Germination Of Rice Research Articles

Eco-friendly green synthesised nano iron particles from weed leaf extract: a potential nutritional source for enhancing the germination and yield of aerobic rice

Eco-friendly green synthesised nano iron particles from weed leaf extract: a potential nutritional source for enhancing the germination and yield of aerobic rice

OsNAL11 and OsGASR9 Regulate the Low-Temperature Germination of Rice Seeds by Affecting GA Content

Low temperatures cause serious threat to rice seed emergence, which has become one of the main limiting factors in the production of direct seeding rice. It is of great importance to study the genes controlling low-temperature tolerance during seed germination and to mine the possible regulatory mechanism for developing new rice varieties with immense low-temperature germination ability. In the current research study, two types of mutants of nal11 and gasr9, derived from the WT (wild type) ZH11, were used for the analysis of low-temperature germinability. The results showed that the nal11 and gasr9 mutants displayed no significant difference in germination rate with ZH11 at room temperature, but the mutants showed significantly lower germination rates, germination potential and germination index, and slowed seedling growth in the simulated direct seeding experiments at low temperatures compared to ZH11. Additionally, the activity of POD, SOD, CAT, and anti-superoxide anion radial activity were significantly reduced, but the levels of MDA and H2O2 were significantly higher in the nal11 and gasr9 mutant seeds that were germinated at low temperatures compared to ZH11. Further analysis revealed that the levels of total active GA, especially GA4 and GA7, were significantly lower in the nal11 and gasr9 mutants than that in ZH11 during low-temperature germination. Based on qRT-PCR analysis, the expression levels of some GA synthesis-related genes were higher, whereas some were lower in the nal11 and gasr9 mutants than those in ZH11, however, the GA metabolism-related genes OsGA2ox8 and OsGA2ox10 and the GA signaling negative regulator gene SLR1 were significantly up-regulated in both nal11 and gasr9 mutants at several time points during low-temperature germination. This may explain the lower GA levels in the nal11 and gasr9 mutants. Furthermore, the interaction between the OsNAL11 and OsGASR9 proteins was confirmed by Y2H, LUC, and Co-IP assays. This study provides preliminary insights into the regulatory mechanism of the OsNAL11 and OsGASR9 genes, which control the low-temperature germination of rice seeds by affecting the GA pathway. Our study will provide the basis for further mining the molecular mechanisms of low-temperature germination in rice and valuable theoretical reference for breeding varieties with strong low-temperature germinability.

Wheat TaTIFY3B and TaTIFY10A play roles in seed germination and abiotic stress responses in transgenic Arabidopsis and rice

BackgroundSeed germination is a key process in the plant life cycle that affects the vegetative and reproductive stages of plants. Although the JAZ gene family has been characterized in many plants, the relationship between the JAZ gene and seed germination is still unclear.ResultsWe identified two members of the JAZ family from wheat, TaTIFY3B and TaTIFY10A. TaTIFY3B and TaTIFY10A were localized in both the cell membrane and nucleus. Spatio-temporal expression analysis of TaTIFY3B and TaTIFY10A in wheat revealed that these genes are essential for the preharvest sprouting (PHS) stage of seed development, with expression levels significantly decreasing during the ripening period. Transgenic rice plants overexpressing wheat TaTIFY3B and TaTIFY10A improved seed germination rates. Transgenic Arabidopsis plants overexpressing wheat TaTIFY10A improved seed germination rates and promoted flowering. In addition, abscisic acid (ABA) and jasmonic acid (JA) were found to induce TaTIFY3B and TaTIFY10A expression. Under different ABA concentrations, the seed germination rates of transgenic rice and Arabidopsis overexpressing TaTIFY3B and TaTIFY10A are superior to wild-type (WT) and mutant plants, and the root lengths of Arabidopsis overexpressing TaTIFY3B and TaTIFY10A also change. Under different JA concentrations, there is no difference in the seed germination rate of rice overexpressing TaTIFY3B and TaTIFY10A compared to WT and mutant plants, but there is a significant difference in the seed germination rate and root length of overexpressing Arabidopsis compared to WT and mutant plants. Under different concentrations of salt and drought treatments, the seed germination rate and root length of overexpressing Arabidopsis of TaTIFY3B and TaTIFY10A are affected.ConclusionsThis study offers a novel perspective for understanding the molecular basis of pre-harvest sprouting and provides potential candidate genes for controlling wheat seed germination.

Tolerance of local gogo rice sprouts under salinity stress conditions

The expansion of rice planting areas in the future needs to be carried out outside Java, as fertile land in Java is shrinking due to land conversion. Most of the land outside Java consists of marginal land, such as areas with high salinity. High salinity levels in the soil cause a decrease in plant germination, growth, and production. The research aimed to examine the tolerance of each cultivar at each level of NaCl concentration, to obtain cultivars that were tolerant to salinity stress, and to determine the NaCl concentration that suppresses the germination of local upland rice. The research was structured using a completely randomized design with a two-factor factorial pattern. The first was the six upland rice cultivars, namely, dongan, jahara, Pulu Konta, pomegranate, kalendeng, and pulu tau leru, while the second factor was the NaCl concentration consisting of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1%. Thus, there were 36 experimental units, which were repeated three times so that there were 108 experimental units. The results of the research showed that there was no interaction with all germination variables; cultivar and concentration had a significant effect on maximum growth potential, germination capacity, germination time, plumule length, radicle length and dry weight of sprouts, while cultivar affected the wet weight of sprouts. Kalendeng has a high salinity tolerance. The use of NaCl concentrations of up to 0.6% has been able to reduce the germination capacity of local upland rice. The conclusion of the research showe that there was no interaction between all germination variables.

The role of Ni- and Cd-resistant rhizobacteria in promoting the growth of rice seedlings and alleviating the combined phytotoxicity of Ni and Cd

The problem of potentially toxic metal pollution is increasingly acute with the development of human society. In this study, we investigated the remediation of nickel (Ni) and cadmium (Cd) co-contamination through inoculating rice with three new-isolated Ni- and Cd-resistant plant growth-promoting rhizobacteria (PGPR) Y3, Y4, and Y5. These three strains possessed growth-promoting properties, including 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, the ability of indoleacetic acid (IAA) production, phosphate solubilization, siderophores production, and exopolysaccharide (EPS) development. According to 16S rDNA sequence homology, strains Y3, Y4, and Y5 were identified as Pseudomonas sp., Chryseobacterium sp., and Enterobacter sp., respectively. Based on the results of rice germination experiments conducted under combined toxicity, we set the contamination concentrations for Ni2+ at 20 μg mL−1 and Cd2+ at 40 μg mL−1. Then we conducted potting experiments at these concentration levels to study the effects of strains Y3, Y4, and Y5 on rice growth under synergistic Ni and Cd stress. The results indicated that the inoculated strains Y3, Y4, and Y5 were effective in promoting the growth of rice seedlings under the combined stress of Ni and Cd, and conferring tolerance to Ni and Cd by increasing the antioxidant enzyme activities of the seedlings. Among them, strain Y3 exhibited stronger ACC deaminase activity, IAA production capacity, and EPS production capacity, showing the most pronounced growth-promoting effect on rice. It was demonstrated that after inoculation with strain Y3, the germination rate of rice seeds increased by 43 %, the fresh weight of stems improved by 35 %, and the chlorophyll content enhanced by 70 % and other growth-promoting phenomena. Additionally, under Ni and Cd stress, strain Y5 performed better than strain Y4 in terms of IAA production capacity and its influence on rice root growth, suggesting that IAA production might play a specifically essential role in root growth under Ni and Cd stress.

Non-destructive visualisation and in situ quantification of micronutrient mobilisation in germinating rice grains using synchrotron-based X-ray fluorescence microscopy

Maintaining micronutrient availability in germinating rice tissues is crucial for seedling vigour and agronomic performance. However, current methods for visualising micronutrient dynamics often require destructive sample preparation. Here we report that synchrotron-based X-ray fluorescence microscopy (XFM) could enable non-destructive, in situ visualisation and quantification of zinc (Zn) mobilisation in intact, germinating rice grains. Using XFM on whole grains of salt-tolerant Pokkali and salt-sensitive Nipponbare varieties, we generated high-resolution elemental maps revealing the spatiotemporal distribution of Zn and other micronutrients. Direct quantification by seed volume using element association window proved inaccurate due to tissue heterogeneity. However, normalisation by areal density showed Zn accumulation was highest in the embryo, followed by the aleurone layer and shoots. Zn was initially localised in the aleurone layer and embryo, with subsequent mobilisation to developing shoots and roots during germination. Calcium was predominantly detected in the hull, while potassium was enriched in growing roots and shoots. This non-destructive XFM method provides unprecedented insights into real-time micronutrient fluxes during rice germination, offering a powerful tool for studying nutrient dynamics in diverse contexts such as biofortification, stress responses, and varietal differences. Our findings contribute to understanding the mechanisms underlying micronutrient allocation during early seedling development, with potential applications in improving rice nutritional quality and seedling establishment.

Genome-Wide Association Study Reveals Loci and New Candidate Gene Controlling Seed Germination in Rice

Improving seed germination and seedling development can potentially increase crop yield and improve quality in direct-seeded rice. This study aimed to detect loci or genes associated with rice seed germination. We reported the phenotypic analysis of seed germination in 103 rice accessions across two years, and a genome-wide association study (GWAS) was conducted to identify loci underlying the genetic regulation of seed germination. A total of seven genetic loci were found to be associated with seed germination, including five loci that overlapped with the previously reported loci/genes, and two novel loci. Of these, two loci (qGP2 and qGP4.1) were stable across different environments. GP4 (Germination percentage 4), encoding a 9-cis-epoxycarotenoid dioxygenase, was identified as the candidate gene of the major locus qGP4.1. A sequence analysis of GP4 revealed that four functional polymorphic sites in the coding region were significantly associated with germination percentage. The disruption of GP4 by gene editing resulted in faster seed germination and seedling establishment. Taken together, we have identified GP4 as a novel gene involved in rice seed germination, and we provide a potential target gene for improving rice seed vigor via gene editing or molecular breeding.

OsRAV1 Regulates Seed Vigor and Salt Tolerance During Germination in Rice

Seed vigor is a complex trait encompassing seed germination, seedling emergence, growth, seed longevity, and stress tolerance, all are crucial for direct seeding in rice. Here, we report that the AP2/ERF transcription factor OsRAV1 (RELATED TO ABI3 AND VP1) positively regulates seed germination, vigor, and salt tolerance. Additionally, OsRAV1 was differently expressed in embryo and endosperm, with the OsRAV1 localized in the nucleus. Transcriptomic analysis revealed that OsRAV1 modulates seed vigor through plant hormone signal transduction and phenylpropanoid biosynthesis during germination. Haplotype analysis showed that rice varieties carrying Hap3 displayed enhanced salt tolerance during seed germination. These findings suggest that OsRAV1 is a potential target in breeding rice varieties with high seed vigor suitable for direct seeding cultivation.

Transcriptome profiling reveals ethylene production by reactive oxygen species in trichloroisocyanuric acid-treated rice seeds.

Reactive oxygen species (ROS) have been extensively suggested to stimulate ethylene production. However, the molecular mechanism by which ROS stimulate ethylene production remains largely unclear. Here, transcriptome profiling was used to verify if ROS could stimulate ethylene production via direct formation of ethylene from ROS. Trichloroisocyanuric acid (TCICA) can stimulate seed germination in rice. When transcriptome profiling was performed to determine the molecular responsiveness of rice seeds to TCICA, TCICA was initially proven to be a ROS-generating reagent. A total of 300 genes potentially responsive to TCICA treatment were significantly annotated to cysteine, and the expression of these genes was significantly upregulated. Nonetheless, the levels of cystine did not exhibit significant changes upon TCICA exposure. Cystine was then proven to be a substrate that reacted with TCICA to form ethylene under FeSO4 conditions. Moreover, 7 of 22 genes responsive to TCICA were common with the hydrogen peroxide (H2O2)-responsive genes. Ethylene was then proven to be produced from cysteine or cystine by reacting with H2O2 under FeSO4 condition, and the hydroxyl radical (OH-) was proposed to be the free radical species responsible for ethylene formation under FeSO4 condition. These results provide the first line of evidence that ethylene can be produced from ROS in a non-enzymatic manner, thereby unveiling one new molecular mechanism by which ROS stimulate ethylene production and offering novel insights into the crosstalk between ethylene and ROS.

Efecto de la pendimentalina sobre el crecimiento celular de rizobacterias Promotoras de Crecimiento Vegetal (PGPR)

Pendimentalin is an herbicide used in short-cycle crops. Its indiscriminate use reduces the beneficial population of microorganisms in production systems. The objective of this work was to evaluate the effect of pendimentalin on the cell growth of rhizobacteria. The research was conducted at the Laboratory of Microbiology and Molecular Biology of the State Technical University of Quevedo, where the following experiments with pendimentalin contamination were carried out: 1) Adaptability of rhizobacteria under in vitro conditions; 2) Tolerance levels of rhizobacteria under different abiotic conditions in vitro; 3) Reduction of stress by rhizobacteria in soils. The rhizobacteria show a higher adaptability at 72 h with absorbance of 2.38 and 2.51 in the strains (CHA0, BA4-19, B03-4, PM3-14 and R4), also during this time they establish a neutral pH, despite the acidic and alkaline conditions. Strain CHA0 presented the highest number of cells under neutral pH (1.09E+09 CFU/mL). Strains BA4-19 and PM3-14 showed a slight improvement in morphological aspects. Rhizobacteria have adaptability at the in vitro level, but their use slightly reduces the toxicity of the herbicide in rice germination and growth processes.

Combined physicochemical and transcriptomic analyses reveal the effect of the OsGA20ox1 gene on the starch properties of germinated brown rice

Genes play a pivotal role in regulating the germination of cereal grains; however, there is limited research on the impact of germination genes on the physicochemical properties of germinated cereal starch. We investigated the effects of the OsGA20ox1 gene on the multiscale structural features and adhesion behavior of germinated brown rice starch. Compared to the knockout lines group, the wild type exhibited a decrease in double-helix content (62.74 %), relative crystallinity (47.39 %), and short-range molecular ordering (2.47 %), accompanied by enhanced erosion on the surface of starch granules. The damage to glycosidic bonds at the double-helix level and the heightened structural amorphization (90.95 %) led to reduced entanglement and interaction among starch molecules, ultimately resulting in reduced characteristic viscosity. Further transcriptomic analysis revealed that OsGA20ox1 could regulate the expression of starch-related enzyme genes in the starch metabolism pathway during germination of brown rice. This study contributes to understanding the role of germination genes in promoting the physicochemical properties of starch in germinated grains, thereby opening up new avenues for the improvement of plant-based starch, and paving the way for further research in this field.

Analysis of genome-wide association studies of low-temperature germination in Xian and Geng rice.

Rice is the leading global staple crop. Low temperatures pose negative impacts on rice's optimal growth and development. Rice cultivars acclimating to low temperatures exhibited improved seedling emergence under direct-seeded sowing conditions, yet little is known about the genes that regulate germination at low temperatures (LTG). In this research investigation, we've performed whole genome sequencing for the 273 rice plant materials. Using the best linear unbiased prediction (BLUP) values for each rice material, we identified 7 LTG-related traits and performed the efficient genetic analysis and genome-wide association study (GWAS). As a result of this, 95 quantitative trait loci (QTLs) and 1001 candidate genes associated with LTG in rice were identified. Haplotype analysis and functional annotation of the candidate genes resulted in the identification of three promising candidate genes (LOC_Os08g30520 for regulating LTG4 and LTG5, LOC_Os10g02625 for regulating LTG6, LTg7 and LTG8, and LOC_Os12g31460 for regulating LTG7, LTg8 and LTG9) involving in the regulation of LTG in rice. This research provides a solid foundation for addressing the LTG issue in rice and will be valuable in future direct-seeded rice breeding programs.

Effects of Different Pretreatments on the GABA Content of Germinated Brown Rice

Brown rice germination increases γ-aminobutyric acid (GABA) levels and enhances its antioxidant activity. In this study, Kaohsiung 145 brown rice was used as the raw material, and soaked in various solutions for 6 h before being processed with either high-pressure processing (HPP) or ultrasonic treatment to increase the GABA content. The GABA and antioxidant components of brown rice were analyzed after 42 h of germination and subsequent air-drying to obtain a moisture content of 14%. The results showed that non-germinated brown rice had GABA at 7.10 mg/100 g and treatment with various soaking solutions (0.1% CaCl2, 0.1% Glu, 0.2% CaCl2, and 0.2% Glu) increased GABA contents. Specifically, 0.1% CaCl2 and 0.1% Glu exhibited higher GABA content, at 42.51 and 44.64 mg/100 g. Furthermore, the GABA content increased synergistically when combined with HPP (100 MPa, 10 min) and ultrasonic (20 min) treatments after soaking. The results showed that the GABA contents in germinated rice were the greatest after ultrasonic treatment, followed by HPP treatment, and the least with only soaking treatment. The treatments with 0.1% CaCl2 and 0.2% Glu combined with ultrasonic processing for 20 min resulted in the highest GABA content at 102.38 and 110.88 mg/100 g, respectively. Finally, 0.1% CaCl2 with ultrasonic treatment for 20 min was chosen, as it demonstrated a considerable improvement in total polyphenols content and DPPH scavenging abilities, as seen by improved scores in subsequent taste evaluations.

<span>Some data about the food composition of amphibians in Cao Lanh city, Dong Thap province </span>

On the rice field ecosystem in Cao Lanh district, Dong Thap province, there are 6 species of amphibians distributed: Duttaphrynus melanostictus, Kaloula pulchra and Hylarana guentheri have the most diversity of feed ingredients; Fejervarya limnocharis, Hoplobatrachus rugulosus and Ichthyophis bannanicus have less food diversity; Scolopendomorpha and Polydesmoidea are the least, accounting for 1,2%. Amphibians have the most food frequency in Coleoptera, followed by Hymenoptera and Orthoptera. Amphibians are usually terrestrial, eating mainly insects. The frequency of pests was lowest in the period from sowing seeds until the rice had 3 leaves germinated, the lowest in the period of yellow rice until after harvest, the highest at the stage of rice with milk in the grain to the stage of green - ripened rice. The frequency of encounters of Hoplobatrachus rugulosus and Fejervarya limnocharis is lowest at the stage of seeding until rice germination, decrease gradually in the period of ripe rice until after harvest, stage 4 (Rice with milk in the grain until green ripening) has the highest frequency. In stage 1, there is the lowest frequency of encountering amphibians and pests, frequency increases gradually to stage 2 and peaks at stage 4, decreasing at stage 5.

Rice seed germination priming by salicylic acid and the emerging role of phytohormones in anaerobic germination.

This Commentary examines a recent study that identified peroxisomal cinnamate: CoA ligases as key enzymes for salicylic acid biosynthesis, which promotes submerged germination by releasing the inhibition of rice germination by indole-acetic acid. This study thus provides important information for developing rice varieties suitable for direct seeding.

Seed Priming with Poly-Gamma-Glutamic Acid (γ-PGA) Improves Rice Germination Performance under Drought Conditions

Drought poses a significant threat to global food security, particularly impacting rice cultivation during the germination stage. In this study, a soil-based system that utilizes soil moisture content was used to simulate optimal and stress conditions to assess the effect of the specific seed priming protocols on germination. Eleven rice varieties, representative of indica and japonica subspecies, grown in different ecosystems and having diverse nutrient contents, were treated with water or solutions of either poly-gamma-glutamic acid (γ-PGA) or denatured γ-PGA. Collected data regarding germinability and stress indices revealed different drought sensitivity between japonica and indica subspecies and genotype-specific responses to priming. Particularly, γ-PGA improved germination of highly susceptible indica varieties whereas water soaking was more effective for the moderately sensitive japonica varieties. Integrative analyses evidenced differences between biofortified and non-biofortified rice under γ-PGA treatment, suggesting a possible correlation between γ-PGA efficacy and Zn/Fe seed content. These findings underline that priming strategies should be tailored based on genotype and therefore this factor should be always taken under consideration for future works. The current study provides relevant information for optimizing seed priming techniques to sustain the development of drought-resilient crops as a sustainable strategy to address agricultural resilience and safeguard food security amidst environmental challenges.

Plant Growth Promotion and Biological Control against Rhizoctonia solani in Thai Local Rice Variety "Chor Khing" Using Trichoderma breve Z2-03.

Several strains of Trichoderma are applied in the field to control plant diseases due to their capacity to suppress fungal pathogens and control plant diseases. Some Trichoderma strains also are able to promote plant growth through the production of indole-3-acetic acid (IAA). In southern Thailand, the local rice variety "Chor Khing" is mainly cultivated in the Songkhla province; it is characterized by slow growth and is susceptible to sheath blight caused by Rhizoctonia solani. Therefore, this research aimed to screen Trichoderma species with the ability to promote plant growth in this rice variety and enact biological control against R. solani. A total of 21 Trichoderma isolates were screened for indole compound production using the Salkowski reagent. The Z2-03 isolate reacted positively to the Salkowski reagent, indicating the production of the indole compound. High-performance liquid chromatography (HPCL) confirmed that Z2-03 produced IAA at 35.58 ± 7.60 μg/mL. The cell-free culture filtrate of the potato dextrose broth (CF) of Z2-03 induced rice germination in rice seeds, yielding root and shoot lengths in cell-free CF-treated rice that were significantly higher than those of the control (distilled water and culture broth alone). Furthermore, inoculation with Trichoderma conidia promoted rice growth and induced a defense response against R. solani during the seedling stage. Trichoderma Z2-03 displayed an antifungal capacity against R. solani, achieving 74.17% inhibition (as measured through dual culture assay) and the production of siderophores on the CAS medium. The pot experiment revealed that inoculation with the Trichoderma sp. Z2-03 conidial suspension increased the number of tillers and the plant height in the "Chor Khing" rice variety, and suppressed the percentage of disease incidence (PDI). The Trichoderma isolate Z2-03 was identified, based on the morphology and molecular properties of ITS, translation elongation factor 1-alpha (tef1-α), and RNA polymerase 2 (rpb2), as Trichoderma breve Z2-03. Our results reveal the ability of T. breve Z2-03 to act as a plant growth promoter, enhancing growth and development in the "Chor Khing" rice variety, as well as a biological control agent through its competition and defense induction mechanism in this rice variety.

Evaluation of anaerobic germination and submergence tolerance in rice (Oryza sativa L.) suitable for direct seeded condition

Evaluation of anaerobic germination and submergence tolerance in rice (Oryza sativa L.) suitable for direct seeded condition

Genome-wide association study reveals that JASMONATE ZIM-DOMAIN 5 regulates seed germination in rice

Seed germination is a complex trait regulated by multiple genes in rice. However, the regulators of rice seed germination have yet to be sufficiently determined. Here, a quantitative trait locus (QTL) for rice seed germination was identified in a genome-wide association study. The candidate gene JASMONATE ZIM-DOMAIN 5 (OsJAZ5) of the QTL was verified that positively regulates seed germination. OsJAZ5 regulation of seed germination involves an OsABI3-mediated abscisic acid pathway. Overexpression of OsJAZ5 facilitated seed germination. The application of OsJAZ5 might be useful for increasing seed germination for rice direct seeding.

Hormonal control of underwater germination in rice

The ability to germinate, develop, and thrive underwater is key to efficient rice cultivation. In this issue of Developmental Cell, Wang etal. (2024) illuminate a hormone synthesis and inactivation cascade that promotes germination of submerged rice seeds and may allow improved germination in the field.