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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. [ABSTRACT FROM AUTHOR]

Deterioration of rice (Oryza sativa L.) affects grain quality and seed viability during storage. Lipoxygenase (LOX), a key enzyme in lipid metabolism, directly affects the rate of ageing. Here, we found that knock-out of lipoxygenase gene OsLOX1 by CRISPR/Cas9 delayed loss of seed viability and quality. Transcriptome analysis showed that during storage, OsLOX1 affected transcription of multiple genes, including genes related to lipid metabolism and antioxidant pathways such as phosphatase and acetaldehyde dehydrogenase, which may regulate the seed storability. The genes significantly down- and up-regulated only in Ningjing 4 after NA for 13 months and 3 days of AA suggesting that OsLOX1 likely promoted seed viability in rice by balancing ageing and storage related genes, and regulated the seed storability through the amino acid synthesis and metabolic pathways. Moreover, knock-out of OsLOX1 without CRISPR/Cas9 not only improved the seed viability, but also had little impact on agronomic traits. More importantly, the OsLOX1 knock-out lines were approved in 2019 (Agricultural Foundation of China Report No. 770). Collectively, our study showed that knock-out of OsLOX1 is beneficial for prolongation of seed viability and can be directly applied to agricultural production. [ABSTRACT FROM AUTHOR]

The properties of different organic fertilizers and their potential for stabilizing toxic metals(loids) in soil have not been fully investigated. This study characterized and evaluated three organic fertilizers from different raw materials. The mushroom residue organic fertilizer (MO) had higher C, H, and O contents and more functional groups (-OH, C-H, and C = O). Its application significantly increased pH (1.00 ~ 1.32 units), organic matter (OM) content (26.58 ~ 69.11%), and cation exchange capacity (CEC) (31.52 ~ 39.91%) of soil. MO treatments can simultaneously reduce the bioavailable TCLP-Cd and TCLP-As in soil, solving the difficulties of remediating the combined Cd and As pollution. MO treatments inhibited the migration of Cd and As from soil to plant, promoting plant growth. Redundancy analysis (RDA) revealed that metal(loid) variations in plants were related to soil properties (40.09%) and TCLP-Cd/As (44.74%). Furthermore, the toxic metals(loids) risk assessment for all organic fertilizers was at safe levels. This study provided a valuable reference for choosing organic fertilizers and presented a novel option for the "producing while remediating" of farmlands with low pollution. [ABSTRACT FROM AUTHOR]

Rice quality has a major impact on its economic value, necessitating the breeding of high-quality grain varieties. In addition, varieties with superior germination and growth at low temperatures are required for direct sowing, which enables the low-cost production of rice. We developed Akikei770, a near-isogenic line from the high-quality, good-tasting cultivar Akitakomachi, carrying the qLTG3-1 gene from the Maratelli cultivar, which enhances low-temperature germinability. Although Akikei770 exhibited improved low-temperature germinability, it was inferior to Akitakomachi in appearance quality of brown rice and in eating quality of cooked rice. In Akikei770, a short arm region of up to 222 kb on chromosome 3 from Maratelli was introgressed, and only the qLTG3-1 gene exhibited polymorphisms within the coding region compared to Akitakomachi. The qLTG3-1 genotype was significantly associated with brown rice quality in the F2 population, which indicates that the qLTG3-1 gene was involved in this trait with no involvement of other chromosomal regions of Akikei770. The functional qLTG3-1 allele in Akikei770, encoding a hybrid glycine-rich protein (HyGRP) that is localized on the cell wall or membrane, enhanced the low-temperature germinability. Because a loss-of-function allele of qLTG3-1 increased the appearance quality of brown rice in a recessive manner, it was concluded that HyGRP, which enhances low-temperature germinability, has a pleiotropic effect that reduces the appearance quality of brown rice. [ABSTRACT FROM AUTHOR]

There is still much to learn with respect to the potential for microplastics (MPs) to interact with environmental toxins and biota. In the present study, we investigated the effect of MPs on the toxicity of copper (Cu) to rice seeds (Oryza sativa L.). The 7‐day median effective concentration (EC50) value of MPs on rice seed germination was 864 mg/L (95% confidence interval [CI] 839 to 897 mg/L). We found that MPs slightly reduced Cu toxicity to rice seeds. The 7‐day EC50 of Cu on rice seed germination increased from 7.29 mg/L (95% CI 7.10–7.52 mg/L) to 7.93 mg/L (95% CI 7.58–8.08 mg/L) in the presence of 20 mg/L MPs. We examined this toxicity reduction phenomenon by investigating the role of MPs in the process of Cu transport, Cu accumulation, and metabolic responses. Further investigation found that the MPs used in the present study hardly adsorbed Cu, but these MPs accumulated on the coats of rice seeds and significantly reduced Cu accumulation in rice seedlings. When Cu concentration was 10 mg/L, the presence of MPs reduced the accumulation of Cu in rice seedlings by 34%. We also found that, compared with only Cu present, the addition of MPs resulted in lower reactive oxygen species accumulation and higher catalase activity and glutathione levels in rice seedlings, which also contributed to Cu toxicity reduction. Collectively, the present study shows that polystyrene MPs have the potential to form associations with plant structures which can ultimately impact heavy metal bioaccessibility and therefore toxicity. Environ Toxicol Chem 2024;43:1870–1879. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Low temperature severely affects rice development and yield. Ethylene signal is essential for plant development and stress response. Here, we reported that the OsEIN2‐OsEIL1/2 pathway reduced OsICE1‐dependent chilling tolerance in rice. The overexpressing plants of OsEIN2, OsEIL1 and OsEIL2 exhibited severe stress symptoms with excessive reactive oxygen species (ROS) accumulation under chilling, while the mutants (osein2 and oseil1) and OsEIL2‐RNA interference plants (OsEIL2‐Ri) showed the enhanced chilling tolerance. We validated that OsEIL1 and OsEIL2 could form a heterxodimer and synergistically repressed OsICE1 expression by binding to its promoter. The expression of OsICE1 target genes, ROS scavenging‐ and photosynthesis‐related genes were downregulated by OsEIN2 and OsEIL1/2, which were activated by OsICE1, suggesting that OsEIN2‐OsEIL1/2 pathway might mediate ROS accumulation and photosynthetic capacity under chilling by attenuating OsICE1 function. Moreover, the association analysis of the seedling chilling tolerance with the haplotype showed that the lower expression of OsEIL1 and OsEIL2 caused by natural variation might confer chilling tolerance on rice seedlings. Finally, we generated OsEIL2‐edited rice with an enhanced chilling tolerance. Taken together, our findings reveal a possible mechanism integrating OsEIN2‐OsEIL1/2 pathway with OsICE1‐dependent cascade in regulating chilling tolerance, providing a practical strategy for breeding chilling‐tolerant rice. Summary Statement: The OsEIN2‐OsEIL1/2 ethylene pathway has negative effect on rice tolerance to low temperature stress through transcriptionally repressing OsICE1‐mediated chilling response. [ABSTRACT FROM AUTHOR]

The genomics and genetic information of Malaysian rice (Oryza sativa L.) is currently limited. It was necessary to conduct genome resequencing of these rice accessions exhibiting different responses to salinity stress. The sequencing was carried out using the Illumina NovaSeq X platform with 30× sequencing coverage to pinpoint variants between salinity tolerant and sensitive rice accessions. The discovery of single nucleotide polymorphisms (SNPs) is crucial for the development of DNA markers associated with salinity tolerance traits. The genome sequence data (FASTQ format) for these accessions have been deposited to the European Nucleotide Archive (ENA) database under the accession number PRJEB71716.

Abstract Background Cadmium (Cd) pollution has declined crop yields and quality. Selenium (Se) is a beneficial mineral element that protects plants from oxidative damage, thereby improving crop tolerance to heavy metals. The molecular mechanism of Se-induced Cd tolerance in rice (Oryza sativa) is not yet understood. This study aimed to elucidate the beneficial mechanism of Se (1 mg/kg) in alleviating Cd toxicity in rice seedlings. Results Exogenous selenium addition significantly improved the toxic effect of cadmium stress on rice seedlings, increasing plant height and fresh weight by 20.53% and 34.48%, respectively, and increasing chlorophyll and carotenoid content by 16.68% and 15.26%, respectively. Moreover, the MDA, ·OH, and protein carbonyl levels induced by cadmium stress were reduced by 47.65%, 67.57%, and 56.43%, respectively. Cell wall metabolism, energy cycling, and enzymatic and non-enzymatic antioxidant systems in rice seedlings were significantly enhanced. Transcriptome analysis showed that the expressions of key functional genes psbQ, psbO, psaG, psaD, atpG, and PetH were significantly up-regulated under low-concentration Se treatment, which enhanced the energy metabolism process of photosystem I and photosystem II in rice seedlings. At the same time, the up-regulation of LHCA, LHCB family, and C4H1, PRX, and atp6 functional genes improved the ability of photon capture and heavy metal ion binding in plants. Combined with proteome analysis, the expression of functional proteins OsGSTF1, OsGSTU11, OsG6PDH4, OsDHAB1, CP29, and CabE was significantly up-regulated under Se, which enhanced photosynthesis and anti-oxidative stress mechanism in rice seedlings. At the same time, it regulates the plant hormone signal transduction pathway. It up-regulates the expression response process of IAA, ABA, and JAZ to activate the synergistic effect between each cell rapidly and jointly maintain the homeostasis balance. Conclusion Our results revealed the regulation process of Se-mediated critical metabolic pathways, functional genes, and proteins in rice under cadmium stress. They provided insights into the expression rules and dynamic response process of the Se-mediated plant resistance mechanism. This study provided the theoretical basis and technical support for crop safety in cropland ecosystems and cadmium-contaminated areas.

Depleting agricultural land and water resources with growing human civilization demands an alternative way for faster and more sustainable crop production techniques to meet the current requirements. Recently, nanotechnology-aided hydroponic agriculture (aquaculture) systems have brought remarkable attention. In this context, the present investigation focuses on applying green synthesized TiO2 nanoparticles in soil-free aquaculture systems to stimulate the germination and growth of Oryza sativa L. TiO2 nanoparticles are synthesized using Dillenia indica fruit extract and characterized using various spectroscopic and microscopic techniques. X-ray diffraction pattern (XRD) confirms the anatase phase of the synthesized TiO2 nanoparticles with an average crystallite size of 6.34 nm. Field emission scanning electron microscopy (FESEM) images exhibit spherical morphology, and high-resolution transmission electron microscopy (HRTEM) analysis indicates the most nanoparticles of sizes below 10 nm. The BET surface analysis indicates the mesoporous nature of synthesized nanoparticles, and their pore sizes are distributed between 1 and 10 nm as confirmed by BJH analysis, which is very similar to the result obtained from HRTEM images. Green synthesized TiO2 nanoparticles in Hoagland nutrient solution enhance germination and growth of Oryza sativa L. via soil-free aquaculture relative to previously commercially produced TiO2 nanoparticles and other metal oxide nanoparticles. Among different concentrations of synthesized TiO2 nanoparticles, a particular concentration (10 mg/L) in the nutrient solution efficiently stimulates germination and growth for Oryza sativa L., relative to the control system. TiO2 nanoparticles with a higher specific surface area adsorb nutrients and facilitate nutrient translocation with improved water uptake inside plants, thus stimulating plant growth and increasing fresh and dry biomass.

Background: Cadmium (Cd) pollution has declined crop yields and quality. Selenium (Se) is a beneficial mineral element that protects plants from oxidative damage, thereby improving crop tolerance to heavy metals. The molecular mechanism of Se-induced Cd tolerance in rice (Oryza sativa) is not yet understood. This study aimed to elucidate the beneficial mechanism of Se (1 mg/kg) in alleviating Cd toxicity in rice seedlings. Results: Exogenous selenium addition significantly improved the toxic effect of cadmium stress on rice seedlings, increasing plant height and fresh weight by 20.53% and 34.48%, respectively, and increasing chlorophyll and carotenoid content by 16.68% and 15.26%, respectively. Moreover, the MDA, ·OH, and protein carbonyl levels induced by cadmium stress were reduced by 47.65%, 67.57%, and 56.43%, respectively. Cell wall metabolism, energy cycling, and enzymatic and non-enzymatic antioxidant systems in rice seedlings were significantly enhanced. Transcriptome analysis showed that the expressions of key functional genes psbQ, psbO, psaG, psaD, atpG, and PetH were significantly up-regulated under low-concentration Se treatment, which enhanced the energy metabolism process of photosystem I and photosystem II in rice seedlings. At the same time, the up-regulation of LHCA, LHCB family, and C4H1, PRX, and atp6 functional genes improved the ability of photon capture and heavy metal ion binding in plants. Combined with proteome analysis, the expression of functional proteins OsGSTF1, OsGSTU11, OsG6PDH4, OsDHAB1, CP29, and CabE was significantly up-regulated under Se, which enhanced photosynthesis and anti-oxidative stress mechanism in rice seedlings. At the same time, it regulates the plant hormone signal transduction pathway. It up-regulates the expression response process of IAA, ABA, and JAZ to activate the synergistic effect between each cell rapidly and jointly maintain the homeostasis balance. Conclusion: Our results revealed the regulation process of Se-mediated critical metabolic pathways, functional genes, and proteins in rice under cadmium stress. They provided insights into the expression rules and dynamic response process of the Se-mediated plant resistance mechanism. This study provided the theoretical basis and technical support for crop safety in cropland ecosystems and cadmium-contaminated areas. Highlights: Se could improve the growth inhibition of rice under Cd stress. Se mediated the increase of photosynthetic pigment content. Se up-regulates functional genes and proteins involved in the photosynthetic system. Se-mediated decreased the content of MDA, ·OH, and protein carbonyl. Se-mediated plant hormone signal transduction plays a vital role in Cd detoxification. [ABSTRACT FROM AUTHOR]

This study was carried during 2023 successive summer growing season on rice (Oryza sativa L.) variety (Giza 183). The investigation aimed to study the effects of paclobutrazol (PBZ) at 90 and 120 mg/L on rice under water deficit stress conditions on growth, relative water content, chlorophyll (chl.) pigments, antioxidant enzymes activity, anatomical parameters, as well as yield and yield component. The results showed that, the highest values of plant growth parameters, chl. contents, anatomical differences of stem and leaf as well as yield and yield component were achieved by PBZ at 90 mg/L. The results indicated that, application of PBZ at 90 mg/L mitigated the adverse effects of water deficit stress. Therefore, this study recommends spraying paclobutrazol at 90 mg/L one month after rice vr. GIZA 183 transplanting. [ABSTRACT FROM AUTHOR]

Key message: Serendipita indica induced metabolic reprogramming in colonized plants complements phosphorus-management in improving their tolerance to arsenic stress on multifaceted biological fronts. Restoration of the anthropic damage done to our environment is inextricably linked to devising strategies that are not only economically sound but are self-renewing and ecologically conscious. The dilemma of heavy metal (HM) dietary ingestion, especially arsenic (As), faced by humans and animals alike, necessitates the exploitation of such technologies and the cultivation of healthy and abundant crops. The remarkable symbiotic alliance between plants and ‘mycorrhizas’ has evolved across eons, benefiting growth/yield aspects as well as imparting abiotic/biotic stress tolerance. The intricate interdependence of Serendipita indica (S. indica) and rice plant reportedly reduce As accumulation, accentuating the interest of microbiologists, agriculturists, and ecotoxicological scientists apropos of the remediation mechanisms of As in the soil–AMF–rice system. Nutrient management, particularly of phosphorus (P), is also praised for mitigating As phytotoxicity by deterring the uptake of As molecules due to the rhizospheric cationic competition. Taking into consideration the reasonable prospects of success in minimizing As acquisition by rice plants, this review focuses on the physiological, metabolic, and transcriptional alterations underlying S. indica symbiosis, recuperation of As stress together with nutritional management of P by gathering case studies and presenting successful paradigms. Weaving together a volume of literature, we assess the chemical forms of As and related transport pathways, discuss As–P–rice interaction and the significance of fungi in As toxicity mitigation, predominantly the role of mycorrhiza, as well as survey of the multifaceted impacts of S. indica on plants. A potential strategy for simultaneous S. indica + P administration in paddy fields is proposed, followed by future research orientation to expand theoretic comprehension and encourage field-based implementation. [ABSTRACT FROM AUTHOR]

Bacterial leaf blight, sometimes known as BLB, is one of the most damaging diseases that may jeopardize the world’s supply of rice. It is caused by the bacterium Xanthomonas oryzae pv. oryzae (Xoo). It has caused sharp decline in production in regions of the globe that produce rice. More than 40 previously characterized resistance (R) genes enable host tolerance for diverse Xoo strains. In this study, three BLB resistant genes, including xa5, xa13, and Xa21, which have been crucial in disease prevention in Bangladesh, were introgressed into populations. These populations were created by crossing IRRI 154, a popular rice variety with a modern genetic background, with IRBB66 (resistant to BLB). Fifteen virulent bacterial isolates were used for BLB infection, and promising recombinants from the F5 and BC2F4 generations were found to be resistant. Using marker assisted selection (MAS) with gene-specific primers on generations F5 and BC2F4, we were able to find that 60 recombinant introgressed lines (RILs) had a pyramiding of BLB resistance genes. In terms of agronomic performance, the RILs outperformed both their donor and recipient parents, demonstrating that the RILs had pyramided three resistance genes, therefore conferring broad-spectrum BLB resistance. The produced BLB-resistant RILs offer substantial future development potential, either as cultivable crops or as BLB resistance donor material for use in boosting the yields of other rice lines. [ABSTRACT FROM AUTHOR]

BackgroundThe occurrence of diseases in rice leaves presents a substantial challenge to farmers on a global scale, hence jeopardizing the food security of an expanding global population. The timely identification and prevention of these diseases are of utmost importance in order to mitigate their impact.MethodsThe present study conducts a comprehensive evaluation of contemporary literature pertaining to the identification of rice diseases, covering the period from 2008 to 2023. The process of selecting pertinent studies followed the guidelines outlined by Kitchenham, which ultimately led to the inclusion of 69 studies for the purpose of review. It is worth mentioning that a significant portion of research endeavours have been directed towards studying diseases such as rice brown spot, rice blast, and rice bacterial blight. The primary performance parameter that emerged in the study was accuracy. Researchers strongly advocated for the combination of hybrid deep learning and machine learning methodologies in order to improve the rates of recognition for rice leaf diseases.ResultsThe study presents a comprehensive collection of scholarly investigations focused on the detection and characterization of diseases affecting rice leaves, with specific emphasis on rice brown spot, rice blast, and rice bacterial blight. The prominence of accuracy as a primary performance measure highlights the importance of precision in the detection and diagnosis of diseases. Furthermore, the efficacy of employing hybrid methodologies that combine deep learning and machine learning techniques is exemplified in enhancing the recognition capacities pertaining to diseases affecting rice leaves.ConclusionThis systematic review provides insight into the significant research endeavours conducted by scholars in the field of rice disease detection during the previous decade. The text underscores the significance of precision in evaluation and calls for the implementation of hybrid deep learning and machine learning methodologies to augment disease identification, presenting possible resolutions to the obstacles presented by these agricultural hazards.

Summary: Heading date (or flowering time) is a key agronomic trait that affects seasonal and regional adaption of rice cultivars. An unoptimized heading date can either not achieve a high yield or has a high risk of encountering abiotic stresses. There is a strong demand on the mild to moderate adjusting the heading date in breeding practice. Genome editing is a promising method which allows more precise and faster changing the heading date of rice. However, direct knock out of major genes involved in regulating heading date will not always achieve a new germplasm with expected heading date. It is still challenging to quantitatively adjust the heading date of elite cultivars with best adaption for broader region. In this study, we used a CRISPR‐Cas9 based genome editing strategy called high‐efficiency multiplex promoter‐targeting (HMP) to generate novel alleles at cis‐regulatory regions of three major heading date genes: Hd1, Ghd7 and DTH8. We achieved a series of germplasm with quantitative variations of heading date by editing promoter regions and adjusting the expression levels of these genes. We performed field trials to screen for the best adapted lines for different regions. We successfully expanded an elite cultivar Ningjing8 (NJ8) to a higher latitude region by selecting a line with a mild early heading phenotype that escaped from cold stress and achieved high yield potential. Our study demonstrates that HMP is a powerful tool for quantitatively regulating rice heading date and expanding elite cultivars to broader regions. [ABSTRACT FROM AUTHOR]

Soil salinity decreases rice yield by 20%, affecting global rice production including in Bangladesh. Some advanced mutant lines were developed through mutation breeding to observe the performance against salinity at the seedling stage. Mutant lines that are tolerant to salinity at the seedling stage can be used to develop salt tolerant varieties. The first experiment evaluated the salinity tolerance of 20 rice genotypes grown under hydroponic conditions at the seedling stage using a completely randomized design (CRD). Binadhan-10 was used as a salt-tolerant check variety.Salinity level of 15 dS/m, shoot length (SL) and shoot weight (SW) were reduced by 5-44% and 12-22%, respectively, in tolerant genotypes and by 51-73% and 26-75% in susceptible genotypes compared to the control condition. Root length (RL) had a marginal reduction of 10-27% in tolerant genotypes and 18-38% in susceptible genotypes. Susceptible genotypes showed drastic change in SL, SW, shoot dry weight (SDW) and root dry weight (RDW) compared to the tolerant genotypes. According to the heatmap, growth parameters SL, SW, SDW, and RDW formed cluster I while RL formed cluster II. According to the radar plot clustering, tolerant genotypes were in cluster-I, moderately tolerant genotypes in cluster-II, and susceptible genotypes in cluster-III, respectively. Four lines (L-4-P-1-1, LIRG-4Seg 1(1)-3, L-4-P-1(1), and L-4- P-1-P-2) identified as salt tolerant. The second experiment evaluated the yield performance of these lines under normal field conditions. The mutant line LIRG-4Seg-1(1)-3 exhibited higher yield (7.6 t/ha) with higher number of effective tillers per plant (9.0) compared to the tested mutants and a longer panicle length (28.9 cm) compared to Binadhan-10 (23.5 cm). This line along with other selected mutants can be further screened at the reproductive phase or utilized as breeding material to develop a salt tolerant variety. [Fundam Appl Agric 2023; 8(4.000): 730-738]

Abstract Background One of the most important cash crops worldwide is rice (Oryza sativa L.). Under varying climatic conditions, however, its yield is negatively affected. In order to create rice varieties that are resilient to abiotic stress, it is essential to explore the factors that control rice growth, development, and are source of resistance. HSFs (heat shock transcription factors) control a variety of plant biological processes and responses to environmental stress. The in-silico analysis offers a platform for thorough genome-wide identification of OsHSF genes in the rice genome. Results In this study, 25 randomly dispersed HSF genes with significant DNA binding domains (DBD) were found in the rice genome. According to a gene structural analysis, all members of the OsHSF family share Gly-66, Phe-67, Lys-69, Trp-75, Glu-76, Phe-77, Ala-78, Phe-82, Ile-93, and Arg-96. Rice HSF family genes are widely distributed in the vegetative organs, first in the roots and then in the leaf and stem; in contrast, in reproductive tissues, the embryo and lemma exhibit the highest levels of gene expression. According to chromosomal localization, tandem duplication and repetition may have aided in the development of novel genes in the rice genome. OsHSFs have a significant role in the regulation of gene expression, regulation in primary metabolism and tolerance to environmental stress, according to gene networking analyses. Conclusion Six genes viz; Os01g39020, Os01g53220, Os03g25080, Os01g54550, Os02g13800 and Os10g28340 were annotated as promising genes. This study provides novel insights for functional studies on the OsHSFs in rice breeding programs. With the ultimate goal of enhancing crops, the data collected in this survey will be valuable for performing genomic research to pinpoint the specific function of the HSF gene during stress responses.

The lack of environmental awareness of agricultural producers is one of the challenges facing the problem of agro-industrial waste, coupled with few resources allocated to the development of new technologies and poor government policies for the management of such waste. An important potential has recently been recognised, with the obtaining of cellulose as the basis of the production of nano biocomposites. The objective of this work was the obtaining and characterisation of cellulose and nanocellulose from agro-industrial residues of rice (Oryza sativa L.) Var. 'Morelos A-2010', in Morelos state. The methodology used included the analysis of husk samples with three replicas, ground and sieved, which were processed by alkaline extraction (NaOH) 5%, bleaching with sodium hypochlorite 1%, followed by a pretreatment with hydrochloric acid (HCl) 0.65%. After drying, the cellulose was subjected to acid hydrolysis with (H2SO4) at 64% and then a sonication process, washings with low centrifugation and final drying of the fibre. The final product was characterised by spectrum in (FTIR), (DSC) and visualisation of its morphology, by Scanning Electron Microscopy (SEM). The results showed potential yields of 29 to 41% cellulose and a purity similar to the commercial standard of crystalline cellulose, which evidenced the possibility of using this agro-industrial by- product of Var rice. 'Morelos A-2010' as a source for obtaining nanocellulose in the region. [ABSTRACT FROM AUTHOR]

Rice grain quality is a multifarious attribute mainly governed by multiple nutritional factors. Grain protein is the central component of rice grain nutrition dominantly affecting eating–cooking qualities. Grain protein content is quantitatively influenced by its protein fractions. Genetic quantification of five protein fractions—albumins, globulins, prolamins, glutelin, and grain protein content—were evaluated by exploiting two BC3F2 mapping populations, derived from Kongyu131/TKM9 (population-I) and Kongyu131/Bg94-1 (population-II), which were grown in a single environment. Correlation studies among protein fractions and grain protein content were thoroughly investigated. A genetic linkage map was developed by using 146 single sequence repeat (SSR) markers in population-I and 167 markers in population-II. In total, 40 QTLs were delineated for five traits in both populations. Approximately 22 QTLs were dissected in population-I, derived from Kongyu131/TKM9, seven QTLs for albumin content, four QTLs for globulin content, three QTLs for prolamin content, four QTLs for glutelin content, and four QTLs for grain protein content. In total, 18 QTLs were detected in population-II, derived from Kongyu131/Bg94-1, five QTLs for albumin content, three QTLs for globulin content, four QTLs for prolamin content, two QTLs for glutelin content, and four QTLs for grain protein content. Three QTLs, qAlb7.1, Alb7.2, and qGPC7.2, derived from population-II (Kongyu131/Bg94-1) for albumin and grain protein content were successfully validated in the near isogenic line (NIL) populations. The localized chromosomal locus of the validated QTLs could be helpful for fine mapping via map-based cloning to discover underlying candidate genes. The functional insights of the underlying candidate gene would furnish novel perceptivity for the foundation of rice grain protein content and trigger the development of nutritionally important rice cultivars by combining marker-assisted selection (MAS) breeding. [ABSTRACT FROM AUTHOR]

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AbstractIn this study, the effects of different vermicompost doses and applications on chlorophyll content and flag leaf development in three different rice cultivars (Oryza sativa L.) were investigated. The study used three different rice cultivars, two different vermicompost applications (foliar and soil), and four different fertilizer doses (0.7, 1.4, 2.1, and 2.8 liters per 100 liters). In this study, the time of measurement was considered as the fourth source of variation, and measurements were made at seven different times. Chlorophyll measurements were made at seven different times, every 10 days, starting from the first leaf formation. The first measurement was made at the beginning of the experiment, and subsequent measurements were made on days 16, 26, 36, 46, 57, and 67. After the plant had completed its development, the flag leaf length (in cm), flag leaf width (in cm), and flag leaf area (in cm2) were also measured. The experiment was planned according to a factorial design on randomized plots with 3 replicates. The analysis results showed that the average flag leaf length was 11.92 ± 2.46 cm, the average flag leaf width was 0.95 ± 0.07 cm, and the average flag leaf area was 8.45 ± 1.83 cm2. Chlorophyll content also varied considerably between measurements made on different days. The application method, time, and dose of vermicompost have been shown to have a significant impact on the amount of chlorophyll and flag leaf area in rice leaves.

AbstractThe panicle architecture is a critical determinant of the reproductive success of rice plants and has a direct impact on grain production. In this study, we evaluated the genetic variation of panicle parameters in fifteen rice genotypes and compared them with five commonly grown cultivars in the study area to assess their potential for crop improvement initiatives. The selection of the 15 genotypes was based on specific criteria, including diversity in origin, grain type, and adaptation to local conditions. Significant morphological variations were observed among the rice accessions for panicle parameters, including panicle length, weight, test weight, panicle number, grains/panicle, chaffs/panicle, and flag leaf area. Principal component analysis (PCA) revealed that the first two axes explained 59.8% of the total variance, indicating substantial variability in panicle features across the genotypes. Panicle length, panicle weight, and flag leaf area were identified as significant variables contributing to phenotypic variation. Multiple correlation analysis indicated that panicle weight was strongly positively correlated with panicle length, flagleaf area, grains/panicle, and test weight but was negatively correlated with panicle number, chaffs/panicle, and panicle angle. Genetic advance as a percentage of the mean (GAM) ranged from 7.226% for panicle number to 70.728% for chaffs/panicle. Traits such as grain/panicle, panicle length, flag leaf area, chaffs/panicle, and test weight exhibited high GAM and heritability, highlighting their significance for selection during crop improvement. Certain rice accessions, namely SVIN123, IR106523-25-34-3-2-13-1-2, Radha-13, and IR15L17315, demonstrated superior panicle weight, larger grains/panicle, and panicle length, making them attractive candidates for future rice breeding projects.

ABSTRACT Rice (Oryza sativa) is among the most important crops worldwide; however, rice crops demand high water consumption. Future projections indicate reduced water availability and severe drought events, which may affect rice crops as the cereal is highly sensitive to drought stress. Thus, cultivars with lower water demand for irrigation or drought escape capacities are among the strategies to address this issue. This study aimed to assess five mutant rice genotypes in terms of growth cycle length, other agronomic interest traits, and drought response in the reproductive stage. The mutant genotypes evaluated showed a shortening of the growth cycle compared to the original cultivar, BRS Pampeira, representing a drought escape strategy. In addition, mutations did not negatively affect plant height and crop yield. However, similar to the original cultivar, mutants are not tolerant to water deficit in the reproductive stage. The genotypes evaluated have potential to be released as early cycle cultivars, which can reduce water demand during the harvest season while presenting a drought escape strategy.

Striped stem borer (SSB) is one of the most damaging pests in rice production worldwide. Previously, we preliminarily demonstrated that indica rice Jiazhe LM, an OsT5H (encoding tryptamine‐5‐hydroxylase) knockout mutant deficient in serotonin, had increased resistance to SSB as compared with its wildtype parent Jiazhe B. However, the full scenario of SSB resistance and the underlying mechanism remain unknown. In this study, we first demonstrated that the OsT5H knockout could generally increase rice resistance to SSB and then proved that the OsT5H knockout does not disrupt the innate defense response of rice plants to SSB infestation, that is, OsT5H knockout mutations neither had significant effect on the transcriptional response of defense genes upon SSB infestation, nor the profile of defense related metabolites and plant hormones, such as lignin, salicylic acid, jasmonic acid, and abscisic acid, nor the activity of reactive oxygen species (ROS) scavenging enzymes and the ROS contents. We then demonstrated that supplementation of serotonin promoted SSB growth and performance in artificial diet feeding experiments. We observed that SSB larvae feeding on Jiazhe B had serotonin 1.72‐ to 2.30‐fold that of those feeding on Jiazhe LM at the whole body level, and more than 3.31 and 1.84 times in the hemolymph and head, respectively. Further studies showed that the expression of genes involved in serotonin biosynthesis and transport was ~88.1% greater in SSB larvae feeding on Jiahze LM than those feeding on Jiazhe B. These observations indicated that SSB increases serotonin synthesis when feeding on serotonin deficient rice but is unable to fully compensate the dietary serotonin deficiency. Put together, the present study strongly suggests that it is the deficiency of serotonin, not the secondary effect of OsT5H knockout on innate defense response confers the SSB resistance in rice, which implies that reducing serotonin level, particularly through inhibition of its inductive synthesis upon SSB damage, could be an efficient strategy for breeding SSB resistant varieties. [ABSTRACT FROM AUTHOR]

Background: One of the most important cash crops worldwide is rice (Oryza sativa L.). Under varying climatic conditions, however, its yield is negatively affected. In order to create rice varieties that are resilient to abiotic stress, it is essential to explore the factors that control rice growth, development, and are source of resistance. HSFs (heat shock transcription factors) control a variety of plant biological processes and responses to environmental stress. The in-silico analysis offers a platform for thorough genome-wide identification of OsHSF genes in the rice genome. Results: In this study, 25 randomly dispersed HSF genes with significant DNA binding domains (DBD) were found in the rice genome. According to a gene structural analysis, all members of the OsHSF family share Gly-66, Phe-67, Lys-69, Trp-75, Glu-76, Phe-77, Ala-78, Phe-82, Ile-93, and Arg-96. Rice HSF family genes are widely distributed in the vegetative organs, first in the roots and then in the leaf and stem; in contrast, in reproductive tissues, the embryo and lemma exhibit the highest levels of gene expression. According to chromosomal localization, tandem duplication and repetition may have aided in the development of novel genes in the rice genome. OsHSFs have a significant role in the regulation of gene expression, regulation in primary metabolism and tolerance to environmental stress, according to gene networking analyses. Conclusion: Six genes viz; Os01g39020, Os01g53220, Os03g25080, Os01g54550, Os02g13800 and Os10g28340 were annotated as promising genes. This study provides novel insights for functional studies on the OsHSFs in rice breeding programs. With the ultimate goal of enhancing crops, the data collected in this survey will be valuable for performing genomic research to pinpoint the specific function of the HSF gene during stress responses. [ABSTRACT FROM AUTHOR]

With the increase in rice production and the increase in the areas to be harvested, it is necessary to introduce new technologies capable of assuming the work of harvesting the grain and knowing its main technical exploitation indicators that facilitate better management of these and greater knowledge of the harvest quality indices, aspects that were unknown in the Juan De Matas Reyes Credit and Services Cooperative (CCS), Pedro Betancourt Municipality, Matanzas Province. The behavior of the different times that intervene in the work day of the harvester was studied, the productivity indexes, the exploitation coefficients and labor quality indicators were calculated, as well as the different causes that originated losses. It was possible to conclude that the NEW HOLLAN TC5070 harvesting machine presents favorable technical conditions to carry out the harvesting work in the rice areas of this production unit. This shows that the main losses of time that the machine had were caused by causes beyond its control, with a greater incidence, the affectations due to organizational causes and meteorological conditions. Its efficiency was affected by the conditions of the crop, which caused a greater loss of grains and a decrease in its productive capacity. [ABSTRACT FROM AUTHOR]

The information on the behaviour of potassium (K+) in tropical paddy rice soils, which is important for a better understanding of the plant availability of K+ is still very limited. We compared the quantity-intensity (Q/I) relationships for K+ under conventional tillage and no-tillage systems in tropical paddy fields in the absence and presence of K+ fertiliser in the addition of nitrogen. The results showed that the values of the activity ratio for K (ARK) and potential buffering capacities (PBCK) in the no-tillage rice field were respectively 16% and 33% higher than that in the conventional tillage field. With the addition of K fertiliser, the value of exchangeable K in equilibrium (ΔK0) in the no-tillage paddy field was 67.9% greater than that in the conventional tillage field. This indicates that K fertilisation is more efficient when applied on a no-tillage paddy field. When the K fertiliser was added (49.8 kg K/ha), the application of N fertiliser at the rate of 115 and 184 kg N/ha resulted in a higher ARK value than that at the rate of 46 kg N/ha. This suggests that the simultaneous application of K and N fertiliser was able to increase exchangeable K in the soil. The application of no-tillage increased of the dry grain yield of rice (about 10%) compared with the application of conventional tillage. Meanwhile, there were significant relationships between the rice yield with the ARK and ΔK0. Moreover, the ARK was significantly correlated with K-uptake.

Sheath blight caused by Rhizoctonia solani AG1-IA is the second most serious disease of rice worldwide. Elucidating the role of multi-drug and toxic compound extrusion (MATE) gene family in host-pathogens interactions may uncover a new possible way to comprehend the mechanism of sheath blight resistance in rice. We foremost explored the role of OsMATE genes against R. solani resistance through comparative transcriptomics in PR114 (susceptible) and ShB-8 (moderately resistant) at 24 and 48 hpi (hours post-inoculation) of R. solani infection, respectively. Six OsMATE genes were differentially expressed and further validated through qRT-PCR. OsMATE6 gene was identified as a potential candidate for sheath blight susceptibility as it was significantly up-regulated in PR114. OsMATE6 is conserved within the wild relatives and might be translocated from Oryza nivara during the domestication of rice. Further studies are focused to verify its role by overexpression and protein interactions to understand the molecular mechanism of sheath blight resistance.

Mesocotyl is an essential organ of rice for pushing buds out of soil and plays a crucial role in seeding emergence and development in direct-seeding. Thus, identify the loci associated with mesocotyl length (ML) could accelerate breeding progresses for direct-seeding cultivation. Mesocotyl elongation was mainly regulated by plant hormones. Although several regions and candidate genes governing ML have been reported, the effects of them in diverse breeding populations were still indistinct. In this study, 281 genes related to plant hormones at the genomic regions associated with ML were selected and evaluated by singlelocus mixed linear model (SL-MLM) and multi-locus random-SNP-effect mixed linear model (mr-MLM) in two breeding panels (Trop and Indx) originated from the 3K re-sequence project. Furthermore, superior haplotypes with longer mesocotyl were also identified for marker assisted selection (MAS) breeding. Totally, LOC_Os02g17680 (explained 7.1-8.9% phenotypic variations), LOC_Os04g56950 (8.0%), LOC_Os07g24190 (9.3%) and LOC_Os12g12720 (5.6- 8.0%) were identified significantly associated with ML in Trop panel, whereas LOC_Os02g17680 (6.5-7.4%), LOC_Os04g56950 (5.5%), LOC_Os06g24850 (4.8%) and LOC_Os07g40240 (4.8-7.1%) were detected in Indx panel. Among these, LOC_Os02g17680 and LOC_Os04g56950 were identified in both panels. Haplotype analysis for the six significant genes indicated that haplotype distribution of the same gene varies at Trop and Indx panels. Totally, 8 (LOC_Os02g17680- Hap1 and Hap2, LOC_Os04g56950-Hap1, Hap2 and Hap8, LOC_Os07g24190- Hap3, LOC_Os12g12720-Hap3 and Hap6) and six superior haplotypes (LOC_Os02g17680-Hap2, Hap5 and Hap7, LOC_Os04g56950-Hap4, LOC_Os06g24850-Hap2 and LOC_Os07g40240-Hap3) with higher ML were identified in Trop and Indx panels, respectively. In addition, significant additive effects for ML with more superior haplotypes were identified in both panels. Overall, the 6 significantly associated genes and their superior haplotypes could be used to enhancing ML through MAS breeding and further promote directseedling cultivation. [ABSTRACT FROM AUTHOR]

Heterotic groups are necessary for high vigor in hybrid rice. However, hybrids produced from crosses between parents from different rice subspecies (i.e., Indica x Japonica) have extensive incompatibility issues exhibited by low seed sets. The study objectives were to evaluate the heterosis in grain yield and yield-related traits between hybrids produced from low and high parental genetic distances (PGDs) and demonstrate the heterotic group approach in rice. From PGDs, eight and three hybrids were assigned to the low and high PGD hybrid groups, respectively. Neighbor-joining clustering and model-based population structure analyses classified the hybrid parents into four heterotic groups, with the low and high PGD hybrid groups found consisting of intra-subpopulation and intersubpopulation crosses, respectively. Replicated yield trials conducted at Beaumont, Texas, transpired in 2019 and 2020. The hybrids exhibited normal seed sets, with at least one of each hybrid's parents determined to possess the wide compatibility S5n allele necessary for normal seed sets in wide crosses. Trait and standard heterosis values estimates included the number of days to heading, plant height, tiller density, and grain yield. Higher trait values and heterosis for tiller density and grain yield occurred in the high than the low PGD hybrid group, especially in the inter-subpopulation crosses with indica rice. PGD had consistent positive correlations with heterosis for grain yield (r = 0.41 to 0.60) and tiller density (0.28 to 0.36) in both years. PGDs aid in determining highly heterotic cross combinations for tiller density and grain yield and in forming heterotic groups. Heterotic grouping is advisable through cluster and structure analyses of genome-wide markers instead of identifying genetically-distant crosses based on pedigree information. [ABSTRACT FROM AUTHOR]

Many agronomic traits that are important in rice breeding are controlled by multiple genes. The extensive time and effort devoted so far to identifying and selecting such genes are still not enough to target multiple agronomic traits in practical breeding in Japan because of a lack of suitable plant materials in which to efficiently detect and validate beneficial alleles from diverse genetic resources. To facilitate the comprehensive analysis of genetic variation in agronomic traits among Asian cultivated rice, we developed 12 sets of chromosome segment substitution lines (CSSLs) with the japonica background, 11 of them in the same genetic background, using donors representing the genetic diversity of Asian cultivated rice. Using these materials, we overviewed the chromosomal locations of 1079 putative QTLs for seven agronomic traits and their allelic distribution in Asian cultivated rice through multiple linear regression analysis. The CSSLs will allow the effects of putative QTLs in the highly homogeneous japonica background to be validated. [ABSTRACT FROM AUTHOR]

Unfavourable environmental conditions, including soil salinity, lead to decreased rice (Oryza sativa L.) productivity, especially at the reproductive stage. In this study, we examined 30 rice varieties, which revealed significant differences in the photosynthetic performance responses under salt stress conditions during the reproductive stage, which ultimately affected yield components after recovery. In rice with a correlation between net photosynthetic rate (PN) and intercellular CO2 concentration (Ci) under salt stress, PN was found to be negatively correlated with filled grain number after recovery. Applying stringent criteria, we identified 130,317 SNPs and 15,396 InDels between two "high-yield rice" varieties and two "low-yield rice" varieties with contrasting photosynthesis and grain yield characteristics. A total of 2,089 genes containing high- and moderate-impact SNPs or InDels were evaluated by gene ontology (GO) enrichment analysis, resulting in over-represented terms in the apoptotic process and kinase activity. Among these genes, 262 were highly expressed in reproductive tissues, and most were annotated as receptor-like protein kinases. These findings highlight the importance of variations in signaling components in the genome and these loci can serve as potential genes in rice breeding to produce a variety with salt avoidance that leads to increased yield in saline soil.

We investigated whether the one-time application of polymer-coated urea (PCU) before transplanting could simultaneously improve the grain yield and nitrogen use efficiency (NUE) of japonica-indica hybrid rice (JIHR) through a field experiment. The local high-yield JIHR cultivar Chunyou-927 was field grown during the rice-growing seasons in 2019 and 2020. The experiment consisted of three treatments: no nitrogen application (0N), application of conventional urea (CU), and the one-time application of PCU. Grain yield was 1.0–1.3 t/ha higher, and agronomic NUE (kg grain yield increase per kg N applied) was 5.2–5.9 kg/kg higher, respectively, under the PCU treatment compared with the CU treatment across the two study years. When compared with the CU treatment, the PCU treatment could (1) improve root morphological trait, (2) reduce redundant vegetative growth during the early growth period, (3) increase matter production during the mid and late growth period, and (4) increase plant activity during the grain-filling period. Overall, our findings indicate that one-time PCU application before transplanting of the JIHR cultivar holds great promise for increasing grain yield and NUE. [ABSTRACT FROM AUTHOR]

Biochar exhibits a profound impact on soil organic carbon (SOC) turnover and dynamics, but the underlying mechanism under field conditions is still unclear. A three-year field experiment was performed to evaluate the impact of peanut shell biochar applied at rates of 0, 33.75, 67.5, and 101.25 t/ha (referred to as B0, B1, B2, and B3, respectively) on SOC content and chemical composition in a saline-sodic paddy field using stable carbon isotope composition and 13C nuclear magnetic resonance technology. With increasing rates of biochar, SOC and aromatic carbon contents and alkyl carbon/oxygen-alkyl carbon and hydrophobic carbon/hydrophilic carbon ratios increased, while alkyl carbon and oxygen-alkyl carbon contents and aliphatic carbon/aromatic carbon ratio decreased. The new carbon from biochar and rice residues accounted for 26.5% of SOC under B0 and increased to above 80.0% under B2 and B3. The decay rate of old carbon was faster in biochar-amended than in unamended soil. SOC content was positively correlated with alkyl carbon/oxygen-alkyl carbon and hydrophobic carbon/hydrophilic carbon ratios but negatively correlated with aliphatic carbon/aromatic carbon ratio. The results suggest that biochar can increase SOC content by increasing its humification, aromaticity, and hydrophobicity. However, negative priming is not the main mechanism for SOC accumulation during the short-term period.

Abstract Background The high-activity adenine base editors (ABEs), engineered with the recently-developed tRNA adenosine deaminases (TadA8e and TadA9), show robust base editing activity but raise concerns about off-target effects. Results In this study, we perform a comprehensive evaluation of ABE8e- and ABE9-induced DNA and RNA mutations in Oryza sativa. Whole-genome sequencing analysis of plants transformed with four ABEs, including SpCas9n-TadA8e, SpCas9n-TadA9, SpCas9n-NG-TadA8e, and SpCas9n-NG-TadA9, reveal that ABEs harboring TadA9 lead to a higher number of off-target A-to-G (A>G) single-nucleotide variants (SNVs), and that those harboring CRISPR/SpCas9n-NG lead to a higher total number of off-target SNVs in the rice genome. An analysis of the T-DNAs carrying the ABEs indicates that the on-target mutations could be introduced before and/or after T-DNA integration into plant genomes, with more off-target A>G SNVs forming after the ABEs had integrated into the genome. Furthermore, we detect off-target A>G RNA mutations in plants with high expression of ABEs but not in plants with low expression of ABEs. The off-target A>G RNA mutations tend to cluster, while off-target A>G DNA mutations rarely clustered. Conclusion Our findings that Cas proteins, TadA variants, temporal expression of ABEs, and expression levels of ABEs contribute to ABE specificity in rice provide insight into the specificity of ABEs and suggest alternative ways to increase ABE specificity besides engineering TadA variants.

Combined pollution of cadmium (Cd) and lead (Pb) occurs frequently in agriculture lands, which has received increasing research attention. However, little is known about the interaction behaviors of Cd and Pb at various concentrations in the mixture. This study evaluated the single and combined effects of Cd and Pb on rice (Oryza sativa L.) root elongation through acute exposure test. The combined pollution was analyzed with the concentration addition (CA) model, independent action (IA) model and mathematical statistical methods. The dose-response results revealed that the interaction could weaken the toxicity of both Pb and Cd, and Cd had a more significant inhibitory effect on Pb toxicity. The predicted values of CA and IA models were consistently lower than the observed values in the relative root elongation range of 0–60%. Further, combining the CA or IA model with mathematical statistical methods, the interaction of Pb and Cd at similar concentrations showed a significant antagonistic effect on rice root elongation. At low Pb concentrations (Cd > 0.0195, Pb < 0.015 mg/L), there was a synergistic effect of the mixture on rice root; at high Pb concentrations (Cd < 0.225, Pb ≥ 1.25 mg/L), Pb dominated the toxicity on rice root. This is the first report of a systematic method for assessing heavy metal interaction at different concentration levels, which may facilitate the formulation of control standards of heavy metal combined pollution in agricultural land.

Rice blast is one of the most serious agricultural diseases in the world. Rice blast can be managed using low nitrogen fertilizers, treatment with chemical fungicides, and the most effective resistant varieties. Many genetic resources have been investigated and used along with molecular markers to breed blast-resistant rice varieties. In this study, the genetic diversity of blast resistance genes using 27 functional/linked markers and rice blast incidence over three years was investigated in 296 Korean rice varieties. Blast incidence was determined using a 0-9 scoring system (0=no lesions to 9=dead leaves) in nursery tests. The blast incidence of 296 rice varieties showed a significant correlation between years (r>0.64, p<0.001). The 261 Japonica varieties showed blast resistance compared to 114 mid-late maturing varieties or 96 medium-maturing varieties. 35 Tongil-type varieties also exhibited greater resistance than Japonica varieties. DNA marker-trait association analysis was conducted using 27 DNA markers linked to 19 blast resistance genes. Twelve DNA markers showed significant associations with the average blast incidence over 3 years. The ‘9871.T7E’ marker linked with Pi40 was strongly associated with blast disease, with a phenotypic variance of 24% over 3 years (p<0.001). Among the varieties harboring the Pi40 allele, early maturing varieties accounted for 87%. These results imply that the blast resistance of early maturing Korean varieties is associated with the Pi40 gene. These results will be beneficial for breeding blast-resistant rice in Korea. [ABSTRACT FROM AUTHOR]

Sheath blight caused by Rhizoctonia solani AG1-IA is the second most serious disease of rice worldwide. Elucidating the role of multi-drug and toxic compound extrusion (MATE) gene family in host-pathogens interactions may uncover a new possible way to comprehend the mechanism of sheath blight resistance in rice. We foremost explored the role of OsMATE genes against R. solani resistance through comparative transcriptomics in PR114 (susceptible) and ShB-8 (moderately resistant) at 24 and 48 hpi (hours post-inoculation) of R. solani infection, respectively. Six OsMATE genes were differentially expressed and further validated through qRT-PCR. OsMATE6 gene was identified as a potential candidate for sheath blight susceptibility as it was significantly up-regulated in PR114. OsMATE6 is conserved within the wild relatives and might be translocated from Oryza nivara during the domestication of rice. Further studies are focused to verify its role by overexpression and protein interactions to understand the molecular mechanism of sheath blight resistance. [ABSTRACT FROM AUTHOR]

Red rice is consumed in whole grain form due to its beneficial nutritional attributes and has become an option for crop diversification. Several factors during plant development can affect the crop'syield. This study evaluated the adaptability and stability of the post-harvest processing of red rice cultivars and compare them with those of white rice cultivars grown in the municipalities of Campos dos Goytacazes, Seropédica, and Pinheiral, RJ, between 2016 and 2018. Two white rice (BRS Esmeralda and IAC 201) and two red rice cultivars (ENA-AR1601 and Virginia) were distributed in the field under randomized block design with five repetitions. Yield, grain class, ingenuity, and whole grain yield were evaluated. The means of these parameters for cultivars in different locations and years were compared by Tukey's test (P < 0.05). The Eberhart and Russell regression model was used to estimate the adaptability and stability parameters. The grain classification of the cultivars ENA-AR1601 and Virginia was medium and long, respectively. The red rice cultivars ENA-AR 1601 and Virginia showed higher productive performance than the national average. The red rice cultivars and BRS Esmeralda showed highly predictable behavior based on the environmental stimulus. With average values of 62% in the two years evaluated, the red rice cultivars showed excellent processing yield. Key words: whole grain, processing, productivity, Oryza sativa L. [ABSTRACT FROM AUTHOR]

Isotope measurements are associated with critical plant resources. Thus, stable rice crop's carbon isotope composition in response to potassium (K) fertilizer was determined, since K is a primary plant nutrient that plays a major role in achieving maximum economic yields. Rice plants were grown in the field and rain shelter under five treatments, which are T1 (no-K), T2 (MOP), T3 (SOP), T4 (Polyhalite) and T5 (conventional fertilizer). The fertilizers were applied 3 days after planting (DAP), 15 DAP, 55 DAP and 75 DAP. Leaf photosynthesis and stomata conductance measurements were taken 85 DAP. The samples were then dried and reserved for carbon isotope analyses. Photosynthesis declined due to K deficiency in the no-K treatment. From this research, we can conclude that stomatal conductance is affected by K fertilizer application where it controls the carboxylation efficiency which may affect the rate of photosynthesis. Later, photosynthesis may influence the discrimination of δ13C isotope value. There is discrimination against this heavier isotope of CO2, this is because CO2 diffuses through stomata by carbon 12 faster than carbon 13 so that is why there is discrimination against carbon 13 in the stomata. [ABSTRACT FROM AUTHOR]

Natural abundance of the stable isotope (d13C and d15N) in plants is widely used to indicate water use efficiency (WUE). However, soil water and texture properties may affect this relationship, which remains largely elusive. Therefore, the purpose of this study was to evaluate d13C as affected by different combinations of alternate wetting and drying irrigation (AWD) with varied soil clay contents in different organs and whole plant and assess the feasibility of using d13C and d15N as a physiological indicator of whole-plant water use efficiency (WUEwhole-plant). Three AWD regimes, I100 (30 mm flooded when soil reached 100% saturation), I90 (30 mm flooded when reached 90% saturation) and I70 (30 mm flooded when reached 70% saturation) and three soil clay contents, 40% (S40), 50% (S50), and 60% (S60), were included. Observed variations in WUEwhole-plant did not conform to theoretical expectations of the organs d13C (d13Corgans) of plant biomass based on pooled data from all treatments. However, a positive relationship between d13Cleaf and WUEET (dry biomass/evapotranspiration) was observed under I90 regime, whereas there were no significant relationships between d13Corgans and WUEET under I100 or I70 regimes. Under I100, weak relationships between d13Corgans and WUEET could be explained by (i) variation in C allocation patterns under different clay content, and (ii) relatively higher rate of panicle water loss, which was independent of stomatal regulation and photosynthesis. Under I70, weak relationships between d13Corgans and WUEET could be ascribed to (i) bigger cracks induced by waterlimited irrigation regime and high clay content soil, and (ii) damage caused by severe drought. In addition, a negative relationship was observed between WUEwhole-plant and shoot d15N (d15Nshoot) across the three irrigation treatments, indicating that WUEwhole-plant is tightly associated with N metabolism and N isotope discrimination in rice. Therefore, d13C should be used cautiously as an indicator of rice WUEwhole-plant at different AWD regimes with high clay content, whereas d15N could be considered an effective indicator of WUEwhole-plant. [ABSTRACT FROM AUTHOR]

The re-occurrence of weedy rice in the imidazolinone (IMI) herbicide-tolerant (HT) rice fields in Malaysia suggested that the weed has evaded the IMI herbicide application. This study aimed to evaluate the seed morphological traits as potential escape mechanisms of weedy rice in response to IMI-herbicide (imazapic+imazapyr) treatment. A total of 96 weedy rice samples collected from IMI-HT rice fields were characterized according to seed characteristics. The samples were evaluated for seed dormancy and susceptibility against IMI-herbicide using a standard germination test. Herbicide-induced germination test recorded a high germination (61.99–74.43%) despite strong initial dormancy (9.09–13.14%), indicating potential dormancy breaking by the herbicide. A total of 64.7% of weedy rice morphotypes displayed high seedlings survival (>10%) after herbicide treatment suggesting variation in potential IMI-resistance of weedy rice. Correlation analysis demonstrated the herbicide responses were associated with various seed adaptive traits, especially on pericarp colour (r = 0.3701), hull colour (r = −0.2457), seed dormancy (r = 0.4351), and shattering capability (r = −0.3110). This study demonstrated that seed morphological and physiological characteristics have a significant correlation with resistance towards IMI-herbicide. Resistant genes might be linked with these weedy traits as part of the adaptive mechanism for weedy rice through consequential conferment of the genes from HT-rice into weedy rice. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The genomics and genetic information of Malaysian rice ( Oryza sativa L.) is currently limited. It was necessary to conduct genome resequencing of these rice accessions exhibiting different responses to salinity stress. The sequencing was carried out using the Illumina NovaSeq X platform with 30× sequencing coverage to pinpoint variants between salinity tolerant and sensitive rice accessions. The discovery of single nucleotide polymorphisms (SNPs) is crucial for the development of DNA markers associated with salinity tolerance traits. The genome sequence data (FASTQ format) for these accessions have been deposited to the European Nucleotide Archive (ENA) database under the accession number PRJEB71716., (© 2024 The Authors.)

Natural abundance of the stable isotope (δ13C and δ15N) in plants is widely used to indicate water use efficiency (WUE). However, soil water and texture properties may affect this relationship, which remains largely elusive. Therefore, the purpose of this study was to evaluate δ13C as affected by different combinations of alternate wetting and drying irrigation (AWD) with varied soil clay contents in different organs and whole plant and assess the feasibility of using δ13C and δ15N as a physiological indicator of whole-plant water use efficiency (WUEwhole-plant). Three AWD regimes, I100 (30 mm flooded when soil reached 100% saturation), I90 (30 mm flooded when reached 90% saturation) and I70 (30 mm flooded when reached 70% saturation) and three soil clay contents, 40% (S40), 50% (S50), and 60% (S60), were included. Observed variations in WUEwhole-plant did not conform to theoretical expectations of the organs δ13C (δ13Corgans) of plant biomass based on pooled data from all treatments. However, a positive relationship between δ13Cleaf and WUEET (dry biomass/evapotranspiration) was observed under I90 regime, whereas there were no significant relationships between δ13Corgans and WUEET under I100 or I70 regimes. Under I100, weak relationships between δ13Corgans and WUEET could be explained by (i) variation in C allocation patterns under different clay content, and (ii) relatively higher rate of panicle water loss, which was independent of stomatal regulation and photosynthesis. Under I70, weak relationships between δ13Corgans and WUEET could be ascribed to (i) bigger cracks induced by water-limited irrigation regime and high clay content soil, and (ii) damage caused by severe drought. In addition, a negative relationship was observed between WUEwhole-plant and shoot δ15N (δ15Nshoot) across the three irrigation treatments, indicating that WUEwhole-plant is tightly associated with N metabolism and N isotope discrimination in rice. Therefore, δ13C should be used cautiously as an indicator of rice WUEwhole-plant at different AWD regimes with high clay content, whereas δ15N could be considered an effective indicator of WUEwhole-plant.

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Main conclusion: The zqdm1identified from a rice mutant is a novel allele of BRD2 and is responsible for regulating rice plant height, grain size and appearance, which has possibilities on improving rice quality. Plant height is an important agronomic trait related to rice yield, and grain size directly determines grain yield in rice (Oryza sativa L.). With the development of molecular biotechnology and genome sequencing technology, more and more key genes associated with plant height and grain size have been cloned and identified in recent years. This study identified the zqdm1 gene from a mutant with reduced plant height and grain size. The zqdm1 gene was revealed to be a new allele of BRASSINOSTEROID DEFICIENT DWARF 2 (BRD2), encoding a FAD-linked oxidoreductase protein involved in the brassinosteroid (BR) biosynthesis pathway, and regulates plant height by reducing cell number of longitudinal sections of the internode and regulates grain size by altering cell expansion. A 369-bp DNA fragment was found inserted at the first exon, resulting in protein-coding termination. This mutation has not been discovered in previous studies. Complementation tests have confirmed that 369-bp insertion in BRD2 was responsible for the plant height and grain size changing in the zqdm1 mutant. Over-expression of BRD2 driven by different promoters into indica rice variety Jiafuzhan (JFZ) results in slender grains, suggesting its function on regulating grain shape. In summary, the current study has identified a new BRD2 allele, which facilitated the further research on the molecular mechanism of this gene on regulating growth and development. [ABSTRACT FROM AUTHOR]