the roots compared with non-colonized plants. Differential expressions of ion transporter genes were found in soybean roots after P. indica colonization. The P. indica colonization positively regulated the transcription level of PM H+-ATPase, SOS1, and SOS2. The study shows that P. indica enhances the growth and salt tolerance of soybean, providing a strategy for the agricultural production of soybean plants in saline-alkali soils.

Overexpression of MsRCI2D and MsRCI2E Enhances Salt Tolerance in Alfalfa (Medicago sativa L.) by Stabilizing Antioxidant Activity and Regulating Ion Homeostasis.

Rare cold-inducible 2 (RCI2) genes from alfalfa (Medicago sativa L.) are part of a multigene family whose members respond to a variety of abiotic stresses by regulating ion homeostasis and stabilizing membranes. In this study, salt, alkali, and ABA treatments were used to induce MsRCI2D and MsRCI2E expression in alfalfa, but the response time and the expression intensity of the MsRCI2D,-E genes were different under specific treatments. The expression intensity of the MsRCI2D gene was the highest in salt- and alkali-stressed leaves, while the MsRCI2E gene more rapidly responded to salt and ABA treatment. In addition to differences in gene expression, MsRCI2D and MsRCI2E differ in their subcellular localization. Akin to MtRCI2D from Medicago truncatula, MsRCI2D is also localized in the cell membrane, while MsRCI2E is different from MtRCI2E, localized in the cell membrane and the inner membrane. This difference might be related to an extra 20 amino acids in the C-terminal tail of MsRCI2E. We investigated the function of MsRCI2D and MsRCI2E proteins in alfalfa by generating transgenic alfalfa chimeras. Compared with the MsRCI2E-overexpressing chimera, under high-salinity stress (200 mmol·L-1 NaCl), the MsRCI2D-overexpressing chimera exhibited a better phenotype, manifested as a higher chlorophyll content and a lower MDA content. After salt treatment, the enzyme activities of SOD, POD, CAT, and GR in MsRCI2D- and -E-overexpressing roots were significantly higher than those in the control. In addition, after salt stress, the Na+ content in MsRCI2D- and -E-transformed roots was lower than that in the control; K+ was higher than that in the control; and the Na+/K+ ratio was lower than that in the control. Correspondingly, H+-ATPase, SOS1, and NHX1 genes were significantly up-regulated, and the HKT gene was significantly down-regulated after 6 h of salt treatment. MsRCI2D was also found to regulate the expression of the MsRCI2B and MsRCI2E genes, and the MsRCI2E gene could alter the expression of the MsRCI2A, MsRCI2B, and MsRCI2D genes. MsRCI2D- and -E-overexpressing alfalfa was found to have higher salt tolerance, manifested as improved activity of antioxidant enzymes, reduced content of reactive oxygen species, and sustained Na+ and K+ ion balance by regulating the expression of the H+-ATPase, SOS1, NHX1, HKT, and MsRCI2 genes.

[Shugan Yiyang capsule increases the expressions of VEGF, IGF and Akt1 in the rat model of arteriogenic erectile dysfunction].

OBJECTIVE: Cytokines such as VEGF and IGF play an important role in maintaining the function of blood vascular endothelium. And Akt1 is an important molecule in the intra-cellular signaling transduction. This study aims to investigate the molecular mechanism of Shugan Yiyang (SGYY) capsule in the treatment of arteriogenic erectile dysfunction (AED) by detecting the expressions and phosphorylation of VEGF, IGF and Akt1 in AED rats. METHODS: We established AED models in 60 three-month-old adult male SD rats by bilateral ligation of the internal iliac artery, and assigned them to a sham operation group, a model control group, a sildenafil group, a low-dose SGYY group (0.5 g/[kg x d]) and a high-dose SGYY group (1 g/[kg x d]). After 30 days of gavage, we assayed the plasma concentrations of VEGF and IGF in the carotid artery of the rats by ELISA, detected the expressions of VEGF and IGF mRNA by real-time PCR and determined the expression and phosphorylation of Aktl protein in the corpus cavernosum penis by Western blot. RESULTS: In the model control group, the expressions of VEGF and IGF mRNA were 0.41 +/- 0.06 and 0.42 +/- 0.06, the plasma concentrations of VEGF and IGF were (28.59 +/- 24.97) pg/ml and (15.82 +/- 4.37) ng/ml, and the expression of p-Aktl/Akt1 was 0.93 +/- 0.14. While in the high-dose SGYY group, the expressions of VEGF and IGF mRNA were 0.77 +/- 0.04 and 0.78 +/- 0.05, the plasma concentrations of VEGF and IGF were (95.83 +/- 37.34) pg/ml and (20.45 +/- 3.83) ng/ml, and the expression of p-Aktl/Aktl was 1.43 +/- 0.50. All the parameters above were significantly higher in the high-dose SGYY than in the model control group (P < 0.05), and so were they in the low-dose SGYY group except the plasma concentration of IGF (P < 0.05). CONCLUSION: SGYY can significantly upregulate the expressions of VEGF, IGF and Akt1 in the corpus cavernosum penis of AED rats, and improve the function of blood vascular endothelium, which is probably an important mechanism of SGYY capsule acting on AED.

A Chinese herbal formula, Shuganyiyang capsule, improves erectile function in male rats by modulating Nos-CGMP mediators.

OBJECTIVE: To evaluate the effects of the Chinese herbal formula Shuganyiyang (SGYY) capsule on arteriogenic erectile dysfunction (ED) in a rat model and to investigate the underlying molecular mechanism. METHODS: Forty male Sprague-Dawley rats were subjected to bilateral ligation of the internal iliac artery and then divided into 4 groups (n=10 per group). They were treated daily with either sildenafil (10.5 mg/kg), or SGYY at 1 of 2 dosages (1 g/kg and 0.5 g/kg) for 30 days. Erectile function was evaluated using cavernous nerve electrical stimulation after treatment, and the cavernous tissue specimens of all animals were harvested for gene and protein examination using real-time reverse transcriptase polymerase chain reaction, Western blot analysis, and cyclic guanosine monophosphate (cGMP) measurement. RESULTS: The ratio of the maximal intracavernous pressure to the mean arterial pressure was significantly higher in the SGYY (1 g/kg and 0.5 g/kg) rats than that in the models (P<.01). The gene and protein expression of 3 subtypes of nitric oxide synthase (NOS)--neuropathic (nNOS), inducible (iNOS), and endothelial (eNOS)--and cGMP concentrations in cavernous tissue in SGYY-treated rats were significantly higher than in the models. However, phosphodiesterase type 5 (PDE5) expression in the SGYY rats was lower than those in models (P<.01 or P<.05). CONCLUSION: SGYY significantly improves the maximal intracavernous pressure in arteriogenic ED in a rat model. The underlying mechanism of action of SGYY involves increasing the expression of some main factors in the NOS-cGMP pathway and reducing the expression of PDE5.