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SUMMARY Plasmodesmata (PD) are nanochannels that facilitate cell‐to‐cell transport in plants. More productive and photosynthetically efficient C4 plants form more PD at the mesophyll (M)‐bundle sheath (BS) interface in their leaves than their less efficient C3 relatives. In C4 leaves, PD play an essential role in facilitating the rapid metabolite exchange between the M and BS cells to operate a biochemical CO2 concentrating mechanism, which increases the CO2 partial pressure at the site of Rubisco in the BS cells and hence photosynthetic efficiency. The genetic mechanism controlling PD formation in C3 and C4 leaves is largely unknown, especially in monocot crops, due to the technical challenge of quantifying these nanostructures with electron microscopy. To address this issue, we have generated stably transformed lines of Oryza sativa (rice, C3) and Setaria viridis (setaria, C4) with fluorescent protein‐tagged PD to build the first spatiotemporal atlas of leaf pit field (cluster of PD) density in monocots without the need for electron microscopy. Across leaf development, setaria had consistently more PD connections at the M‐BS wall interface than rice while the difference in M‐M pit field density varied. While light was a critical trigger of PD formation, cell type and function determined leaf pit field density. Complementary temporal mRNA sequencing and gene co‐expression network analysis revealed that the pattern of pit field density correlated with differentially expressed PD‐associated genes and photosynthesis‐related genes. PD‐associated genes identified from our co‐expression network analysis are related to cell wall expansion, translation and chloroplast signalling. [ABSTRACT FROM AUTHOR]

Bacterial secondary metabolites have an important role in encouraging the growth of plants by influencing phytohormone production and metabolism. The effect of secondary metabolites secreted by an actinobacterium Zhihengliuella sp. ISTPL4 (Z. sp. ISTPL4) on growth promotion in the Oryza sativa plant was studied. The growth of Z. sp. ISTPL4 has been evaluated in the presence of Arsenic (As) up to the concentration range of 0.2–1.9 mM followed by observing the growth of rice in the presence of As. The present study was carried out to analyze the significant role of metabolites released by Z. sp. ISTPL4 in growth-promoting activities of plants. We have also reported various metabolites released by Oryza sativa after microbial inoculation under normal growth conditions and in the presence of As stress. It was observed that 43 metabolites were released by Z. sp. ISTPL4 under normal conditions and 34 metabolites were released in the presence of As stress. Some of these metabolites including Hexadecane, Heptadecane, Hexadecanoic acid methyl ester, Eicosane, Cyclo (L-prolyl-L-valine) were common among metabolites released by Z. sp. ISTPL4 in the presence of normal growth conditions and under As stress. The area percentage of hexadecenoic acid methyl ester, methyl stearate, octadecanoic acid, 2,3-dihydroxypropyl ester was higher in the presence of As stress than its concentration under normal growth conditions while hexadecane is released in the presence of As stress only. These metabolites are involved in antimicrobial, antiproliferative antioxidants and plant growth promotion by stimulating gibberellin synthesis. The results of our research indicate that under different biotic and abiotic stress conditions, the actinobacterium Z. sp. ISTPL4 can be deployed to improve sustainable agricultural practices. [Display omitted] • Zhihengliuella sp. ISTPL4 tolerate up to 2 mM concentration of arsenate. • Secondary metabolite production in Zhihengliuella sp. ISTPL4. • Abiotic stress-mediated secondary metabolite production in rice. [ABSTRACT FROM AUTHOR]

The rice albumin (RAG) gene family belongs to the Tryp_alpha_amyl family. RAG2, specifically expressed in 14–21 DAP (days after pollination) seeds, regulates grain yield and quality. In this study, we identified another RAG family gene, RAL6, which exhibits specific expression in developing seeds, particularly in 7, 10, and 15 DAP seeds. Employing the CRISPR/Cas9 system, we analyzed functions of RAL6 and found that the ral6 lines (ral6-1, ral6-2, ral6-3, and ral6-4) displayed thinner seeds with significantly decreased 1000-grain weight and grain thickness compared to ZH11. Additionally, the cell width of spikelet cells, total protein and glutelin contents were significantly reduced in ral6. The germination assay and 1% TTC staining revealed a significant decrease in seed vigor among the ral6 lines. The alpha-amylase activity in ral6 mutant seeds was also markedly lower than in ZH11 seeds after 2 days of imbibition. Furthermore, co-expression analysis and GO annotation showed that co-expressed genes were involved in immune response, oligopeptide transport, and the glucan biosynthetic process. Collectively, our findings suggest that RAL6 plays a coordinating role in regulating grain weight and seed germination in rice. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), Spodoptera frugiperda, is a serious pest that threatens a range of important crops worldwide. It originated in America and rapidly dispersed throughout Africa and Asia in 2018. There are two subtypes, corn-strain (C-strain) and rice-strain (R-strain), that have different host plant preferences, and the individuals damaging maize in China were identified as C-strain. In the present study, we found FAW individuals damaging rice plants in the field of Guangdong Province, China. FAW larvae and male adults were collected, and the majority of FAWs were characterized as CO I R-strain Tpi C-strain, which is similar to the FAWs damaging maize in China. The FAW adults preferred laying eggs on maize plants more than on rice plants. Compared to those that were fed maize leaves, the FAW larvae were unable to survive when fed 4-week-old rice plants, whereas they could complete their life cycle on 2-week-old rice plants, for which the total survival rate was 8%. The pre-adult- and pupal-stage durations were prolonged, and the fecundity of adult females decreased. Thus, the FAWs found in paddy fields showed better fitness on maize than on rice in the laboratory. Owing to their low survival rate on rice plants, they were unlikely to damage paddy fields in large areas, but populations of FAWs in paddy fields should be monitored. [ABSTRACT FROM AUTHOR]

Decreasing nitrogen (N) supply affected the normal growth of Oryza sativa (O. sativa) seedlings, reducing CO2 assimilation, stomatal conductance (gs), the contents of chlorophylls (Chl) and the ratio of Chl a/Chl b, but increasing the intercellular CO2 concentration. Polyphasic chlorophyll a fluorescence transient and relative fluorescence parameters (JIP test) results indicated that N deficiency increased Fo, but decreased the maximum quantum yield of primary photochemistry (Fv/Fm) and the maximum of the IPphase, implying that N-limiting condition impaired the whole photo electron transport chain from the donor side of photosystem II (PSII) to the end acceptor side of PSI in O. sativa. N deficiency enhanced the activities of the antioxidant enzymes, such as ascorbate peroxidase (APX), guaiacol peroxidase (GuPX), dehydro–ascorbate reductase (DHAR), superoxide dismutase (SOD), glutathione peroxidase (GlPX), glutathione reductase (GR), glutathione S-transferase (GST) and O-acetylserine (thiol) lyase (OASTL), and the contents of antioxidant compounds including reduced glutathione (GSH), total glutathione (GSH+GSSG) and non-protein thiol compounds in O. sativa leaves. In contrast, the enhanced activities of catalase (CAT), DHAR, GR, GST and OASTL, the enhanced ASC–GSH cycle and content of sulfur-containing compounds might provide protective roles against oxidative stress in O. sativa roots under N-limiting conditions. Quantitative real-time PCR (qRT-PCR) analysis indicated that 70% of the enzymes have a consistence between the gene expression pattern and the dynamic of enzyme activity in O. sativa leaves under different N supplies, whereas only 60% of the enzymes have a consistence in O. sativa roots. Our results suggested that the antioxidant system and sulfur metabolism take part in the response of N limiting condition in O. sativa, and this response was different between leaves and roots. Future work should focus on the responsive mechanisms underlying the metabolism of sulfur-containing compounds in O. sativa under nutrient deficient especially N-limiting conditions. [ABSTRACT FROM AUTHOR]

SUMMARY: Soil salinity significantly limits rice productivity, but it is poorly understood how excess sodium (Na+) is delivered to the grains at the reproductive stage. Here, we functionally characterized OsHAK4, a member of the clade IV HAK/KUP/KT transporter subfamily in rice. OsHAK4 was localized to the plasma membrane and exhibited influx transport activity for Na+, but not for K+. Analysis of organ‐ and growth stage‐dependent expression patterns showed that very low expression levels of OsHAK4 were detected at the vegetative growth stage, but its high expression in uppermost node I, peduncle, and rachis was found at the reproductive stage. Immunostaining indicated OsHAK4 localization in the phloem region of node I, peduncle, and rachis. Knockout of OsHAK4 did not affect the growth and Na+ accumulation at the vegetative stage. However, at the reproductive stage, the hak4 mutants accumulated higher Na+ in the peduncle, rachis, husk, and brown rice compared to the wild‐type rice. Element imaging revealed higher Na+ accumulation at the phloem region of the peduncle in the mutants. These results indicate that OsHAK4 plays a crucial role in retrieving Na+ from the phloem in the upper nodes, peduncle, and rachis, thereby preventing Na+ distribution to the grains at the reproductive stage of rice. [ABSTRACT FROM AUTHOR]

Heat and drought stress, which often co-occur due to water evaporation, are two major abiotic factors limiting the production of rice (Oryza sativa L.) It is crucial to enhance understanding of the effects of these abiotic stresses in rice, particularly for rice-producing countries like Malaysia, which has yet to achieve rice selfsufficiency. This greenhouse study was conducted to evaluate the morphological changes of two important Malaysian cultivars (‘MR219’ and ‘MR303’) at vegetative, reproductive, and ripening stages, as well as their physiological response and yield components under normal (control), heat, drought, and combined heatdrought stress conditions. Individual heat stress greatly influenced rice growth and yield, with significant differences (p < 0.01) observed across all examined parameters except the grain to leaf area index ratio (GtoLAI). Conversely, individual drought stress mostly affected yield-related parameters, with significant differences (p < 0.01) in grain weight (GW), harvest index (HI), and percentage of filled grain (%FG). Interestingly, the combined stresses in this study did not significantly affect plant height (PH) for all growth stages and most yield-related traits (HI, GW, and GtoLAI). The majority of the significant changes (p < 0.01) were observed on physiological traits, including chlorophyll a (Chl A) and b (Chl B). We found a positive correlation between HI and %FG (R² = 0.3974**) under heat and drought stress, indicating that improving either of these traits can boost rice production. Collectively, our study revealed that the individual effects of heat and drought on rice growth and yield can differ from the effects of combined stress. [ABSTRACT FROM AUTHOR]

Soil salinization, a rising issue globally, is a negative effect of the ever-changing climate, which has drawn attention to, and exacerbated problems related to soil degradation and the decline in wetland rice (Oryza sativa L.) production, leading to an unstable national economy. The use of rhizosphere inhabiting microorganisms (plant growth-promoting rhizobacteria, PGPR) is a viable method for boosting agricultural production on saline soils and reduce salt stress in rice crops. The objective of this studywas to support the development of rice under salt stress by using a consortium of bacterial strains. ‘Pokkali’ rice plants inoculated with single Bacillus tequilensis and B. aryabhattai isolates were compared with consortium and non-inoculated plants while salinity was increased and by irrigation with tap water (control), 30 mM (5 dS m-1 ) and 60 mM (10 dS m-1 ) NaCl. The present study exhibited that inoculation of a mixed inoculum at 5 dS m-1 resulted in significantly higher dry weight of the shoots and roots of seedlings (9.29 and 1.24 g, respectively)which was due to the increased SPAD value, proline content (7.55 µmol g-1 FW), and antioxidant enzyme activity in the inoculated plants. The higher accumulation of osmoprotectants such as proline supported Na+ ion reduction and antioxidant enzymes such as ascorbate peroxidase and reduced polyphenol oxidase content protect against higher cellular damage, eventually leading to increase plant growth performance in saline soil. This study demonstrates some positive effects of the locally isolated salt tolerant consortium PGPR strains on the growth of rice plants under salt stress conditions. [ABSTRACT FROM AUTHOR]

Main conclusion: Excess of KRP4 in the developing kernels in rice causes poor filling of the grains possibly through inhibition of CDKA;2 and CDKB;1 activity mediated by its interaction with CDKF;3. The potential yield of the rice varieties producing compact and heavy panicles bearing numerous spikelets is compromised because a high percentage of spikelets remain poorly filled, reportedly because of a high expression of KRPs that causes suppression of endosperm cell proliferation. To test the stated negative relationship between KRP expression and grain filling, Orysa;KRP4 was overexpressed under the control of seed-specific glutelin promoter in IR-64 rice variety that shows good grain filling. The transgenic lines showed more than 15-fold increase in expression of KRP4 in the spikelets concomitant with nearly 50% reduction in grain filling compared with the wild type without producing any significant changes on the other yield-related parameters like panicle length and the spikelets numbers that were respectively 30.23 ± 0.89 cm and 229.25 ± 33.72 per panicle in the wild type, suggesting a highly organ-targeted effect of the genetic transformation. Yeast two-hybrid test revealed CDKF;3 as the interacting partner of KRP4, and CDKF;3 was found to interact with CDKA;2, CDKB;1 and CDKD;1. Significant decrease in grain filling in the transgenic lines compared with the wild type due to overexpression of KRP4 could be because of suppression of the activity of CDKB;1 and CDKA;2 by inhibition of their phosphorylation directly by CDKF;3, or mediated through inhibition of phosphorylation of CDKD;1 by CDKF;3. The study thus indicated that suppression of expression of KRP(s) by genetic manipulation of their promoters could be an important way of improving the yield of the rice varieties bearing compact and heavy panicles. [ABSTRACT FROM AUTHOR]

The use of biofertilizers is becoming an economical and environmentally friendly alternative to promote sustainable agriculture. Biochar from microalgae/cyanobacteria can be applied to enhance the productivity of food crops through soil improvement, slow nutrient absorption and release, increased water uptake, and long-term mitigation of greenhouse gas sequestration. Therefore, the aim of this study was to evaluate the stimulatory effects of biochar produced from Spirulina (Arthrospira platensis) biomass on the development and seed production of rice plants. Biochar was produced by slow pyrolysis at 300°C, and characterization was performed through microscopy, chemical, and structural composition analyses. Molecular and physiological analyses were performed in rice plants submitted to different biochar concentrations (0.02, 0.1, and 0.5 mg mL-1) to assess growth and productivity parameters. Morphological and physicochemical characterization revealed a heterogeneous morphology and the presence of several minerals (Na, K, P, Mg, Ca, S, Fe, and Si) in the biochar composition. Chemical modification of compounds post-pyrolysis and a highly porous structure with micropores were observed. Rice plants submitted to 0.5 mg mL-1 of biochar presented a decrease in root length, followed by an increase in root dry weight. The same concentration influenced seed production, with an increase of 44% in the number of seeds per plant, 17% in the percentage of full seeds per plant, 12% in the weight of 1,000 full seeds, 53% in the seed weight per plant, and 12% in grain area. Differential proteomic analyses in shoots and roots of rice plants submitted to 0.5 mg mL-1 of biochar for 20 days revealed a fine-tuning of resource allocation towards seed production. These results suggest that biochar derived from Arthrospira platensis biomass can stimulate rice seed production. [ABSTRACT FROM AUTHOR]

Summary Terpene synthases (TPSs) are key enzymes in terpenoids synthesis of plants and play crucial roles in regulating plant defence against pests and diseases. Here, we report the functional characterization of OsTPS19 and OsTPS20, which were upregulated by the attack of brown planthopper (BPH). BPH female adults performed concentration‐dependent behavioural responses to (S)‐limonene showing preference behaviour at low concentrations and avoidance behaviour at high concentrations. Overexpression lines of OsTPS19 and OsTPS20, which emitted higher amounts of the monoterpene (S)‐limonene, decreased the hatching rate of BPH eggs, reduced the lesion length of sheath blight caused by Rhizoctonia solani and bacterial blight caused by Xanthomonas oryzae. While knockout lines of OsTPS19 and OsTPS20, which emitted lower amounts of (S)‐limonene, were more susceptible to these pathogens. Overexpression of OsTPS19 and OsTPS20 in rice plants had adverse effects on the incidence of BPH, rice blast, and sheath blight in the field and had no significant impacts on rice yield traits. OsTPS19 and OsTPS20 were found to be involved in fine‐tuning the emission of (S)‐limonene in rice plants and play an important role in defence against both BPH and rice pathogens. [ABSTRACT FROM AUTHOR]

The virulence of Magnaporthe oryzae largely hinges on its secretory effectors. Therefore, identification and thorough understanding of the effector functionality is crucial for unravelling the pathogenicity of the pathogen. In the present study, we employed a modified computational pipeline with deep machine learning techniques with an integration of Magnaporthe effector reference datasets (MOED) that predicted 434 M. oryzae candidate secretory effector proteins (MoCSEPs) from the genomic data. The reliability of the modified CSEP prediction workflow through utilization of precise parametric filtering is considered valid as it predicted 100 functional effectors (97.08%) out of 103 previously identified effector proteins within the Magnaporthe genus. Insights into secretion patterns and subcellular localization elucidated the role of these proteins in host cell recognition. Furthermore, structural classification of MoCSEPs, based on conserved motifs, combined with an exploration of their biological functions, revealed their significance in host adaptability and localization. Experimental validation done through examining expression of the MoCSEPs revealed varied secretion patterns in the resistant (40 expressed) and susceptible (92 expressed) rice cultivars at different time intervals after pathogen inoculation owing to different degrees of resistance by the host cultivars. The present work thus provides the strategic model of canonical parametric evaluation within the MOED and deepens the understanding on the role of secretory proteins of M. oryzae in establishing successful parasitic infection in rice. The predicted MoCSEPs could be used as biomarkers for disease diagnosis and tracking evolutionary shifts in M. oryzae. [ABSTRACT FROM AUTHOR]

Because virus vectors can spread systemically autonomously, they are powerful vehicles with which to deliver genome-editing tools into plant cells. Indeed, a vector based on a positive-strand RNA virus, potato virus X (PVX), harboring SpCas9 and its single guide RNA (sgRNA), achieved targeted mutagenesis in inoculated leaves of Nicotiana benthamiana. However, the large size of the SpCas9 gene makes it unstable in the PVX vector, hampering the introduction of mutations in systemic leaves. Smaller Cas variants are promising tools for virus vector-mediated genome editing; however, they exhibit far lower nuclease activity than SpCas9. Recently, AsCas12f, one of the smallest known Cas proteins so far (one-third the size of SpCas9), was engineered to improve genome-editing activity dramatically. Here, we first confirmed that engineered AsCas12f variants including I123Y/D195K/D208R/V232A exhibited enhanced genome-editing frequencies in rice. Then, a PVX vector harboring this AsCas12f variant was inoculated into N. benthamiana leaves by agroinfiltration. Remarkably, and unlike with PVX-SpCas9, highly efficient genome editing was achieved, not only in PVX-AsCas12f-inoculated leaves but also in leaves above the inoculated leaf (fourth to sixth upper leaves). Moreover, genome-edited shoots regenerated from systemic leaves were obtained at a rate of >60%, enabling foreign DNA-free genome editing. Taken together, our results demonstrate that AsCas12f is small enough to be maintained in the PVX vector during systemic infection in N. benthamiana and that engineered AsCas12f offers advantages over SpCas9 for plant genome editing using virus vectors. [ABSTRACT FROM AUTHOR]

This study demonstrated the plant growth-promoting capabilities of native actinobacterial strains obtained from different regions of the rice plant, including the rhizosphere (FT1, FTSA2, FB2, and FH7) and endosphere (EB6). We delved into the molecular mechanisms underlying the beneficial effects of these plant-microbe interactions by conducting a transcriptional analysis of a select group of key genes involved in phytohormone pathways. Through in vitro screening for various plant growth-promoting (PGP) traits, all tested isolates exhibited positive traits for indole-3-acetic acid synthesis and siderophore production, with FT1 being the sole producer of hydrogen cyanide (HCN). All isolates were identified as members of the Streptomyces genus through 16S rRNA amplification. In pot culture experiments, rice seeds inoculated with strains FB2 and FTSA2 exhibited significant increases in shoot dry mass by 7% and 34%, respectively, and total biomass by 8% and 30%, respectively. All strains led to increased leaf nitrogen levels, with FTSA2 demonstrating the highest increase (4.3%). On the contrary, strains FB2 and FT1 increased root length, root weight ratio, root volume, and root surface area, leading to higher root nitrogen content. All isolates, except for FB2, enhanced total chlorophyll and carotenoid levels. Additionally, qRT-PCR analysis supported these findings, revealing differential gene expression in auxin (OsAUX1, OsIAA1, OsYUCCA1, OsYUCCA3), gibberellin (OsGID1, OsGA20ox-1), and cytokinin (OsIPT3, OsIPT5) pathways in response to specific actinobacterial treatments. These actinobacterial strains, which enhance both aboveground and belowground crop characteristics, warrant further evaluation in field trials, either as individual strains or in consortia. This could lead to the development of commercial bioinoculants for use in integrated nutrient management practices. [ABSTRACT FROM AUTHOR]

In response to various stressors, the calmodulin-binding transcription activator (CAMTA) can regulate downstream genes involved in calcium (Ca2+)/calmodulin signaling after binding to calmodulin (CAM) or calmodulin-like (CML) proteins. We previously reported seven OsCAMTA genes available throughout the rice (Oryza sativa) genome and their docking with the best probable interactors. This refined study demonstrated the evolutionary conservation of OsCAMTA motif structure and its correlation with 41 different plant species through phylogenetic tree construction along with the detailed molecular docking study focusing specifically on the calmodulin-binding domain (CaMBD) of each CAMTA protein with all available CAM/CML proteins across the rice genome. More insights regarding these were obtained from gene duplication studies through synteny analysis. Protein–protein interactions by STRING database analysis were conducted to know the involvement of OsCAMTA proteins in various development and stress-dependent pathways by identifying probable interactors. Tissue-specific expression analysis through qRT-PCR revealed that all the OsCAMTA genes except OsCAMTA7a and OsCAMTA7b were abundantly expressed in the roots of rice plants. Transcript expressions of rice CAMTAs under differential salt concentrations have depicted their participation in salt stress activity. Gene expression analysis in various temperatures indicated the most up-regulation of OsCAMTA7b, OsCAMTA4 and OsCAMTA3b at 4 ºC, 37 ºC and 42 ºC, respectively. In comparison to earlier research on OsCAMTA genes, this study is the most comprehensive fine-tuned and well-honed research conducted through tissue-specific expression study, followed by spatio-temporal expression analysis under different stresses with protein–protein interaction studies, molecular docking and prediction of microRNA to target each of the OsCAMTAs. [ABSTRACT FROM AUTHOR]

Interspecific F1 hybrids between Asian (Oryza sativa) and African rice (Oryza glaberrima) exhibit severe sterility caused by the accumulation of hybrid sterility genes/loci at 15 or more loci. The mechanisms underlying the hybrid sterility genes are largely unknown; however, a few genes associated with the killer–protector system, which is the system most frequently associated with hybrid sterility genes, have been identified. We previously produced fertile plants as tetraploids derived from diploid interspecific F1 hybrids through anther culture; therefore, it was suggested that hybrid sterility could be overcome following tetraploidization. We investigated whether tetraploid interspecific plants produced by crossing are fertile and tested the involvement of hybrid sterility genes in the process. Fertile tetraploid interspecific F1 hybrid plants were obtained by crossing 2 tetraploids of O. sativa and O. glaberrima. To elucidate the relationships between pollen fertility and the hybrid sterility loci in the tetraploid F1 microspores, we performed genetic analyses of the tetraploid F2 hybrids and diploid plants obtained from the microspores of tetraploid interspecific hybrids by anther culture. The result suggested that the tetraploid interspecific hybrids overcame pollen and seed infertility based on the proportion of loci with the killer–protector system present in the tetraploids. The heterozygous hybrid sterility loci with the killer–protector system in the tetraploid segregate the homozygous killed allele (16.7–21.4%), with more than three-quarters of the gametes surviving. We theoretically and experimentally demonstrated that fertile rice progenies can be grown from tetraploid interspecific hybrids. [ABSTRACT FROM AUTHOR]

Reasonable nitrogen (N) application is a promising strategy for reducing crop cadmium (Cd) toxicity. However, the specific form of N and the required amount that affect Cd tolerance and accumulation in rice remain unclear. This study explored the influence of different N-fertilizer forms (NH 4 NO 3 , NH 4 Cl, and KNO 3) and dosages on Cd tolerance and uptake in Cd-stressed N-sensitive and N-insensitive indica rice accessions. The results indicated that the Cd tolerance of N-sensitive indica accessions is more robust than that of N-insensitive ones. Furthermore, the shoot Cd content and Cd translocation rate in both N-sensitive and N-insensitive indica accessions decreased with an appropriate supply of NH 4 NO 3 and NH 4 Cl, whereas they were comparable or slightly increased with increased KNO 3. Unfortunately, we did not find significant and regular differences in Cd accumulation or translocation between N-sensitive and N-insensitive rice accessions. Consistent with the reduction of shoot Cd content, the addition of NH 4 NO 3 and NH 4 Cl also inhibited the instantaneous root Cd2+ uptake. The expression changes of Cd transport-related genes under different N forms and dosages suggested that the decreased shoot Cd content, caused by the increased supply of NH 4 NO 3 and NH 4 Cl, is likely achieved by reducing the transcription of OsNRAMP1 and OsIRT1. In summary, our findings reveal that an appropriate supply of NH 4 NO 3 and NH 4 Cl could reduce Cd uptake and transport in rice seedlings, suggesting that rational N management could reduce the Cd risk in rice production. [ABSTRACT FROM AUTHOR]

A field study was conducted at the ICAR-Indian Institute of Rice Research to investigate insect pest populations and their natural enemies in different organic rice modules during the rabi 2020 season. Three organic rice regimes, farmers' practice and untreated control were compared across three phenological stages in rice for the population dynamics of pests and natural enemies of Hemiptera and Hymenoptera. Sampling was done fortnightly for three months using various methods such as visual counting, sticky traps, sweep netting, and D-net. Pest and predator populations peaked during the vegetative stage, while parasitoids peaked during the reproductive stage. Pest population means were highest in untreated control during the reproductive and ripening stages exhibiting the impact of treatments. The predator population was highest in untreated control during the vegetative and reproductive stage, while parasitoid population size was highest in Pseudomonas treatment in the vegetative and reproduction stages of the crop and the Trichoderma treatment in the ripening stage. Predator diversity was highest in untreated control during vegetative and reproductive stages of the crop while parasitoid diversity was maximum during reproductive and ripening stage. Pearson's correlation coefficient between the population of pests and natural enemies was found to be positive and highly significant. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa) is one of the essential staple foods highly consumed globally, with nearly 40% to 45% of the global population estimated to consume rice. Therefore, consumable rice should have low levels of harmful elements. This study investigates fluoride (F¯) content in raw rice (uncooked rice) and evaluates Probabilistic Health Risk Assessment (PHRA) through Monte Carlo simulation (MCS) due to the consumption of F¯ enriched rice. The literature review reveals that limited studies have been conducted on the investigation of F¯ in raw rice. The fluoride (F¯) concentration in raw rice varies across the studied countries, indicating the need for additional studies to facilitate a more accurate comparison. The F¯ content in raw rice varied among the studied countries, making it difficult to definitively state that the concentration of F¯ in one country is higher. However, the concentration of F¯ in raw rice in India is notably elevated. This study also highlighted the importance of investigating the F¯ content in raw rice. The study will be highly helpful for policymakers to formulate guidelines for water used for irrigation. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa) is a staple food worldwide, yet faces significant threats from over 100 insect species, including 20 economic pests that are causing serious yield loss to rice plants. In many Asian nations, stink bugs belonging to the genus Scotinophara coarctata (Fabricius, Entomolgia systematica emendata et aucta, secundum classes, ordines, genera, species adjectis synonymis, locis, observationibus, descriptionibus, Suppl.: 1–572. Proft, Hafniae, 1798), Pentatomidae, Hemiptera are a common pest of rice. Black bug sucks the sap from the rice plants, and heavily infested rice plants turn yellowish brown and further die causing "bug burned" symptoms. Excessive sucking by more number of bugs causes maximum damage to rice crop in all affected areas. This review is focused on the nature of damage, taxonomy, alternate host, biology, light trap studies, influence of host varieties on the population development of black bug, EIL, ETL, yield loss, sustainable integrated BB management including cultural practices, exploiting the pest diversionary approaches for the management of black bug, biological control by parasites, predators and entomogenous fungi, efficacy of insecticides and botanicals in the management. This review is focused on the sustainable pest management practices for black bug in rice. [ABSTRACT FROM AUTHOR]

Salinity stress immensely inhibits rice (Oryza sativa L.) growth, development, and productivity. Hence, two rice introgression lines, Morkho60-2 and BC4F4 132-12-61, were previously developed from 'RD6' rice via markerassisted backcrossing and their adaptive salt-tolerant mechanisms were characterized in this study. Their seedling physiological and transcriptional responses to salinity stress were observed in comparison to the parental 'RD6' and 'Pokkali'. The salt stress responses were assessed under 150 mM NaCl treatment for 9 d. Interestingly, like 'Pokkali', salinity did not affect the growth parameters of the new rice genotypes. 'Pokkali', Morkho60-2, and BC4F4 132-12-61 also showed lower shoot Na+ content (0.91-1.05 vs. 2.83 mg g-1 DW), and higher selective transport of K+ over Na+ (i.e., ST value of 6.57-10.98 vs. 2.65) than RD6 genotype under salinity stress. Accordingly, the partial least squares-discriminant analysis of all physiological parameters suggested shoot Na+ accumulation and ST value as the key discriminating parameters between 'RD6' and the new genotypes. Transcriptional responses of Na+ homeostasis-related genes further supported the findings. In comparison to the salt susceptible 'RD6' rice, Na+ vacuolar compartmentalization was suggested in Morkho60-2 roots due to the higher abundance of OsNHX1 (i.e., relative expression of 2.65 vs. 1.59) and OsNHX2 (2.42 vs. 1.29) transcripts. Morkho60-2 also displayed a significant upregulation of root OsSOS1 (2.02 vs. 1.18), which may contribute to root Na+ exclusion. Therefore, we suggest that selective transport of K+ over Na+ and Na+ exclusion enhanced ion homeostasis in the newly improved rice genotypes, allowing the seedlings to adapt to the saline condition. [ABSTRACT FROM AUTHOR]

Calcium (Ca) and cadmium (Cd) are transition metals coexisting in the ecosystem. Ca is indispensable for the growth and development of plants as well as animals, while Cd is regarded as a toxic heavy metal for the living system. The transportation of Cd in the biological systems often used the pathways of Ca because of chemical similarities. High concentrations of cadmium replace Ca, Mn, and Zn from their respective metalloprotein sites and strongly associated with them. Replaced minerals from their metalloprotein sites are often released as an oxidative ion that is detrimental to it. The common transportation mechanism of Ca and Cd is implicit in the role of common and similar transporters for transporting them in plants. Thus, our study was done to identify the transporters for Ca and Cd and characterize them for similarity in terms of cotransportation system. A profile-based search program identified 44 transporters genes for Ca transportation and 70 genes for cadmium transportation. They were categorized into different groups based on the presence of signature motifs and domains. Identified transporters were characterized for genomic distribution, gene structure, annotation, conserved signature motifs, and domain. Further, cis motif analysis, heat map, gene ontology, and protein–protein interaction were conducted for Ca and Cd transporter genes. In silico expression showed Os05g0319800-1304 and Os0319800-6065 transporter genes were overexpressed for Ca and Os07g00232800-40298 and Os07g00384500-25924 transporter genes overexpressed for Cd transporter. These genes could be used as a candidate genes for enhancing the Ca concentration with reduced Cd content in rice using biotechnological approaches. Twenty-seven genes were found as the common transporters for Ca and Cd. Both active and passive transporter mechanisms act as cotransporters for Ca and Cd. The common signature motifs and domains can be targeted for the characterization of cotransporters of different minerals. [ABSTRACT FROM AUTHOR]

The development of the embryo sac is an important factor that affects seed setting in rice. Numerous genes associated with embryo sac (ES) development have been identified in plants; however, the function of the DEAD-box RNA helicase family genes is poorly known in rice. Here, we characterized a rice DEAD-box protein, RH52A, which is localized in the nucleus and cytoplasm and highly expressed in the floral organs. The knockout mutant rh52a displayed partial ES sterility, including degeneration of the ES (21%) and the presence of a double-female-gametophyte (DFG) structure (11.8%). The DFG developed from two functional megaspores near the chalazal end in one ovule, and 3.4% of DFGs were able to fertilize via the sac near the micropylar pole in rh52a. RH52A was found to interact with MFS1 and ZIP4, both of which play a role in homologous recombination in rice meiosis. RNA-sequencing identified 234 down-regulated differentially expressed genes associated with reproductive development, including two, MSP1 and HSA1b , required for female germline cell specification. Taken together, our study demonstrates that RH52A is essential for the development of the rice embryo sac and provides cytological details regarding the formation of DFGs. [ABSTRACT FROM AUTHOR]

Heat stress (HS) occurring during the grain-filling period has a detrimental effect on grain yield and quality in rice (Oryza sativa). The development of heat-resilient cultivars could partly solve this issue if tolerant alleles can be identified and incorporated into the germplasm. In this study, we posit that some of the phenotypic variations for heat resilience during grain development could be due to variations in gene expression among accessions. To test this, we characterized the HS response of 10 diverse rice accessions from three major sub-populations using physiological and transcriptome analyses. At a singlegrain level, grain width and grain thickness emerged as the most heat-sensitive traits. During a transient HS, IND-3 was categorized as highly sensitive, while five accessions exhibited moderate heat sensitivity, and four accessions were tolerant. Only a core set of 29.4% of the differentially expressed genes was common to the three rice sub-populations. Heat-tolerant accession TEJ-5 uniquely triggered an unfolded protein response (UPR) under HS, as evident from the induction of OsbZIP50 and downstream UPR genes. OsbZIP58, a gene that positively regulates grain filling, was more highly induced by HS in IND-2 despite its moderate heat sensitivity. Collectively, our analysis suggests that both unique gene expression responses and variation in the level of responses for a given pathway distinguish diverse accessions. Only some of these responses are associated with single-grain phenotypes in a manner consistent with the known roles of these genes and pathways. [ABSTRACT FROM AUTHOR]

Hybridization generates biodiversity, and wide hybridization plays a pivotal role in enhancing and broadening the useful attributes of crops. The hybridization barrier between wheat and rice, the two most important cereals, was recently overcome by in vitro production of allopolyploid wheat–rice hybrid zygotes, which can develop and grow into mature plants. In the study, genomic sequences and compositions of the possible hybrid plants were investigated through short- and long-read sequencing analyses and fluorescence in situ hybridization (FISH)-based visualization. The possible hybrid possessed whole wheat nuclear and cytoplasmic DNAs and rice mitochondrial (mt) DNA, along with variable retention rates of rice mtDNA ranging from 11% to 47%. The rice mtDNA retained in the wheat cybrid, termed Oryzawheat, can be transmitted across generations. In addition to mitochondrial hybridization, translocation of rice chromosome 1 into wheat chromosome 6A was detected in a F1 hybrid individual. OryzaWheat can provide a new horizon for utilizing inter-subfamily genetic resources among wheat and rice belonging to different subfamilies, Pooideae and Ehrhartoideae, respectively. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In light of projected climate changes that are expected to disrupt crop yields in previously stable regions, it is essential to understand how these changes will affect food supplies. This study investigated the combined effect of light and temperature on the yield of wheat (Triticum aestivum L.) and rice (Oryza sativa L.) in a controlled environment. Three treatment combinations were tested: 30.2 mol.m−2.d−1 with a 17.5 °C average ("low"), 38.9 mol.m−2.d−1 and 22.5 °C ("medium"), and 47.5 mol.m−2.d−1 and 27.5 °C ("high"). The low treatment resulted in the highest wheat yield, with total dry biomasses of 233 g, 140 g, and 115 g for the low, medium, and high treatments. Rice showed the highest growth in the medium and high treatments, with total dry biomasses of 145 and 144 g. The medium and high treatment biomasses were not statistically significant for wheat or rice at 95% confidence. However, the wheat's edible biomass did significantly decrease between every treatment. These results demonstrate that wheat thrives in colder climates, even with less light available, while an increase in temperature will have either a positive or insignificant effect on rice within this study's temperature range. [ABSTRACT FROM AUTHOR]

The limited availability of Phosphorus (P) in the soil poses a significant challenge to of rice productivity in rainfed tropical regions. There has been a constant demand of diverse donors for enhancing tolerance to P‐deficient soils. In this study, we evaluated 181 aus rice accessions of the 3000 Rice Genome Project (3 K‐RGP) for grain yield and six other agronomical traits under control (~20 mg kg−1 available P) and low‐P (8–10 mg kg−1 available P) field trials. The objectives were to assess the level of low‐P tolerance in the aus germplasm and select stable high‐yielding accessions using stress tolerance attributes. We also surveyed the presence of PSTOL1 gene and Pup1 polymorphisms to find the effect of PSTOL1 as well as t Pup1 haplotypes on low‐P tolerance. Principal component analysis (PCA) using five stress tolerance attributes revealed that attributes like mean productivity (MP) and stress tolerance index (STI) are useful for selecting high‐yielding accessions with stable yield under stress and control conditions. Notably, accessions like Kalabokari, Devarasi, ARC 12021, Jasure Aus, ARC 7336 and ARC 12101 had higher level of tolerance than the check varieties Vandana and Sahbhagi Dhan. Majority of aus accessions carried the PSTOL1 gene (73%) and had the tolerant haplotype of Pup1 (65%) like the tolerant checks. Although, at large, the PSTOL1‐positive accessions were more vigorous, and high yielding under low‐P, there were a few PSTOL1‐negative aus accessions showing higher level of tolerance. The findings suggest that non‐PSTOL1 type tolerance exists in aus rice which needs to be substantiated through further studies. [ABSTRACT FROM AUTHOR]

The current and future tidal swamplands are very strategic as one of the Indonesia national food barns considering the decreasing of productive land. Utilization of tidal swampland for agriculture, especially rice farming in South Kalimantan by local farmers began spontaneously hundreds of years ago. Most of the tidal swampland in South Kalimantan is still planted with local rice (Oryza sativa L.) varieties. Various local rice varieties planted by farmers include Siam, Bayar, Pandak, and Lemo varieties. These local varieties have been collected, identified, and conserved ex-situ in the tidal fields of South Kalimantan. The technology of local varieties of rice cultivation from seedling to harvest is carried out traditionally and uses traditional tools. Numerous local varieties collected and conserved, undergo crossbreeding with superior varieties to generate new high-yielding varieties with flavours favoured by the local populace. The Siam Unus serves as local variety for crossbreeding, while the superior varieties include Cisokan and Dodokan. The crossing of Siam Unus with Cisokan yields Margasari variety, and with Dodokan, it produces Martapura variety. Both varieties enjoy significant popularity among farmers and the local communities in the tidal areas of South and Central Kalimantan. This paper reviews research on traditional rice farming of tidal swampland and its impact on breeding and conservation programs in South Kalimantan. [ABSTRACT FROM AUTHOR]

Acid sulphate soils (ASS) can be classified as marginal soils due to their limited carrying capacity for rice (Oryza sativa L.) growth and production such as very low soil pH, high Fe content, and low soil nutrient content. A number of reclamation projects of ASS have not provided satisfactory outcomes due to a limited grasp of both the characteristics of the ASS and effective management methods. However, the precise cultivation system allows rice plants to grow well. The Banjarese-local rice cultivation system (BLRCS) is indigenous technology developed by Banjarese tribe in Kalimantan Island to enabling rice plant to grow and produce well in ASS. This review was addressed to provide scientifically describe and explain the chemical processes occurring in the soil under the BLRCS practice in ASS utilization for rice cultivation, consequently the utilization of ASS becomes more productive and environmentally friendly. The BLRCS is capable of enabling local rice plants to grow and produce well in ASS due to the improvement of ASS soil properties during growing season. Planting schedules were arranged based on the land hydrological conditions and use local rice varieties. The proper of land preparation and organic matter (OM) management in submerged condition during the growth and development stages of the rice plant lead Fe solubility becomes control, soil pH increase and nutrient in sufficient level for plant. [ABSTRACT FROM AUTHOR]

Rapid elongation of coleoptiles from rice seeds to reach the water surface enables plants to survive submergence stress and therefore plays a crucial role in allowing direct seeding in rice cultivation. Gibberellin (GA) positively influences growth in rice, but the molecular mechanisms underlying its regulation of coleoptile elongation under submerged conditions remain unclear. In this study, we performed a weighted gene co-expression network analysis to conduct a preliminarily examination of the mechanisms. Four key modules were identified with high correlations to the GA regulation of submergence tolerance. The genes within these modules were mainly involved in the Golgi apparatus and carbohydrate metabolic pathways, suggesting their involvement in enhancing submergence tolerance. Further analysis of natural variation revealed that the specific hub genes Os03g0337900 , Os03g0355600 , and Os07g0638400 exhibited strong correlations with subspecies divergence of the coleoptile elongation phenotype. Consistent with this analysis, mutation of Os07g0638400 resulted in a lower germination potential and a stronger inhibition of coleoptile elongation under submerged conditions. The hub genes identified in this study provide new insights into the molecular mechanisms underlying GA-dependent tolerance to submergence stress in rice, and a potential basis for future modification of rice germplasm to allow for direct seeding. [ABSTRACT FROM AUTHOR]

Genetic diversity can be seen as a source of options to grow diverse and nutritious foods with fewer resources, adapted to more hostile environments and making crops less susceptible to pests. In this sense, the present work was carried out with the objective of determining the genetic diversity, based on their genealogy, of the 20 rice cultivars released by the National Institute of Agricultural Sciences of Cuba in the 1984-2020 period. Through the CROPDIVER V. 01.20.19 program, the combined genealogical tree of all cultivars was elaborated, their parentage coefficients, the percentage of participation and the contribution of each ancestor in the cultivars obtained were calculated, in addition the dendrogram was constructed using parentage coefficient as genetic similarity estimate. The results showed that the genealogical tree, of the 20 cultivars obtained, is made up of 28 Ancestors and 65 cultivars or improved lines, the highest level of contribution falls on four ancestors and 12 contribute the genes present in the cytoplasm, through the maternal way. Although, as a whole, the obtained germplasm is consanguineous, the grouping carried out differentiated three groups of cultivars that allow establishing genetic similarities between them and making recommendations for their use in Cuban rice production. [ABSTRACT FROM AUTHOR]

This study was carried out at the farm of producer Rodolfo Miranda in Los Palacios municipality with the objective of seeking a relationship between yield, its components and other traits in rice genotypes treated with the biostimulants Biobras-16® and QuitoMax®. A completely randomized design was used with eighteen treatments (a control without application and independent applications of Biobras-16® and QuitoMax®) and three replicates each, and six quantitative traits were evaluated. The data matrix obtained was processed by means of Multivariate Principal Component Analysis, Multiple Linear Regression and Pearson correlations. The results revealed that most of the variables evaluated showed correlations, except full grains per panicle that was not interrelated with any other trait. The Principal Component analysis explained 74 % of the total variance, all the original variables contributed to the first component, except full and vain grains per panicle that contributed to the second component. Groups I and II included the cultivar INCA LP-7 and Line 4 in combination with the products under study and Line 3 with Biobras-16®. They were characterized by having the highest values for all traits, except vain grains per panicle, and the model proposed by the multiple linear regression analysis explained more than 85 % of the variability in yield, being an optimal predictor of this trait for studies under similar conditions. [ABSTRACT FROM AUTHOR]

Genebanks, other than their pivotal role as diversity conservation repositories, regenerate part of their collection every year to maintain their material in optimal conditions. During regeneration cycles, morpho-physiological data are collected, contributing to the creation of large datasets that offer a valuable resource of information. In Italy, rice cultivation has been documented since the second half of the 15th century, and nowadays, Italy contributes more than 50% of the total European rice production. The ex situ collection of rice (mainly Oryza sativa L. subgroup japonica) held at the Research Center for Cereal and Industrial Crops (CREA-CI) of Vercelli is quite unique in Italy and its establishment dates back to the beginning of the 20th century. The collection is hereby presented through the analysis of 21 years of historic data, from 2001 to 2022, in 17 different locations in Northern Italy, for a total of 6592 entries, 677 genotypes analyzed and 9 phenotypic traits under investigation. An R script has been developed to analyze the dataset. The BLUEs calculation, heritability, PCA and correlation with weather data provided a comprehensive overview of the germplasm stored in the genebank. The great variability and phenotypic diversity were assessed, key aspects from the perspective of breeding programs. This work starts a re-evaluation of historic data, historic cultivars, and represents the first step toward the shift of the genebank to a bio-digital resource center. [ABSTRACT FROM AUTHOR]

This research evaluated different rice genotypes regarding physicochemical and instrumental parameters of grain quality and associated the data with sensory analysis to support the creation of rules for classification of the culinary quality of rice (texture), based on isolated or combined parameters. The combination of amylose content and gelatinization temperature was able to predict the rice quality. According to the sensorial panel, the instrumental stickiness was able to segregate rice with very low amylose content or waxy to the other ones. Regarding pasting properties, rice that presented high final viscosity (310-480 RVU), setback (165-245 RVU), and pasting temperature (78 - 88 °C), and low values for breakdown (15-120 RVU), associated with a high stickiness (>-5N) was desirable by the Brazilian consumers. The classification rules created through the relationship between the physicochemical parameters and the texture profile evaluated by the sensory panel will help to verify the culinary profile of the rice samples (through free software), which makes it easier to predict the probability of rice meeting the desired quality standards. [ABSTRACT FROM AUTHOR]

The accumulation of arsenic (As) in rice (Oryza sativa L.) grain poses a significant health concern in Bangladesh. To address this, we investigated the efficacy of various organic amendments and phytoremediation techniques in reducing As buildup in O. sativa. We evaluated the impact of five doses of biochar (BC; BC0.1: 0.1%, BC0.28: 0.28%, BC0.55: 0.55%, BC0.82: 0.82% and BC1.0: 1.0%, w/w), vermicompost (VC; VC1.0: 1.0%, VC1.8: 1.8%, VC3.0: 3.0%, VC4.2: 4.2% and VC5.0: 5.0%, w/w), and floating duckweed (DW; DW100: 100, DW160: 160, DW250: 250, DW340: 340 and DW400: 400 g m− 2) on O. sativa cultivated in As-contaminated soil. Employing a three-factor five-level central composite design and response surface methodology (RSM), we optimized the application rates of BC-VC-DW. Our findings revealed that As contamination in the soil negatively impacted O. sativa growth. However, the addition of BC, VC, and DW significantly enhanced plant morphological parameters, SPAD value, and grain yield per pot. Notably, a combination of moderate BC-DW and high VC (BC0.55VC5DW250) increased grain yield by 44.4% compared to the control (BC0VC0DW0). As contamination increased root, straw, and grain As levels, and oxidative stress in O. sativa leaves. However, treatment BC0.82VC4.2DW340 significantly reduced grain As (G-As) by 56%, leaf hydrogen peroxide by 71%, and malondialdehyde by 50% compared to the control. Lower doses of BC-VC-DW (BC0.28VC1.8DW160) increased antioxidant enzyme activities, while moderate to high doses resulted in a decline in these activities. Bioconcentration and translocation factors below 1 indicated limited As uptake and translocation in plant tissues. Through RSM optimization, we determined that optimal doses of BC (0.76%), VC (4.62%), and DW (290.0 g m− 2) could maximize grain yield (32.96 g pot− 1, 44% higher than control) and minimize G-As content (0.189 mg kg− 1, 54% lower than control). These findings underscore effective strategies for enhancing yield and reducing As accumulation in grains from contaminated areas, thereby ensuring agricultural productivity, human health, and long-term sustainability. Overall, our study contributes to safer food production and improved public health in As-affected regions. [ABSTRACT FROM AUTHOR]

Implementing a cropping intensity program with rice cultivation four times a year (CI 400) can be achieved using early maturing varieties of rice. However, this development needs to pay attention to the adaptability of the varieties planted to ensure successful implementation. The adaptability approach is a combination of assessing stability and productivity potential. This concept has been developed and applied in several studies, including research on rice. However, this approach is considered less comprehensive because it is nonparametric and only focuses on one stability analysis. Therefore, a systematic integration of various stability analyses, including index methods, is needed to comprehensively assess adaptability, particularly for early-maturing rice in South Sulawesi. This region is characterized by a dynamic climate zone and is one of the top four highest rice producers in Indonesia. Meanwhile, this study aims to develop a comprehensive adaptability index and select the best early-maturing rice varieties, especially in South Sulawesi. The investigation was conducted in Bone, Soppeng, and Gowa over two seasons using a nested randomized complete block design, with organized replications in each environment (location-season). Additionally, there was a significant focus on the application of five early-maturing and two check rice varieties, with each factor repeated three times at each location, totaling 126 experimental units. The results showed that the adaptability index, by combining stability rank accumulation with yield min max standardization, was effective at assessing the yield potential and stability of early-maturing rice varieties in supporting CI 400. Inpari 13 had the best index value at 0.55, followed by Cakrabuana at 0.31; hence both were recommended as adaptive early-maturing rice varieties, especially in South Sulawesi. [ABSTRACT FROM AUTHOR]

Rice is a significant staple crop that provides food and livelihoods for millions of people worldwide. However, climate change and frequent cyclonic storms with heavy rains during grain maturation periods have led to a significant reduction in rice yield and quality (20–30%) due to pre-harvest sprouting (PHS) damage. PHS has become a widespread issue globally, resulting in significant economic losses for Indian farmers, amounting to billions of rupees annually and severely impacting the country’s economy. Developing protocol and PHS-resistant rice genotypes is essential to mitigate the significant economic losses experienced by farmers and meet the growing demand for food grain with the increasing population. This study was aimed to developing the efficient protocol to identify PHS-resistant rice genotypes by evaluating 96 genotypes under laboratory and field conditions at 20, 25, 30, 35 and 40 days after flowering (DAF). To evaluate the PHS resistant genotypes we have developed the efficient and standard protocol for the present study. The results showed a positive correlation between phenotypic responses under laboratory and field conditions. Based on the germination percentage exhibited under laboratory and field conditions, the genotypes were grouped into four clusters using K-clustering and dendrogram clustering analysis. Out of 96 genotypes evaluated 19 grouped as highly susceptible (45 to 88%), 14 were moderately susceptible (10 to 45%), 51 were moderately resistant (0.10 to 10.00%), and 12 were highly resistant with zero percent germination at all flowering stages. The study also evaluated the genotypes for days to germination from 20 to 40 DAF. The highly susceptible genotypes germinated earlier (3 days) than moderately susceptible and resistant genotypes (4 to 6 days). Zero days were assigned to highly resistant genotypes since no germination was recorded. In nutshell, the novel PHS-resistant rice genotypes identified in this study could serve as donors for future crop improvement programs. [ABSTRACT FROM AUTHOR]

F‐box protein is a subunit of the SCF (SKP1‐CUL1‐F‐box protein) E3 ubiquitin ligase complex, which plays a critical role in regulating different pathways in plant immunity. In this study, we identified the rice (Oryza sativa) F‐box protein OsFBX156, which targets the heat shock protein 70 (OsHSP71.1) to regulate resistance to the rice blast fungus Magnaporthe oryzae. Overexpression of OsFBX156 or knockout of OsHSP71.1 in rice resulted in the elevation of pathogenesis‐related (PR) genes and an induction burst of reactive oxygen species (ROS) after flg22 and chitin treatments, thereby enhancing resistance to M. oryzae. Furthermore, OsFBX156 can promote the degradation of OsHSP71.1 through the 26S proteasome pathway. This study sheds lights on a novel mechanism wherein the F‐box protein OsFBX156 targets OsHSP71.1 for degradation to promote ROS production and PR gene expression, thereby positively regulating rice innate immunity. [ABSTRACT FROM AUTHOR]

We investigated the expression and functions of a transcription factor gene, RDD3. It displays sequence similarity to RDD1, which controls various nutrient ion accumulation and uptake in rice. The RDD3 protein was specifically localized to protoxylems and metaxylems in the vascular bundles. RDD3-overexpressing (RDD3-OX) plants increased the RDD3 protein levels early in the light period and improved NH4+ and Mg2+ uptake and accumulation in the shoots. Furthermore, photosynthetic CO2 assimilation and stomatal conductance in RDD3-OX plants were higher than in wild-type plants, although shoot dry weight was decreased in mature RDD3-OX plants. Subsequent microarray analysis indicated that the late embryogenesis abundant (LEA) protein genes associated with drought responses were upregulated in RDD3-OX plants, whereas WRKY transcription factor genes were downregulated despite participating in defenses against biotic and abiotic stresses. Examining drought stress tolerance indicated that RDD3-OX plants were more tolerant than wild-type plants. These results indicate that increased RDD3 protein levels early in the light period improve nitrogen and magnesium accumulation and drought stress tolerance in RDD3-OX plants. [ABSTRACT FROM AUTHOR]

Rice straw is not easy to decompose, it takes a long time to compost, and the anaerobic bacteria involved in the decomposition process produce a large amount of carbon dioxide (CO2), indicating that applications for rice straw need to be developed. Recycling rice straw in agricultural crops is an opportunity to increase the sustainability of grain production. Several studies have shown that the probiotic population gradually decreases in the soil, leading to an increased risk of plant diseases and decreased biomass yield. Because the microorganisms in the soil are related to the growth of plants, when the soil microbial community is imbalanced it seriously affects plant growth. We investigated the feasibility of using composted rice stalks to artificially cultivate microorganisms obtained from the Oryza sativa-planted environment for analyzing the mycobiota and evaluating applications for sustainable agriculture. Microbes obtained from the water-submerged part (group-A) and soil part (group-B) of O. sativa were cultured in an artificial medium, and the microbial diversity was analyzed with internal transcribed spacer sequencing. Paddy field soil was mixed with fermented paddy straw compost, and the microbes obtained from the soil used for O. sativa planting were designated as group-C. The paddy fields transplanted with artificially cultured microbes from group-A were designated as group-D and those from group-B were designated as group-E. We found that fungi and yeasts can be cultured in groups-A and -B. These microbes altered the soil mycobiota in the paddy fields after transplantation in groups-D and -E compared to groups-A and -B. Development in O. sativa post treatment with microbial transplantation was observed in the groups-D and -E compared to group-C. These results showed that artificially cultured microorganisms could be efficiently transplanted into the soil and improve the mycobiota. Phytohormones were involved in improving O. sativa growth and rice yield via the submerged part-derived microbial medium (group-D) or the soil part-derived microbial medium (group-E) treatments. Collectively, these fungi and yeasts may be applied in microbial transplantation via rice straw fermentation to repair soil mycobiota imbalances, facilitating plant growth and sustainable agriculture. These fungi and yeasts may be applied in microbial transplantation to repair soil mycobiota imbalances and sustainable agriculture. [ABSTRACT FROM AUTHOR]

SUMMARY: Rapid alkalinization factors (RALFs), belonging to a family of small secreted peptides, have been considered as important signaling molecules in diverse biological processes, including immunity. Current studies on RALF‐modulated immunity mainly focus on Arabidopsis, but little is reported in crop plants. The rice immune receptor XA21 confers immunity to the bacterial blight pathogen, Xanthomonas oryzae pv. oryzae (Xoo). Here, we pursued functional characterization of rice RALF26 (OsRALF26) up‐regulated by Xoo during XA21‐mediated immune response. When applied exogenously as a recombinant peptide, OsRALF26 induced a series of immune responses, including pathogenesis‐related genes (PRs) induction, reactive oxygen species (ROS) production, and callose deposition in rice and/or Arabidopsis. Transgenic rice and Arabidopsis overexpressing OsRALF26 exhibited significantly enhanced resistance to Xoo and Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), respectively. In yeast two‐hybrid, pull‐down assays, and co‐immunoprecipitation analyses, rice FER‐like receptor 1 (OsFLR1) was identified as a receptor of OsRALF26. Transient expression of OsFLR1 in Nicotiana benthamiana leaves displayed significantly increased ROS production and callose deposition after OsRALF26 treatment. Together, we propose that OsRALF26 induced by Xoo in an XA21‐dependent manner is perceived by OsFLR1 and may play a novel role in the enforcement of XA21‐mediated immunity. Significance Statement: In‐depth insights about rice immunity help us develop new strategy to protect economically important monocot crops from increasing numbers of pathogens. Here, by studying how rice rapid alkalinization factor 26 (OsRALF26), one of small secreted peptides, activates immune responses, we tried to broaden our understanding of the mechanism of the RALF perception in rice plants. [ABSTRACT FROM AUTHOR]

To better understand the salt tolerance of the wild rice, Oryza coarctata, root tissue‐specific untargeted comparative metabolomic profiling was performed against the salt‐sensitive Oryza sativa. Under control, O. coarctata exhibited abundant levels of most metabolites, while salt caused their downregulation in contrast to metabolites in O. sativa. Under control conditions, itaconate, vanillic acid, threonic acid, eicosanoids, and a group of xanthin compounds were comparatively abundant in O. coarctata. Similarly, eight amino acids showed constitutive abundance in O. coarctata. In contrast, under control, glycerolipid abundances were lower in O. coarctata and salt stress further reduced their abundance. Most phospholipids also showed a distribution similar to the glycerolipids. Fatty acyls were however significantly induced in O. coarctata but organic acids were prominently induced in O. sativa. Changes in metabolite levels suggest that there was upregulation of the arachidonic acid metabolism in O. coarctata. In addition, the phenylpropanoid biosynthesis as well as cutin, suberin, and wax biosynthesis were also more enriched in O. coarctata, likely contributing to its anatomical traits responsible for salt tolerance. The comparative variation in the number of metabolites like gelsemine, allantoin, benzyl alcohol, specific phospholipids, and glycerolipids may play a role in maintaining the superior growth of O. coarctata in salt. Collectively, our results offer a comprehensive analysis of the metabolite profile in the roots of salt‐tolerant O. coarctata and salt‐sensitive O. sativa, which confirm potential targets for metabolic engineering to improve salt tolerance and resilience in commercial rice genotypes. [ABSTRACT FROM AUTHOR]

Oryza sativa L. or commonly known as rice belongs to the family of Poaceae. In Malaysia, rice is normally cultivated either as lowland or upland rice. Sarawak is a state with diverse types of rice. All Sarawak rice are landraces. Despite the fact that Sarawak is rich in rice biodiversity, the assessment of the morphological traits which may provide basic information that is useful for the future breeding programs is still unavailable. The nomenclature of the landraces is based on the name given by the farmers. Problems arise when landraces having the same morphological characteristics were given different names and vice versa. In addition, the purity of seeds is unreliable. Common practices by the local farmers such as planting different rice landraces in the same field either in one plot or in different plots but very near to each other has contributed to the impurity of the seeds. The present study was undertaken with the objective to characterise the morphological traits of 22 lowland and 22 upland rice accessions from the North-Western region of Sarawak. The morphological traits observed on the 44 rice accessions viz., blade colour, ligule shape, ligule colour, auricle colour, heading days, flowering days, panicle type, culm length, panicle number, number of filled grain, seed length and grain colour exhibited variations. There are variations which may be considered in future Sarawak rice breeding programs. [ABSTRACT FROM AUTHOR]

Sulfur (S) is an essential macronutrient for plants and its availability in soils is an important determinant for growth and development. Current regulatory policies aimed at reducing industrial S emissions together with changes in agronomical practices have led to a decline in S contents in soils worldwide. Deficiency of sulfate—the primary form of S accessible to plants in soil—has adverse effects on both crop yield and nutritional quality. Hence, recent research has increasingly focused on unraveling the molecular mechanisms through which plants detect and adapt to a limiting supply of sulfate. A significant part of these studies involves the use of omics technologies and has generated comprehensive catalogs of sulfate deficiency-responsive genes and processes, principally in Arabidopsis together with a few studies centering on crop species such as wheat, rice, or members of the Brassica genus. Although we know that sulfate deficiency elicits an important reprogramming of the transcriptome, the transcriptional regulators orchestrating this response are not yet well understood. In this review, we summarize our current knowledge of gene expression responses to sulfate deficiency and recent efforts towards the identification of the transcription factors that are involved in controlling these responses. We further compare the transcriptional response and putative regulators between Arabidopsis and two important crop species, rice and tomato, to gain insights into common mechanisms of the response to sulfate deficiency. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa) is one of the most important crops for humans. The homologs of ent-kaurene synthase (KS) in rice, which are responsible for the biosynthesis of gibberellins and various phytoalexins, are identified by their distinct biochemical functions. However, the KS-Like (KSL) family's potential functions related to hormone and abiotic stress in rice remain uncertain. Here, we identified the KSL family of 19 species by domain analysis and grouped 97 KSL family proteins into three categories. Collinearity analysis of KSLs among Poaceae indicated that the KSL gene may independently evolve and OsKSL1 and OsKSL4 likely play a significant role in the evolutionary process. Tissue expression analysis showed that two-thirds of OsKSLs were expressed in various tissues, whereas OsKSL3 and OsKSL5 were specifically expressed in the root and OsKSL4 in the leaf. Based on the fact that OsKSL2 participates in the biosynthesis of gibberellins and promoter analysis, we detected the gene expression profiles of OsKSLs under hormone treatments (GA, PAC, and ABA) and abiotic stresses (darkness and submergence). The qRT-PCR results demonstrated that OsKSL1, OsKSL3, and OsKSL4 responded to all of the treatments, meaning that these three genes can be candidate genes for abiotic stress. Our results provide new insights into the function of the KSL family in rice growth and resistance to abiotic stress. [ABSTRACT FROM AUTHOR]

Defoliation is an inevitable abiotic stress for forage and turf grasses because harvesting, grazing, and mowing are general processes for their production and management. Vegetative regrowth occurs upon defoliation, a crucial trait determining the productivity and persistence of these grasses. However, the information about the molecular regulation of this trait is limited because it is still challenging to perform molecular analyses in forage and turf grasses. Here, we used rice as a model to investigate vegetative regrowth upon defoliation at physiological and molecular levels. This study analyzed stubble and regrown leaves following periodic defoliation using two rice varieties with contrasting regrowth vigor. Vigorous regrowth was associated with maintained chlorophyll content and photosystem II performance; a restricted and promoted mRNA accumulation of sucrose synthase (SUS) I and III subfamilies, respectively; and reduced enzymatic activity of SUS. These results suggest that critical factors affecting vegetative regrowth upon defoliation are de novo carbohydrate synthesis by newly emerged leaves and proper carbohydrate management in leaves and stubble. Physiological and genetic analyses have demonstrated that the reduced sensitivity to and inhibited biosynthesis of cytokinin enhance regrowth vigor. Proper regulation of these metabolic and hormonal pathways identified in this study can lead to the development of new grass varieties with enhanced regrowth vigor following defoliation. [ABSTRACT FROM AUTHOR]

SUMMARY: Members of the glycosyltransferase (GT)43 and GT47 families have been associated with heteroxylan synthesis in both dicots and monocots and are thought to assemble into central cores of putative xylan synthase complexes (XSCs). Currently, it is unknown whether protein–protein interactions within these central cores are specific, how many such complexes exist, and whether these complexes are functionally redundant. Here, we used gene association network and co‐expression approaches in rice to identify four OsGT43s and four OsGT47s that assemble into different GT43/GT47 complexes. Using two independent methods, we showed that (i) these GTs assemble into at least six unique complexes through specific protein–protein interactions and (ii) the proteins interact directly in vitro. Confocal microscopy showed that, when alone, all OsGT43s were retained in the endoplasmic reticulum (ER), while all OsGT47s were localized in the Golgi. co‐expression of OsGT43s and OsGT47s displayed complexes that form in the ER but accumulate in Golgi. ER‐to‐Golgi trafficking appears to require interactions between OsGT43s and OsGT47s. Comparison of the central cores of the three putative rice OsXSCs to wheat, asparagus, and Arabidopsis XSCs, showed great variation in GT43/GT47 combinations, which makes the identification of orthologous central cores between grasses and dicots challenging. However, the emerging picture is that all central cores from these species seem to have at least one member of the IRX10/IRX10‐L clade in the GT47 family in common, suggesting greater functional importance for this family in xylan synthesis. Our findings provide a new framework for future investigation of heteroxylan biosynthesis and function in monocots. Significance Statement: Our findings support the presence of at least three unique rice OsXSCs, whereby each OsXSC central core is made up of interactions between specific OsGT43 and OsGT47 family members. To effectively improve crops and biofuel production, manipulation of heteroxylan synthesis during plant development must consider the specificity of protein–protein interactions between GT43s and GT47s. [ABSTRACT FROM AUTHOR]