Search Results (34)

Efficient allocation of mineral nutrients and photoassimilates is essential for grain development in rice. However, the transcriptional programs governing nutrient transport at key reproductive stages remain largely unresolved. Here, we performed a comprehensive transcriptome analysis of rice (Oryza sativa L.) across spatial (nodes, roots, and five other tissues) and temporal (seven reproductive stages) dimensions to elucidate the molecular basis of nutrient transport and allocation. RNA-seq profiling of node I identified stage-specific gene expression patterns, with the grain filling stage marked by strong induction of transporters involved in mineral allocation (e.g., OsYSL2, OsZIP3, OsSULTR3;3, SPDT) and carbohydrate distribution (e.g., OsSWEET13, OsSWEET14, OsMST6). Comparative analysis with the neck-panicle node (NPN) and root revealed tissue-specific regulatory networks, including nitrate (OsNRT1.1A, OsNRT2.3) and phosphate (OsPHT1;4, OsPHO1;3) transporters enriched at the grain filling stage. Root expression of Cd/As-related transporters (OsNRAMP5, OsCd1, OsLsi1, OsLsi2, OsLsi3) during grain filling highlights the contribution of belowground uptake to grain metal accumulation. Together, our study establishes a spatiotemporal atlas of nutrient transporter gene activity during rice reproductive development and identifies candidate genes regulating upward and lateral nutrient allocation. These findings provide insights into improving nutrient use efficiency and reducing toxic metal accumulation in rice grains through targeted manipulation of nodal and root transport systems. Full article

Seed storage proteins (SSPs) play a pivotal role in determining the development, quality, and nutritional value of rice seeds. In this study, we conducted a transcriptome-based correlation analysis to identify novel transcription factors (TFs) potentially involved in the biosynthesis and accumulation of SSPs. Our analysis revealed nine TFs—OsGATA8, OsMIF1, OsMIF2, OsGZF1, OsbZIP58, OsS1Fa1, OsS1Fa2, OsICE2, and OsMYB24—that exhibit strong co-expression with key SSP genes, including those encoding glutelin and prolamin. Gene expression profiling using quantitative RT-PCR and GUS reporter assays revealed that these TFs are predominantly expressed during seed development, with peak expression observed at 10 days after flowering (DAF). Promoter analysis further demonstrated an enrichment of seed-specific and hormone-responsive cis-regulatory elements, reinforcing the seed-preferential expression patterns of these TFs. Collectively, our findings identify a set of candidate TFs likely involved in SSP regulation and seed maturation, providing a foundation for the genetic enhancement of rice seed quality and nutritional content through targeted breeding and biotechnological approaches. Full article

Background/Objectives: Low-temperature stress during the grain-filling stage negatively affects rice grain quality and yield. Understanding the physiological and molecular mechanisms underlying cold tolerance is critical for breeding rice varieties with improved resilience. Methods: In this study, eight rice varieties with differential cold tolerance—LD1603, 13108, LD18, and 4-1021 (cold-tolerant) and LD3, LD4, LD121, and LD1604 (cold-sensitive)—were subjected to 17.5 °C low-temperature stress during grain filling in a naturally illuminated phytotron. Amylose and protein content, as well as taste quality, were analyzed. RNA sequencing was performed to identify differentially expressed genes and transcription factors associated with cold response. Results: Under low-temperature stress, amylose and protein content significantly increased in all eight varieties. The taste quality of cold-sensitive varieties declined markedly, whereas cold-tolerant varieties maintained higher and more stable taste quality values. Transcriptomic analysis revealed that key enzyme genes (INV, SUS, HXK, FRK, amyA, and TPP) in the starch and sucrose metabolism pathway were significantly upregulated in cold-tolerant varieties (LD18 and 4-1021), but suppressed in cold-sensitive varieties. Several cold-responsive transcription factors from the NAC, WRKY, AP2/ERF, MYB, and bZIP families were also identified. Weighted gene co-expression network analysis (WGCNA) further revealed hub TFs (OsWRKY1, OsWRKY24, OsWRKY53, and OsMYB4) and structural genes (OsPAL04 and OsCDPK7) potentially involved in cold tolerance during grain filling. Conclusions: This study enhanced our understanding of the molecular response to low temperature during rice grain filling and provided candidate genes for developing cold-tolerant rice varieties through molecular breeding. Full article

Cadmium (Cd) pollution in paddy soils causes a great threat to safe rice production in China. In this review, we summarized the key advances in the research of Cd pollution sources and statuses in Chinese soil and rice, explore the mechanisms of Cd transformation in the rice–soil system, discuss the agronomic strategies for minimizing Cd accumulation in rice grains, and highlight advancements in developing rice cultivars with low Cd accumulation. Anthropogenic activity is a main source of Cd in farmland. Cd in soil solutions primarily enters rice roots through a symplastic pathway facilitated by transporters like OsNRAMP5, OsIRT1, and OsCd1, among which OsNRAMP5 is identified as the primary contributor. Subsequently, Cd translocation is from roots to grains through the xylem and phloem, regulated by transporters such as OsHMA2, OsLCT1, and OsZIP7. Meanwhile, Cd sequestration in vacuoles controlled by OsHMA3 plays a crucial role in regulating Cd mobility during its translocation. Cd accumulation in rice was limited by the available Cd concentration in soil solutions, Cd uptake, and translocation in rice plants. Conventional agronomic methods aimed at reducing grain Cd in rice by suppressing Cd bio-availability without decreasing soil Cd content have been proven limited in the remediation of Cd-polluted soil. In recent years, based on the mechanisms of Cd absorption and translocation in rice, researchers have screened and developed low-Cd-accumulation rice varieties using molecular breeding techniques. Among them, some new cultivars derived from the null mutants of OsNRAMP5 have demonstrated a more than 93% decrease in grain Cd accumulation and can be used for applications in the next years. Therefore, the issue of Cd contamination in the rice of China may be fully resolved within a few years. Full article

The current study assessed the synergistic effects of PGPR and Si in alleviating drought stress in rice. Bacteria were isolated from Phragmites australis inhabiting an urban riverbank. Among the isolated strains, Pseudomonas qingdaonensis NZ 1 showed promising results under in vitro drought stress induced by PEG-6000 (−0.28 MPa). To further investigate the synergistic effect of Pseudomonas qingdaonensis NZ 1 and silicon, a plant growth experiment was conducted comprising the control (dH₂O) and plants treated with NZ 1, Si (1 mM), and NZ 1+Si under normal and drought stress conditions. The results revealed that NZ 1+Si-treated plants showed improved plant growth parameters, chlorophyll contents, relative water contents, antioxidant potential, and nutrient uptake under normal and drought conditions. Moreover, endogenous abscisic acid and jasmonic acid levels were substantially reduced, while the salicylic acid level was increased in NZ 1+Si-treated plants. Moreover, the relative expression of the ABA metabolic genes OsNCED3 and OsCYP707A6 and transcription factors OsbZIP23 and OsDREB1B were significantly altered. Furthermore, the leaf Si, calcium, potassium, and phosphorus contents were increased in NZ 1+Si-treated drought-stressed plants, along with the upregulation of OsLSi1. The combined application of NZ 1 and Si offers a sustainable agricultural strategy to effectively mitigate the detrimental effects of drought. Full article

The molecular mechanism of arbuscular mycorrhizal fungi (AMF) in reducing cadmium (Cd) accumulation in plants remains unclear. In this respect, the effects of Rhizophagus intraradices (Ri) inoculation under Cd stress on rice growth, the uptake of Cd along with other elements, and the expression of Cd transport genes, including OsNRAMP1/5, were studied using wild-type (WT) and osnramp5 mutant rice. The results showed that Ri inoculation did not affect rice growth. The uptake of Cd of the osnramp5 mutant was much lower than the WT, as 27.6%, 17.5%, and 39.9% of Cd were noted in the grains, shoots, and roots, respectively. For the WT, Cd alone significantly promoted the OsNRAMP5 expression in shoots, but Ri inoculation significantly suppressed OsNRAMP5 expression and significantly reduced its grain and shoot Cd by 44.4% and 62.3%, respectively, compared to the Cd alone treatment. In contrast, for the osnramp5 mutant, Ri inoculation did not influence OsNRAMP5 expression or the grain and shoot Cd. Furthermore, the expression of other Cd transporters (OsIRT1, OsZIP3/7, OsCAX1a) in both varieties were not changed under the treatments. In conclusion, Ri inoculating significantly reduced Cd uptake by rice, with the molecular mechanism by negative regulation of expression of the OsNRAMP5 gene. Full article

Introduction: Regional differences in socioeconomic status (SES) are well known, and we believe that the use of geocoding (zip code) can facilitate the introduction of targeted interventions for underserved populations. This is a single-center, retrospective analysis of data extracted from the cancer registry at the Capital Health Cancer Center in Pennington, N. The Capital Health Cancer Center in central New Jersey primarily serves two counties, catering to a diverse patient population from a wide range of socioeconomic backgrounds. Methods: We abstracted 1269 consecutive cases of colorectal cancer (CRC) diagnosed and treated between 2000 and 2019 from the Cancer Registry of the Capital Health Cancer Center (CHCC). Using the definition of SES based on previously published work, and zip codes (geocoding), we created four SES levels. We stratified our subjects according to their stage at diagnosis, age at diagnosis, race, and ethnicity. The primary outcome variable was overall survival (OS). Results: There was a statistically significant difference in OS based on SES, with the highest overall survival (OS) in the high-SES group (47 months) and the shortest OS in the low and mid-low-SES groups (40.4 and 30 months, respectively). Subjects living in high-SES areas were predominantly white (88.2%) and diagnosed at a later age (mean of 68.9 years of age) compared to individuals who lived in a low-SES area, who were predominantly non-white (72.6%) and diagnosed somewhat earlier in life (65.1 years of age). White people were diagnosed later in life (70.9 years of age) compared to non-white populations, including Black (66.5), Asian (61.7), and Hispanic (58.5) (p = 0.001) populations, but this did not lead to a significant difference in OS (p = 0.56). Stage at diagnosis was a significant predictor of OS, but was unrelated to SES (p = 0.066). A Cox proportional hazard ratio (HR) model showed that the risk of dying from colorectal cancer decreases with a higher socioeconomic status (SES). Those from mid-high-SES backgrounds had a 19% lower risk (HR 0.81), and those from high-SES areas had a 45% lower risk (HR 0.55) compared to individuals from low-SES areas. Conclusions: The vulnerability of patients with CRC in central New Jersey is a complex issue, influenced by many different variables. Our results indicate that SES is the most critical factor affecting OS after being diagnosed with CRC. Full article

The rising interest in foliar nutrient spraying as a strategy to boost crop yields has led to investigations of how such application influences nutrient uptake and accumulation, especially in edible plant parts. Despite its importance, the effects of single versus simultaneous nutrient application on plant absorption, transport, and accumulation have been underexplored. This study addresses this knowledge gap by examining the physiological and molecular responses of rice to foliar application of nitrogen (N) and zinc (Zn) individually and in combination at different growth stages. We assessed how the treatments affect rice grain yield and nutrient accumulation in relation to the expression of Zn transport-related genes. Foliar application of N+Zn+ at the tillering stage resulted in a 62.01% increase in grain yield compared to the control. Additionally, Zn concentrations in brown rice were increased by 26.04% and 34.20% when N0Zn+ and N+Zn+ treatments, respectively, were applied at panicle initiation. Gene expression analysis revealed that the timing and nutrient combination significantly influenced rice productivity and grain Zn concentration. At the tillering stage, the N+Zn+ treatment elevated the expression of Zn transporters such as OsZIP3, OsZIP4, and OsZIP9 in leaves, thereby enhancing grain yield. At panicle initiation, the nutrient treatments influenced a broad range of genes, including OsZIP4, OsZIP9, OsHAM2, OsDUR3, OsAAP1, OsGS1;1, and OsFd-GOGAT, affecting grain Zn and N accumulation. These insights are crucial for developing targeted nutrient management strategies to optimize rice yield and grain nutritional quality for the benefit of consumers. Full article

Respiratory burst oxidase homologs (Rbohs) are the primary producers of reactive oxygen species (ROS), which have been demonstrated to play critical roles in plant responses to abiotic stress. Here, we explored the function of OsRbohH in heat and drought stress tolerance by generating overexpression lines (OsRbohH-OE). OsRbohH was highly induced by various abiotic stress and hormone treatments. Compared to wild-type (WT) controls, OsRbohH-OE plants exhibited enhanced tolerance to heat and drought, as determined by survival rate analyses and total chlorophyll content. Histochemical staining revealed that OsRbohH-OE accumulated less ROS. This is consistent with the observed increase in catalase (CAT) and peroxidase (POD) activities, as well as a reduced electrolyte leakage rate and malondialdehyde (MDA) content. Moreover, OsRbohH-OE exhibited enhanced sensitivity to exogenous abscisic acid (ABA), accompanied by altered expression levels of ABA synthesis and catabolic genes. Further analysis indicated that transgenic lines had lower transcripts of ABA signaling-related genes (OsDREB2A, OsLEA3, OsbZIP66, and OsbZIP72) under heat but higher levels under drought than WT. In conclusion, these results suggest that OsRbohH is a positive regulator of heat and drought tolerance in rice, which is probably performed through OsRbohH-mediated ROS homeostasis and ABA signaling. Full article

Grain size is one of the critical factors determining rice yield. Previous studies have found the grain-size-regulating function of Gα in rice. However, the regulatory mechanism underlying the development of rice grain mediated by Gα is still unclear. To reveal the functional mechanism of Gα in grain size regulation, a mutant of Gα (Gα-Cas9) was firstly constructed through a CRISPR/Cas9 strategy and was then grown in a greenhouse and field. The results showed that the seed length, plant height, 1000-grain weight, and spike length were significantly decreased in Gα-Cas9 compared to wild-type (WT) Pi-4b. During the grain filling stage, the increase in the grain dry weight of Pi-4b occurred earlier than that of Gα-Cas9. The total starch content and amylose content of matured grains of Pi-4b were higher than those of Gα-Cas9. Secondly, transcriptome sequencing analysis of Gα-Cas9 and Pi-4b during grain filling was performed to elucidate the functional pathways regulated by Gα. In total, 2867 and 4534 differentially expressed genes (DEGs) were discovered at 5 DAF and 10 DAF, and the starch and sucrose metabolism pathway enriched by DEGs was involved in grain size regulation mediated by Gα. Gα regulated the expression of starch-synthesis-related genes during grain filling, and the Gα protein interacted with OsNYC4 to trigger the sugar signaling pathway to promote starch accumulation in grain. Additionally, the GW2-WG1-OsbZIP47 pathway was switched off by Gα to relieve the inhibition of rice grain development. In this study, the results should provide new insights into the G protein signal transduction pathway. Full article

Zinc (Zn)- and iron (Fe)-regulating transport-like proteins (ZIPs) are a class of proteins crucial for metal uptake and transport in plants, particularly for Zn and Fe absorption and distribution. These proteins ensure the balance of trace elements essential for plant growth, development, and metabolic activities. However, the role of the rice (Oryza sativa) OsZIP gene family in manganese (Mn) and selenium (Se) transport remains underexplored. This research conducted an all-sided analysis of the rice OsZIPs and identified 16 OsZIP sequences. Phylogenetic analysis categorized the OsZIPs predominantly within the three subfamilies. The expression levels of OsZIPs in rice root and leaf subjected to Mn and Se toxicity stress were examined through quantitative real-time PCR (qRT–PCR). The findings revealed significant differential expression of many OsZIPs under these conditions, indicating a potential regulating effect in the response of rice to Mn and Se toxicity. This work lays a foundation for further functional studies of OsZIPs, enhancing our understanding of the response mechanisms of rice to Mn and Se toxicity and their roles in growth, development, and environmental adaptation. Full article

Salt stress is a significant challenge that severely hampers rice growth, resulting in decreased yield and productivity. Over the years, researchers have identified biomarkers associated with salt stress to enhance rice tolerance. However, the understanding of the mechanism underlying salt tolerance in rice remains incomplete due to the involvement of multiple genes. Given the vast amount of genomics and transcriptomics data available today, it is crucial to integrate diverse datasets to identify key genes that play essential roles during salt stress in rice. In this study, we propose an integration of multiple datasets to identify potential key transcription factors. This involves utilizing network analysis based on weighted co-expression networks, focusing on gene-centric measurement and differential co-expression relationships among genes. Consequently, our analysis reveals 86 genes located in markers from previous meta-QTL analysis. Moreover, six transcription factors, namely LOC_Os03g45410 (OsTBP2), LOC_Os07g42400 (OsGATA23), LOC_Os01g13030 (OsIAA3), LOC_Os05g34050 (OsbZIP39), LOC_Os09g29930 (OsBIM1), and LOC_Os10g10990 (transcription initiation factor IIF), exhibited significantly altered co-expression relationships between salt-sensitive and salt-tolerant rice networks. These identified genes hold potential as crucial references for further investigation into the functions of salt stress response in rice plants and could be utilized in the development of salt-resistant rice cultivars. Overall, our findings shed light on the complex genetic regulation underlying salt tolerance in rice and contribute to the broader understanding of rice’s response to salt stress. Full article

Plant cells accumulate osmotic substances (e.g., sugar) to protect cell components and maintain osmotic balance under drought stress conditions. Previous studies found that pOsHAK1:OsFLN2 promotes sugar metabolism and improves the drought tolerance of rice plants under drought stress. This study further evaluated the effect of the ectopic expression of the OsSUT1 gene driven by the OsHAK1 promoter on the sugar transport and drought tolerance of rice. The results showed that the net photosynthetic rate and sucrose phosphate synthase activity of plants expressing the OsSUT1 gene were not significantly different from those of wild-type (WT) rice plants under drought conditions. However, the sucrose transport rate in the phloem increased in the transgenic plants, and the sucrose contents were significantly lower in the leaves but significantly higher in the roots of transgenic plants than those in WT plants. The pOsHAK1:OsSUT1 and pOsHAK1:OsFLN2 transgenic lines had similar rates of long-distance sucrose transport and drought tolerance, which were higher than those of the WT plants. The relative water content of the transgenic plants was higher, while their water loss rate, hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) contents were lower than those of the WT plants. The stress-responsive gene OsbZIP23 and the antioxidant-related gene OsCATB were significantly upregulated in the drought-treated transgenic lines, while the senescence indicator gene SGR and the stress-responsive gene OsNAC2 were down-regulated compared to WT plants. These results showed that promoting the long-distance sugar transport through the expression of pOsHAK1:OsSUT1 could produce an improved drought tolerance effect similar to that of pOsHAK1:OsFLN2, providing an effective way to improve the drought tolerance of cereal crops at the seedling stage. Full article

In plants exposed to ultraviolet B radiation (UV-B; 280–315 nm), metabolic responses are activated, which reduce the damage caused by UV-B. Although several metabolites responding to UV-B stress have been identified in plants, the accumulation of these metabolites at different time points under UV-B stress remains largely unclear, and the transcription factors regulating these metabolites have not been well characterized. Here, we explored the changes in metabolites in rice after UV-B treatment for 0 h, 6 h, 12 h, and 24 h and identified six patterns of metabolic change. We show that the rice transcription factor OsbZIP18 plays an important role in regulating phenylpropanoid and flavonoid biosynthesis under UV-B stress in rice. Metabolic profiling revealed that the contents of phenylpropanoid and flavonoid were significantly reduced in osbzip18 mutants compared with the wild-type plants (WT) under UV-B stress. Further analysis showed that the expression of many genes involved in the phenylpropanoid and flavonoid biosynthesis pathways was lower in osbzip18 mutants than in WT plants, including OsPAL5, OsC4H, Os4CL, OsCHS, OsCHIL2, and OsF3H. Electrophoretic mobility shift assays (EMSA) revealed that OsbZIP18 bind to the promoters of these genes, suggesting that OsbZIP18 function is an important positive regulator of phenylpropanoid and flavonoid biosynthesis under UV-B stress. In conclusion, our findings revealed that OsbZIP18 is an essential regulator for phenylpropanoid and flavonoid biosynthesis and plays a crucial role in regulating UV-B stress responses in rice. Full article

The most important volatile in determining the aroma of fragrant rice is 2-Acetyl-1-pyrroline (2-AP); however, the transcriptional regulation mechanism of 2-AP biosynthesis in fragrant rice is still unclear. In this study, Osp5cs1 knockout mutant lines and OsP5CS1 over-expression lines were constructed by the genetic transformation of the Indica rice cultivar, i.e., ‘Zhonghua11′, which knocks out OsBADH2 to produce fragrance in aromatic rice. The OsP5CS1 gene was also identified as a key gene in the 2-AP biosynthesis pathway of aromatic rice. The OsP5CS1 promoter was used as bait, and the OsbZIP60-like transcription factor was screened by yeast one-hybrid assays. The OsbZIP60-like transcription factor specifically bound to the OsP5CS1 gene. The dual luciferase reporting system found that the OsbZIP60-like transcription factor promoted the transcriptional activation of OsP5CS1. Compared with the wild type, OsP5CS1 gene expression was significantly down-regulated in the Osbzip60-like mutant and resulted in a substantial reduction in 2-AP biosynthesis. Moreover, the OsP5CS1 gene expression was significantly up-regulated in OsbZIP60-like over-expressed plants, and the 2-AP concentrations were also increased, whereas the Osbzip60-like mutants were found to be sensitive to Zn deficiency. Overall, the OsbZIP60-like transcription factor promoted the 2-AP accumulation. This study provides a theoretical basis for the transcriptional regulation mechanism of 2-AP biosynthesis and explores the function of the OsbZIP transcription factor in fragrant rice. Full article