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Summary Background Chemoprevention of colorectal adenoma and colorectal cancer remains an important public health goal. The present study aimed to investigate the clinical potential and safety of berberine for prevention of colorectal adenoma recurrence. Methods This double-blind, randomised, placebo-controlled trial was done in seven hospital centres across six provinces in China. Individuals aged 18–75 years who had at least one but no more than six histologically confirmed colorectal adenomas that had undergone complete polypectomy within the 6 months before recruitment were recruited and randomly assigned (1:1) to receive berberine (0·3 g twice daily) or placebo tablets via block randomisation (block size of six). Participants were to undergo a first follow-up colonoscopy 1 year after enrolment, and if no colorectal adenomas were detected, a second follow-up colonoscopy at 2 years was planned. The study continued until the last enrolled participant reached the 2-year follow-up point. All participants, investigators, endoscopists, and pathologists were blinded to treatment assignment. The primary efficacy endpoint was the recurrence of adenomas at any follow-up colonoscopy. Analysis was based on modified intention-to-treat, with the full analysis set including all randomised participants who received at least one dose of study medication and who had available efficacy data. The study is registered with ClinicalTrials.gov , number NCT02226185 ; the trial has ended and this report represents the final analysis. Findings Between Nov 14, 2014, and Dec 30, 2016, 553 participants were randomly assigned to the berberine group and 555 to the placebo group. The full analysis set consisted of 429 participants in the berberine group and 462 in the placebo group. 155 (36%) participants in the berberine group and 216 (47%) in the placebo group were found to have recurrent adenoma during follow-up (unadjusted relative risk ratio for recurrence 0·77, 95% CI 0·66–0·91; p=0·001). No colorectal cancers were detected during follow-up. The most common adverse event was constipation (six [1%] of 446 patients in the berberine group vs one [ Interpretation Berberine 0·3 g twice daily was safe and effective in reducing the risk of recurrence of colorectal adenoma and could be an option for chemoprevention after polypectomy. Funding National Natural Science Foundation of China.

Hydrogen sulfide (H

Salicylic acid (SA) is the phytohormone responsible for the regulation of growth and response to environmental stress in plants. In the present study, the application of 1 μM SA significantly enhanced the SA content in rice roots and improved their growth when affected by Al toxicity by concomitantly decreasing the Al content of the root apex. The addition of SA significantly inhibited the synthesis of pectin and hemicellulose, suppressed the activity of pectin methylesterase (PME), and decreased the cell wall Al content. The expression of OsSTAR1 (sensitive to Al rhizotoxicity) and OsSTAR2 was induced by SA to mask the Al-binding sites in the cell walls. The expression of OsALS1 (Al sensitive) was also stimulated by SA, which improved the transport of cytoplasmic Al into the vacuoles. In rice affected by Al toxicity, SA significantly increased the activity of catalase and peroxidase and reduced the H2O2 content and malondialdehyde content. The expression of OsACS1 (ACC synthase) and OsACO1 (ACC oxidase) was inhibited by SA and thus inhibited ethylene emission. The addition of ethylene precursor 1-aminocylopropane-1-carboxylic acid (ACC) along with SA under Al toxicity conditions aggravated the inhibition of root elongation, accompanied by an increased Al content in the root apex and cell walls, increased pectin content, and rendered PME activity greater than with single Al treatment. However, the addition of aminoethoxyvinylglycine (AVG, inhibitor of the ACC synthase) along with SA under Al toxicity conditions showed the opposite effect, indicating that SA inhibited ethylene emission, thus reducing the Al deposition on cell walls.

When boron (B) deficiency and aluminum (Al) toxicity co-exist in acidic soils, crop productivity is limited. In the current study, we found that 3 μM of B pretreatment significantly enhances rice root elongation under Al toxicity conditions. Pretreatment with B significantly decreases the deposition of Al in rice apoplasts, suppresses the synthesis of cell wall pectin, inhibits cell wall pectin methylesterase (PME) activity and its gene expression, and increases the expression of OsSTAR1 and OsSTAR2, which are responsible for reducing the Al content in the cell walls. In addition, B pretreatment significantly increases OsALS1 expression, thereby facilitating the transfer of Al from the cytoplasm to the vacuoles. However, B pretreatment had no effect on Al uptake and citric acid secretion. Pretreatment with B significantly increases the activity of ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT), thus increasing the elimination rate of H2O2 in rice roots. Co-treatment using B and H2O2 does not increase root growth under Al toxicity conditions; it also improves pectin synthesis, enhances PME activity, and increases Al deposition in root cell walls. However, the co-treatment of B and H2O2 scavenger 4-hydroxy-TEMPO has an opposite effect. The above results indicate that applying B fertilizers in acidic soil can help decrease the side effects of Al toxicity on rice growth.

Aluminum (Al3+ ) toxicity in acidic soils limits crop productivity worldwide. In this study, we found that putrescine (PUT) significantly alleviates Al toxicity in rice roots. The addition of 0.1 mM PUT promoted root elongation and reduced the Al content in the root apices of Nipponbare (Nip) and Kasalath (Kas) rice under Al toxicity conditions. Exogenous treatment with PUT reduced the cell wall Al content by reducing polysaccharide (pectin and hemicellulose) levels and pectin methylesterase (PME) activity in roots and decreased the translocation of Al from the external environment to the cytoplasm by downregulating the expression of OsNRAT1, which responsible to encode an Al transporter protein Nrat1 (Nramp aluminum transporter 1). The addition of PUT under Al toxicity conditions significantly inhibited ethylene emissions and suppressed the expression of genes involved in ethylene biosynthesis. Treatment with the ethylene precursor 1-aminocylopropane-1-carboxylic acid (ACC) significantly improved ethylene emission, inhibited root elongation, increased the Al accumulation in root tips and the root cell wall, and increased cell wall pectin and hemicellulose contents in both rice cultivars under Al toxicity conditions. The ethylene biosynthesis antagonist aminoethoxyvinylglycine (AVG, inhibitor of the ACC synthase) had the opposite effect and reduced PME activity. Together, our results show that PUT decreases the cell wall Al contents by suppressing ethylene emissions and decreases the symplastic Al levels by downregulating OsNRAT1 in rice.

Hydrogen sulfide (H2S) improves aluminum (Al) resistance in rice; however, the underlying molecular mechanism remains unclear. In the present study, treatment with 30-μM Al significantly inhibited rice root growth and increased the total Al content and apoplastic and cytoplasm Al concentration in the rice roots. However, pretreatment with NaHS (H2S donor) reversed these negative effects. Transcriptomics and physiological experiments confirmed that H2S increased the ATP, sucrose, glutathione, and ascorbic acid contents, which was accompanied by decreased O2·- and H2O2 contents, to alleviate Al toxicity. H2S significantly inhibited ethylene emissions in the rice and then inhibited pectin synthesis and increased the pectin methylation degree to reduce cell wall Al deposition. The phytohormones indole-3-acetic and brassinolide were also involved in the alleviation of Al toxicity by H2S. In addition, other pathways of material and energy metabolism, secondary metabolism, cell wall components, signal transduction, and transcriptional and translational pathways in the rice roots were also regulated by H2S under Al toxicity conditions. These findings improve our understanding of how H2S affects rice responses to Al toxicity, which will facilitate further studies on crop safety.

BACKGROUND In neutral or alkaline soils, iron (Fe) easily forms insoluble complexes, which makes it difficult for plants to utilize Fe in the soil for nutrition. Polyester sulfur-coated urea (PSCU) is a novel controlled-release fertilizer widely used in China and some foreign countries, and it has been proven that sulfur film from controlled-release fertilizers can significantly improve the activation of Fe and other elements in the soil. However, few studies have focused on the effects of PSCU application on Fe accumulation in rice grain in alkaline soils. RESULTS Both our field and pot experiments proved that PSCU application could significantly improve rice grain yield and Fe concentration in brown rice in alkaline soil. This effect differs with different types of alkaline soils (i.e. medium-saline, sandy soil and/or silt soil). PSCU is released slowly, and the release rate is different in different alkaline soils. Rice shoot nitrogen (N) uptake was significantly enhanced with PSCU application. CONCLUSION The results suggested that PSCU application in alkaline soils could significantly enhance brown rice Fe concentration and production. This effect differed with different kinds of alkaline soils. The study identified some efficient fertilizers to improve the Fe status in alkaline soils. © 2021 Society of Chemical Industry.

Water and nitrogen are two important factors controlling rice growth and development. Suitable water-nitrogen interaction can alter nitrogen forms and oxygen environmental factors via regulating water content in the rhizosphere of paddy soil, promote the construction of root morphology, improve leaf photosynthesis and the allocation equilibrium of the photosynthetic products between the source and sink organs, and consequently increase rice population quality and grain yield. The microbial regulation mechanisms driven by the environmental factors (水分和氮素是影响水稻生长发育的两个重要环境因子。适宜的水氮耦合模式可通过“以水调氮、以水控氧”调控稻田根际氮形态和溶氧量等环境因子,促进良好根系形态构建,提高叶片光合速率和光合产物“源-库”分配平衡,提高水稻群体质量和产量形成。同时,稻田水氮氧环境因子驱动的微生物调控机制在水稻-土壤系统氮高效利用方面也发挥重要作用。本文重点阐述了水氮耦合下水分、氮形态和溶氧量对水稻生长发育、光合作用、碳氮代谢、稻田氮转化过程及其微生物调控机制等方面的研究进展,展望并提出了未来亟待加强的研究方向:1)开展水氮耦合下水稻根际溶氧量时空动态分布特征及氧环境调控关键因子研究;2)明确不同基因型水稻根源信号增氧响应特征及其对水稻生长发育的影响调控机制;3)阐明根际氧环境驱动的关键微生物过程对稻田氮转化和氮素利用的影响。.

Background Abscisic acid (ABA) and proline play important roles in rice acclimation to different stress conditions. To study whether cross-talk exists between ABA and proline, their roles in rice acclimation to hypoxia, rice growth, root oxidative damage and endogenous ABA and proline accumulation were investigated in two different rice genotypes (‘Nipponbare’ (Nip) and ‘Upland 502’ (U502)). Results Compared with U502 seedlings, Nip seedlings were highly tolerant to hypoxic stress, with increased plant biomass and leaf photosynthesis and decreased root oxidative damage. Hypoxia significantly stimulated the accumulation of proline and ABA in the roots of both cultivars, with a higher ABA level observed in Nip than in U502, whereas the proline levels showed no significant difference in the two cultivars. The time course variation showed that the root ABA and proline contents under hypoxia increased 1.5- and 1.2-fold in Nip, and 2.2- and 0.7-fold in U502, respectively, within the 1 d of hypoxic stress, but peak ABA production (1 d) occurred before proline accumulation (5 d) in both cultivars. Treatment with an ABA synthesis inhibitor (norflurazon, Norf) inhibited proline synthesis and simultaneously aggravated hypoxia-induced oxidative damage in the roots of both cultivars, but these effects were reversed by exogenous ABA application. Hypoxia plus Norf treatment also induced an increase in glutamate (the main precursor of proline). This indicates that proline accumulation is regulated by ABA-dependent signals under hypoxic stress. Moreover, genes involved in proline metabolism were differentially expressed between the two genotypes, with expression mediated by ABA under hypoxic stress. In Nip, hypoxia-induced proline accumulation in roots was attributed to the upregulation of OsP5CS2 and downregulation of OsProDH, whereas upregulation of OsP5CS1 combined with downregulation of OsProDH enhanced the proline level in U502. Conclusion These results suggest that the high tolerance of the Nip cultivar is related to the high ABA level and ABA-mediated antioxidant capacity in roots. ABA acts upstream of proline accumulation by regulating the expression of genes encoding the key enzymes in proline biosynthesis, which also partly improves rice acclimation to hypoxic stress. However, other signaling pathways enhancing tolerance to hypoxia in the Nip cultivar still need to be elucidated.

NH4+ and NO3− are two major nitrogen sources that differentially affect the uptake and transfer of other nutrients in rice (Oryza sativa), although their effects on Fe remobilization under Fe-starvation conditions are largely unknown. Here, by investigating the rice cultivar ‘Kasalath’ (Kas), which is tolerant of nutrient-deficient soil, we found that NH4+ negatively regulates the hemicellulose 1 content in root cell walls and stimulates the secretion of phenolic compounds from roots under −Fe conditions, thus facilitating the release of cell wall Fe and increasing soluble Fe levels in roots. NH4+ significantly increased the translocation of Fe from root to shoot by upregulating the expression of OsFRDL1 in roots and increasing the Fe content in the xylem. We further found that the higher putrescine content in rice roots under NH4+ conditions led to a higher nitric oxide (NO) content compared with NO3− conditions, and that NO is involved in the NH4+-stimulated cell wall Fe reutilization. The addition of the NO donor sodium nitroprusside significantly reduced the hemicellulose 1 content in cell walls and increased Fe release from cell walls, ultimately increasing the soluble Fe content in rice and alleviating chlorosis under −Fe conditions. Taken together, our findings demonstrate that NH4+ promotes Fe remobilization from the cell wall in rice.

Background: Chemoprevention of colorectal adenoma and cancer remains its importance in public health. The rate of adenoma recurrence in the first year after polypectomy is very high in East Asian populations. We aimed to investigate the clinical potential and safety of Berberine hydrochloride for colorectal adenoma recurrence. Methods: This double-blind, randomised, placebo-controlled clinical trial was done in seven hospital centers across six provinces in China. Patients with recently diagnosed adenomas and after complete polypectomy were recruited and randomized into a BBR group (Berberine hydrochloride 0.3g, twice daily) or a placebo group. They were anticipated for at least one follow-up colonoscopy until a diagnosis of CRA/CRC or the last enrolled patient reached the 2-year follow-up. The primary efficacy endpoint was the recurrence of adenomas at any follow-up colonoscopy. The secondary outcomes were the recurrences of polypoid lesions as well as advanced adenomas or CRC. Findings: Between Nov 14, 2014 and Dec 29, 2018, 1136 patients were screened for eligibility, and 1108 underwent randomization. 553 patients were assigned to receive Berberine hydrochloride and 555 to placebo. An unadjusted RR for recurrent adenomas and all polypoid lesions were 0.77 (95% CI, 0.66 to 0.91) and 0.77 (95% CI, 0.67 to 0.89), representing a decrease of 22.72% and 22.70%, respectively. No CRC occurred during the whole trial. Interaction test showed taking BBR was effective in female with unadjusted RR for recurrent adenomas of 0.58 (95% CI, 0.41 to 0.81); P=0.07 (Alpha = 0.10). No serious adverse events were reported. Interpretation: Although the mechanism has not been fully elucidated yet, Berberine hydrochloride was effective to reduce colorectal adenoma recurrence after polypectomy. Trial Registration: This trial is registered with ClinicalTrials.gov number NCT02226185. Funding Statement: This project was supported by grants from the National Natural Science Foundation of China (81421001, 81530072, 81830081 and 8177100232), the funds from Shanghai Shenkang Center (SHDC12018121), from Shanghai Municipal Key Clinical Specialty, and from Innovative research team of high-level local universities in Shanghai. The project was also partially supported by Top-Notch project of China and Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant (20152514). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: Approval for this study was obtained from the Ethics Committee of Renji Hospital, Shanghai Jiao-Tong University School of Medicine on 13th August 2014. The protocol and informed consent forms were also approved by the institutional ethics committees at each of the participating clinical centers.

When boron (B) deficiency and aluminum (Al) toxicity co-exist in acidic soils, crop productivity is limited. In the current study, we found that 3 μM of B pretreatment significantly enhances rice root elongation under Al toxicity conditions. Pretreatment with B significantly decreases the deposition of Al in rice apoplasts, suppresses the synthesis of cell wall pectin, inhibits cell wall pectin methylesterase (PME) activity and its gene expression, and increases the expression of OsSTAR1 and OsSTAR2, which are responsible for reducing the Al content in the cell walls. In addition, B pretreatment significantly increases OsALS1 expression, thereby facilitating the transfer of Al from the cytoplasm to the vacuoles. However, B pretreatment had no effect on Al uptake and citric acid secretion. Pretreatment with B significantly increases the activity of ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT), thus increasing the elimination rate of H

In plants, different forms of nitrogen (NO3− or NH4+) affect nutrient uptake and environmental stress responses. In the present study, we tested whether NO3− and NH4+ affect the ability of rice (Oryza sativa) to tolerate the toxic heavy metal cadmium (Cd). Compared with NO3−, NH4+ treatment significantly increased chlorophyll contents and reduced Cd2+ levels in rice cultivars Nipponbare (japonica) and Kasalath (indica) grown in 0.2 mM Cd2+. NH4+ significantly reduced the pectin and hemicellulose contents and inhibited the pectin methylesterase (PME) activity in rice roots, thereby reducing the negative charges in the cell wall and decreasing the accumulation of Cd2+ in roots. In addition, NH4+ reduced the absorption and root-to-shoot translocation of Cd2+ by decreasing the expression of OsHMA2 and OsNramp5 in the root. Levels of the signaling molecule putrescine were significantly higher in the roots of both rice cultivars provided with NH4+ compared with NO3−. The addition of putrescine reduced Cd2+ contents in both rice cultivars and increased the chlorophyll content in shoots by reducing root cell wall pectin and hemicellulose contents, inhibiting PME activity and suppressing the expression of OsHMA2 and OsNramp5 in the root. Taken together, these results indicate that NH4+ treatment alleviated Cd toxicity, enabling rice to withstand the noxious effects of Cd by modifying the cell wall Cd-binding capacity due to alterations of pectin and hemicellulose contents and Cd transport, processes induced by increasing putrescine levels. Our findings suggest methods to decrease Cd accumulation in rice by applying NH4+ fertilizers.

Organic nitrogen can play an important role in plant growth, and soil pH changed greatly due to the over-use of chemical fertilizers, but the effects of soil pH on the competitive uptake of amino acids by plants and rhizosphere microorganisms are lack of detailed research. To study the effects of soil pH on the uptake of amino acids by maize and soil microorganisms, two soils from Hangzhou and Tieling were selected, and the soil pH was changed by the electrokinesis, then the化学合成肥料的大量使用导致土壤pH发生显著变化,但其对植物与根际微生物竞争吸收氨基酸的影响机制尚不明确.本试验通过电解法调节杭州红壤和铁岭棕壤两种土壤pH, 采用外源添加

Phosphorus (P) deficiency limits rice production. Increasing the remobilization of P stored in the root cell wall is an efficient way to alleviate P starvation in rice. In the current study, we found that the addition of 50 μM H2O2 significantly increased soluble P content in rice. H2O2 stimulated pectin biosynthesis and increased pectin methylesterase (PME) activity, thus stimulating the release of P from the cell wall in roots. H2O2 also regulates internal P homeostasis by increasing the expression of P transporter genes OsPT2, OsPT6, and OsPT8 at different treatment times. In addition, the H2O2 treatment increased the expression of nitrate reductase (NR) genes OsNIA1 and OsNIA2 and the activity of NR, then increased the accumulation of nitric oxide (NO) in the rice root. The application of the NO donor sodium nitroprusside (SNP) and the H2O2 scavenger 4-hydroxy-TEMPO significantly increased soluble P content by increasing pectin levels and PME activity to enhance the remobilization of P from the cell wall. However, the addition of NO scavenger 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) with and without H2O2 had the opposite effect, suggesting that NO functions downstream of H2O2 to increase the remobilization of cell wall P in rice.

Yield decline from continuous cropping of aerobic rice is a constraint to the widespread adoption of plastic film mulching cultivation (PFMC); rice straw incorporation has been proposed to counter this negative effect of long term PFMC. Shifts in water management from flooded to aerobic conditions are known to influence the availability of N and might have an influence on rice quality. A long-term (2001–2010) field experiment was conducted to examine the effects of five fertilizer nitrogen (N) application rates (0, 45, 90, 135, 180 kg N ha−1) and rice straw incorporation on rice grain yield, milled rice quality and soil quality under PFMC in non-flooded conditions. There were significant responses in grain yield to various N fertilizer rates and rice straw incorporation during 2008 to 2010. Total amino acids and protein concentrations in polished rice increased with increasing N rates. Split-plot factor significantly affected soil fertility and rice plant N uptake in our study. With rice straw incorporation, total annual and mean amount of soil organic matter was improved by 6.4%, 7.6% and 12.2%; NH4OAC-extractable K amount was improved by 28.2%, 64.0% and 52.9%; N uptake was improved by 20.4%, 23.9% and 23.6%, respectively, from the year of 2008 to 2010. Dynamics of rice grain yield, soil organic matter, alkali-hydrolyzable N and NH4OAC-extractable K from 2001 to 2010 proved that rice straw incorporation obviously improved rice grain yield and soil quality under continuous PFMC. Our results suggest that there is a possibility of reversing yield decline observed in the continuous PFMC system by using rice straw incorporation.

The extraction and comparison of soil amino acids using different extractants (deionized water, K2SO4, Na2SO4, NaCl, KCl) were reported. Results showed that 0.5 mol L−1 K2SO4 with a 5 times extraction was a better method to assess the concentration of extractable amino acids in soils. The total amino acids extracted from soil planted for tea were similar to the total inorganic nitrogen. While they extracted from vegetable soil and paddy soil were much lower than the total inorganic nitrogen.

Objective: To investigate the amounts of extractable organic nitrogen (EON), and the relationships between EON and total extractable nitrogen (TEN), especially the amino acids (AAs) adsorbed by soils, and a series of other hydrolyzed soil nitrogen indices in typical land use soil types from southeast China. Under traditional agricultural planting conditions, the functions of EON, especially AAs in the rhizosphere and in bulk soil zones were also investigated. Methods: Pot experiments were conducted using plants of pakchoi (Brassica chinensis L.) and rice (Oryza sativa L.). In the rhizosphere and bulk soil zone studies, organic nitrogen components were extracted with either distilled water, 0.5 mol/L K2SO4 or acid hydrolysis. Results: K2SO4-EON constituted more than 30% of TEN pools. K2SO4-extractable AAs accounted for 25% of EON pools and nearly 10% of TEN pools in rhizosphere soils. Overall, both K2SO4-EON and extractable AAs contents had positive correlations with TEN pools. Conclusions: EON represented a major component of TEN pools in garden and paddy soils under traditional planting conditions. Although only a small proportion of the EON was present in the form of water-extractable and K2SO4-extractable AAs, the release of AAs from soil exchangeable sites might be an important source of organic nitrogen (N) for plant growth. Our findings suggest that the content of most organic forms of N was significantly greater in rhizosphere than in bulk soil zone samples. However, it was also apparent that the TEN pool content was lower in rhizosphere than in bulk soil samples without added N.

Plastic film mulching cultivation (PFMC) under non-flooded condition has been considered as a new water-saving technique in rice production, while yield decline from continuous cropping of aerobic rice is a constraint to the widespread adoption of PFMC. Rice straw incorporation has been proposed to counter this negative effect in recent decades. This study examined the effects of three cultivation methods and rice straw incorporation on rice grain yield and quality using "Liangyoupeijiu" (an indica hybrid). The three cultivation treatments were: conventional flooding cultivation (CFC); non-flooded plastic film mulching cultivation (PFMC); no mulching cultivation in non-flooded condition (NMC). Compared with that under CFC, average rice grain yield under PFMC from 2008 to 2010 was significantly improved by 8.0%, while total amino acids content was decreased by 3.5%, no obvious effect was observed on rice protein, Fe and Zn concentrations in rice; under NMC, the reduction in yield, protein, total amino acids and Fe concentrations were 5.1%, 4.4%, 9.3%, and 11.8%, respectively. With rice straw incorporation, grain yield was improved by 113.6, 142.6, and 522.1 kg ha 1 under CFC, NMC, and PFMC, respectively. Average rice grain yield, Fe and Zn contents in brown rice were significantly improved by 3.3%, 3.1%, and 6.4% with rice straw incorporation. The results of the three years showed the same trend in rice grain yield and nutrition quality. The results indicated that PFMC could improve not only grain yield, but also part of rice nutrition quality. Rice straw incorporation could significantly improved rice grain yield as well as Fe and Zn concentrations in brown rice, which would be a good method to overcome grain yield decline under long term PFMC.