Oryza Sativa Research Articles

The effect of the Fitostemin-WP® biostimulator on yield and quality characteristics of rice (Oryza sativa L.)

In order to avoid yield and quality reduction of rice, it is essential to provide nutrition rice plants require. Therefore, a field experiment was conducted at the research area of the Institute of Agriculture - Skopje, Department of Field Crops, Ss. Cyril and Methodius University in Skopje, Republic of Macedonia, in Kochani, a rice production region. The experiment was set up to determine the effects of the Fitostemin-WP® biostimulator on some yield and quality properties of an Italian rice variety Opale during the vegetative seasons in 2020 and 2021. Standard agrotechnical methods for crop production were applied. Fitostemin-WP® is an herbal product in the form of powder and it consists of herbal extracts and minerals. It is used for increasing crop yield. The field experiment was arranged in a Zade method with a Fitostemin-WP® treatment and a control one in 3 replications. Only basic fertilizers (350kg/ha NPK and 200kg/ha Urea (46% N)) were applied on the control plot, while the treatment plot, besides basic fertilization, was also treated with Fitostemin-WP® with 100 g/ha dosage once during the vegetation period (tillering stage). The following parameters were examined in this study, namely the biological, grain and straw yield, the number of productive tillers/m2, panicle weight, and milling fractions. Results were analyzed with the ANOVA and LSD test. According to the results from this study, statistically significant differences were not found in these two years of field experiments for the examined parameters. However, the values for the brokens have shown some significant differences between the years, but not between the treatment and the control. This can result from the environmental impact during the vegetative period. More frequent usage of Fitostemin-WP® during the vegetation period of the rice plant may show more significant results.

Screening of Arsenic toxicity in Oryza sativa L. (rice) and assessment of variation in growth, ROS, and antioxidant responses in tolerant and sensitive rice cultivars

ABSTRACT Arsenic (As) in rice plants has toxic effects on their quality and human health. In the present study, 100 rice cultivars have been screened in hydroponics to analyze As toxicity and select As-tolerant and sensitive rice cultivars. The findings showed that rice cultivars responded differently to As stress at varying levels of effect. As treatments significantly changed morphological traits, the arsenic tolerance index (ATI %), pigments, and H2O2 concentrations. The rice cultivars Luit and Swarna demonstrated remarkable results (tolerant and sensitive) in terms of growth, as well as in terms of ATI, chlorophyll content, H2O2 content, and enzymatic and non-enzymatic antioxidants. Arsenic-induced pigment degradation and antioxidant content reduction were greater in Swarna than in Luit. Moreover, the results of biochemical analysis correlated with the morphological parameters. The selected As-tolerant and sensitive cultivars may be used to explore the tolerance mechanism in greater depth, which will require further molecular investigations.

Sequence-based analysis of the rice CAMTA family: haplotype and network analyses

The calmodulin-binding transcription activator (CAMTA) family contributes to stress responses in many plant species. The Oryza sativa ssp. japonica genome harbors seven CAMTA genes; however, intraspecific variation and functional roles of this gene family have not been determined. Here, we comprehensively evaluated the structure and characteristics of the CAMTA genes in japonica rice using bioinformatics approaches and RT-qPCR. Within the CAMTA gene and promoter sequences, 527 single nucleotide polymorphisms were retrieved from 3,024 rice accessions. The CAMTA genes could be subdivided into 5–14 haplotypes. Association analyses between haplotypes and phenotypic traits, such as grain weight and salt stress parameters, identified phenotypic differences between rice subpopulations harboring different CAMTA haplotypes. Co-expression analyses and the identification of CAMTA-specific binding motifs revealed candidate genes regulated by CAMTA. A Gene Ontology functional enrichment analysis of 690 co-expressed genes revealed that CAMTA genes have key roles in defense responses. An interaction analysis identified 30 putative CAMTA interactors. Three genes were identified in co-expression and interaction network analyses, suggesting that they are potentially regulated by CAMTAs. Based on all information obtained together with the phenotypes of the CRISPR-Cas9 knockout mutant lines of three OskCAMTA genes generated, CAMTA1 likely plays important roles in the response to salt stress in rice. Overall, our findings suggest that the CAMTA gene family is involved in development and the salt stress response and reveal candidate target genes, providing a basis for further functional characterization.

Involvement of plasma membrane H+-ATPase in the nitrate-nutrition uptake and utilization in indica rice

Utilization of nitrogen by crops is essential for sustainable agriculture. The transport of nitrate (NO3−) across the plasma membrane is a critical gateway for N uptake and subsequent utilization. This process requires proton (H+) coupled cotransport, which is driven by proton motive force, provided by plasma membrane (PM) H+-ATPase. In this report, two indica rice varieties [Meixiangzhan 2 (MXZ) and Jifengyou 1002 (JFY)] in South China were selected and cultivated in hydroponic solution with 0.5 mM or 2.0 mM NO3− as the N source. The JFY exhibited stronger growth with higher biomass than MXZ under both 0.5 mM and 2.0 mM NO3−. PM H+-ATPase activity of JFY roots was significantly higher than that of MXZ. The higher PM H+-ATPase activity in JFY was consistent with a higher abundance of PM H+-ATPase protein and higher transcription levels of OSAs, such as OSA2, OSA7 and OSA8 in roots, OSA3, OSA7 and OSA8 in leaves. The expression of nitrate transporters (OsNRT1;1b, OsNRT2.1, OsNRT2.2, and OsNAR2.1) were also higher in roots or shoots of JFY than those in MXZ. Under 0.5 mM and 2.0 mM NO3−, the NO3− absorption and translocation rate, nitrate content, as well as nitrate reductase (NR) activity were all significantly higher in JFY, as compared to those in MXZ. Taken together, in JFY and MXZ, a higher level of PM H+-ATPase protein and higher activity coupled with greater efficiency in nitrate uptake, translocation and assimilation, suggesting the existence of a close correlation between PM H+-ATPase and nitrate utilization in indica rice. PM H+-ATPase may one of the elite genes that can contribute to nitrate use efficiency in rice.

Quantitatively Tracking the Speciation and Dynamics of Selenium Nanoparticles in Rice Plants.

The uptake, translocation, and transformation of engineered nanoparticles (ENPs) in plants present significant challenges due to the lack of effective determination methods. This is especially true for selenium nanoparticles (SeNPs), which hold promise for Se-biofortified agriculture and exhibit dynamic behaviors within plant system. Herein, we proposed a novel approach that incorporates enzymic digestion and membrane filtration to selectively extract SeNPs and dissolved Se from plant tissues, employing rice (Oryza sativa) plant as a model. Subsequently, the SeNPs retained on the membrane were quantified using inductively coupled plasma mass spectrometry (ICPMS), while the dissolved Se in the filtrate, including selenite (Se(IV)), selenate (Se(VI)), and seleno amino acid, were analyzed by liquid chromatography coupled with ICPMS (LC-ICPMS). Recoveries of 83.5-91.4% for SeNPs and 73.6-99.4% for dissolved Se at a spiking level of 8 μg/g in quality control samples were obtained. With the established method, it was discovered that SeNPs taken up by rice leaves can transform into Se (IV) and organic Se, and all the Se species could be translocated downward, but only Se (IV) and SeNPs could be excreted through the roots. These findings provide valuable insights into the fate of SeNPs in plants and their related biological responses.

Calcium-Dependent Protein Kinase 5 and 13 enhance salt tolerance in rice by directly activating OsMPK3/6 kinases.

Mitogen-activated protein kinases (MAPKs/MPKs) are pivotal regulators in many stress-signaling pathways in plants. The dual phosphorylation of the TXY motif by MAP Kinase Kinases (MKKs) is essential for activating MAPKs. Here, we reveal a mechanism for MAPK activation that bypasses the need for MKKs. We identified rice (Oryza sativa) calcium-dependent protein kinase 5 (OsCPK5) and OsCPK13as positive regulators in salt stress tolerance. These kinases are essential for the full activation of OsMPK3 and OsMPK6 in response to elevated sodium levels, with both OsMPK3 and OsMPK6 also acting as positive regulators in rice salt tolerance. Biochemical analysis demonstrated that OsCPK5/13 directly interact with and activate OsMPK3/6 by phosphorylating the TXY motif in vitro and in vivo. Additionally, we have discovered that OsCPK5/13 relocate from the cell membrane to the nucleus in response to salt stress. This process relies on their N-terminal myristoylation and a calcium-dependent phosphorylation event within the N-terminus. Our results elucidate a MAPK activation pathway in rice that is independent of traditional MKK-mediated phosphorylation, highlighting the crucial roles of OsCPK5 and OsCPK13 in directly phosphorylating and activating OsMPK3/6, which are important for rice tolerance to salt stress.

Dynamic alterations and ecological implications of rice rhizosphere bacterial communities induced by an insect-transmitted reovirus across space and time

BackgroundCereal diseases caused by insect-transmitted viruses are challenging to forecast and control because of their intermittent outbreak patterns, which are usually attributed to increased population densities of vector insects due to cereal crop rotations and indiscriminate use of pesticides, and lack of resistance in commercial varieties. Root microbiomes are known to significantly affect plant health, but there are significant knowledge gaps concerning epidemics of cereal virus diseases at the microbiome-wide scale under a variety of environmental and biological factors.ResultsHere, we characterize the diversity and composition of rice (Oryza sativa) root-associated bacterial communities after infection by an insect-transmitted reovirus, rice black-streaked dwarf virus (RBSDV, genus Fijivirus, family Spinareoviridae), by sequencing the bacterial 16S rRNA gene amplified fragments from 1240 samples collected at a consecutive 3-year field experiment. The disease incidences gradually decreased from 2017 to 2019 in both Langfang (LF) and Kaifeng (KF). BRSDV infection significantly impacted the bacterial community in the rice rhizosphere, but this effect was highly susceptible to both the rice-intrinsic and external conditions. A greater correlation between the bacterial community in the rice rhizosphere and those in the root endosphere was found after virus infection, implying a potential relationship between the rice-intrinsic conditions and the rhizosphere bacterial community. The discrepant metabolites in rhizosphere soil were strongly and significantly correlated with the variation of rhizosphere bacterial communities. Glycerophosphates, amino acids, steroid esters, and triterpenoids were the metabolites most closely associated with the bacterial communities, and they mainly linked to the taxa of Proteobacteria, especially Rhodocyclaceae, Burkholderiaceae, and Xanthomonadales. In addition, the greenhouse pot experiments demonstrated that bulk soil microbiota significantly influenced the rhizosphere and endosphere communities and also regulated the RBSDV-mediated variation of rhizosphere bacterial communities.ConclusionsOverall, this study reveals unprecedented spatiotemporal dynamics in rhizosphere bacterial communities triggered by RBSDV infection with potential implications for disease intermittent outbreaks. The finding has promising implications for future studies exploring virus-mediated plant-microbiome interactions.2AL1xEb7k2nunVBmbuNCsVVideo

Ecology and diversity of arbuscular mycorrhizal fungi (AMF) in rice (Oryza sativa L.) in South India: an ecological analysis of factors influencing AMF in rice fields.

This study examined the diversity of arbuscular mycorrhizal fungi (AMF), mean spore density (MSD), and root colonization in relation to factors such as agroclimatic zones, rice varieties and soil types in paddy fields of South India. The aim was to understand how these factors influence AMF association in rice, facilitating their effective use as a biological tool in paddy cultivation. AMF were identified through light microscopy of spores, while MSD and percentage-root-length colonization (PRLC) were measured using standard methods. Correlation and principal component analyses were performed to explore the interrelationships between AMF characteristics and various environmental, soil, and plant variables. Sixteen AMF species were identified across 29 rice varieties from three agroclimatic zones, 6 soil orders, and 18 soil series over 2 seasons. Notably, 70% of chemicalized rice fields lacked AMF spores, and only 50% exhibited root colonization. This study offers new insights into the role of AMF in rice cultivation. The AMF diversity and root colonization in relation to environmental variables underscore their significant impact on AMF in particular crop fields.

Transcriptomic Analysis of the CNL Gene Family in the Resistant Rice Cultivar IR28 in Response to Ustilaginoidea virens Infection.

Rice false smut, caused by Ustilaginoidea virens, threatens rice production by reducing yields and contaminating grains with harmful ustiloxins. However, studies on resistance genes are scarce. In this study, the resistance level of IR28 (resistant cultivar) to U. virens was validated through artificial inoculation. Notably, a reactivation of resistance genes after transient down-regulation during the first 3 to 5 dpi was observed in IR28 compared to WX98 (susceptible cultivar). Cluster results of a principal component analysis and hierarchical cluster analysis of differentially expressed genes (DEGs) in the transcriptome exhibited longer expression patterns in the early infection phase of IR28, consistent with its sustained resistance response. Results of GO and KEGG enrichment analyses highlighted the suppression of immune pathways when the hyphae first invade stamen filaments at 5 dpi, but sustained up-regulated DEGs were linked to the 'Plant-pathogen interaction' (osa04626) pathway, notably disease-resistant protein RPM1 (K13457, CNLs, coil-coiled NLR). An analysis of CNLs identified 245 proteins containing Rx-CC and NB-ARC domains in the Oryza sativa Indica genome. Partial candidate CNLs were shown to exhibit up-regulation at both 1 and 5 dpi in IR28. This study provides insights into CNLs' responses to U. virens in IR28, potentially informing resistance mechanisms and genetic breeding targets.

Retraction Note: Salt acclimation differentially regulates the metabolites commonly involved in stress tolerance and aroma synthesis in indica rice cultivars

Retraction Note: Salt acclimation differentially regulates the metabolites commonly involved in stress tolerance and aroma synthesis in indica rice cultivars

Effect of chemical weed management on growth, yield and economics of drum seeded rice (Oryza sativa)

Field experiment was conducted at Periyanarkunam, Bhuvanagiri Taluk, Cuddalore District during Kuruvai 2021 and 2022 to study the effect of different herbicidal weed management on growth, yield and economics of drum seeded rice (Oryza sativa L.) variety ‘ASD 16’. The experiment was conducted in randomized block design with four replications. The treatments comprised of six weed management practices and are made up of a combination of herbicides (pre-emergence, early-post and post-emergence herbicides) with hand weeding, which was com- pared with unweeded control and twice hand weeding on 25 and 45 DAS. Application of bensulfuron methyl 0.6% + pretilachlor 6% GR @ 660 g a.i./ha PE fb metsulfuron methyl 10% + chlorimuron ethyl 10% WP @ 4 g a.i./ha PoE on 25 DAS fb hand weeding on 45 DAS recorded the highest weed control efficiency of 77.55 and 74.23% during Kuruvai 2021 and 2022 respectively, growth attributes at 60 DAS viz., plant height (96.82 and 91.79 cm), tillers/m2 (367 and 343) and dry matter production (8.01 and 7.78 t/ha), yield attributes like productive tillers/m2 (319 and 312), filled grains/panicle (100.64 and 98.42), grain yield (6.19 and 6.11 t/ha) and benefit cost ratio (2.78 and 2.49) during Kuruvai 2021 and 2022, respectively over bispyribac sodium 10% SC @ 25 g a.i./ha PoE on 20 DAS fb hand weeding on 45 DAS (farmers practice). Hence, it is an efficient weed management practice and an economically feasible method for achieving the maximum growth, yield and economics of drum seeded rice.

Carcinogenic risks of inorganic arsenic in white rice in Asia

This study estimated the incremental lifetime cancer risk (ILCR) of inorganic arsenic (iAs) from white rice ingestion in eight countries (China, Korea, Pakistan, Saudi Arabia, Thailand, Vietnam, Bangladesh, and Cambodia) in Asia by using data collected from published literature (n = 4857). ILCR of iAs exposure from white rice ingestion substantially varied with region, ranging from 0.37 to 13.46 per 10000 people, with an average of 6.12 per 10000 people. Bangladesh had the highest ILCR, followed by Cambodia, Vietnam, Thailand, China, Korea, Saudi Arabia, and Pakistan. Carcinogenic risks of iAs exposure from white rice ingestion in China, Korea, Thailand, Vietnam, Bangladesh, and Cambodia are at an unacceptable level (more than 1 per 10000 people). Linear regression analysis indicated that ingestion rate and inorganic arsenic content were the critical factors determining regional differences in carcinogenic risk of iAs exposure from white rice ingestion in Asia.

Co-application of fly ash and zeolite increases N uptake but decreases P uptake and biomass of rice fertilized with fermented liquid manure

ABSTRACT Fermented liquid pig manure (LPM) can be used as a nutrient source to replace synthetic fertilizers (SF). However, concerns remain regarding nitrogen (N) and phosphorus (P) losses from rice (Oryza sativa L.) paddies fertilized with LPM. Fly ash (FA) has a high calcium content (Ca) and zeolite (Z) has a high negative-charge; thus, they can immobilize P and N through the fixation of P with Ca and NH4 + onto negatively charged sites, respectively. This study investigated the effects of the co-application of FA and Z (FAZ) on the nutrient availability and growth of rice fertilized with LPM. Four treatments were evaluated: no input (control), synthetic fertilizer (SF), and LPM at two levels, with or without FAZ application, for 104 days. The pH (pHwater), electrical conductivity (ECwater), N (Nwater), and P (Pwater) concentrations in the ponding water of rice fields were analyzed 18 times during rice growth. The rice biomass and uptake of N and P were measured, and the concentrations of mineral N and available P in soil were determined after harvest. LPM application increased (p < 0.001) N and P availability in the absence of FAZ, leading to rice biomass comparable to that of SF. However, FAZ diminished the fertilization effects of LPM on rice growth. The Nwater decreased by 50% and the rice uptake of N increased by 6% after FAZ application, probably because of the retention of N by Z and its subsequent release. By contrast, FAZ increased (p < 0.001) soluble Pwater (85% for LPMS) and decreased (p = 0.004) P uptake (8%–40%), reducing the rice biomass by 20%–25%. The decreased P uptake is probably due to the strong immobilization of P by FA. Therefore, it is cautioned that P-limitation through immobilization of P by FA under alkaline conditions may hinder rice growth in FAZ-amended paddy fertilized with LPM. An appropriate application rate of FA for improved P nutrition needs to be explored.

The Effect of Pyrolysis Temperature and Raw Materials Mass Comparison on the Characteristics of Briquettes from a Mixture of Rice Husk (Oryza sativa L.) and Jengkol Peel (Pithecellobium jiringa) Using Starch Adhesives

The Effect of Pyrolysis Temperature and Raw Materials Mass Comparison on the Characteristics of Briquettes from a Mixture of Rice Husk (Oryza sativa L.) and Jengkol Peel (Pithecellobium jiringa) Using Starch Adhesives

Study the Effect of Integrated Nutrient Management with Bio-inoculants on Yield Attributes and Yields of Rice (Oryza sativa L.)

The experiments were conducted during the kharif season of 2021-22 and 2022-23 at the S.I.F, Chandra Shekhar Azad University of Agriculture &amp; Technology, Kanpur. The experiment consists of 18 treatment combinations in randomized block design with three replications of different combinations of inorganic fertilizer, organic and bio-inoculants in rice. Based on results emanated from the investigation it can be concluded that among the productivity parameters viz: The statistically maximum grain yield (q ha-1), straw yield (q ha-1) and biological yield (q ha-1) were found (47.38, 47.56 q ha-1), (66.82, 67.22q ha-1 ) and (114.20, 114.78 q ha-1 ) in 2021-22 and 2022-23 respectively in the treatments recorded in the treatment T17 - 100% NPK+ 5 ton ha-1 FYM + Azolla (300 kg ha-1) + S (30 kg ha-1) + Zinc (5 kg ha-1) during both years of experimentation and the plant growth traits viz: panicle length (28.93cm), panicle weight (g) (5.86g) number of grain panicle-1 (127) grains weight panicle-1 (4.11) and test weight (g) (24.97g) were recorded statistically maximum with the treatment T17 -100% NPK+ 5 ton ha-1 FYM + Azolla (300 kg ha-1) + S (30 kg ha-1) + Zinc (5 kg ha-1) during the experimentation.

Potassium supply for improvement of cereals growth under drought: A review

AbstractPotassium (K) is an essential macronutrient that determines crop productivity and promotes crop growth under conditions of abiotic stress. In this review paper, peer‐reviewed publications (experimental data) dealing with the role of K administration in the control of cereals growth under drought stress are reviewed and analyzed. Most published research on the impact of K administration on cereals growth under drought focuses primarily on bread wheat (Triticum aestivum L.) and maize (Zea mays L.), along with barley (Hordeum vulgare L.), rice (Oryza sativa L.), pearl millet (Pennisetum glaucum L.), and sorghum (Sorghum bicolor L.). The beneficial effect of K on cereals growth under drought has been related to maintenance of water balance in the crops, increased activity of the antioxidant enzymes, increased synthesis of osmolytes, contribution to a low sodium (Na)/K ratio, extension of the grain filling period, and increase of the grain growth rate and weight. Moreover, K was suggested as a possible way for enhancing nitrogen use efficiency (e.g., bread wheat and sorghum). Nevertheless, the beneficial effect of foliar applied K in dried soil during grain filling differed among bread wheat cultivars, highlighting that the effect of K supply on grain weight may differ depending on application method, that is, administration through the soil or the foliage. Overall, K supply could be exploited as a tool for increasing cereal tolerance to drought, for example, by considering late administration of K through top dressing applications or foliar sprayings. Yet additional information is needed on the rate and the K form, along with the most suitable growth stage for application. Such information could help agronomists develop strategies for high‐quality cereal production in stressful environments.

Optimizing rice (Oryza sativa) growth, productivity, profitability and nutrient uptake with coated urea and organic manure in the new alluvial zone of West Bengal

A two-year field experiment was carried out at experimental farm of BCKV, Nadia, West Bengal during kharif seasons of 2019–20 and 2020–21 to study the effect of combined application of coated urea and organic manure on performance of rice. The experiment was laid-out in a randomized complete block design with four replications and treatment comprised 5 treatment combinations, such as T1 , control plot (without N); T2 , 100% recommended dose of nitrogen (RDN) through neem-coated urea (NCU); T3 , 75% RDN through NCU + 25% RDN through FYM (farm yard manure); T4, 100% RDN through polymer sulphur coated urea (PSCU); T5, 75% RDN through PSCU+25% RDN through FYM. The results showed that 75% RDN through PSCU+25% RDN through FYM re- sulted in maximum growth attributes, viz. plant height (110.8 cm), maximum number of effective tillers per square meter (416/m2 ), highest dry-matter accumulation (DMA) (740 g/m2 ), leaf area index (LAI) (4.47) and crop growth rate (CGR) (6.56 g/m2 /day), highest yield components like panicle length (23.5 cm), panicle weight (9.95 g), num- ber of filled grains/panicle (113), test-weight (21.3 g) and maximum grain yield (4.79 t/ha) and straw yield (5.53 t/ ha). Similarly, maximum amount of total nutrient uptake by crop (99.7, 40.1 and 208 kg/ha NPK), protein yield (418 kg/ha), gross returns (` 71.8 × 103 /ha), net return (` 52 × 103 /ha) and B: C ratio (2.73) were noticed under T5 treat- ment. Therefore, it is advisable to implement a comprehensive nutrient management strategy T5 (75% RDN through PSCU + 25% RDN through FYM) in rice cultivation. This approach enhances growth, yield, nutrient absorption, and quality, ultimately boosting agricultural productivity, profitability, and sustainability.

Bio-prospecting fluoride tolerant bacteria for their optimistic contribution in instigating resilience against fluoride stress in Oryza sativa L.

In recent years, the effects of fluoride (F) pollution in numerous ecosystems such as groundwater, soil, etc. Have become a major issue worldwide. This increase in F pollution is a direct consequence of the unbridled use of fertilizers in agricultural and several other human activities that require immediate and appropriate action. Therefore, this manuscript reveals important findings on the efficacy of bacteria isolated from agricultural fields in central Chhattisgarh in manifesting resistance to F and in reversing the F-induced oxidative damage in susceptible Oryza sativa L, (Var. MTU1010). Chronic exposure of Oryza sativa L. to sodium fluoride (NaF) (50 mg L−1) severely impeded growth and various physiological parameters such as germination percentage, biomass and root and shoot length and stimulated the formation of reactive oxygen species (ROS), which enhanced electrolyte leakage and formation of cytotoxic products like malondialdehyde. To this end, potential bacterial strains, namely MT2A, MT3A, MT4A, and Du3A were isolated, screened for various plant growth promoting (PGP) traits and used to explore their efficiency to mitigate F toxicity in Oryza sativa L. in vivo. The seedlings inoculated with the bacterial strains showed significant development as evidenced by an increase in root and shoot length, biomass and chlorophyll content. Additionally, inoculation of these strains in combination with F stress significantly decreased oxidative stress by increasing the expression of protective genes encoding antioxidant enzymes and boosted agronomic traits remarkably. Overall, the manuscript demonstrates the pivotal role played by the isolated bacteria in abating ill effects of F in the Oryza sativa L. seedlings and proves their potential as protective bioagents against F stress.

Exploring genetic variation and genetic components under salinity stress among Basmati and Non-Basmati rice (Oryza sativa L.) cultivars

Rice (Oryza sativa L.) is an essential cereal crop which feeds more than half of the world’s population. Rice is cultivated on one-tenth of the world's arable land (approximately 150 million hectares (ha)). Its production is critically affected by salinity stress, which harms photosynthesis and growth, causing biomass loss and partial sterility. The extent of salinization of cultivable soil is increasing by 10% annually. It is predicted that more than 50% of the world's land will be damaged by salinization by 2050. In Pakistan, approximately 6.30 Mha of land is severely affected by salt stress. To cope with this problem, this study was conducted to identify saline-tolerant rice cultivars, 14 rice cultivars (PK1121 aromatic, Nonabokra, Kalomonok, PK10683, PK8892 Tol-19, Shaheen Tol-19, Chenab Tol-19, Punjab Basmati, Super Basmati 2019, Basmati 2000, Basmati 370, Basmati 385, Super Basmati, and Basmati 515 Tol-19) were grown in a 5.5 electrical conductivity (EC) salinity block to investigate their tolerance to salinity stress. Seven rice cultivars (Nonabokra, Basmati 2000, Kalomonok, Basmati 370, Basmati 385, Super Basmati, and Basmati 515 Tol-19) exhibited tolerance to salinity. Basmati 370 was tolerant to a high salinity level of 5.5 EC and showed high yield than other cultivars, however, Nonabokra outperformed other cultivars in terms of all yield attributes investigated in this study. These results were also verified via molecular screening of these genotypes by using already reported DNA markers. Polymorphic SSR marker (RM7075) associated with the SaltTOl QTL to evaluate the tolerance of rice varieties to salinity. This study showed that Nonabokra, Basmati 2000, Kalomonok, Basmati 370, Basmati 385, Super Basmati, and Basmati 515 Tol-19 performed better against salt stress and may be used as salinity-tolerant lines for future rice breeding programs.

A multi-omics approach reveals differences in toxicity and mechanisms in rice (Oryza sativa L.) exposed to anatase or rutile TiO2 nanoparticles

Titanium dioxide nanoparticles (TiO2 NPs) have been widely used in agriculture, which increased the risk to soil-plant systems. Studies have demonstrated that TiO2 NPs can induce phytotoxicity. However, the toxicity mechanisms, particularly under the stress of TiO2 NPs with different crystalline forms, remain inadequately reported. In this study, we combined transcriptomics and metabolomics to analyze the toxicity mechanisms in rice (Oryza sativa L.) under the stress of anatase (AT) or rutile (RT) TiO2 NPs (50 mg/kg, 40 days). The length (decreased by 1.1-fold, p = 0.021) and malondialdehyde concentration (decreased by 1.4-fold, p = 0.0027) of rice shoots was significantly reduced after AT exposure, while no significant changes were observed following RT exposure. Antioxidant enzyme activities were significantly altered both in the AT and RT groups, indicating TiO2 NPs induced rice oxidative damage (with changes of 1.1 to 1.4-fold, p < 0.05). Additionally, compared to the control, AT exposure altered 3247 differentially expressed genes (DEGs) and 56 significantly differentially metabolites in rice (collectively involved in pyrimidine metabolism, TCA cycle, fatty acid metabolism, and amino acid metabolism). After RT exposure, 2814 DEGs and 55 significantly differentially metabolites were identified, which were collectively involved in fatty acid metabolism and amino acid metabolism. Our results indicated that AT exposure led to more pronounced changes in biological responses related to oxidative stress and had more negative effects on rice growth compared to RT exposure. These findings provide new insights into the phytotoxic mechanisms of TiO2 NPs with different crystalline forms. Based on the observed adverse effects, the study emphasizes that any form of TiO2 NPs should be used with caution in rice ecosystems. This study is the first to demonstrate that AT is more toxic than RT in paddy ecosystems, providing crucial insights into the differential impacts and toxic mechanisms of TiO2 NPs with different crystalline forms. These findings suggest prioritizing the use of RT when TiO2 NPs are necessary in agricultural development to minimize toxicity risks.