Largescale multicenter study of a serum metabolite biomarker panel for the diagnosis of breast cancer.

Breast cancer (BC) is currently the most prevalent malignancy worldwide, and finding effective non-invasive biomarkers for routine clinical detection of BC remains a significant challenge. Here, we performed non-targeted and targeted metabolomics analysis on the screening, training and validation cohorts of serum samples from 1,947 participants. A metabolite biomarker model including glutamate, erythronate, docosahexaenoate, propionylcarnitine, and patient's age was established for detecting BC. This model demonstrated better diagnostic performance than carbohydrate antigen 15-3 (CA15-3) and carcinoembryonic antigen (CEA) alone in discriminating BC from healthy controls both in the training and validation cohorts [area under the curve (AUC), 0.954; sensitivity, 87.1% and specificity, 93.5% for the training cohort and 0.834, 68.3%, and 85.2%, respectively, for the validation cohort 1]. This study has established a noninvasive approach for the detection of BC, which shows potential as a suitable supplement to the clinical screening methods currently employed for BC.

Pulmonary and renal long COVID at two-year revisit.

This study investigated host responses to long COVID by following up with 89 of the original 144 cohorts for 1-year (N = 73) and 2-year visits (N = 57). Pulmonary long COVID, characterized by fibrous stripes, was observed in 8.7% and 17.8% of patients at the 1-year and 2-year revisits, respectively, while renal long COVID was present in 15.2% and 23.9% of patients, respectively. Pulmonary and renal long COVID at 1-year revisit was predicted using a machine learning model based on clinical and multi-omics data collected during the first month of the disease with an accuracy of 87.5%. Proteomics revealed that lung fibrous stripes were associated with consistent down-regulation of surfactant-associated protein B in the sera, while renal long COVID could be linked to the inhibition of urinary protein expression. This study provides a longitudinal view of the clinical and molecular landscape of COVID-19 and presents a predictive model for pulmonary and renal long COVID.

NHX5/NHX6/SPY22 complex regulates BRI1 and brassinosteroid signaling in Arabidopsis.

NHX5 and NHX6, Arabidopsis endosomal antiporters, play a vital role in facilitating ion and pH homeostasis in endosomal compartments. Studies have found that NHX5 and NHX6 are essential for protein trafficking, auxin homeostasis, and plant growth and development. Here, we report the role of NHX5 and NHX6 in brassinosteroid (BR) signaling. We found that hypocotyl growth was enhanced in nhx5 nhx6 under epibrassinolide (eBR) treatment. nhx5 nhx6 bri1 was insensitive to eBR treatment, indicating that NHX5 and NHX6 are downstream of the BRI1 receptor in BR signaling. Moreover, confocal observation with both hypocotyls and root tips showed that BRI1-YFP localization in the plasma membrane (PM) was reduced in nhx5 nhx6. Interestingly, brefeldin A (BFA) treatment showed that formation of the BFA bodies containing BRI1 and their disassembling were disrupted in nhx5 nhx6. Further genetic analysis showed that NHX5/NHX6 and SYP22 may act coordinately in BR signaling. NHX5 and NHX6 may regulate SYP22 function by modulating cellular K+ and pH homeostasis. Importantly, NHX5 and NHX6 colocalize and interact with SYP22, but do not interact with BRI1. In summary, our findings indicate that NHX5/NHX6/SYP22 complex is essential for the regulation of BRI1 recycling and PM localization. The H+-leak facilitated by NHX5 and NHX6 offers a means of controlling BR signaling in plants.

Physical therapy for acute and sub-acute low back pain: A systematic review and expert consensus.

OBJECTIVE: To review the effectiveness of different physical therapies for acute and sub-acute low back pain supported by evidence, and create clinical recommendations and expert consensus for physiotherapists on clinical prescriptions. DATA SOURCES: A systematic search was conducted in PubMed and the Cochrane Library for studies published within the previous 15 years. REVIEW METHODS: Systematic review and meta-analysis, randomized controlled trials assessing patients with acute and sub-acute low back pain were included. Two reviewers independently screened relevant studies using the same inclusion criteria. The Physiotherapy Evidence Database and the Assessment of Multiple Systematic Reviews tool were used to grade the quality assessment of randomized controlled trials and systematic reviews, respectively. The final recommendation grades were based on the consensus discussion results of the Delphi of 22 international experts. RESULTS: Twenty-one systematic reviews and 21 randomized controlled trials were included. Spinal manipulative therapy and low-level laser therapy are recommended for acute low back pain. Core stability exercise/motor control, spinal manipulative therapy, and massage can be used to treat sub-acute low back pain. CONCLUSIONS: The consensus statements provided medical staff with appliable recommendations of physical therapy for acute and sub-acute low back pain. This consensus statement will require regular updates after 5-10 years.

Study on mechanical properties and acoustic emission characteristics of deep diorite under uniaxial compression.

The research object is diorite in the Lingbei TBM section of the Hanjiang-To-Weihe River Qinling tunnel, with a buried depth of over 1 km. Using MTS-2000 microcomputer-controlled electro-hydraulic servo universal testing machine and DS5-16b acoustic emission (AE) monitoring system, uniaxial compression and acoustic emission monitoring tests were carried out on rock samples, to study the uniaxial compression mechanical properties and acoustic emission characteristics of the deep diorite. The results of the study indicate that: (1) During uniaxial compression, diorite undergoes four stages: initial compaction, elasticity, yield and failure, in which the curve of the initial compaction stage is significantly smoother. The uniaxial compressive strength is 41.95 MPã102.42 MPa, with an average of 74.07 Mpa; The axial peak strain ranges from 1 % to 1.4 %, and the failure mode belongs to brittle ductile splitting failure. (2) The cumulative ringing count and energy showed a very slow increase trend during the calm period; After entering a surge period (with the appearance of Kaiser points), both show a significant transition state; During the slow increase period, the overall growth rate of the two slowed down and remained almost silent. (3) On the basis of the analysis of RA-AF values during the deformation and rupture process of diorite, it can be seen that the damage type of diorite is tensile damage by the significant low RA value and high AF value characteristics, which coincides with the actual damage fracture characteristics of the rocks in the sample. (4) During the compaction stage, there are few acoustic emission location points, which correspond to low energy and are mainly distributed at the higher and lower ends of the sample; After entering the elasticity stage, the number of positioning points significantly increases and gradually expands towards the middle; Near Kaiser point, the number of location points and corresponding energy are both in a sharp increase state, and this trend is in good agreement with the changes in the ringing count-time and energy-time curves. (5) The damage time mainly starts at the end of the calm period, and the pattern of change in the damage curve coincides with the localization point and energy evolution. The results of the research can be used as a referential basis for the development of the excavation, protection and other construction plans for the Lingbei TBM section of the Hanjiang-To-Weihe River Qinling tunnel or similar surrounding rock tunnels, as well as for further conducting triaxial unloading tests on diorite.

The signalling pathways, calcineurin B-like protein 5 (CBL5)-CBL-interacting protein kinase 8 (CIPK8)/CIPK24-salt overly sensitive 1 (SOS1), transduce salt signals in seed germination in Arabidopsis.

For plant growth under salt stress, sensing and transducing salt signals are central to cellular Na+ homoeostasis. The calcineurin B-like protein (CBL)-CBL-interacting protein kinase (CIPK) complexes play critical roles in transducing salt signals in plants. Here, we show that CBL5, an ortholog of CBL4 and CBL10 in Arabidopsis, interacts with and recruits CIPK8/CIPK24 to the plasma membrane. Yeast cells coexpressing CBL5, CIPK8/CIPK24 and SOS1 demonstrated lesser Na+ accumulation and a better growth phenotype than the untransformed or SOS1 transgenic yeast cells under salinity. Overexpression of CBL5 improved the growth of the cipk8 or cipk24 single mutant but not the cipk8 cipk24 double mutant under salt stress, suggesting that CIPK8 and CIPK24 were the downstream targets of CBL5. Interestingly, seed germination in cbl5 was severely inhibited by NaCl, which was recovered by the overexpression of CBL5. Furthermore, CBL5 was mainly expressed in the cotyledons and hypocotyls, which are essential to seed germination. Na+ efflux activity in the hypocotyls of cbl5 was reduced relative to the wild-type under salt stress, enhancing Na+ accumulation. These findings indicate that CBL5 functions in seed germination and protects seeds and germinating seedlings from salt stress through the CBL5-CIPK8/CIPK24-SOS1 pathways.

Design, synthesis, and antifungal mechanism of carbaline fluorescent probes / 药学学报

Three carboline fluorescent probes F1-F3 were designed and synthesized, based on lead compound JYJ-19, an antifungal compound discovered previously by our group. The antifungal activity in vitro results showed that compound F1 had moderate antifungal activity (MIC80 = 32 μg·mL-1). The stokes shift of F1 is 70 nm. The fluorescent probe F1 has good optical properties and can be used for fluorescence imaging research. Subcellular localization experiments results showed that F1 was enriched in the mitochondria of fungal cells. The detection of intracellular reactive oxygen species levels shows that JYJ-19 enhances intracellular reactive oxygen species levels. The above results indicated that carboline compounds could exert antifungal effects by acting on fungal mitochondria.

Research progress of natural product evodiamine-based antitumor drug design strategies / 药学学报

Natural products are important sources for the discovery of anti-tumor drugs. Evodiamine is the main alkaloid component of the traditional Chinese herb Wu-Chu-Yu, and it has weak antitumor activity. In recent years, a number of highly active antitumor candidates have been discovered with a significant progress. This article reviews the research progress of evodiamine-based antitumor drug design strategies, in order to provide reference for the development of new drugs with natural products as leads.

Integrative proteomics and metabolomics study reveal enhanced immune responses by COVID-19 vaccine booster shot against Omicron SARS-CoV-2 infection.

Since its outbreak in late 2021, the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been widely reported to be able to evade neutralizing antibodies, becoming more transmissible while causing milder symptoms than previous SARS-CoV-2 strains. Understanding the underlying molecular changes of Omicron SARS-CoV-2 infection and corresponding host responses are important to the control of Omicron COVID-19 pandemic. In this study, we report an integrative proteomics and metabolomics investigation of serum samples from 80 COVID-19 patients infected with Omicron SARS-CoV-2, as well as 160 control serum samples from 80 healthy individuals and 80 patients who had flu-like symptoms but were negative for SARS-CoV-2 infection. The multiomics results indicated that Omicron SARS-CoV-2 infection caused significant changes to host serum proteome and metabolome comparing to the healthy controls and patients who had flu-like symptoms without COVID-19. Protein and metabolite changes also pointed to liver dysfunctions and potential damage to other host organs by Omicron SARS-CoV-2 infection. The Omicron COVID-19 patients could be roughly divided into two subgroups based on their proteome differences. Interestingly, the subgroup who mostly had received full vaccination with booster shot had fewer coughing symptom, changed sphingomyelin lipid metabolism, and stronger immune responses including higher numbers of lymphocytes, monocytes, neutrophils, and upregulated proteins related to CD4+ T cells, CD8+ effector memory T cells (Tem), and conventional dendritic cells, revealing beneficial effects of full COVID-19 vaccination against Omicron SARS-CoV-2 infection through molecular changes.

G-Quadruplex/Hemin-Mediated Polarity-Switchable and Photocurrent-Amplified System for Escherichia coli O157:H7 Detection.

The contamination of food by pathogens is a serious problem in global food safety, and current methods of detection are costly, time-consuming, and cumbersome. Therefore, it is necessary to develop rapid, portable, and sensitive assays for foodborne pathogens. In addition, assays for foodborne pathogens must be resistant to interference resulting from the complex food matrix to prevent false positives and negatives. In this study, hemin and reduced graphene oxide-MoS2 sheets (GMS) were used to design a near-infrared (NIR)-responsive photoelectrochemical (PEC) aptasensor with target-induced photocurrent polarity switching based on a hairpin aptamer (Hp) with a G-quadruplex motif. A ready-to-use analytical device was developed by immobilizing GMS on the surface of a commercial screen-printed electrode, followed by the attachment of the aptamer. In the presence of Escherichia coli O157:H7, the binding sites of Hp with the G-quadruplex motif were opened and exposed to hemin, leading to the formation of a G-quadruplex/hemin DNAzyme. Crucially, after binding to hemin, the charge transfer pathway of GMS changes, resulting in a switch of the photocurrent polarity. Further, G-quadruplex/hemin DNAzyme enhanced the cathodic photocurrent, and the proposed sensor exhibited a wide linear range ((25.0-1.0) × 107 CFU/mL), a low limit of detection (2.0 CFU/mL), and good anti-interference performance. These findings expand the applications of NIR-responsive PEC materials and provide versatile PEC methods for detecting biological analytes, especially for food safety testing.

Widely targeted metabolomics reveals the effect of different raw materials and drying methods on the quality of instant tea.

Introduction: Instant teas are particularly rich in tea polyphenols and caffeine and have great potential as food ingredients or additives to improve the quality of food and enhance their nutritional and commercial value. Methods: To determine the relationships between raw material, drying method, and sensory and other quality attributes, instant teas were prepared from three tea varieties, namely black, green and jasmine tea, using two drying methods, namely spray-drying (SD) and freeze-drying (FD). Results: Both the raw tea material and drying method influenced the quality of the finished instant teas. Black tea was quality stable under two drying, while green tea taste deteriorated much after SD. Jasmine tea must be produced from FD due to huge aroma deterioration after SD. FD produced instant tea with higher sensory quality, which was attributed to the lower processing temperature. Chemical compositional analysis and widely targeted metabolomics revealed that SD caused greater degradation of tea biochemical components. The flavonoids content changed markedly after drying, and metabolomics, combined with OPLS-DA, was able to differentiate the three varieties of tea. Instant tea preparations via SD often lost a large proportion of the original tea aroma compounds, but FD minimized the loss of floral and fruity aroma compounds. Changes in the tea flavonoids composition, especially during drying, contributed to the flavor development of instant tea. Discussion: These results will provide an practicle method for high-quality instant tea production through choosing proper raw tea material and lowering down drying temperature with non-thermal technologies like FD.

Addition of transarterial chemoembolization improves outcome of tyrosine kinase and immune checkpoint inhibitors regime in patients with unresectable hepatocellular carcinoma.

Background: Transarterial chemoembolization (TACE) is the standard treatment for hepatocellular carcinoma (HCC); the value of its combination with systemic therapy is worthy of further exploration. This study aimed to investigate the efficacy and safety of TACE combined with tyrosine kinase inhibitor (TKI) and immune checkpoint inhibitor (ICI) in the treatment of unresectable HCC. Methods: In this retrospective observational, single-center study, 147 patients with unresectable HCC were divided into a TACE group (n=98) and a non-TACE group (n=49) based on whether TACE was performed during TKI plus ICI therapy. The survival outcomes and adverse events (AEs) of the two groups were compared. Results: Data from patients with unresectable HCC who received TKI plus ICI treatment between July 2017 and April 2020 were collected. The median intrahepatic tumor size was 8.7 cm [interquartile range (IQR), 5.9-12.4 cm]. At data cut-off, overall survival (OS) of the TACE group was significantly longer than that of the non-TACE group (19.5 and 10.8 months, respectively, P=0.005). In the high-risk cohort (with main or contralateral portal vein tumor thrombi and/or bile duct invasion and/or a tumor burden >50% of liver), the OS of the TACE group was still longer than that of the non-TACE group (14.9 and 8.7 months, respectively, P=0.031). Major AEs were tolerated in both groups, and there was no significant difference in their incidence (34.7% and 30.6%, respectively, P=0.621). Conclusions: TACE treatment combined with TKI plus ICI regime resulted in longer OS than treatment with TKI plus ICI alone for patients with unresectable HCC.

Flavonoid synthesis in Lamiophlomis rotata from Qinghai-Tibet Plateau is influenced by soil properties, microbial community, and gene expression.

Lamiophlomis rotata is a medicinal plant in Qinghai-Tibet Plateau, in which flavonoid compounds are the major medicinal components. However, it remains unclear how flavonoid metabolism of L. rotata is influenced by soil properties and microbial community. In this study, we collected L. rotata seedlings and rhizosphere soils from five habitats ranging from 3750 to 4270 m of altitude and analyzed the effects of habitat conditions on flavonoid metabolism. The activities of peroxidase, cellulase, and urease were increased with altitude, while those of alkaline phosphatase, alkaline protease, and sucrase were decreased with altitude. Analysis of OTUs showed that the total number of bacterial genera was higher than that of fungal genera. The highest number of fungal genera was 132, and that of bacterial genera was 33 in Batang (BT) town in Yushu County at an altitude of 3880 m, suggesting that the fungal communities may play a critical role in L. rotata rhizosphere soils. Flavonoids in leaves and roots of L. rotata shared a similar pattern, with a trend of increasing levels with altitude. The highest flavonoid content measured, 12.94 mg/g in leaves and 11.43 mg/g in roots, was from Zaduo (ZD) County at an altitude of 4208 m. Soil peroxidases affected quercetin content in leaves of L. rotata, while the fungus Sebacina affected flavonoid content in leaves and roots of L. rotata. The expression of PAL, F3'H, FLS, and FNS genes showed a declining trend in leaves with altitude, while F3H showed an increasing trend in both leaves and roots. Overall, soil physicochemical properties and microbial community affect flavonoid metabolism in L. rotata in Qinghai-Tibet Plateau. The variations in flavonoid content and gene expression as well as their associations with soil factors revealed the complexity of the growth conditions and genetic makeup in L. rotata habitats of Qinghai-Tibet Plateau.

[Shaofu Zhuyu Decoction attenuates fibrosis in endometriosis through regulating PTEN/Akt/mTOR signaling pathway].

The present study aimed to investigate the protective role of Shaofu Zhuyu Decoction(SFZY) against endometriosis fibrosis in mice, and decipher the underlying mechanism through the phosphatase and tensin homolog deleted on chromosome ten(PTEN)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR) pathway. Eighty-five BALB/c female mice were randomly assigned into a blank group, a model group, high-, medium, and low-dose SFZY(SFZY-H, SFZY-M, and SFZY-L, respectively) groups, and a gestrinone suspension(YT) group. The model of endometriosis was induced by intraperitoneal injection of uterine fragments. The mice in different groups were administrated with corresponding groups by gavage 14 days after modeling, and the blank group and model group with equal volume of distilled water by gavage. The treatment lasted for 14 days. The body weight, paw withdrawal latency caused by heat stimuli, and total weight of dissected ectopic focus were compared between different groups. The pathological changes of the ectopic tissue were observed via hematoxylin-eosin(HE) and Masson staining. Real-time PCR was employed to measure the mRNA levels of α-smooth muscle actin(α-SMA) and collagen type Ⅰ(collagen-Ⅰ) in the ectopic tissue. The protein levels of PTEN, Akt, mTOR, p-Akt, and p-mTOR in the ectopic tissue were determined by Western blot. Compared with the blank group, the modeling first decreased and then increased the body weight of mice, increased the total weight of ectopic focus, and shortened the paw withdrawal latency. Compared with the model group, SFZY and YT increased the body weight, prolonged the paw withdrawal latency, and decreased the weight of ectopic focus. Furthermore, the drug administration, especially SFZY-H and YT(P<0.01), recovered the pathological and reduced the area of collagen deposition. Compared with the blank group, the modeling up-regulated the mRNA levels of α-SMA and collagen-Ⅰ in the ectopic focus, and such up-regulation was attenuated after drug intervention, especially in the SFZY-H and YT groups(P<0.05,P<0.01). Compared with the blank group, the modeling down-regulated the protein level of PTEN and up-regulated the protein levels of Akt, mTOR, p-Akt, and p-mTOR(P<0.01, P<0.001). Drug administration, especially SFZY-H and YT, restored such changes(P<0.01). SFZY may significantly attenuate the focal fibrosis in the mouse model of endometriosis by regulating the PTEN/Akt/mTOR signaling pathway.

[Integrated management during the perinatal period for total anomalous pulmonary venous connection]. / å®Œå ¨æ€§è‚ºé™è„‰å¼‚ä½è¿žæŽ¥çš„å›´ç”ŸæœŸä¸€ä½“åŒ–ç®¡ç†.

OBJECTIVES: To evaluate the clinical effectiveness of integrated management during the perinatal period for fetuses diagnosed with total anomalous pulmonary venous connection (TAPVC) by prenatal echocardiography. METHODS: Clinical data of 64 cases of TAPVC fetuses diagnosed by prenatal echocardiography and managed with integrated perinatal care in Qingdao Women and Children's Hospital from January 2017 to December 2021 were retrospectively analyzed. Integrated perinatal care included multidisciplinary collaboration among obstetrics, fetal medicine, ultrasound, pediatric cardiology, pediatric anesthesia, and neonatology. RESULTS: Among the 64 TAPVC fetuses, there were 29 cases of supracardiac type, 27 cases of intracardiac type, 2 cases of infracardiac type, and 6 cases of mixed type. Chromosomal analysis was performed in 42 cases, and no obvious abnormalities were found. Among the 64 TAPVC fetuses, 37 were induced labor, and 27 were followed up until term birth. Among the 27 TAPVC cases, 2 cases accepted palliative care, 2 cases were referred to another hospital for treatment and lost to follow-up, while the remaining 23 cases underwent primary repair surgery. One case died within 6 months after the operation due to low cardiac output syndrome, while the other 22 cases were followed up for (2.1±0.3) years with good outcomes (2 cases underwent a second surgery within 1 year after the first operation due to anastomotic stenosis or pulmonary vein stenosis). CONCLUSIONS: TAPVC fetuses can achieve good outcomes with integrated management during the perinatal period.

Plastid KEA-type cation/H+ antiporters are required for vacuolar protein trafficking in Arabidopsis.

Arabidopsis plastid antiporters KEA1 and KEA2 are critical for plastid development, photosynthetic efficiency, and plant development. Here, we show that KEA1 and KEA2 are involved in vacuolar protein trafficking. Genetic analyses found that the kea1 kea2 mutants had short siliques, small seeds, and short seedlings. Molecular and biochemical assays showed that seed storage proteins were missorted out of the cell and the precursor proteins were accumulated in kea1 kea2. Protein storage vacuoles (PSVs) were smaller in kea1 kea2. Further analyses showed that endosomal trafficking in kea1 kea2 was compromised. Vacuolar sorting receptor 1 (VSR1) subcellular localizations, VSR-cargo interactions, and p24 distribution on the endoplasmic reticulum (ER) and Golgi apparatus were affected in kea1 kea2. Moreover, plastid stromule growth was reduced and plastid association with the endomembrane compartments was disrupted in kea1 kea2. Stromule growth was regulated by the cellular pH and K+ homeostasis maintained by KEA1 and KEA2. The organellar pH along the trafficking pathway was altered in kea1 kea2. Overall, KEA1 and KEA2 regulate vacuolar trafficking by controlling the function of plastid stromules via adjusting pH and K+ homeostasis.

Proteomic investigation and biomarker identification of lung and spleen deficiency syndrome in HIV/AIDS immunological nonresponders.

Background: Human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) immunological nonresponders (HIV/AIDS-INRs) whose CD4+ cell counts do not rebound after highly active antiretroviral therapy (HAART) treatment usually experience severely impaired immune function and high mortality. Traditional Chinese medicine (TCM) has many advantages in the field of AIDS, especially its promotion of patients' immune reconstitution. Accurate differentiation of TCM syndromes is a prerequisite for guiding an effective TCM prescription. However, the objective and biological evidence for identification of the TCM syndromes in HIV/AIDS-INRs remains lacking. Lung and spleen deficiency (LSD) syndrome, a typical HIV/AIDS-INR syndrome, was examined on in this study. Methods: We first performed a proteomic study of LSD syndrome in INRs (INRs-LSD) using tandem mass tag combined with liquid chromatography-tandem mass spectrometry (TMT-LC-MS/MS) and screened them against the healthy and undocumented identifiable groups. The TCM syndrome-specific proteins were subsequently validated based on bioinformatics analysis and enzyme-linked immunosorbent assay (ELISA). Results: A total of 22 differentially expressed proteins (DEPs) were screened in INRs-LSD compared to the healthy group. Based on bioinformatic analysis, these DEPs were found to be mainly associated with the immunoglobin A (IgA)-generated intestinal immune network. In addition, we examined the TCM syndrome-specific proteins alpha-2-macroglobulin (A2M) and human selectin L (SELL) with ELISA and found that they were both upregulated, which was consistent with the proteomic screening results. Conclusions: A2M and SELL were finally identified as potential biomarkers for INRs-LSD, providing a scientific and biological basis for identifying typical TCM syndromes in HIV/AIDS-INRs and an opportunity to build a more effective TCM treatment system for HIV/AIDS-INRs.

Prohexadione-calcium alleviates the leaf and root damage caused by salt stress in rice (Oryza sativa L.) at the tillering stage.

Salt stress, as a principal abiotic stress, harms the growth and metabolism of rice, thus affecting its yield and quality. The tillering stage is the key growth period that controls rice yield. Prohexadione-calcium (Pro-Ca) can increase the lodging resistance of plants by reducing plant height, but its effects on rice leaves and roots at the tillering stage under salt stress are still unclear. This study aimed to evaluate the ability of foliar spraying of Pro-Ca to regulate growth quality at the rice tillering stage under salt stress. The results showed that salt stress reduced the tillering ability of the rice and the antioxidant enzyme activity in the roots. Salt stress also reduced the net photosynthetic rate (Pn), stomatal conductance (Gs) and intercellular CO2 concentration (Ci) of the rice leaves and increased the contents of osmotic regulatory substances in the leaves and roots. The application of exogenous Pro-Ca onto the leaves increased the tiller number of the rice under salt stress and significantly increased the photosynthetic capacity of the leaves. Additionally, it increased the activities of antioxidant enzymes and the AsA content. The contents of an osmotic regulation substance, malondialdehyde (MDA), and H2O2 in the leaves and roots also decreased. These results suggested that Pro-Ca can increase the tillering ability, photosynthetic capacity, osmotic adjustment substance content levels and antioxidant enzyme activity levels in rice and reduce membrane lipid peroxidation, thus improving the salt tolerance of rice at the tillering stage.

Prohexadione calcium enhances rice growth and tillering under NaCl stress.

Salt stress affects crop quality and reduces crop yields, and growth regulators enhance salt tolerance of crop plants. In this report, we examined the effects of prohexadione-calcium (Pro-Ca) on improving rice (Oryza sativa L.) growth and tillering under salt stress. We found that NaCl stress inhibited the growth of two rice varieties and increased malondialdehyde (MDA) levels, electrolyte leakage, and the activities of the antioxidant enzymes. Foliar application of Pro-Ca reduced seedling height and increased stem base width and lodging resistance of rice. Further analyses showed that Pro-Ca application reduced MDA content, electrolyte leakage, and membrane damage in rice leaves under NaCl stress. Pro-Ca enhanced the net photosynthetic rate (Pn), stomatal conductance (Gs), and intercellular CO2 concentration (Ci) of rice seedlings, while increasing the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbic acid peroxidase (APX) at the tillering stage under salt stress. Overall, Pro-Ca improves salt tolerance of rice seedlings at the tillering stage by enhancing lodging resistance, reducing membrane damages, and enhancing photosynthesis and antioxidant capacities of rice seedlings.