Oryza Sativa Research Articles

Skin Prick Tests and Enzyme-Linked Immunosorbent Assays among Allergic Patients Using Allergenic Local Pollen Extracts.

Allergic respiratory diseases are prevalent in the Philippines, with allergic rhinitis and asthma occurring at 20% and 8.7% of the population, respectively. The diagnosis of respiratory allergies is achieved by a combination of patient history and different screening tools, especially for the identification of the allergic triggers such as allergy skin prick test (SPT) and serum-specific IgE enzyme-linked immunosorbent assays (sIgE ELISA). The Philippines, being a tropical country, have a wide variety of plant species with potential to produce allergenic pollen grains. Knowledge of the sensitization profiles of Filipino allergic patients to our local pollen allergens is currently limited. The aim of this study is to determine the sensitization profile of patients with respiratory allergies (allergic rhinitis and/or asthma) through the allergy skin prick test (SPT) using allergenic local pollen extracts. It also aimed to determine if there is a positive agreement between the SPT and sIgE ELISA positivity rate and whether the results have relationship with the pollen purity and the protein content of the extracts. Pollen allergens were extracted from Amaranthus spinosus (pigweed), Mimosa pudica (makahiya), Tridax procumbens (wild daisy), Imperata cylindrica (cogon), Oryza sativa (rice), Pennisetum polystachion (foxtail grass), Sorghum halepense (Johnson grass), Albizia saman (acacia), Cocos nucifera (coconut), Leucaena leucocephala (ipil-ipil), and Mangifera indica (mango). SPT was performed at the Allergy Clinic of the University of the Philippines-Philippine General Hospital on patients with allergic rhinitis and/or bronchial asthma. Blood samples were collected from patients who developed wheal diameters of 3 mm or more than the negative control. Sera were tested against the same pollen extracts using ELISA. Of the one hundred sixty-five (165) patients who submitted for skin prick test, 129 showed positive SPT results to the pollen extracts. Weeds were the most sensitizing (51.9%-58.1%). Blood samples were collected from these patients and tested for sIgE ELISA and among them, 71 were positive in the sIgE ELISA. Highest sensitization rates in sIgE ELISA were found in coconut, pigweed, Johnson grass, and rice. The highest positive agreements or the proportion of patients with positive sIgE ELISA among those with positive SPT were in coconut, followed by Johnson grass, pigweed, and rice. Most of the pollen sensitized patients on SPT are polysensitized. SPT is a safe, simple, and rapid method for the diagnosis of IgE-mediated allergy. The lower number of positive patients in sIgE ELISA may be attributed to the low serum IgE levels and low quantities of effectual allergen components in extracts. Results of both SPT and ELISA must be correlated with a patient's clinical history, particularly the patient's exposures, and physical examination.

Phenotypic, Physiological, and Gene Expression Analysis for Nitrogen and Phosphorus Use Efficienies in Three Popular Genotypes of Rice (Oryza sativa Indica).

Crop nitrogen (N) and phosphorus (P) use efficiencies (NUE/PUE) are important to minimize wastage and nutrient pollution, but no improved crop for both is currently available. We addressed them together in rice, in the view of its high consumption of NPK fertilizers. We analyzed 46 morphophysiological parameters for the N/P response in three popular indica genotypes, namely, BPT 5204, Panvel 1, and CR Dhan 301 at low, medium, and normal N/P doses. They include 18 vegetative, 15 physiological, and 13 reproductive parameters. The segregation of significantly N/P-responsive parameters correlating with NUE/PUE revealed 21 NUE, 22 PUE, and 12 common parameters. Feature selection analyses revealed the common high-ranking parameters including the photosynthetic rate at the reproductive stage, tiller number, root-shoot ratio, culm thickness, and flag leaf width. The venn selection using the reported NUE/PUE-related candidate genes in rice revealed five genes in common for both, namely OsIAA3, OsEXPA10, OsCYP75B4, OsSultr3;4, and OsFER2, which were associated with three of the common traits for NUE/PUE. Their expression studies using qRT-PCR revealed the opposite regulation in contrasting genotypes for OsSultr3;4 and OsEXPA10 in N-response and for OsFER2 in P-response, indicating their role in contrasting N/P use efficiencies. Overall, CR Dhan 301 has the highest NUE and PUE followed by Panvel 1 and BPT5204 among the studied genotypes.

Field performance and nitrous oxide emissions of transgenic nitrogen use efficient rice lines cultivated in tropical paddy fields.

Nitrogen (N) fertilizers make up the majority of the input used in rice production, and their excess application leads to significant environmental pollution. Developing rice varieties with improved nitrogen use efficiency (NUE) is essential to maintain the sustainability of rice production. This study aims to evaluate the performance of transgenic Oryza sativa japonica cv. Kitaake expressing the barley (Hordeum vulgare) alanine aminotransferase (HvAlaAT) gene in response to different levels of N fertilizer application under tropical paddy field conditions. Results from this study demonstrate that transgenic nitrogen use efficient Kitaake rice (Kitaake NUE) displays a grain yield increase of up to 41% compared to Kitaake null. Transgenic Kitaake NUE expressing the HvAlaAT gene displays a higher N uptake and achieves a higher nitrogen use efficiency compared to control plants while maintaining lower nitrous oxide (N2O) fluxes. The reduction in N2O emissions in Kitaake NUE compared to Kitaake null ranges from 37.5 to 96.3%. The transgenic Kitaake NUE used in this study has potential as a donor to improve the nitrogen use efficiency of indica rice for better adaptability to tropical conditions.

Refining the major-effect QTL and candidate genes associated with grain number per panicle by QTL-seq in rice (Oryza sativa L.)

Refining the major-effect QTL and candidate genes associated with grain number per panicle by QTL-seq in rice (Oryza sativa L.)

Excess supply of sulfur mitigates thallium toxicity to rice (Oryza sativa L.) growth in hydroponic experiment

Sulfur (S) is an essential element for the growth of rice plants (Oryza sativa L.), crucial for enhancing crop yield and grain quality. However, its potential in mitigating thallium (Tl) toxicity in rice remains unclear. In this study, a hydroponic experiment was performed to investigate the effects of low, medium and high S application levels (LS, MS, HS) on Tl accumulation in rice at three Tl exposure levels (0, 0.5 and 1 mg·L−1). Our findings reveal that the exogenous S application could alleviate Tl toxicity, enhancing fresh weight and shoot length of rice plant. Additionally, HS (HS, SO42− content was 387.84 mg·L−1) group significantly increased chlorophyll and glutathione (GSH) content by 6.46 to 21.38 % and 2.15 to 7.31 % respectively, while reducing malondialdehyde (MDA) levels by 17.43 to 28.48 %, compared to MS (MS, SO42− content was 193.41 mg·L−1) group. Fe content in rice roots and iron plaque consistently increased with S provision under Tl-free and Tl-contaminated conditions. In Tl exposure environment, HS and LS (LS, SO42− content was 1.02 mg·L−1) groups exhibited significant differences in Fe contents and iron plaque in rice root. Moreover, in Tl exposure environment, S application reduced Tl concentration in iron plaque, root, and shoot, HS treatment showed Tl content reduction from 16.29 % to 25.89 %, compared to LS treatment. Our findings underscore the potential of S application in hydroponic environment to promote rice growth and mitigate Tl accumulation, offering insights for developing effective Tl remediation strategies by using S-contained fertilizers.

Exogenous selenium mitigates cadmium uptake and accumulation in two rice (Oryza sativa L.) varieties in cadmium-contaminated soil

Rice grown in cadmium (Cd)-contaminated soil, is a potential threat to human health, but exogenous selenium (Se) application on rice can mitigate Cd toxicity. However, the mechanisms underlying Se mitigation of Cd stress in ratoon rice (RR) are still poorly understood. We conducted a pot experiment with moderate Cd-contaminated yellow–brown paddy soil on two rice varieties ‘Taoyouxiangzhan’ (TX) and ‘Liangyou 6326’(LY). For all treatments, 1.0 mg kg−1 sodium selenite solution was added to soil. Treatment T1 was sodium selenite only, and in the other treatments 100 mg L−1 Se solution was sprayed on the leaves at seedling stage (T2), at tillering stage (T3), and in early anthesis stage (T4). Se treatments decreased Cd accumulation in rice grains and herbage. Under foliar spraying 100 mg L−1 Se at the seedling + 1.0 mg kg−1 Se in soil (T2), leaf Cd content decreased 16.95% in the current season and grains content decreased 46.67% in the subsequent season. Furthermore, grain Se content increased 0.94 mg kg−1 for the TX variety combined with the analysis of Cd bio-accumulation factor in grains, and Se treatments effectively decreased Cd grain concentrations due to reduced Cd translocation from roots to grains. TX variety rice showed a more pronounced response to Se treatments than LY.

Transcription factor-mediated gene regulatory networks contributes to reproductive stage drought tolerance in rice (Oryza sativa)

Present study was carried out during rainy (kharif) seasons of 2020–22 at ICAR-Indian Agricultural Research Institute, New Delhi, to examine transcription factors (TFs) in drought tolerance using two rice (Oryza sativa L.) cultivars, drought-tolerant Nagina-22 and drought-sensitive IR-64. Immature panicles were used to prepare transcriptome libraries, sequenced with Paired-End 150 bp chemistry for both control and drought-treated samples. Bioinformatic analysis of the data using TFs extracted from PlantTF database revealed that majority (335) of the TFs were up-regulated in Nagina-22, while 92 were down-regulated under stress. Conversely, a significant number of TFs (359) were down-regulated in IR-64 under stress. Gene ontology and gene regulatory network analyses of the differentially expressed TFs indicated that several crucial biological processes and molecular functions were enriched with higher number of up-regulated TFs in Nagina-22 under stress. Significantly up-regulated expression of TFs, particularly WRKY, ERF, MYB, NAC, and bHLH, in panicle of N-22 must be responsible for terminal drought tolerance. Our findings confirm the master-regulator role of TFs in gene-regulatory networks essential for tolerance to complex trait like drought. The information might be valuable in selecting potential candidate parental lines for drought tolerance breeding and genetic manipulation of rice cultivars towards the development of climate-resilient cultivars.

Chemical composition and bio-efficacy of agro-waste plant extracts and their potential as bioinsecticides against Culex pipiens mosquitoes

Mosquitoes are considered one of the most lethal creatures on the planet and are responsible for millions of fatalities annually through the transmission of several diseases to humans. Green trash is commonly employed in agricultural fertilizer manufacturing and microbial bioprocesses for energy production. However, there is limited information available on the conversion of green waste into biocides. This study investigates the viability of utilizing green waste as a new biopesticide against Culex pipiens mosquito larvae. The current study found that plant extracts from Punica granatum (98.4 % mortality), Citrus sinensis (92 % mortality), Brassica oleracea (88 % mortality), Oryza sativa (81.6 % mortality), and Colocasia esculenta (53.6 % mortality) were very good at killing Cx. pipiens larvae 24 h post-treatment. The LC50 values were 314.43, 370.72, 465.59, 666.67, and 1798.03 ppm for P. granatum, C. sinensis, B. oleracea, O. sativa, and C. esculenta, respectively. All plant extracts, particularly P. granatum extract (14.93 and 41.87 U/g), showed a significant reduction in acid and alkaline phosphate activity. Additionally, pomegranate extract showed a significant decrease (90 %) in field larval density, with a stability of up to five days post-treatment. GC–MS results showed more chemical classes, such as terpenes, esters, fatty acids, alkanes, and phenolic compounds. HPLC analysis revealed that the analyzed extracts had a high concentration of phenolic and flavonoid components. Moreover, there are many variations among these plants in the amount of each compound. The docking interaction showed a simulation of the atomic-level interaction between a protein and a small molecule through the binding site of target proteins, explaining the most critical elements influencing the enzyme's activity or inhibitions. The study's findings showed that the various phytochemicals found in agro-waste plants had high larvicidal activity and provide a safe and efficient substitute to conventional pesticides for pest management, as well as a potential future in biotechnology.

The rice R2R3 MYB transcription factor FOUR LIPS connects brassinosteroid signaling to lignin deposition and leaf angle.

Leaf angle is an important agronomic trait for crop architecture and yield. In rice (Oryza sativa), the lamina joint is a unique structure connecting the leaf blade and sheath that determines leaf angle. Brassinosteroid (BR) signaling involving GLYCOGEN SYNTHASE KINASE-3 (GSK3)/SHAGGY-like kinases and BRASSINAZOLE-RESISTANT1 (BZR1) has a central role in regulating leaf angle in rice. In this study, we identified the atypical R2R3-MYB transcription factor FOUR LIPS (OsFLP), the rice homolog of Arabidopsis (Arabidopsis thaliana) AtFLP, as a participant in BR-regulated leaf angle formation. The spatiotemporal specificity of OsFLP expression in the lamina joint was closely associated with lignin deposition in vascular bundles and sclerenchyma cells. OsFLP mutation caused loose plant architecture with droopy flag leaves and hypersensitivity to BRs. OsBZR1 directly targeted OsFLP, and OsFLP transduced BR signals to lignin deposition in the lamina joint. Moreover, OsFLP promoted the transcription of the phenylalanine ammonia-lyase family genes OsPAL4 and OsPAL6. Intriguingly, OsFLP feedback regulated OsGSK1 transcription and OsBZR1 phosphorylation status. In addition, an Ala-to-Thr substitution within the OsFLP R3 helix-turn-helix domain, an equivalent mutation to that in Osflp-1, affected the DNA-binding ability and transcriptional activity of OsFLP. Our results reveal that OsFLP functions with OsGSK1 and OsBZR1 in BR signaling to maintain optimal leaf angle by modulating the lignin deposition in mechanical tissues of the lamina joint.

Productivity, nutrient status and energy dynamics of rice (Oryza sativa) genotypes under different tillage systems in unirrigated ecosystem

Productivity, nutrient status and energy dynamics of rice (Oryza sativa) genotypes under different tillage systems in unirrigated ecosystem

ERFVII-controlled hypoxia responses are in part facilitated by MEDIATOR SUBUNIT 25 in Arabidopsis thaliana.

Flooding impairs plant growth through oxygen deprivation, which activates plant survival and acclimation responses. Transcriptional responses to low oxygen are generally associated with the activation of group VII ETHYLENE-RESPONSE FACTOR (ERFVII) transcription factors. However, the exact mechanisms and molecular components by which ERFVII factors initiate gene expression are not fully elucidated. Here, we show that the ERFVII factors RELATED TO APETALA 2.2 (RAP2.2) and RAP2.12 cooperate with the Mediator complex subunit AtMED25 to coordinate gene expression under hypoxia in Arabidopsis thaliana. Respective med25 knock-out mutants display reduced low-oxygen stress tolerance. AtMED25 physically associates with a distinct set of hypoxia core genes and its loss partially impairs transcription under hypoxia due to decreased RNA polymerase II recruitment. Association of AtMED25 with target genes requires the presence of ERFVII transcription factors. Next to ERFVII protein stabilisation, also the composition of the Mediator complex including AtMED25 is potentially affected by hypoxia stress as shown by protein-complex pulldown assays. The dynamic response of the Mediator complex to hypoxia is furthermore supported by the fact that two subunits, AtMED8 and AtMED16, are not involved in the establishment of hypoxia tolerance, whilst both act in coordination with AtMED25 under other environmental conditions. We furthermore show that AtMED25 function under hypoxia is independent of ethylene signalling. Finally, functional conservation at the molecular level was found for the MED25-ERFVII module between A. thaliana and the monocot species Oryza sativa, pointing to a potentially universal role of MED25 in coordinating ERFVII-dependent transcript responses to hypoxia in plants.

Authentication of premium Asian rice varieties: Stable isotope ratios and multi-elemental content for the identification of geographic fingerprints

Over 90 percent of the world's rice is produced and consumed in the Asia-Pacific region. Varieties such as Thai Jasmine rice and Paw San (or “Myanmar pearl rice”) are globally recognised as premium, while more local high-grade varieties include the Indonesian Ciherang and Inpari. Being able to trace the origin of these products has become necessary, since they are marketed at relatively higher prices compared to other cultivars, and they often become the target of fraudulent activities. In this work, we aimed to identify variables that could distinguish the premium-producing regions within each country, by Isotope Ratio Mass Spectrometry (IRMS) and Inductively Coupled Plasma- Mass Spectrometry (ICP-MS). Low-Level Data Fusion (LLDF) followed the analysis of more than 300 authentic samples, and (O)PLS-DA models yielded very high accuracy values. The most important geo-differentiating variables (VIP>1.4) were identified as: δ13C, δ18O, δ2H, δ34S, Co, Rb, Cu, Ba and Zn.

The responses of weed communities to field nutrients and their ecological benefits in rice fields: A review

AbstractWhile traditionally perceived as yield‐reducing elements in rice (Oryza sativa L.) cultivation, weed communities in paddy fields play a crucial role in the ecosystem. These communities, when selectively retained, can significantly enhance ecosystem services. This review examines the impact of various weed communities on rice in different paddy fields, their response to field nutrients, and the ecological benefits they offer. These benefits include nitrogen retention, promotion of microbial diversity, and reduction of diseases, pests, and weed proliferation. Examples of such benefits are seen in weeds like Lemna minor L. and Azolla imbricata (Roxb.) Nakai, which help in nitrogen fixation and act as biocontrol agents against harmful pests. However, current research in this area faces challenges, including the lack of intelligent and precise weed control technologies, comprehensive green control strategies, and expertise in weed management. Our findings suggest a strategic approach to weed control in paddy fields, emphasizing the importance of preserving weed species that have minimal impact on rice yields but offer significant ecological advantages. These practices can lead to grass‐mediated weed control and enhanced nutrient absorption, thereby reducing fertilizer loss. Ultimately, this approach could reduce the reliance on chemical fertilizers and herbicides in paddy fields, laying the groundwork for greener rice cultivation and sustainable agricultural practices.

Effects of tillage management on soil organic carbon mineralization under double cropping rice system of southern China

Soil organic carbon (SOC) plays a vital role in maintaining or enhancing soil fertility and quality of paddy field, but there is still limited information about how SOC mineralization responds to different tillage managements under the double-cropping rice (Oryza sativa L.) system in southern of China. Therefore, this study was designed to explore the changes in SOC content, soil enzyme activities (invertase, cellulose and urease), SOC mineralization at 0–10 cm and 10–20 cm layers and its relationship with 7-years tillage management under the double-cropping rice system of southern China. The experiment included four tillage managements: rotary tillage with all residues removed as a control (RTO), conventional tillage with residue incorporation (CT), rotary tillage with residue incorporation (RT), and no-tillage with residue retention (NT). The results indicated that SOC and soil labile organic carbon contents at 0–10 cm and 10–20 cm layers in paddy field with CT and RT treatments were significantly higher than the RTO treatment. Compared to the RTO treatment, SOC mineralization and accumulation at 0–10 cm and 10–20 cm layers in paddy field with CT, RT and NT treatments were increased. SOC accumulation and potential mineralization at 0–10 cm layer with NT treatment were significantly higher than the CT, RT and RTO treatments. Soil mineralization constant at 10–20 cm layer with CT treatment was significantly higher than those of RT, NT and RTO treatments. This result indicated SOC mineralization rate and accumulation at 10–20 cm layer of CT, RT, NT and RTO treatments were lower than those of treatments at 0–10 cm layer. Compared to RTO treatment, soil invertase, cellulose and urease activities with CT and RT treatments were significantly increased. Compared to RTO treatment, soil invertase, cellulose and urease activities at 0–20 cm layer of CT treatment increased by 22.6%, 46.2% and 89.0%, respectively. There was significantly positive correlation between SOC accumulation and SOC content, soil invertase, cellulose, urease activities, but SOC accumulation was significantly negative correlated with soil pH, bulk density. Therefore, CT and RT treatments were beneficial managements to improve SOC content and SOC mineralization in the double-cropping rice field of southern China.

Effect of Trichoderma harzianum and Selected Botanicals on Brown Leaf Spot of Paddy (Oryza sativa L.) Caused by Helminthosporium oryzae (Breda de Haan)

Effect of Trichoderma harzianum and Selected Botanicals on Brown Leaf Spot of Paddy (Oryza sativa L.) Caused by Helminthosporium oryzae (Breda de Haan)

Health risk assessment of metal contamination in Malaysian rice (Oryza sativa): The impact of parboiling on toxic metal reduction prior to cooking

SummaryMetal contamination in rice grains is a critical global issue, posing serious health risks and affecting food safety, especially in countries like Malaysia where rice is a staple food. This study aimed to assess the effectiveness of various cooking treatments, with a focus on parboiling before absorption cooking (PBA), in reducing metal contamination in Malaysian rice. Metal levels were measured using tandem inductively coupled plasma mass spectrometry (ICP‐MS/MS), and health risks were assessed following USEPA guidelines. Parboiling before absorption cooking was found to eliminate 77.9% of toxic metals and 68.4% of essential metals while keeping arsenic (As), cadmium (Cd) and lead (Pb) concentrations below permissible limits. Deterministic health risk assessment indicated that PBA reduced hazard index by 84.5% and lifetime carcinogenic risk (LCR) from As exposure by 88.9%. Hazard quotient for nickel (Ni) and zinc (Zn) remained acceptable for all age groups except for As in children, where LCR exceeded permissible limits. Monte Carlo simulations revealed that over 95% of individuals across age groups faced unacceptable non‐carcinogenic and carcinogenic risks from As exposure, regardless of cooking method. In conclusion, PBA effectively lowered metal concentrations and health risks, especially for toxic metals in rice. Future studies could enhance risk assessment accuracy by analysing metal bioavailability and speciation of metals particularly As.

A secreted fungal laccase targets the receptor kinase OsSRF3 to inhibit OsBAK1–OsSRF3-mediated immunity in rice

The identification effector targets and characterization of their functions are crucial for understanding pathogen infection mechanisms and components of plant immunity. Here, we identify the effector UgsL, a ustilaginoidin synthetase with a key role in regulating virulence of the rice false smut fungus Ustilaginoidea virens. Heterologous expression of UgsL in rice (Oryza sativa) enhances plant susceptibility to multiple pathogens, and host-induced gene silencing of UgsL enhances plant resistance to U. virens, indicating that UgsL inhibits rice immunity. UgsL interacts with STRUBBELIG RECEPTOR KINASE 3 (OsSRF3). Genome editing and overexpression of OsSRF3 demonstrate that OsSRF3 plays a pivotal role in the resistance of rice to multiple pathogens. Remarkably, overexpressing OsSRF3 enhances resistance without adversely affecting plant growth or yield. We show that BRASSINOSTEROID RECEPTOR-ASSOCIATED KINASE 1 (OsBAK1) interacts with and phosphorylates OsSRF3 to activate pathogen-triggered immunity, inducing the mitogen-activated protein kinase cascade, a reactive oxygen species burst, callose deposition, and expression of defense-related genes. UgsL interferes with the phosphorylation of OsSRF3 by OsBAK1. Furthermore, UgsL mediates OsSRF3 degradation by facilitating its association with the ubiquitin-26S proteasome. Our results reveal that OsSRF3 positively regulates immunity in rice and that UgsL mediates its degradation, thereby inhibiting the activation of OsBAK1–OsSRF3-mediated immune pathways.

Generic Workflow of a Highly Effective and Easy Anther Culture Method for Both Japonica and Indica Rice.

As one of the most important staple crops in the world, rice plays a pivotal role in world food security. The creation of doubled haploids based on anther culture is an important technology for rice breeding. However, at present, rice anther culture technology still faces many problems, such as genotype dependency, especially genotypes of indica rice. In this study, fifteen rice genotypes, including twelve japonica rice genotypes and three indica rice genotypes, were randomly selected and used to study anther culture by using a modified M8 medium. The results showed that the total callus induction rates of these different rice genotypes ranged from 0.81 to 13.95%, with an average of 6.64%, while the callus induction rates calculated for the top ten highest callus inductions for each rice genotype ranged from 2.75 to 17.00%, with an average of 10.56%. There were varying gaps between the total callus induction rates and the callus induction rates in these different rice genotypes. The fact that the gaps for some rice genotypes were relatively large indicated that standard tiller or anther collection was not applicable to all rice genotypes and that there was still a lot of room for improvement in the callus induction rate of some rice genotypes through optimization of the sampling method. The plantlet regeneration rates ranged from 12.55 to 456.54%, with an average of 200.10%. Although there were many albinos from anther culture for some rice genotypes, these would still meet the requirement if the rice genotypes had higher callus induction rates or regeneration rates. The percentages of seed setting of regenerated green seedlings ranged from 14% to 84%, with an average of 48.73%. Genetic diversity analysis showed that the genetic background of these different rice genotypes was representative, and the phylogenetic tree and Principal Component Analysis (PCA) divided them into indica and japonica types. Therefore, in this study, an anther culture method suitable for both indica and japonica rice genotypes was established, which could improve doubled haploid breeding in rice.

Combined toxicity of multiwall carbon nanotubes and cadmium on rice (Oryza sativa L.) growth in soil

The comprehensive effects of nanoparticles and coexisting heavy metals on plant growth are still unclear, especially in soil medium. The single and combined effects of multiwall carbon nanotubes (MWCNTs) and cadmium (Cd) on rice (Oryza sativa L.) growth were examined in this study through a 4 months pot experiment in 2022. Rice plants were exposed to different concentrations of MWCNTs (100 and 500 mg kg−1) in the presence of 5.0 mg kg−1 Cd stress. At the tillering stage, the 500 mg kg−1 MWCNTs addition reduced plant height by 8.0% and increased soluble protein content in the leaves by 13.7%, demonstrating that a single MWCNTs had a slight negative impact on rice growth. When exposed to Cd stress, the inclusion of 500 mg kg−1 MWCNTs led to a 6.7%–9.0% decrease in bioavailable Cd level in soil, resulting in considerable reductions in Cd content in roots (23.4%–29.9%), shoots (24.5%–28.3%) and grains (28.3%–66.2%). Compared to the single Cd treatment, the O. sativa L. leaves treated with Cd and MWCNTs (500 mg kg−1) had considerably reduced levels of malondialdehyde (MDA), soluble protein, and activities of antioxidant enzymes (POD, CAT, and SOD). The findings of this study indicated that appropriate concentrations of MWCNTs application in soil could alleviate Cd-induced toxicity on rice growth.

Genome-wide identification and expression analysis of the SPL gene family and its response to abiotic stress in barley (Hordeum vulgare L.)

BackgroundSquamosa promoter-binding protein-like (SPL) is a plant-specific transcription factor that is widely involved in the regulation of plant growth and development, including flower and grain development, stress responses, and secondary metabolite synthesis. However, this gene family has not been comprehensively evaluated in barley, the most adaptable cereal crop with a high nutritional value.ResultsIn this study, a total of 15 HvSPL genes were identified based on the Hordeum vulgare genome. These genes were named HvSPL1 to HvSPL15 based on the chromosomal distribution of the HvSPL genes and were divided into seven groups (I, II, III, V, VI, VII, and VIII) based on the phylogenetic tree analysis. Chromosomal localization revealed one pair of tandem duplicated genes and one pair of segmental duplicated genes. The HvSPL genes exhibited the highest collinearity with the monocotyledonous plant, Zea mays (27 pairs), followed by Oryza sativa (18 pairs), Sorghum bicolor (16 pairs), and Arabidopsis thaliana (3 pairs), and the fewest homologous genes with Solanum lycopersicum (1 pair). The distribution of the HvSPL genes in the evolutionary tree was relatively scattered, and HvSPL proteins tended to cluster with SPL proteins from Z. mays and O. sativa, indicating a close relationship between HvSPL and SPL proteins from monocotyledonous plants. Finally, the spatial and temporal expression patterns of the 14 HvSPL genes from different subfamilies were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Based on the results, the HvSPL gene family exhibited tissue-specific expression and played a regulatory role in grain development and abiotic stress. HvSPL genes are highly expressed in various tissues during seed development. The expression levels of HvSPL genes under the six abiotic stress conditions indicated that many genes responded to stress, especially HvSPL8, which exhibited high expression under multiple stress conditions, thereby warranting further attention.ConclusionIn this study, 15 SPL gene family members were identified in the genome of Hordeum vulgare, and the phylogenetic relationships, gene structure, replication events, gene expression, and potential roles of these genes in millet development were studied. Our findings lay the foundation for exploring the HvSPL genes and performing molecular breeding of barley.