Oryza Sativa Research Articles

Plant Factory Speed Breeding Significantly Shortens Rice Generation Time and Enhances Metabolic Diversity

Rice (Oryza sativa L.) plays a pivotal role in global food security, yet its breeding is constrained by its long generation time and seasonality. To enhance rice breeding efficiency and meet future food demands, we have developed a vertical hydroponic breeding system integrated with light-emitting diodes (LEDs) lighting in a closed plant factory (PF), which significantly accelerates rice growth and generation advancement. The results show that indica rice can be harvested as early as after 63 days of cultivation, a 50% reduction compared with field cultivation, enabling the annual harvesting of 5–6 generations within the PF. A hyperspectral imaging system (HSI) and attenuated total reflectance infrared (ATR-IR) spectroscopy were further employed to characterize the chemical composition of the PF- and field-cultivated rice. Metabolomics analysis with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) revealed that, compared with the field-cultivated rice, the PF-cultivated rice exhibited an up-regulation of total phenolic acids along with 68 non-volatile and 19 volatile metabolites, such as isovitexin, succinic acid, and methylillicinone F. Overall, this study reveals the unique metabolic profile of PF-cultivated rice and highlights the potential of PFs to accelerate the breeding of crops such as rice, offering an innovative agricultural strategy to support food security in the face of global population growth and climate change.

Effect of critical limit of saline water irrigation in suitable rice (Oryza sativa L.) varieties

Effect of critical limit of saline water irrigation in suitable rice (Oryza sativa L.) varieties

Methyltransferase 1 (OsMTS1) interacts with hydroxycinnamoyltransferase 1 (OsHCT1) and promotes heading by upregulating heading date 1 (Hd1)

Heading date determines the distribution and yield potentials of rice, and is an ideal target for crop improvement using CRISPR/Cas9 genome editing system. In this study, we reported the loss-of-function of Methyltransferase 1 (MTS1), which promotes heading in rice. Here, we constructed knockouts and overexpression transgenic plants of OsMTS1 in ZH8015 and Nipponbare (NIP) for the first time to validate its heading date function in rice subspecies Oryza sativa ssp. Indica and O. Sativa ssp. Japonica, respectively. The OsMTS1 knockouts in ZH8015 and NIP rice significantly promoted heading date under both natural short days (NSD) and natural long days (NLD) conditions, while the overexpression of OsMTS1 significantly delayed heading date in ZH8015 and NIP rice under both NSD and NLD conditions. Likewise, the complementation transgenic plants displayed late heading date phenotype. OsMTS1 repressed heading through up-regulating Heading date 1 (Hd1) and down-regulating Early heading date 1 (Ehd1) and Heading date 3a (Hd3a). The OsMTS1 protein interacted with OsHCT1 proteins using a yeast two-hybrid (Y2H) assay. The Y2H and overexpression confirmed that OsMTS1 interacted with OsHCT1, which delayed heading by 4.7 days under NLD. Taken together, CRISPR/Cas9, genetic complementation, and overexpression results validated that OsMTS1 represses heading in Indica and Japonica rice under both NLD and NSD conditions. These results demonstrated that OsMTS1 is a useful target for breeding early maturing rice varieties by CRISPR/Cas9 gene editing of the functional allele.

Exogenous MgH2-derived hydrogen alleviates cadmium toxicity through m6A RNA methylation in rice

Cadmium (Cd) contamination poses a substantial threat to crop yields and human health. While magnesium hydride (MgH2) has been reported as a hydrogen (H2) donor that promotes plant growth under heavy metal contamination, its role in rice remains elusive. Herein, seedlings of Oryza sativa L. Japonica variety Zhonghua 11 (ZH11) were selected and exposed to 20 µL of 1-mol/L cadmium chloride (CdCl2) solution via hydroponics to simulate Cd stress. Meanwhile, 0.1 mg of MgH2 was used to slow-release H2 to the experimental group to explore its potential effects on rice over a 2-week period. The results indicated that Cd exposure severely inhibited the growth and development of ZH11 rice seedlings. However, the exogenous slow-release of H2 from MgH2 effectively mitigated this inhibitory effect by restoring the balance of reactive oxygen species (ROS), maintaining endogenous H2 homeostasis, and supporting the photosynthetic system. High-performance liquid chromatography analysis revealed that exogenous H2 reduces m6A RNA methylation levels in mRNA under Cd stress. Consequently, MeRIP-seq was conducted to investigate the effect of Cd exposure in rice in the presence and absence of H2. The m6A modifications were enriched at the start codon, stop codon, and 3′ UTR. By integrating RNA-seq data, 118 transcripts were identified as differentially methylated and expressed genes under Cd stress. These gene annotations were associated with ROS, biological stress, and hormonal responses. Notably, 297 differentially methylated and expressed genes were identified under Cd stress in the presence of H2, linked to heavy metals, protein kinases, and calcium signaling regulation. Cd strongly activates the MAPK pathway in response to stress. Exogenous H2 reduces Cd accumulation as well as enhances plant tolerance and homeostasis by lowering m6A levels, thereby decreasing the mRNA stability of these genes. Our findings indicate that MgH2, by supplying H2, regulates gene expression through m6A RNA methylation and confers Cd tolerance in rice. This study provides potential candidate genes for studying the remediation of heavy metal pollution in plants.

Suitability of early indica rice for the preparation of rice noodles by its starch properties analysis

The research was conducted to explore the affiliation between the physicochemical properties of rice noodles and rice starch of early indica rice samples of varying amylose content. 3 various types of rice samples were analyzed to uncover how amylose content influences rice noodles' quality. Findings revealed that primarily sensory scores differ in palatability, while textural disparity lies in hardness and chewiness. The higher hardness and chewiness values were correlated with higher sensory scores. Rice with lower amylose content demonstrates elevated solubility, swelling power, and crystallinity along with poor retrogradation resulting in inferior-quality noodles. Sensory scores and textural properties were proved to be associated with the distribution of branched starch molecule chain lengths. Noodles of higher sensory scores had more stable gel structure and improved elasticity. These findings underscore the critical role of amylose content and starch molecular structure in determining the suitability of early indica rice for noodle preparation.

Coupled reduction in arsenic methylation and methanogenesis with silicate amendment in arsenic-enriched paddy soils

Methanogens play an important role in the demethylation of arsenic. Soil amendments that inhibit methanogens can increase dimethylarsinic acid (DMA), which is responsible for straighthead disease in rice. A decrease in methanogenesis caused by silicate fertilizer may increase DMA concentration in paddy soils and rice grains; the relationship between these two factors and their impacts on DMA concentration remains unclear. We applied silicate fertilizer (2 Mg ha−1) to japonica and indica rice grown on arsenic-spiked soils and found a simultaneous reduction in methane emissions and pore-water DMA concentration, compared to no-silicate fertilization. Gene and transcript copies of mcrA and arsM, as well as dominant methanogens and arsenic-methylating microbes decreased significantly with silicate fertilization. However, the sulfate-reducing bacteria and the gene and transcript copies of dsrB did not change significantly in response to the application of silicate fertilizer to paddy soils. The abundance of arsenic methylating microbes was significantly and positively correlated with the abundance of methanogens, but not with the abundance of sulfate-reducing bacteria. Methylomonas and Methylobacter, which harbor the arsM gene, were suppressed under silicate fertilization, suggesting that they have the potential to methylate As and play a crucial role in reducing pore-water DMA in As-enriched flooded paddy soils. Increasing Fe concentration, soil pH, and Eh value decreased pore-water DMA concentration, while decreasing arsenite concentration, arsM and mcrA gene abundance decreased it. While silicate fertilization decreased arsenite and DMA concentrations in pore-water, it had no significant effect on rice DMA content, but significantly decreased arsenite content. Results reveal that methanogens and arsenic-methylating microbes have a synergistic relationship under silicate fertilization that facilitates a significant reduction in methane emissions and DMA concentration in As-enriched paddy soils.

Area-wide survey and monitoring of insecticide resistance in the brown planthopper, Nilaparvata lugens (Stål), from 2020 to 2023 in China

The brown planthopper (BPH), Nilaparvata lugens (Stål), is a notorious pest affecting Asian rice crops. The evolution of insecticide resistance in BPH has emerged as a significant challenge in effectively managing this pest. This study revealed the resistance status of BPH to nine insecticides in ten provinces and Shanghai City in China from 2020 to 2023. Monitoring results showed that the resistance of BPH to triflumezopyrim, nitenpyram, and dinotefuran increased rapidly. The average resistance ratio of BPH to triflumezopyrim increased from 2.5 to 7.1 fold, nitenpyram from 18.3 to 37.7 fold, and dinotefuran from 119.5 to 268.1 fold. All populations remained extremely high resistance to imidacloprid, thiamethoxam, and buprofezin. Most field populations of BPH maintained moderate resistance to chlorpyrifos and sulfoxaflor, and high resistance to pymetrozine by rice stem dipping method. However, considering the reproduction-inhibiting character of pymetrozine, susceptible to low resistance levels to pymetrozine were monitored by Insecticide Resistance Action Committee (IRAC) NO.005 method. This result indicated that pymetrozine might lose efficacy in the control of application generation, but it could significantly inhibit the reproduction of field populations of BPH. Additionally, we compared the expression levels of 11 nicotinic acetylcholine receptor (nAChR) genes, the targets of nAChR competitive modulators, in four field populations (FY23, YH23, LJ23, LP23) and susceptible strain. The expression level of nAChR α4 was significantly reduced in all field populations, while α1, α2, α6, and α7 were significantly reduced in some field populations. Our findings provide valuable information for resistance management strategies in N. lugens and offer new insights into the resistance mechanisms of nAChR competitive modulators.

Assessment of Heterosis and inbreeding Depression for Yield, and its Associated Components Traits in Rice (Oryza sativa L.)

The present investigation entitled was carried out at Main Rice Research Centre, Navsari Agricultural University, Navsari during kharif-2023 with an objectives to obtain information on manifestation of heterosis and extent of inbreeding depression involved in the inheritance of various yield attributing characters in rice (Oryza sativa L.). This study comprised three crosses using four diverse lines. The experimental material comprised of five generations each cross of pair parents i.e. P1, P2, F1, F2 and F3 of three different crosses were conducted in Compact Family Block Design with three replications during kharif 2023. For grain yield per plant all the three crosses (IRBB 55 × Mahisagar, IRBB 55 × GR-11 and IRBB 55 × TN-1) exhibited significant and positive relative heterosis as well as heterobeltiosis. Among them the highest mid parent heterosis of 39.67% and heterobeltiosis of 7.56% were exhibited by cross IRBB 55 × GR-11. This hybrid showed positive and significant relative heterosis for all the four important characters viz., productive tillers per plant, panicle length, grains per panicle and 100 grain weight. While, the inbreeding depression was found significant and positive for all the three crosses which is not desirable for grain yield per plant. Here, all the three crosses exhibited positive heterosis followed by positive inbreeding depression indicated that trait is under influence of non-additive type of gene action and heterosis breeding would be found rewarding for improvement for grain yield per plant.

Influence of Iron and Zinc Biofortification on Growth and Yield of Drilled Rice (Oryza Sativa L.)

A field experiment was conducted during kharif 2022 and 2023 to study the effect of iron and zinc biofortification on the growth and yield of drilled rice (Oryza sativa L.) at Krushi Vigyan Kendra, Navsari Agricultural University, Dediapada, Gujarat. The experiment was laid out in a randomized block design with ten treatments. Based on pooled analysis, almost all the growth attributes (periodical plant height, number of tillers plant-1, leaf area, leaf area index and dry matter accumulation plant-1), yield attributes (productive tillers m-2, number of filled grains panicle-1, panicle length, weight of panicle and 1000 grain weight), grain yield (3035 kg ha-1) and straw yield (5336 kg ha-1) were recorded significantly higher under treatment T10 (soil ZnSO4 + FeSO4 each @ 25 kg ha-1 and foliar ZnSO4 + FeSO4 each @ 0.5% at 30 & 60 DAS). Based on the results, it concluded that for achieving higher growth and yield in drilled rice, the crop should be fertilized with soil ZnSO4 + FeSO4 each @ 25 kg ha-1 and foliar ZnSO4 + FeSO4 each @ 0.5% at 30 & 60 DAS along with RDF and soil ZnSO4 + FeSO4 each @ 25 kg ha-1 along with RDF.

Influence of polyethylene glycol, sodium nitroprusside, and carbon sources on in vitro callus induction and regeneration in drought-tolerant and drought-sensitive rice (Oryza sativa L.)

Influence of polyethylene glycol, sodium nitroprusside, and carbon sources on in vitro callus induction and regeneration in drought-tolerant and drought-sensitive rice (Oryza sativa L.)

Plant growth promoting signatory volatiles emitted by a drought-tolerant bacterium Bacillus altitudinis FD48 and its role in moisture stress alleviation in rice (Oryza sativa L.)

Increasing evidence implies that bacterial volatile organic compounds (bVOCs) play a significant role in plant-microbe interaction. Plant associated bacteria produces plant growth modulating volatiles elicits induced systemic tolerance (IST) in plants against a multitude of abiotic stress. Induction of IST and plant growth promotion by signatory bVOCs of Bacillus altitudinis FD48 against drought are reported in this study. The rice seedlings exposed to bVOCs blends of FD48 showed a one-fold increase in whole plant biomass and auxin content (3 µmol g-1 FW) under induced moisture stress. The effect of bVOCs highly depends on the inoculum load. Higher inoculum quantity (100 µL) is detrimental to plant growth. bVOCs produced by FD48 profiled at different growth intervals in GC–MS-ATD revealed a total of 40 bioactive compounds both under stress (PEG 6000) and non-stressed conditions. Interestingly, potential plant growth-promoting compounds such as 1-Hexanol, 2,3-butanediol, dimethyl disulfide, benzene, butanoic acid, pentadecane, and acetic acid are more pronounced. Few compounds produced under non-stress were found to increase during stress (example, 2,3-Butanediol, and acetic acid). This study unraveled the significant biosynthetic pathways induced by FD48 bVOC blends, such as pyruvate metabolism, tryptophan metabolism, sulfur metabolism, fatty acid biosynthesis, and ethanol degradation that anchors in abating moisture stress. Hence, it can be concluded that PGPB B. altitudinis FD48 produced bVOCs could be potential orchestrators of induced systemic tolerance in plants against moisture stress.

Analysis of the Application of Vitamin B1 on the Response of Salinity Stress Resistance in Several Varieties of Rice (Oryza Sativa L.)

One of the most common stresses in rice cultivation is salinity. Rice plants stressed by salinity exhibit changes such as yellowing leaves, drying tips, and chlorosis. The efforts made by the government and farmers so far include implementing cultivation scheduling techniques, planting patterns, and using stress-resistant varieties, as well as improving soil to increase water-holding capacity through lime application. Each of these efforts comes with its own risks. Another approach to enhance the growth and yield of rice plants is the application of vitamins. Providing vitamins can stimulate the growth of plant organs, as they play a crucial role in the growth process by acting as catalysts for metabolism. Research has indicated that vitamin B1 can significantly promote plant growth under stressful conditions. This study aims to investigate the positive effects of various concentrations of vitamin B1 on the growth and yield of rice plants while also reducing salinity stress. The method used involved planting three varieties of rice—IR-46, Inpari-32, and Pokkali—in planting buckets using the TABELA system. Vitamin B1 was applied at concentrations of 0, 5, and 10 mM during the peak vegetative phase, with salinity stress of 6 dS/m introduced one day after vitamin application. The plants were maintained under salinity stress conditions until harvest, during which morphological and phytochemical analyses were conducted. Morphological analysis included measurements of plant height, number of tillers, number of productive tillers, number of grains per panicle, and percentage of healthy grains. Biochemical parameters measured included total chlorophyll and electrolyte leakage analysis. The results indicate that vitamin B1 can effectively reduce stress in plants affected by salinity.

Grain Appearance Quality of Parental and \(F_2\) Segregating Populations of Aus Rice (Oryza sativa L.)

Longer grain length with smaller grain breadth, length-breadth ratio and 1000-grain weight is considered desirable character for the development of fine grain premium quality rice. In the present experiment, grain appearance quality of 15 F2 families and 10 parental genotypes were determined to select fine grain rice. The maximum mean value for thousand seed weight was found from the genotypes P2 (29.32g), P1 (28.89g), and F2 generations of P2 x P5 (32.77g), P2 x P1 (27.30g), P1 x P4 (26.04g) and were considered as high yielders in terms of grain weight. The highest mean values for grain length were found from the genotypes P6 (9.95 mm; grain breadth 2.23 mm), P7 (9.36 mm; grain breadth 2.62 mm), and F2 generations of P6 x P7 (9.46 mm; grain breadth 2.44 mm), P3 x P6 (9.40 mm; grain breadth 2.18 mm), P7 x P6 (9.37 mm; grain breadth 2.29 mm), P7 x P3 (9.36 mm; grain breadth 2.33 mm). The F2 progenies of the cross P1 x P4 (7.79 to 11.61 mm) and P6 x P3 (7.69 to 11.11 mm) showed extremes performance for grain length indicating transgressive segregation for this trait. The superior genotypes with desirable grain characters could be selected from transgressive segregation of F2 families for the development of new varieties of fine grain rice.

Identification of Candidate Genes for Cold Tolerance at Seedling Stage by GWAS in Rice (Oryza sativa L.).

Due to global climate change, cold temperatures have significantly impacted rice production, resulting in reduced yield and quality. In this study, we investigated two traits related to the cold tolerance (CT) of 1992 diverse rice accessions at the seedling stage. Geng accessions exhibited higher levels of CT compared to xian accessions, with the GJ-tmp subgroup displaying the strongest CT. However, extreme CT accessions were also identified within the xian subspecies. Through GWAS analysis based on the survival rate (SR) and leaf score of cold tolerance (SCT), a total of 29 QTLs associated with CT at the seedling stage were identified, among which four QTLs (qSR3.1a, qSR4.1a, qSR11.1x, and qSR12.1a) were found to be important. Furthermore, five candidate genes (LOC_Os03g44760, LOC_Os04g06900, LOC_Os04g07260, LOC_Os11g40610, and LOC_Os12g10710) along with their favorable haplotypes were identified through gene function annotation and haplotype analysis. Pyramiding multiple favorable haplotypes resulted in a significant improvement in CT performance. Subsequently, three selected accessions (CX534, B236, and IRIS_313-8565), carrying different superior alleles for CT, were selected and recommended for molecular breeding for CT using marker-assisted selection (MAS). The findings from this study provide valuable resources for enhancing rice's ability for CT while laying a foundation for the future cloning of novel genes involved in conferring CT.

Comparative analysis of lowland rice (Oryza sativa L. var. PSB Rc18) performance across different farming systems

Organic farming is gaining recognition as a viable alternative to conventional methods, promising soil health preservation and sustained crop productivity with economic benefits. This study evaluated the physiological, growth, and yield responses of the PSB Rc18 rice variety and appraised its economic feasibility under different production systems. The experiment was laid out in Randomized Complete Block Design (RCBD) with four replications and three treatments: T1-best bet organic production system, T2-farmers’ organic production system in Leyte, and T3-farmers’ conventional production system in Leyte. The crop growth rate (CGR) of PSB Rc18 remained consistent across the different systems. However, the Net Assimilation Rate (NAR) peaked significantly between 42-56 days after transplanting (DAT) in the T2. Additionally, the Leaf Area Index (LAI) in T1 was comparable to that of T3. Rice grown under T1 reached heading and maturation earlier than T3. Although T3 produced the highest fresh straw, most productive tillers, and heaviest total biomass, the grain yield was similar across all production systems. Economically, T2 outperformed with a superior benefit-cost ratio of $0.55 and $0.94 per USD invested, considering both regular and premium prices for organic palay. These findings highlight organic farming practices' economic and agronomic viability, suggesting that promoting organic farming can be a beneficial alternative to conventional methods in Leyte. This study underscores the potential for integrating organic practices to enhance sustainability and economic outcomes in rice production, making both T1 and T2 significant options for farmers in Eastern Visayas.

Effect of Foliar Application of Nano fertilizers on Soil Properties of Rice (Oryza sativa L.) Under Western UP, India

An experiment was conducted during kharif 2022 and 2023 at the Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, Uttar Pradesh, to study the Effect of Foliar Application of Nano on Soil properties of Rice (Oryza sativa L.) Under Western UP. The investigation was carried out with fourteen treatments viz. Control, RDF (N:P:K-120:60:40 kg ha-1 + 25 kg zinc sulphate), 100% RDF + Nano urea, 100% RDF + Nano potash, 100% RDF + Nano Zn, 100% RDF + Nano urea + Nano potash + Nano Zn, 75% RDF + Nano urea, 75% RDF + Nano potash, 75% RDF + Nano Zn, 75% RDF + Nano urea + Nano potash + Nano Zn, 50% RDF + Nano urea, 50% RDF + Nano potash, 50% RDF + Nano Zn and 50% RDF + Nano urea + Nano potash + Nano Zn. The nano fertilizers were applied at tillering stage (35 DAT). Result revealed that highest soil properties viz., organic matter % (0.48 & 0.52), available nitrogen (225.6 & 228.7 kg ha-1), available phosphorus (19.5 & 20.7 kg ha-1), available potassium (235.6 & 233.8 kg ha-1) and available zinc (0.80 & 0.83 g ha-1) were recorded with application of 100% RDF + Nano urea + Nano potash + Nano Zn spray at tillering stage (35 DAT) respectively, during both the years. The lowest values of these parameters were recorded under control treatment.

Products of allelopathic plants for organic weed management: Environmentally approach

Allelopathic substances from different crops may have synergistic effects and can be applied in the mixture. In the previous research, several crop plants have been identified as phytotoxic against various weeds like sorghum, brassica, and sunflower. However, the effect of their tank mixture with each other was never studied in cotton before. Furthermore, it was not sure before this study whether the allele chemicals present in these crops viz. sorghum, sunflower and brassica can have synergistic or additive effects when applied in combination. Herbicides account for 42% of global pesticides’ use. Therefore, recent emphases have been on biological weed control measures so as to reduce dependence on synthetic herbicides and finding alternative strategies for weed control in agro ecosystems. Allelopathy is one of such strategies that can be explored for biological weed control of cropping systems. The mimosine that occurs in Leucaena has the potential to be used as a bio-herbicide in weed management. Mimosine is the main allelochemicals in Leucaena and is responsible for the strong allelopathic activity of the plant. The allelopathic effects of L. leucocephala towards several agricultural crops and forest trees have been reported. Plant seedlings of various crops possess allelopathic potential or weed-suppressing activity, including cucumber (Cucumber sativa L.), oat (Avena spp.) and rice (Oryza sativa L.). The main barley allelochemicals are the alkaloids gramine and hordenine which play a significant role in barley allelopathic potential and its defense against weeds, insects, or pathogens. In particular, barley allelopathic extracts have the ability to reduce emergence and growth of serious weeds like winter wild oat (Avena sterilis L.), hood canary grass (Phalaris paradoxa L.), black grass (Alopecurus myosuroides Huds.), great brome (Bromus diandrus Roth.), and wild mustard (Sinapis arvensis L.). This growth reduction has been mainly attributed to lipid peroxidation. Tamarindus contains allelochemicals on roots, leaves, seeds and bark , however, its allelopathic potential has not yet been compared to that of other allelopathic species such as Parthenium. Citharexylum (Citharexylum spinosum L) is equally a tree, a tropical plant with numerous usages but also know to have some allelopathic potential. Flower extracts have proved to be extremely potent to lettuce seed germination and seedlings growth and are very little known regarding its leaves phytotoxity. Consequently, the current experiment will provide additional information regarding Citharexylum leave allelopathic potential. Sunflower (Helianthus annuus L.). In Asteraceae members including sunflower, the main allelochemicals are sesquiterpenes, especially heliannuoles, sesquiterpene lactones and bisnorse squiterpenes, in addition to triterpenes and flavonoids Its allelopathic effects have been tested on both other crops and weeds, in field conditions and in vitro bioassays. In recent years, the allelopathic potential of Cynara cardunculus L., an herbaceous perennial species belonging to the Mediterranean basin, was assessed on seed germination and seedling growth of some weeds and target crops. Allelochemicals responsible for C. cardunculus allelopathy are the sesquiterpene lactones cynaropicrin, deacylcynaropicrin, 11, 13-dihydro-deacylcynaropicrin, aguerin B, grosheimin, 11,13-dihydroxy-8-deoxygrosheimin and cy-naratriol, as well as polyphenols such as caffeoylquinic and dicaffeoylquinic acids, luteolin and apigenin derivatives. Around 800 species of plants produce biologically active substances, but only a few of them are used in agricultural practice. However, in recent years, there has been an increase in interest in allelopathy due to the effective use of allelochemicals in plant protection, such as bioherbicides, bio insecticides, biofungicides and growth regulators.

Discovery of a conserved translationally repressive upstream open reading frame within the iron-deficiency response regulator IDEF2

BackgroundIron (Fe) deficiency affects 30–50% of the world’s population. Genetic biofortification of staple crops is a promising strategy for improving human nutrition, but the number of effective precision breeding targets for Fe biofortification is small. Upstream open reading frames (uORFs) are cis-regulatory elements within the 5’ leader sequence (LS) of genes that generally repress translation of the main open reading frame (mORF).ResultsWe aligned publicly available rice (Oryza sativa L.) ribo-seq datasets and transcriptomes to identify putative uORFs within important Fe homeostasis genes. A dual luciferase assay (DLA) was used to determine whether these uORFs cause repression of mORF translation and pinpoint LS regions that can be mutated for mORF derepression. A translationally repressive uORF region was identified in two positive regulators of the Fe-deficiency response: IDEF1 and IDEF2. The IDEF2-uORF peptide was highly conserved among monocots and a mutation series in the 5’ LS of the wheat (Triticum aestivum L.) TaIDEF2-A1 gene demonstrated variable mORF derepression.ConclusionsTogether these results reveal a possible regulatory mechanism by which IDEF2 transcription factors modulate the Fe deficiency response in monocots, and highlight novel precision breeding targets to improve crop nutrition and abiotic stress tolerance.

Light curve parametrization of three rice (Oryza sativa L.) cultivars based on mechanistic models

Light curve parametrization of three rice (Oryza sativa L.) cultivars based on mechanistic models

Combining Ability Analysis for Quality Traits in Selected Rice Varieties (Oryza sativa L.)

Fifteen hybrid combinations developed by crossing five lines and three testers were assessed for milling and physio-chemical qualities to evaluate the combining ability of the parents using a line x tester design. This investigation provided information about the general combining ability (GCA) of parents and the specific combining ability (SCA) effects of crosses from eight popular inbred varieties. C70 was considered the best general combiner for the head rice recovery trait, while the crosses involving C70 with DH18 and CR203, 13/2 with TBR225 and Xi23, and OM6976 with TBR45 showed significant positive specific combining ability (SCA) effects. Xi23 and OM6976 among the lines showed significant general combining ability (GCA) effects indicating them to be good general combiners for obtaining hybrids with desirable (low or intermediate) properties of amylose content. The variances due to SCA were of greater magnitude than GCA for all the traits, revealing the preponderance of non-additive gene action for all the studied attributes. In all the studied quality traits, the narrow sense heritabilities were ordered as follows: head rice recovery > amylose content > gel consistency > alkali digestion > hulling percentage > milling percentage. The narrow sense heritabilities in these traits were quite low, ranging from 8.11% to 14.4%. Among the eight parents, C70, Xi23, and TBR225 were the most ideal for high-quality line breeding.