Analysis of Rice Blast Fungus Genetic Diversity and Identification of a Novel Blast Resistance OsDRq12 Gene.

The rice blast fungus Magnaporthe oryzae poses a significant challenge to maintaining rice production. Developing rice varieties with resistance to this disease is crucial for its effective control. To understand the genetic variability of blast isolates collected between 2015 and 2017, the 27 monogenic rice lines that carry specific resistance genes were used to evaluate blast disease reactions. Based on criteria such as viability, virulence, and reactions to resistance genes, 20 blast isolates were selected as representative strains. To identify novel resistance genes, a quantitative trait locus analysis was carried out utilizing a mixture of the 20 representative rice blast isolates and a rice population derived from crossing the blast-resistant cultivar 'Cheongcheong' with the blast-susceptible cultivar 'Nagdong'. This analysis revealed a significant locus, RM1227-RM1261 on chromosome 12, that is associated with rice blast resistance. Within this locus, 12 disease resistance-associated protein genes were identified. Among them, OsDRq12, a member of the nucleotide-binding, leucine-rich repeat disease resistance family, was chosen as the target gene for additional computational investigation. The findings of this study have significant implications for enhancing rice production and ensuring food security by controlling rice blast and developing resistant rice cultivars.

Halotolerant endophytic bacteria alleviate salinity stress in rice (oryza sativa L.) by modulating ion content, endogenous hormones, the antioxidant system and gene expression.

Excessive salinity reduces crop production and negatively impacts agriculture worldwide. We previously isolated endophytic bacterial strains from two halophytic species: Artemisia princeps and Chenopodium ficifolium. We used three bacterial isolates: ART-1 (Lysinibacillus fusiformis), ART-10 (Lysinibacillus sphaericus), and CAL-8 (Brevibacterium pityocampae) to alleviate the impact of salinity stress on rice. The impact of 160 mM NaCl salinity on rice was significantly mitigated following inoculation with these bacterial strains, resulting in increased growth and chlorophyll content. Furthermore, OsNHX1, OsAPX1, OsPIN1 and OsCATA expression was increased, but OsSOS expression was decreased. Inductively coupled plasma mass spectrometry (ICP-MS) revealed reduced K+ and Na+ levels in shoots of bacteria-inoculated plants, whereas that of Mg2+ was increased. Bacterial inoculation reduced the content of total flavonoids in rice leaves. Salinized plants inoculated with bacteria showed reduced levels of endogenous salicylic acid (SA) and abscisic acid (ABA) but increased levels of jasmonic acid (JA). In conclusion, the bacterial isolates ART-1, ART-10, and CAL-8 alleviated the adverse effect of salinity on rice growth, which justifies their use as an eco-friendly agricultural practice.

Efficient identification of palatability-related genes using QTL mapping in rice breeding.

The gelatinization temperature of rice is an important factor in determining the eating and cooking quality, and it affects consumer preference. The alkali digestion value (ADV) is one of the main methods used to test the quality of rice and has a high correlation with the gelatinization temperature. For the development of high-quality rice, it is important to understand the genetic basis of palatability-related traits, and QTL analysis is a statistical method linking phenotypic data and genotype data and is an effective method to explain the genetic basis of variation in complex traits. QTL mapping related to the ADV of brown and milled rice was performed using the 120 Cheongcheong/Nagdong double haploid (CNDH) line. As a result, 12 QTLs related to ADV were detected, and 20 candidate genes were selected from the RM588-RM1163 region of chromosome 6 through screening by gene function analysis. The comparison of the relative expression level of candidate genes showed that OsSS1q6 is highly expressed in CNDH lines with high ADV in both brown rice and milled rice. In addition, OsSS1q6 has high homology with the starch synthase 1 protein and interacts with various starch biosynthesis-related proteins, such as GBSSII, SBE, and APL. Therefore, we suggest that OsSS1q6 identified through QTL mapping could be one of the various genes involved in the gelatinization temperature of rice by regulating starch biosynthesis. This study can be used as basic data for breeding high-quality rice and provides a new genetic resource that can increase the palatability of rice. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01392-2.

Quantitative Trait Loci Mapping Identified Candidate Genes Involved in Plant Height Regulation in Rice.

Rice plant height is an agricultural trait closely related to biomass, lodging tolerance, and yield. Identifying quantitative trait loci (QTL) regions related to plant height regulation and developing strategies to screen potential candidate genes can improve agricultural traits in rice. In this study, a double haploid population (CNDH), derived by crossing 'Cheongcheong' and 'Nagdong' individuals, was used, and a genetic map was constructed with 222 single-sequence repeat markers. In the RM3482-RM212 region on chromosome 1, qPh1, qPh1-1, qPh1-3, qPh1-5, and qPh1-6 were identified for five consecutive years. The phenotypic variance explained ranged from 9.3% to 13.1%, and the LOD score ranged between 3.6 and 17.6. OsPHq1, a candidate gene related to plant height regulation, was screened in RM3482-RM212. OsPHq1 is an ortholog of gibberellin 20 oxidase 2, and its haplotype was distinguished by nine SNPs. Plants were divided into two groups based on their height, and tall and short plants were distinguished and clustered according to the expression level of OsPHq1. QTLs and candidate genes related to plant height regulation, and thus, biomass regulation, were screened and identified in this study, but the molecular mechanism of the regulation remains poorly known. The information obtained in this study will help develop molecular markers for marker-assisted selection and breeding through rice plant height control.

Enhancing the Expression of the OsF3H Gene in Oryza sativa Leads to the Regulation of Multiple Biosynthetic Pathways and Transcriptomic Changes That Influence Insect Resistance.

The white-backed planthopper (WBPH) is a major pest of rice crops and causes severe loss of yield. We previously developed the WBPH-resistant rice cultivar "OxF3H" by overexpressing the OsF3H gene. Although there was a higher accumulation of the flavonoids kaempferol (Kr) and quercetin (Qu) as well as salicylic acid (SA) in OxF3H transgenic (OsF3H or Trans) plants compared to the wild type (WT), it is still unclear how OsF3H overexpression affects these WBPH resistant-related changes in gene expression in OxF3H plants. In this study, we analyze RNA-seq data from OxF3H and WT at several points (0 h, 3 h, 12 h, and 24 h) after WBPH infection to explain how overall changes in gene expression happen in these two cultivars. RT-qPCR further validated a number of the genes. Results revealed that the highest number of DEGs (4735) between the two genotypes was detected after 24 h of infection. Interestingly, it was found that several of the DEGs between the WT and OsF3H under control conditions were also differentially expressed in OsF3H in response to WBPH infestation. These results indicate that significant differences in gene expression between the "OxF3H" and "WT" exist as the infection time increases. Many of these DEGs were related to oxidoreductase activity, response to stress, salicylic acid biosynthesis, metabolic process, defense response to pathogen, cellular response to toxic substance, and regulation of hormone levels. Moreover, genes involved in salicylic acid (SA) and ethylene (Et) biosynthesis were upregulated in OxF3H plants, while jasmonic acid (JA), brassinosteroid (Br), and abscisic acid (ABA) signaling pathways were found downregulated in OxF3H plants during WBPH infestation. Interestingly, many DEGs related to pathogenesis, such as OsPR1, OsPR1b, OsNPR1, OsNPR3, and OsNPR5, were found to be significantly upregulated in OxF3H plants. Additionally, genes related to the MAPKs pathway and about 30 WRKY genes involved in different pathways were upregulated in OxF3H plants after WBPH infestation. This suggests that overexpression of the OxF3H gene leads to multiple transcriptomic changes and impacts plant hormones and pathogenic-related and secondary-metabolites-related genes, enhancing the plant's resistance to WBPH infestation.

Bio-Efficacy of Chrysoeriol7, a Natural Chemical and Repellent, against Brown Planthopper in Rice.

Brown planthopper (BPH, Nilaparvata lugens Stal.) is the most damaging rice pest affecting stable rice yields worldwide. Currently, methods for controlling BPH include breeding a BPH-resistant cultivar and using synthetic pesticides. Nevertheless, the continuous cultivation of resistant cultivars allows for the emergence of various resistant races, and the use of synthetic pesticides can induce environmental pollution as well as the emergence of unpredictable new pest species. As plants cannot migrate to other locations on their own to combat various stresses, the production of secondary metabolites allows plants to protect themselves from stress and tolerate their reproduction. Pesticides using natural products are currently being developed to prevent environmental pollution and ecosystem disturbance caused by synthetic pesticides. In this study, after BPH infection in rice, chrysoeriol7 (C7), a secondary metabolite that induces resistance against BPH, was assessed. After C7 treatment and BPH infection, relative expression levels of the flavonoid-related genes were elevated, suggesting that in plants subjected to BPH, compounds related to flavonoids, among the secondary metabolites, play an important role in inducing resistance. The plant-derived natural compound chrysoeriol7 can potentially thus be used to develop environmentally friendly pesticides. The suggested control of BPH can be effectively used to alleviate concerns regarding environmental pollution and to construct a relatively safe rice breeding environment.

The Role of Exogenous Gibberellic Acid and Methyl Jasmonate against White-Backed Planthopper (Sogatella furcifera) Stress in Rice (Oryza sativa L.).

Rice (Oryza sativa L.) is one of the essential staple foods for more than half of the world's population, and its production is affected by different environmental abiotic and biotic stress conditions. The white-backed planthopper (WBPH, Sogatella furcifera) causes significant damage to rice plants, leading to substantial economic losses due to reduced production. In this experiment, we applied exogenous hormones (gibberellic acid and methyl jasmonate) to WBPH-infested rice plants and examined the relative expression of related genes, antioxidant accumulation, the recovery rate of affected plants, endogenous hormones, the accumulation of H2O2, and the rate of cell death using DAB and trypan staining, respectively. The expression of the transcriptional regulator (OsGAI) and gibberellic-acid-mediated signaling regulator (OsGID2) was upregulated significantly in GA 50 µM + WBPH after 36 h. OsGAI was upregulated in the control, GA 50 µM + WBPH, GA 100 µM + WBPH, and MeJA 100 µM + WBPH. However, after 48 h, the OsGID2 was significantly highly expressed in all groups of plants. The glutathione (GSH) values were significantly enhanced by GA 100 µM and MeJA 50 µM treatment. Unlike glutathione (GSH), the catalase (CAT) and peroxidase (POD) values were significantly reduced in control + WBPH plants. However, a slight increase in CAT and POD values was observed in GA 50 + WBPH plants and a reduction in the POD value was observed in GA 100 µM + WBPH and MeJA 50 µM + WBPH plants. GA highly recovered the WBPH-affected rice plants, while no recovery was seen in MeJA-treated plants. MeJA was highly accumulated in control + WBPH, MeJA 50 µM + WBPH, and GA 100 µM + WBPH plants. The H2O2 accumulation was highly decreased in GA-treated plants, while extensive cell death was observed in MeJA-treated plants compared with GA-treated plants. From this study, we can conclude that the exogenous application of GA can overcome the effects of the WBPH and enhance resistance in rice.

QTL Mapping and Candidate Gene Analysis for Seed Germination Response to Low Temperature in Rice.

Low temperature is a serious threat to the seed emergence of rice, which has become one of the main limiting factors affecting rice production in the world. It is of great significance to find the candidate genes controlling low-temperature tolerance during seed germination and study their functions for breeding new rice cultivars with immense low-temperature tolerance during seed germination. In the current experiment, 120 lines of the Cheongcheong Nagdong Double Haploid (CNDH) population were used for quantitative trait locus (QTL) analysis of low-temperature germinability. The results showed a significant difference in germination under low different temperature (LDT) (15 °C, 20 °C) conditions. In total, four QTLs were detected on chromosome 3, 6, and 8. A total of 41 genes were identified from all the four QTLs, among them, 25 genes were selected by gene function annotation and further screened through quantitative real-time polymerase chain reaction (qRT-PCR). Based on gene function annotation and level of expression under low-temperature, our study suggested the OsGPq3 gene as a candidate gene controlling viviparous germination, ABA and GA signaling under low-temperature. This study will provide a theoretical basis for marker-assisted breeding and lay the basis for further mining molecular mechanisms of low-temperature germination tolerance in rice.

Identification of a Major QTL and Validation of Related Genes for Tiller Angle in Rice Based on QTL Analysis.

An ideal plant architecture is an important condition to achieve high crop yields. The tiller angle is an important and complex polygenic trait of rice (Oryza sativa L.) plant architecture. Therefore, the discovery and identification of tiller angle-related genes can aid in the improvement of crop architecture and yield. In the present study, 222 SSR markers were used to establish a high-density genetic map of rice doubled haploid population, and a total of 8 quantitative trait loci (QTLs) were detected based on the phenotypic data of the tiller angle and tiller crown width over 2 years. Among them, four QTLs (qTA9, qCW9, qTA9-1, and qCW9-1) were overlapped at marker interval RM6235-RM24288 on chromosome 9 with a large effect value regarded as a stable major QTL. The selected promising related genes were further identified by relative gene expression analysis, which gives us a basis for the future cloning of these genes. Finally, OsSAURq9, which belongs to the SMALL AUXIN UP RNA (SAUR), an auxin-responsive protein family, was selected as a target gene. Overall, this work will help broaden our knowledge of the genetic control of tiller angle and tiller crown width, and this study provides both a good theoretical basis and a new genetic resource for the breeding of ideal-type rice.

Screening and identification of genes affecting grain quality and spikelet fertility during high-temperature treatment in grain filling stage of rice.

BACKGROUND: Recent temperature increases due to rapid climate change have negatively affected rice yield and grain quality. Particularly, high temperatures during right after the flowering stage reduce spikelet fertility, while interfering with sugar energy transport, and cause severe damage to grain quality by forming chalkiness grains. The effect of high-temperature on spikelet fertility and grain quality during grain filling stage was evaluated using a double haploid line derived from another culture of F1 by crossing Cheongcheong and Nagdong cultivars. Quantitative trait locus (QTL) mapping identifies candidate genes significantly associated with spikelet fertility and grain quality at high temperatures. RESULTS: Our analysis screened OsSFq3 that contributes to spikelet fertility and grain quality at high-temperature. OsSFq3 was fine-mapped in the region RM15749-RM15689 on chromosome 3, wherein four candidate genes related to the synthesis and decomposition of amylose, a starch component, were predicted. Four major candidate genes, including OsSFq3, and 10 different genes involved in the synthesis and decomposition of amylose and amylopectin, which are starch constituents, together with relative expression levels were analyzed. OsSFq3 was highly expressed during the initial stage of high-temperature treatment. It exhibited high homology with FLOURY ENDOSPERM 6 in Gramineae plants and is therefore expected to function similarly. CONCLUSION: The QTL, major candidate genes, and OsSFq3 identified herein could be effectively used in breeding rice varieties to improve grain quality, while tolerating high temperatures, to cope with climate changes. Furthermore, linked markers can aid in marker-assisted selection of high-quality and -yield rice varieties tolerant to high temperatures.

Item repetition and retrieval processes in cued recall: Analysis of recall-latency distributions.

The SAM (search of associative memory) model provides a unified account of accuracy effects, assuming that retrieval is a cue-dependent two-stage process of sampling and recovery, which depends on the strength of items relative to all others and on that item associated with the sampling trace, respectively. On the other hand, the relative strength model uniquely provides latency predictions, assuming that recall latency is determined solely by relative strength (similar to the sampling rule in SAM): Latency should remain unchanged for strong and weak items in pure lists, but will be shorter for strong items than for weak items in mixed lists. To test the predictions, the present study examined accuracy and latency distributions, which were fit with the ex-Gaussian, using item repetition as a means of strengthening. Massed versus spaced repetitions were used where repetitions were either cue-target pairs or cue alone. When repetitions were spaced in mixed lists, accuracy and latency both increased with cue-target repetitions, relative to cue-only repetitions, and slow recall for cue-target repetitions was due to initially nonretrievable items. However, even after successful recall on a pretest, cue-target repetitions led to an increase in latency in pure lists. These findings are difficult to reconcile with relative-strength explanations of latency. They indeed suggest that (1) separate traces are created for each repetition, (2) memory traces are updated if the item is retrieved (otherwise, new traces are stored), and (3) recovery plays a role in latency, which are discussed with the distinction between sampling and recovery of SAM.

Sparse and distributed coding of episodic memory in neurons of the human hippocampus.

Neurocomputational models hold that sparse distributed coding is the most efficient way for hippocampal neurons to encode episodic memories rapidly. We investigated the representation of episodic memory in hippocampal neurons of nine epilepsy patients undergoing intracranial monitoring as they discriminated between recently studied words (targets) and new words (foils) on a recognition test. On average, single units and multiunits exhibited higher spike counts in response to targets relative to foils, and the size of this effect correlated with behavioral performance. Further analyses of the spike-count distributions revealed that (i) a small percentage of recorded neurons responded to any one target and (ii) a small percentage of targets elicited a strong response in any one neuron. These findings are consistent with the idea that in the human hippocampus episodic memory is supported by a sparse distributed neural code.

Solution processed organic photodetector utilizing an interdiffused polymer/fullerene bilayer.

Low dark current (off-current) and high photo current are both essential for a solution processed organic photodetector (OPD) to achieve high photo-responsivity. Currently, most OPDs utilize a bulk heterojunction (BHJ) photo-active layer that is prepared by the one-step deposition of a polymer:fullerene blend solution. However, the BHJ structure is the main cause of the high dark current in solution processed OPDs. It is revealed that the detectivity and spectral responsivity of the OPD can be improved by utilizing a photo-active layer consisting of an interdiffused polymer/fullerene bilayer (ID-BL). This ID-BL is prepared by the sequential solution deposition (SqD) of poly(3-hexylthiophene) (P3HT) and [6,6] phenyl C61 butyric acid methyl ester (PCBM) solutions. The ID-BL OPD is found to prevent undesirable electron injection from the hole-collecting electrode to the ID-BL photo-active layer resulting in a reduced dark current in the ID-BL OPD. Based on dark current and external quantum efficiency (EQE) analysis, the detectivity of the ID-BL OPD is determined to be 7.60 × 10(11) Jones at 620 nm. This value is 3.4 times higher than that of BHJ OPDs. Furthermore, compared to BHJ OPDs, the ID-BL OPD exhibited a more consistent spectral response in the range of 400 - 660 nm.

Synthesis and Electrochemical Characterization of Nitrate-Doped Polypyrrole/Ag Nanowire Nanorods as Supercapacitors.

Polypyrrole (PPy)-capped silver nanowire (Ag NW) nanomaterials (core-shell rod-shaped Ag NW@PPy) were synthesized using a one-port suspension polymerization technique. The thickness of the PPy layer on the 50 nm thickness/15 µm length Ag NW was effectively controlled to 10, 40, 50, and 60 nm. Thin films cast from one-dimensional conductive Ag NW@PPy formed a three-dimensional (3D) conductive porous network structure and provided excellent electrochemical performance. The 3D Ag NW@PPy network can significantly reduce the internal resistance of the electrode and maintain structural stability. As a result, a high specific capacitance of 625 F/g at a scan rate of 1 mV/s was obtained from the 3D porous Ag NW@PPy composite film. The cycling performance over a long period exceeding 10,000 cycles was also evaluated. We expect that our core-shell-structured Ag NW@PPy composites and their 3D porous structure network films can be applied as electrochemical materials for the design and manufacturing of supercapacitors and other energy storage devices.

OsCKq1 Regulates Heading Date and Grain Weight in Rice in Response to Day Length.

BACKGROUND: Photoperiod sensitivity is among the most important agronomic traits of rice, as it determines local and seasonal adaptability and plays pivotal roles in determining yield and other key agronomic characteristics. By controlling the photoperiod, early-maturing rice can be cultivated to shorten the breeding cycle, thereby reducing the risk of yield losses due to unpredictable climate change. Furthermore, early-maturing and high-yielding rice needs to be developed to ensure food security for a rapidly growing population. Early-maturing and high-yielding rice should be developed to fulfill these requirements. OsCKq1 encodes the casein kinase1 protein in rice. OsCKq1 is a gene that is activated by photophosphorylation when Ghd7, which suppresses flowering under long-day conditions, is activated. RESULTS: This study investigates how OsCKq1 affects heading in rice. OsCKq1-GE rice was analyzed the function of OsCKq1 was investigated by comparing the expression levels of genes related to flowering regulation. The heading date of OsCKq1-GE lines was earlier (by about 3 to 5 days) than that of Ilmi (a rice cultivar, Oryza sativa spp. japonica), and the grain length, grain width, 1,000-grain weight, and yield increased compared to Ilmi. Furthermore, the culm and panicle lengths of OsCKq1-GE lines were either equal to or longer than those of Ilmi. CONCLUSIONS: Our research demonstrates that OsCKq1 plays a pivotal role in regulating rice yield and photoperiod sensitivity. Specifically, under long-day conditions, OsCKq1-GE rice exhibited reduced OsCKq1 mRNA levels alongside increased mRNA levels of Hd3a, Ehd1, and RFT1, genes known for promoting flowering, leading to earlier heading compared to Ilmi. Moreover, we observed an increase in seed size. These findings underscore OsCKq1 as a promising target for developing early-maturing and high-yielding rice cultivars, highlighting the potential of CRISPR/Cas9 technology in enhancing crop traits.

Exogenous melatonin induces salt and drought stress tolerance in rice by promoting plant growth and defense system.

Due to global climate change, crops are certainly confronted with a lot of abiotic and biotic stress factors during their growth that cause a serious threat to their development and overall productivity. Among different abiotic stresses, salt and drought are considered the most devastating stressors with serious impact on crop's yield stability. Here, the current study aimed to elucidate how melatonin works in regulating plant biomass, oxidative stress, antioxidant defense system, as well as the expression of genes related to salt and drought stress in rice plants. Eight groups of rice plants (3 replicates, 5 plants each) underwent varied treatments: control, melatonin, salt, drought, salt + drought, salt + melatonin, drought + melatonin, and salt + drought + melatonin. Melatonin (100 µM) was alternately applied a week before stress exposure; salt stress received 100 mM NaCl every 3 days for 3 weeks, and drought stress involved 10% PEG. Young leaves were randomly sampled from each group. The results showed that melatonin treatment markedly reduces salt and drought stress damage by promoting root, shoot length, fresh and dry weight, increasing chlorophyll contents, and inhibiting excessive production of oxidative stress markers. Salt and drought stress significantly decreased the water balance, and damaged cell membrane by reducing relative water contents and increasing electrolyte leakage. However, melatonin treated rice plants showed high relative water contents and low electrolyte leakage. Under salt and drought stress conditions, exogenous application of melatonin boosted the expression level of salt and drought stress responsive genes like OsSOS, OsNHX, OsHSF and OsDREB in rice plants. Taken together, our results reveal that melatonin treatment significantly increases salt and drought tolerance of rice plants, by increasing plant biomass, suppressing ROS accumulation, elevating antioxidants defense efficiency, and up-regulating the expression of salt and drought stress responsive genes.

Determining arsenic stress tolerance genes in rice (Oryza sativa L.) via genomic insights and QTL mapping with double haploid lines.

Arsenic, a hazardous heavy metal with potent carcinogenic properties, significantly affects key rice-producing regions worldwide. In this study, we present a quantitative trait locus (QTL) mapping investigation designed to identify candidate genes responsible for conferring tolerance to arsenic toxicity in rice (Oryza sativa L.) during the seedling stage. This study identified 17 QTLs on different chromosomes, including qCHC-1 and qCHC-3 on chromosome 1 and 3 related to chlorophyll content and qRFW-12 on chromosome 12 related to root fresh weight. Gene expression analysis revealed eight candidate genes exhibited significant upregulation in the resistant lines, OsGRL1, OsDjB1, OsZIP2, OsMATE12, OsTRX29, OsMADS33, OsABCG29, and OsENODL24. These genes display sequence alignment and phylogenetic tree similarities with other species and engaging in protein-protein interactions with significant proteins. Advanced gene-editing techniques such as CRISPR-Cas9 to precisely target and modify the candidate genes responsible for arsenic tolerance will be explore. This approach may expedite the development of arsenic-resistant rice cultivars, which are essential for ensuring food security in regions affected by arsenic-contaminated soil and water.

Utilization of the Winkler scale of plants using big data temperature presented by the Korea Meteorological Administration.

Introduction: Rice is an important food source that can provide a stable supply of calories for most people around the world. However, owing to the recent rapid temperature rise, we are facing social issues related to the increase in the Winkler scale. In this study, a strategy for screening potential candidate genes related to the yield according to the Winkler scale is presented, and the possibility of using a candidate gene identified through sequence haplotype and homology analysis as a breeding source is suggested. Methods: QTL for the Winkler scale was identified using a population of 120 double haploids derived from a cross between Cheongchoneg, Indica, and Nagdong, Japonica. Results and discussion: A total of 79 candidate genes were detected in the identified QTL region, and OsHAq8 was finally screened. Through haplotype analysis, OsHAq8 was derived from the Indica group and orthologous to Graminae's activator of Hsp90 ATPase, suggesting that it is a candidate gene involved in yield according to temperature during the growing period. The expression level of OsHAq8 increased as the Winkler scale increased. The findings of this study can serve as a crucial indicator for predicting harvest time and grain quality while achieving a stable yield through marker selection and adaptation to climate change. Climate change occurs more frequently. In these situations, it is very important to predict harvest time and apply relevant candidate genes to breeding. The candidate genes presented in this study can be effectively applied to rice breeding in preparation for climate change.

Investigation of the Relationship between Genetic and Breeding Characteristics of WBPH Behavior according to Resistant Materials in Rice.

Rice accounts for most of the calories consumed by the world's population. However, the whitebacked planthopper (WBPH), Sogatella furcifera (Horvath), is an insect that can cause rice yield loss. WBPH sucks the stems of rice and negatively affects yield and grain quality. Therefore, numerous insecticides have been developed to control WBPH in rice fields. However, chemical pesticides cause serious problems such as environmental pollution and ecosystem disturbance. Here, we research the possibility of using previously reported rice extracts obtained using methanol, Chrysoeriol 7(C7) and Cochlioquinone-9 (cq-9), as potential insect repellents. WBPH was caged with C7 or cq-9 and monitored, and the WBPH behavior was recorded. The number of WBPHs approaching the periphery of the C7 and cq-9 was very low. In cages containing the C7 and cq-9, only 13 and 7 WBPHs out of 100, respectively, walked around the material. In addition, foliar spraying with C7 and cq-9 did not negatively affect the plant height. The expression level of genes related to resistance was maintained at a high level in the resistant lines when treated with WBPHs alone, but was at a similar level to those of the controls when treated with C7 or cq-9. Interfering with WBPH access did not adversely affect the plant phenotype. Recently, people's interest in the environment has increased, and the use of plant-derived materials is also increasing. There is a new trend towards using plant extracts as an environmentally friendly means of managing resistance to WBPH during the rice cultivation period, while also avoiding environmental pollution.

Evaluation of Amino Acid Profiles of Rice Genotypes under Different Salt Stress Conditions.

Amino acids are building blocks of proteins that are essential components of a wide range of metabolic pathways in plant species, including rice species. Previous studies only considered changes in the amino acid content of rice under NaCl stress. Here, we evaluated profiles of essential and non-essential amino acids in four rice genotype seedlings in the presence of three types of salts, namely NaCl, CaCl2, and MgCl2. Amino acid profiles in 14-day-old rice seedlings were determined. The total essential and non-essential amino acid contents in cultivar Cheongcheong were considerably increased upon NaCl and MgCl2 application, whereas total amino acids were increased upon NaCl, CaCl2, and MgCl2 application in the cultivar Nagdong. The total amino acid content was significantly lower in the salt-sensitive cultivar IR28 and salt-tolerant Pokkali under different salt stress conditions. Glycine was not detected in any of the rice genotypes. We observed that cultivars with the same origin respond similarly to each other under salinity stress conditions: cultivars Cheongcheong and Nagdong were found to show increased total amino acid content, whereas the content in foreign cultivars IR28 and Pokkali was found to decrease. Thus, our findings showed that the amino acid profile of each rice cultivar might depend on the origin, immune level, and genetic makeup of the respective cultivar.