Oryza Sativa Research Articles

Promotion of germination, rooting, and seedling emergence of rice (Oryza sativa L.) by soaking seeds in converter slag suspension before sowing

ABSTRACT Seed soaking is an important process in rice cultivation. Allowing seeds to absorb sufficient water before sowing improves their germinability, germination vigor, and seedling emergence. The use of converter slag, which is a fertilizer and soil amendment, can increase crop yields and suppress diseases. However, there are no reports on the effect of the converter slag on initial rice plant growth when applied at the seed soaking stage. In this study, we investigated the effects of soaking rice seeds in two types of converter slag suspensions on the early growth of rice plants from germination to seedling emergence. We conducted laboratory tests with simulated cultivation processes (germination forcing and root-elongation forcing). The seeds soaked in converter slag suspensions showed improved germinability and coleoptile elongation under anaerobic conditions, as well as improved rooting ability and seminal root elongation under aerobic conditions. Seeds soaked in converter slag suspensions and water were sown using five sowing methods (standard seedling raising; Japanese-type direct sowing at surface, shallow, and deep soil depths; and Italian-type direct sowing). Overall, the seedlings that grew from seeds treated with the converter slag suspensions showed faster seedling emergence and better growth. These results show that soaking seeds in Ca2+-rich converter slag suspensions can promote the early growth of rice plants by avoiding low-oxygen disorders and improve subsequent seedling establishment. Thus, converter slag suspensions are suitable for germination but unsuitable for microbial growth due to high alkaline conditions (pH 11–11.5), which may omit both water changes and germination forcing process.

Impact of hydro-priming durations on viability, growth and seed yield of two rice (<i>Oryza sativa</i>) varieties

Impact of hydro-priming durations on viability, growth and seed yield of two rice (<i>Oryza sativa</i>) varieties

Impact of Nano Zinc and Consortia on Growth, Yield Attributes and Yield of Rice (Oryza sativa) in Central Zone of Uttar Pradesh

This field study evaluated the effect of various nutrient sources, including NPK, farmyard manure (FYM), consortia, and nano zinc, on rice (Oryza sativa) growth, yield, and soil quality in the Central Zone of Uttar Pradesh. Fourteen treatments were tested using a randomized block design with three replications. The treatment combining 75% NPK, FYM @ 5 tons/ha, consortia, and nano zinc (T8) consistently showed superior results, with the highest plant height (97.09 cm at harvest), maximum dry matter accumulation (36.49 g/m²), and the most effective tillers (181.20/m²). T8 also recorded a significantly higher grain yield (43.6 q/ha) compared to the control (19.79 q/ha). The results demonstrate that integrating FYM, consortia, and nano zinc with reduced NPK enhances rice growth and yield, supporting sustainable rice production in the region.

Studies on Genetic Variability and Heritability in Rice Genotypes (Oryza sativa. L.) under Salinity

Rice (Oryza sativa L.) is one of the most important staple food crops in the world because more than half of the world's population depends on rice for their livelihood. By 2050, the world's rice productivity will need to double in order to keep up with population growth. Narrow genetic base in the released variety has made the improvement in plateaus. In order to go more than the yield barrier, the genetic base must be broadened. Heritability and genetic variability were measured in eighty-six rice genotypes in terms of yield and yield contributing traits under saline soils. Significant differences were found between the genotypes for all of the studied traits according to analysis of variance. High PCV and GCV were recorded for the traits viz., mortality percentage (%), total number of grains per panicle, number of un-filled grains per panicle, sterility percentage (%) and seed yield per plant (g). The traits showed a significant degree of genetic advancement together with high heritability were mortality percentage (%), 1000 grain weight (g) and seed yield per plant (g). Genetic advance over mean were high for mortality percentage (%), number of productive tillers/m2, total number of grains per panicle (g), number of un-filled grains per panicle (g), sterility percentage (%), 1000 grain weight (g) and seed yield per plant (g). This study provides information about the variability and heritability measures which may supplement the breeding program to break the yield plateaus.

Effect of Nano Urea and Nano DAP on Growth, Yield and Nutrient Uptake of Transplanted Rice (Oryza sativa L.)

Foliar nutrition is aimed to eliminate the problems of fixation and immobilization of nutrients. Hence, foliar nutrition is being recognized as a significant way of fertilizing modern agriculture, especially under rainfed conditions. Nano fertilizers because of smaller size and higher surface area are efficient as compared to conventional and produce better results when used in combined form. The experiment was laid out in Randomized complete block design with three replications. A field experiment was conducted in black clayey at Agricultural Research Station, Dhadesugur, during Kharif 2023. There were eight treatment combinations, consisting of different levels of conventional and nano fertilizers. RDF - 150:75:75 kg N:P2O5:K2O ha-1 and 50 % of N, entire P and K were applied as basal and remaining 50 % of N was top dressed at tillering and panicle initiation stage. RNR- 15048 variety of transplanted rice. Application of 50 % Rec. N with soil application + 50 % Rec. N through nano urea with two applications (at tillering and panicle initiation stage) + Rec. P & K with soil application recorded significantly higher number of green leaves, leaf area and leaf area index at harvest (52.7, 954.8 cm2 plant-1 and 4.77, respectively). It also produced higher panicle length (20.1 cm), number of grains panicle-1 (242.3), panicle weight (3.73 g plant-1), test weight (19.1 g) and grain yield (5578 kg ha-1). Nutrient content and uptake also showed higher values for the same treatment. Combined application of conventional and nano fertilizers helped to increase growth, growth attributes like number of leaves, leaf area, leaf area index, yield attributes, yield, nutrient content and nutrient uptake of transplanted rice.

Four MYB transcription factors regulate suberization and non-localized lignification at the root endodermis in rice.

In response to variable environments, rice (Oryza sativa) roots have developed lignified and suberized diffusion barriers at the endodermis to permit selective nutrient uptake for optimal growth. Here, we demonstrate that endodermal suberization and non-localized lignification are redundantly regulated by four MYB transcription factors: OsMYB39a, OsMYB41, OsMYB92a, and OsMYB92b. These transcription factors function downstream of the OsMYB36a/b/c, CASPARIAN STRIP INTEGRITY FACTOR (OsCIF)-SCHENGEN3 (OsSGN3), and stress-inducible signaling pathways in rice. Knockout of all four MYB genes resulted in the complete absence of endodermal suberin lamellae (SL) and almost no lignin deposition between the Casparian strip and the cortex-facing lignified band at cell corners under all conditions examined. In contrast, endodermis-specific overexpression of any of these MYB genes was sufficient to induce strong endodermal suberization and non-localized lignification near the root tip. Furthermore, OsMYB92a-overexpressing lines showed an altered ionomic profile and enhanced salinity tolerance. Transcriptome analysis identified 152 downstream genes regulated by OsMYB39a/41/92a/92b, including the key SL formation gene OsCYP86A1 and other genes involved in endodermal lignification and suberization under normal and stress conditions. Our results provide important insights into the molecular mechanisms underlying suberization and non-localized lignification at the root endodermis and their physiological significance in ion homeostasis and acclimation to environmental stress.

Comprehensive Transcriptomic Analysis Reveals Defense-Related Genes and Pathways of Rice Plants in Response to Fall Armyworm (Spodoptera frugiperda) Infestation.

Rice (Oryza sativa L.) serves as a substitute for bread and is a staple food for half of the world's population, but it is heavily affected by insect pests. The fall armyworm (Spodoptera frugiperda) is a highly destructive pest, threatening rice and other crops in tropical regions. Despite its significance, little is known about the molecular mechanisms underlying rice's response to fall armyworm infestation. In this study, we used transcriptome analysis to explore the global changes in gene expression in rice leaves during a 1 h and 12 h fall armyworm feeding. The results reveal 2695 and 6264 differentially expressed genes (DEGs) at 1 and 12 h post-infestation, respectively. Gene Ontology (GO) and KEGG enrichment analyses provide insights into biological processes and pathways affected by fall armyworm feeding. Key genes associated with hormone regulation, defense metabolic pathways, and antioxidant and detoxification processes were upregulated, suggesting the involvement of jasmonic acid (JA) signaling, salicylic acid biosynthesis pathways, auxin response, and heat shock proteins in defense during 1 h and 12 h after fall armyworm infestation. Similarly, key genes involved in transcriptional regulation and defense mechanisms reveal the activation of calmodulins, transcription factors (TFs), and genes related to secondary metabolite biosynthesis. Additionally, MYB, WRKY, and ethylene-responsive factors (ERFs) are identified as crucial TF families in rice's defense response. This study provides a comprehensive understanding of the molecular dynamics in rice responding to fall armyworm infestation, offering valuable insights for developing pest-resistant rice varieties and enhancing global food security. The identified genes and pathways provide an extensive array of genomic resources that can be used for further genetic investigation into rice herbivore resistance. This also suggests that rice plants may have evolved strategies against herbivorous insects. It also lays the groundwork for novel pest-resistance techniques for rice.

Synergistic application of melatonin and silicon oxide nanoparticles modulates reactive oxygen species generation and the antioxidant defense system: a strategy for cadmium tolerance in rice.

Unfavorable environmental conditions pose a major barrier to sustainable agriculture. Among the various innovative strategies developed to protect plants from abiotic stress, the use of phytohormones and nanoparticles as "stress mitigators" has emerged as one of the most important and promising approaches. The objective of this study was to observe the protective role of melatonin (Mel) and silicon oxide nanoparticles (SiO-NPs) in rice (Oryza sativa L.) seedlings under cadmium (Cd) stress. Rice seedlings have reduced growth and phytochemical attributes when grown in Cd-contaminated (0.8 mM) pots. Seedlings under Cd stress had 38% less shoot length (SL), 53% total soluble sugar (TSS) and 57% protein content. However, superoxide dismutase (SOD), hydrogen peroxide (H2O2) and malondialdehyde (MDA) increased by 51%, 37% and 34%, respectively, under Cd stress. Beside this, activities such as peroxidase (POX) also elevated in the plants subjected with Cd-stress. In contrast, Mel (100 µm) as foliar spray and SiO-NPs (100 mg/L) as root dipping reduced oxidative stress in rice seedlings under Cd stress by reducing reactive oxygen species (ROS) generation. Furthermore, the application of Mel and/or SiO-NPs significantly increased the activity of antioxidative enzymes that scavenge ROS. The combined application of SiO-NPs and Mel increased growth, gas exchange and photosynthetic attributes, chlorophyll value, and protein content. It causes alleviation in the activity of SOD, CAT and POX by 73%, 62% and 65%, respectively. Overall, this study findings show that Mel and/or SiO-NPs can potentially protect the rice crop against oxidative damage under Cd stress.

OsPUB75-OsHDA716 mediates deactivation and degradation of OsbZIP46 to negatively regulate drought tolerance in rice.

Histone deacetylases (HDACs) play crucial roles in plant stress responses via modification of histone as well as non-histone proteins; however, how HDAC-mediated deacetylation of non-histone substrates affects protein functions remains elusive. Here, we report that the Reduced Potassium Dependency3/Histone Deacetylase1 (RPD3/HDA1)-type histone deacetylase OsHDA716 and plant U-box (PUB) E3 ubiquitin ligase OsPUB75 form a complex to regulate rice drought response via deactivation and degradation of basic leucine zipper (bZIP) transcription factor OsbZIP46 in rice (Oryza sativa). OsHDA716 decreases ABA-induced drought tolerance, and mechanistic investigations showed that OsHDA716 interacts with and deacetylates OsbZIP46, a key regulator in ABA signaling and drought response, thus inhibiting its transcriptional activity. Furthermore, OsHDA716 recruits OsPUB75 to facilitate ubiquitination and degradation of deacetylated OsbZIP46. Therefore, the OsPUB75-OsHDA716 complex exerts double restrictions on the transcriptional activity and protein stability of OsbZIP46, leading to repression of downstream drought-responsive gene expression and consequently resulting in reduced drought tolerance. Conversely, OsbZIP46 acts as an upstream repressor to repress OsHDA716 expression, and therefore OsHDA716 and OsbZIP46 form an antagonistic pair to reciprocally inhibit each other. Genetic evidence showed that OsHDA716 works with OsbZIP46 in a common pathway to antagonistically regulate rice drought response, revealing that plants can fine-tune stress responses by the complex interplay between chromatin regulators and transcription factors. Our findings unveil an acetylation-dependent regulatory mechanism governing protein functions and shed light on the precise coordination of activity and stability of key transcription factors through a combination of different post-translational modifications.

A Cyclin Gene OsCYCB1;5 Regulates Seed Callus Induction in Rice Revealed by Genome Wide Association Study

Plant tissue culture is extensively employed in plant functional genomics research and crop genetic improvement breeding. The callus induction ability is critical for utilizing Agrobacterium-mediated genetic transformation. In this study, we conducted a genome-wide association study (GWAS) utilizing 368 rice accessions to identify traits associated with callus induction rate (CIR), resulting in the identification of a total of 104 significant SNP loci. Integrated with gene function annotation and transcriptome analysis, 13 high-confidence candidate genes involved in auxin-related, CYC cyclins, and histone H3K9-specific methyltransferase were identified in significant loci. Furthermore, we also verified a candidate gene, Os05g0493500 (OsCycB1;5), and employed the CRISPR/Cas9 system to generate OsCycB1;5 knockout mutants in rice (Oryza sativa L.). The OscycB1;5 mutant displays significantly reduced callus induction and proliferation capacity, this result indicating OsCycB1;5 is required for the callus formation in rice. Overall, this study provides several reliable loci and high-confidence candidate genes that may significantly affect callus formation in rice. This information will offer valuable insights into the mechanisms underlying callus formation not only in rice but also in other plants.

Phytochrome B promotes blast disease resistance and enhances yield in rice.

Phytochromes are red/far-red light receptors that regulate various aspects of plant growth, development and stress responses. The precise mechanism by which Phytochrome B (PhyB)-mediated light signaling influences plant defense and development remains unclear. In this study, we showed that PhyB enhances rice (Oryza sativa) blast disease resistance, tillering, and grain size compared to wild-type plants. Notably, PhyB interacted with and degraded grassy tiller 1 (GT1), a negative regulator of tiller development. Knockdown of GT1 in a phyB background partially rescued the diminished tillering of phyB. However, GT1 negatively regulates rice resistance to blast, suggesting that PhyB degradation of GT1 promotes tillering but not blast resistance. Previously, PhyB was found to interact with and degrade phytochrome-interacting factor 15 (PIL15), a key regulator of seed development that reduces rice resistance to blast and seed size. pil15 mutation in phyB mutants rescued phyB seed size and blast resistance, suggesting that PhyB might interact with and degrade PIL15 to negatively regulate blast resistance and seed size. PIL15 directly activated sugar will be eventually exported transporter 2a (SWEET2a). sweet2a mutants were less susceptible to blast disease compared to wild type. Collectively, these data demonstrate that PhyB promotes rice yield and blast resistance by inhibiting the transcription factors GT1 and PIL15 and downstream signaling.

Isolation, Identification and Evaluation of the Effective Phyto-Compounds for The Management of Groundnut Beetles Infesting Stored Groundnut (Arachis Hypogaea L.)

The effectiveness of various botanicals was tested against the Major Pest of shelled groundnuts, the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenbebrionidae), under artificial infestation, in Laboratory conditions for one year. Essential Oils isolated by Clevengers Apparatus , @1%v/w of Pongamia glabra (Karanja Oil), Azadirachta indica (Neem Oil), Brassica campestris (Mustard Oil) , Crown oil (Resin of Shorea robusta) , Dalbergia sisso (Sisso Oil), Oryza sativa (Rice bran oil), Helianthus annus (Sunflower Oil) , Ricinus communis (Castor Oil), Aegle marmelos (Bael Oil), Sesamum indicum (Til Oil), etc were tested for their bioefficacy against the Major Pest, of shelled groundnuts, red flour beetle Tribolium castaneum, (Herbst) Tenebrionidae, Coleoptera, under artificial infestation, in Laboratory conditions for one year. Out of all these plant products only, Crown oil (Resin of Shorea robusta) gave 100 % pod/Kernel protection for one year. The LD 50 values were found out to be - 0.5% v/w. Spectroscopic GC MS analysis of, Crown oil (Resin of Shorea robusta) are identified as 2-Ethyl-oxetane (RT 2.223), as the major product It may be due to the strong aromatic nature of these phyto-product. Hence these phyto-product may be used as fumigants or insect repellants against Tribolium castaneum and can be included in the package of practices to save stored groundnut in storage.

OsPDIL1-5: dual role in promoting growth and development while modulating drought stress tolerance in rice (Oryza sativa L.).

Drought tolerance and plant growth are critical factors affecting rice yield, and identifying genes that can enhance these traits is essential for improving crop resilience and productivity. Using a growth-depressed and drought-tolerant (gddt) mutant of the indica rice variety Huanghuazhan (HHZ) generated by radiation mutagenesis, we discovered a novel gene, GDDT, which plays a dual role in plant biology: it acts as a positive regulator of growth and development, but as a negative regulator of drought resistance. The gddt mutant displayed a marked reduction in plant growth and seed setting rate, yet exhibited an unexpected advantage in terms of drought tolerance. Our research revealed that the enhanced drought tolerance of the gddt mutant is primarily due to a decrease in stomatal size, density, and aperture, which reduces water loss, and an activation of the reactive oxygen species (ROS) scavenging system, which helps protect the plant from oxidative stress. These physiological changes are observed both under drought conditions and in normal growth conditions. This discovery highlights the importance of GDDT as a pleiotropic gene with significant implications for both plant growth and drought resistance. Through map-based cloning, we determined that the protein disulfide isomerase-like (PDIL) gene OsPDIL1-5 is the GDDT gene. The protein encoded by this gene was localized to the endoplasmic reticulum, consistent with its predicted function. Our findings provide new insights into the role of PDIL genes in rice and suggest that further study of GDDT could lead to a better understanding of how these genes contribute to the complex interplay between plant growth, development, and stress responses. This knowledge could pave the way for the development of rice varieties that are more resilient to drought, thereby increasing crop yields and ensuring food security in water-limited environments.

Productivity and Profitability of kharif Rice (Oryza sativa L.) under Seedling Age and Nitrogen Management

Aim: The aim of the experiment is to know the effect of seedling age and nitrogen management on growth, yield attributes, yield and economics of kharif rice. Study Design: The experiment was laid out in split-plot design. Place and Duration of Study: Research Farm of Agricultural Research Station, Brinjhagiri, Chhatabar of Faculty of Agricultural Sciences, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar (Odisha), during kharif season of 2023. Methodology: Three seedling ages viz. S1: 3 weeks (21 days), S2: 4 weeks (28 days) and S3: 5 weeks (35 days) as main plot treatment and four nitrogen management strategies i.e. N1: 100% N through urea, N2: 50% N through urea + 50% N through neem cake, N3: 50% N through urea + 50% N through FYM and N4: 50% N through FYM + 50% N through neem cake as sub-plot treatments replicated thrice. The net plot size was 4m × 3m. Results: S2 resulted highest grain yield (4.74t ha-1) and straw yield (7.18t ha-1). N1 produced highest grain yield (4.54t ha-1) and straw yield (6.96t ha-1). Maximum net return (Rs.60367) and return per rupee investment (1.98) received from 4 weeks old seedling with 100% N through urea application. Conclusion: Transplantation of 4 weeks old seedling (28 days) and 50% N through urea + 50% N through neem cake can be recommended to achieve higher yield. Maximum net return (Rs.60367), gross return (Rs.121687) and return per rupee investment (1.98) received from 4 weeks old seedling with 100% N through urea application.

The Threat of the Fall Armyworm to Asian Rice Production Is Amplified by the Brown Planthopper.

The recent invasion of the fall armyworm (FAW) into Asia not only has had a major impact on maize yield but is feared to also pose a risk to rice production. We hypothesized that the brown planthopper (BPH) may aggravate this risk based on a recently discovered mutualism between the planthopper and the rice striped stem borer. Here we show that BPH may indeed facilitate a shift of FAW to rice. FAW females were found to strongly prefer to oviposit on BPH-infested rice plants, which emitted significantly elevated levels of five volatile compounds. A synthetic mixture of these compounds had a potent stimulatory effect on ovipositing females. Although FAW caterpillars exhibited relatively poor growth on both uninfested and BPH-infested rice, a considerable portion completed their development on young plants. Moreover, FAW were found to readily pupate and survive in exceedingly moist soils typical for rice cultivation, further highlighting FAW's potential to switch to rice. We conclude that BPH, by changing the bouquet of volatiles emitted by rice plants, may greatly facilitate this switch. These findings, together with a current increase of nonflooded upland rice in Asia, warrant careful monitoring and specific control measures against FAW to safeguard Asian rice production.

Seeing the unseen in characterizing RNA editome during rice endosperm development

Rice (Oryza sativa L.) endosperm is essential to provide nutrients for seed germination and determine grain yield. RNA editing, a post-transcriptional modification essential for plant development, unfortunately, is not fully characterized during rice endosperm development. Here, we perform systematic analyses to characterize RNA editome during rice endosperm development. We find that most editing sites are C-to-U CDS-recoding in mitochondria, leading to increased hydrophobic amino acids and changed structures of mitochondrial proteins. Comparative analysis of RNA editome reveals that CDS-recoding sites present higher editing frequencies with lower variabilities and their resultant recoded amino acids tend to exhibit stronger evolutionary conservation across many land plants. Furthermore, we classify mitochondrial genes into three groups, presenting distinct patterns in terms of CDS-recoding events. Besides, we conduct genome-wide screening to detect pentatricopeptide repeat (PPR) proteins and construct PPR-RNA binding profiles, yielding candidate PPR editing factors related to rice endosperm development. Taken together, our findings provide valuable insights for deciphering fundamental mechanisms of rice endosperm development underlying RNA editing machinery.

Golden Hull: A Potential Biomarker for Assessing Seed Aging Tolerance in Rice

Seed aging is a complex process that involves various physiological and biochemical changes leading to a decline in seed viability during storage. However, the specific biomarkers for assessing the degree of seed aging in rice remain elusive. In this study, we isolated a golden hull mutant, gh15, from the indica rice Z15 by employing a radiation mutagenesis technique. Compared with the wild type (WT) Z15, the mutant gh15 displayed a golden hue in the hull, stem, and internodes, while no significant differences were observed in the key agronomic traits. A genetic analysis showed that the gh15 phenotype is regulated by a single recessive gene, which possibly encodes cinnamyl alcohol dehydrogenase OsCAD2. Significant differences of seed aging tolerance were observed between gh15 and WT after six months of natural storage and artificial aging treatment, with gh15 exhibiting a markedly lower aging tolerance compared to the WT. Haplotype assays indicated that the Hap2 of OsCAD2 was significantly associated with the dark coloration of the hull and lower seed aging tolerance. The molecular marker of OsCAD2 associated with seed color was explored in rice. These findings demonstrate that the golden hull serves as a potential biomarker for the rapid assessment of seed aging tolerance in rice.

Mechanistic insight into interactive effect of microplastics and arsenic on growth of rice (Oryza sativa L.) and soil health indicators

Microplastics (MPs) pollution has recently become a major concern for agroecosystems. The interplay between MPs, and heavy metal(loid)s in the soil can intensify the risks to plant growth and human health. The current study investigated the interactive effects of arsenic (As) and biodegradable and petroleum-based conventional MPs on rice growth, As bioavailability, soil bacterial communities, and soil enzyme activities. As-contaminated soil (5 mg kg−1) was treated with conventional MPs i.e., polystyrene (PS) and polyethylene (PE) and biodegradable MPs i.e., polylactic acid (PLA) and polybutylene adipate terephthalate (PBAT) at 0.1 % and 1 % rates. In a pot experiment, rice plants were cultivated in soil co-contaminated with As and MPs. PLA-MPs exhibited significant interactions with As, increasing its bioavailability and impairing rice plant growth by enhancing plant oxidative stress. The results illustrated that T2 treatment (PLA-MPs @ 1 % + As 5 mg kg−1) significantly decreased the root and shoot lengths, root and shoot dry weights as well as the rates of photosynthesis, transpiration, intercellular CO2, and stomatal conductance in rice plants. Biodegradable PLA-MPs @ 1 % resulted in increased uptake of As in rice roots, stems, and leaves by 13.4 %, 38.9 %, and 20.6 %, respectively. In contrast, conventional PE-MPs @ 1 % showed contradictory results with As uptake declined by 2.2 %, 5.1 %, and 9.9 % in rice roots, stem and leaves. Soil enzyme kinetics showed that biodegradable MPs increased the activities of soil catalase, dehydrogenase, and phytase enzymes, whereas both conventional PS and PE-MPs decreased their activities. Moreover, As and PLA-MPs combined stress altered soil bacterial communities by increasing the relative abundance of Protobacteria, Acidobacteria, Chloroflexi, and Firmicutes phyla by 49 %, 29 %, 82 %, and 57 %, respectively. This study provides new insights into MPs-As interactions in soil-plant system and ecological risks associated with their coexistence.

Co-culture of rice and aquatic animals enhances soil organic carbon: A meta-analysis

Co-culture of rice (Oryza sativa) and aquatic animals (CRAAs) is an efficient eco-agricultural model and has been widely implemented in many Asia countries. However, its impact on soil organic carbon (SOC) content has not been synthesized and the relative effects of different CRAAs practices on SOC have not been assessed. Our meta-analysis aims to synthesize the effect of diverse CRAAs regimes on SOC content based on results from 200 field experiments. Our results showed that overall, CRAAs significantly increased SOC content by 11.6 % (P < 0.05). The highest relative effect on SOC content was found under the rice and amphibian coculture (P < 0.05). Also, CRAAs increased SOC content more significantly in temperate regions (19.1 %) than in subtropical (9.7 %) and tropical (12.1 %) regions (P < 0.05). In addition, CRAAs were more effective in enhancing SOC content in paddy soils with high nitrogen content (total nitrogen [TN] >1.2 g·N kg−1 soil) or alkaline soils. Further, SOC increased more in the CRAAs with japonica than indica rice, increasing 17.8 % and 6.1 % as compared to their respective rice-monoculture controls. Random forest analysis revealed that animal type was the most important factor influencing SOC under CRAAs. Together, these results indicate that CRAAs can significantly enhance SOC, particularly in low-N, alkaline paddy soils. Our findings suggest that CRAAs with appropriate rice and animal varieties can provide unique opportunities for soil C sequestration, while enhancing farmers' profitability.

Engineering a novel pathway for efficient biosynthesis of salicin in Escherichia coli

Salicin is a natural glycoside compound widely used to treat fever, inflammation, and analgesia. Currently, salicin is primarily extracted from willow bark, which is not only cumbersome in terms of extraction and separate steps, but also subject to seasonal and geographic limitations. In this study, a highly efficient biosynthetic pathway for salicin synthesis was designed and constructed in E. coli. The most important precursor in the synthetic pathway of salicin designed in this study is salicyl alcohol. Building on a previously constructed biosynthetic salicylic acid metabolic pathway, the production of salicyl alcohol in shake flask fermentation reached 1.7 g/L by increasing the supply of shikimic acid pathway precursor PEP and salicyl alcohol precursor chorismate. According to the principle of substrate similarity, this study identified the key enzyme OsSGT1 from Oryza sativa, which uses E. coli endogenous UDP-glucose as a glycosyl donor to glycosylate salicyl alcohol into salicin. By redefining the optimal substrate of OsSGT1, and balancing metabolic flux along with increasing the supply of UDP-glucose, salicin production in shake flasks reached 4 g/L. Finally, culturing the high-yield strain in a 3-L fermenter resulted in the synthesis of 14.62 g/L of salicin. To the best of our knowledge, this achievement marks the highest salicin production through microbial fermentation to date.