ETHNOPHARMACOLOGICAL RELEVANCE:Areca nut has long been prescribed in Traditional Chinese Medicine for respiratory disorders resembling pulmonary fibrosis (PF). Its classical effects of resolving phlegm and dissipating chest stagnation, documented in Shennong Bencao Jing, align closely with PF's hallmark pathologies of interstitial scarring and excessive collagen accumulation, yet the mechanistic basis for its anti-fibrotic activity remains unelucidated. AIM OF THE STUDY:This study validated the anti-PF efficacy of areca nut procyanidins (ANP) and elucidated their multi-target mechanisms. MATERIALS AND METHODS:A multi-faceted approach integrating network pharmacology, molecular docking, and in vivo/vitro experiments was employed. Rat PF models induced by bleomycin were treated with ANP (1, 5, 15 mg/kg) for 28 days. LPS-stimulated 3T6 fibroblasts were used to evaluate cellular mechanisms. RESULTS:Network pharmacology predicted 72 common targets, with enrichment in the TGF-β and MAPK pathways. Molecular docking confirmed strong binding affinity of ANP to TGF-β1 (-8.8 kcal/mol) and Smad3 (-6.8 kcal/mol). In vivo, medium- and high-dose ANP significantly ameliorated lung histopathology, reduced collagen deposition (HYP), and restored antioxidant biomarkers (T-AOC, MPO, GSH). Mechanistically, ANP concurrently suppressed the TGF-β/Smad/ERK signaling cascade, characterized by the downregulation of TGF-β1, p-Smad3/4, and p-ERK, alongside the restoration of the inhibitory Smad7. In vitro, ANP inhibited fibroblast migration, inflammation (IL-1β, TNF-α), and extracellular matrix production. CONCLUSION:By multi-target inhibition of the TGF-β/Smad/ERK cascade, ANP ameliorates PF, consistent with areca nut's traditional phlegm-resolving and nodule-dissipating properties. Compared with pirfenidone, ANP exhibits superior safety and multi-pathway activity, rendering it a promising botanical therapeutic agent for PF.

Trehalose is widely involved in growth, development, metabolic regulation, as well as stress resistance of many angiosperms. Whether it plays roles in stress tolerance of gymnospermae had not been evaluated. Larix gmelinii, which is a native afforestation conifer in north China, shows strong drought-tolerance in Pinaceae family. Here, the role of trehalose in abiotic stress tolerance of Larix gmelinii were analyzed. Results showed that trehalose pretreatment at 30 mM achieved the best protection on L. gmelinii seedlings, with an obviously increase in antioxidant enzymes activity and chlorophyll content, and a decrease in MDA content. Trehalose pretreatment lowered the transcript level of genes related to starch and sucrose metabolism, but elevated the content of sucrose, starch and trehalose in L. gmelinii seedlings. Altogether 8 LgTPS and 2 LgTPP genes were selected from the transcriptome. Most LgTPSs and LgTPPs were induced by drought, cold, or salt stress. Overexpression of both LgTPS1.1 and LgTPPI in A. thaliana enhanced tolerance of the transgenic lines to salt stress. Overall, our results showed that the trehalose metabolism pathway was also one of the key pathways to combat abiotic stress in L. gmelinii, and this work will shed light on further related study in other conifers.

IntroductionNitrogen (N) can significantly affect the photosynthetic rate (Pn) of plants. Under traditional nitrogen fertilization (TNF) or inappropriate nitrogen application, leaf N is often redistributed to support the seed protein accumulation rather than the photosynthesis in the later stages of crop growth. Controlled-release fertilizers (CRF) have been reported to effectively reduce the nitrogen loss by matching the release pattern with crop N demand, thus increasing the yield. However, the changes in N allocation to enhance the photosynthesis under CRF have rarely been addressed.MethodsA two-year field experiment was conducted in the Hetao Irrigation District, Inner Mongolia, China from 2019 to 2020 to evaluate the effects of different fertilization strategies on soil NO3-N concentration, leaf nitrogen content, photosynthetic characteristics, yield, and nitrogen use efficiency (NUE) in sunflowers. The treatments included the CRF application rates of 135, 225, and 315 kg/ha (CRF135, CRF225, and CRF315), and that of TNF at 225 kg/ha (TNF225).ResultsThe results demonstrated that applying CRF at an appropriate rate maintained a high level of photosynthetic nitrogen content in the leaves during the later growth stages. This rate ensured a suitable soil NO3-N concentration (SNC), resulting in a 76.10% higher proportion of photosynthetic nitrogen (Npsn) than TNF at the same rate, significantly enhancing the photosynthetic nitrogen efficiency (PNUE) and highlighting the crucial role of nitrogen management in improving the crop productivity and NUE. Additionally, at CRF225, the net photosynthesis (Pn), stomatal conductance (Gs), and intercellular CO2 concentration (Ci) at maturity increased by 32.80%, 96.16%, and 13.56%, respectively, compared to TNF, leading to an 11.84% improvement in yield and a 9.70% increase in NUE.DiscussionThe correlation analysis confirmed a strong positive relationship between leaf N redistribution and photosynthetic efficiency, demonstrating the potential of CRF to improve the photosynthetic efficiency, optimize the N management, and promote the environmental sustainability in sunflower cultivation.

Lilium pumilum is widely distributed in northeast Asia. It exhibits strong resistance and possesses high ornamental value. However, it currently lacks an efficient and stable transformation system. Therefore, we aimed to establish an effective genetic transformation system using the Agrobacterium-mediated method for L. pumilum, enabling gene transfer into the plant for gene function research and genetic engineering breeding. Our genetic transformation system achieved a transformation efficiency of 7.25 % under specific conditions: a kanamycin (Kana) concentration of 120 mg/L, 3 days of pre-cultivation, an A. tumefaciens concentration of 0.7 OD600, an acetosyringone (AS) concentration of 20 mg/L, and a 15-minute infection period. We investigated the function of the LpNAC6 from L. pumilum by observing phenotypic and physiological changes under stresses induced by salt, alkali, and drought. Furthermore, overexpression of LpNAC6 resulted in enhanced stress tolerance as evidenced by increased levels of SOD, POD, CAT enzymes, improved photosynthetic indices, and elevated chlorophyll contents; as well as reduced levels of MDA and reactive oxygen species (ROS). These findings demonstrate that we have successfully established a transgenic transformation method for L. pumilum while also providing essential information for cultivating stress-tolerant Lilium species and advancing our understanding of the functions of LpNAC6 in plants.

Camellia (Camellia japonica) is a semi-shaded plant that is highly vulnerable to heat stress. To investigate the mechanisms underlying heat stress in C. japonica, two C. japonica cultivars, “Xiaotaohong” and “Zhuapolian”, which exhibit significant differences in heat tolerance, were selected from four common cultivars. The selection methods included phenotypic observations and physiological index detection, including relative electric conductivity (REC), malondialdehyde (MDA) content, superoxide dismutase (SOD) enzyme activity, relative water content (RWC), and chlorophyll content. RNA-seq analysis yielded 980 million reads and identified 68,455 differentially expressed genes (DEGs) in the two C. japonica cultivars during heat stress compared to the control samples. Totals of 12,565 and 16,046 DEGs were differentially expressed at 16 h and 32 h, respectively, in “Xiaotaohong” during heat stress. In “Zhuapolian”, 40,280 and 37,539 DEGs were found at 16 h and 32 h, respectively. KEGG enrichment analysis revealed that both cultivars were enriched in the “plant hormone signal transduction” and “circadian rhythm” pathways at two stages, indicating the critical role these pathways play in the heat stress response. The differences in the tolerance between the two cultivars are likely linked to pathways such as “plant hormone signal transduction”, “photosynthesis”, and “circadian rhythm”. Some members of heat shock proteins (HSPs) are associated with the heat stress response. It is speculated that transcription factor families contributing to the tolerance differences include AP2/ERF, C3H, bHLH, bZIP, and MYB-related with a small number of heat shock factors (HSFs) also induced by the stress. In conclusion, these results reveal the changes in the physiological indices and molecular networks of two C. japonica cultivars under heat stress. This study lays the foundation for the breeding of superior heat-resistant C. japonica cultivars and for further molecular research.

Cultivating rice varieties with robust blast resistance is the most effective and economical way to manage the rice blast disease. However, rice blast disease comprises leaf and panicle blast, which are different in terms of resistance mechanisms. While many blast resistant rice cultivars were bred using genes conferring resistance to only leaf or panicle blast, mining durable and effective quantitative trait loci (QTLs) for both panicle and leaf blast resistance is of paramount importance. In this study, we conducted a pangenome-wide association study (panGWAS) on 9 blast resistance related phenotypes using 414 international diverse rice accessions from an international rice panel. This approach led to the identification of 74 QTLs associated with rice blast resistance. One notable locus, qPBR1, validated in a F4:5 population and fine-mapped in a Heterogeneous Inbred Family (HIF), exhibited broad-spectrum, major and durable blast resistance throughout the growth period. Furthermore, we performed transcriptomic analysis of 3 resistant and 3 sensitive accessions at different time points after infection, revealing 3,311 differentially expressed genes (DEGs) potentially involved in blast resistance. Integration of the above results identified 6 candidate genes within the qPBR1 locus, with no significant negative effect on yield. The results of this study provide valuable germplasm resources, QTLs, blast response genes and candidate functional genes for developing rice varieties with enduring and broad-spectrum blast resistance. The qPBR1, in particular, holds significant potential for breeding new rice varieties with comprehensive and durable resistance throughout their growth period.

Strong seedling vigor is imperative to achieve stable seedling establishment and enhance the competitiveness against weeds in rice direct seeding. Shoot length (SL) is one of the important traits associated with seedling vigor in rice, but few genes for SL have been cloned so far. In the previous study, we identified two tightly linked and stably expressed QTLs for SL, qSL-1f and qSL-1d by genome-wide association study, and cloned the causal gene (LOC_Os01g68500) underlying qSL-1f. In the present study, we identify LOC_Os01g66100 (i.e. the semidwarf gene SD1), a well-known gene controlling plant height (PH) at the adult-plant stage, as the causal gene underlying qSL-1d through gene-based haplotype analysis and knockout transgenic verification. By measuring the phenotypes (SL and PH) of various haplotypes of the two genes and their knockout lines, we found SD1 and LOC_ Os01g68500 controlled both SL and PH, and worked in the same direction, which provided the directly genetic evidence for a positive correlation between SL and PH combined with the analysis of SL and PH in the diverse natural population. Moreover, the knockout transgenic experiments suggested that SD1 had a greater effect on PH compared with LOC_ Os01g68500, but no significant difference in the effect on SL. Further investigation of the pyramiding effects of SD1 and LOC_Os01g68500 based on their haplotype combinations suggested that SD1 may play a dominant role in controlling SL and PH when the two genes coexist. In this study, the effect of SD1 on SL at the seedling stage is validated. In total, two causal genes, SD1 and LOC_ Os01g68500, for SL are cloned in our studies, which controlled both SL and PH, and the suitable haplotypes of SD1 and LOC_ Os01g68500 are beneficial to achieve the desired SL and PH in different rice breeding objectives. These results provide a new clue to develop rice varieties for direct seeding and provide new genetic resources for molecular breeding of rice with suitable PH and strong seedling vigor.

BACKGROUND:Larix gmelinii is an excellent stress resistant coniferous tree species with a wide distribution and important economic and ecological value. However, at seedling stage, L. gmelinii is extremely susceptible to abiotic stresses, and systematic research on the adaptation mechanisms of L. gmelinii seedlings to abiotic stress is still lacking. RESULTS:Phenotypic observation and physiological index detection showed that L. gmelinii seedlings wilted with needles withered and yellowish at later stages of drought and salt stress; Under low temperature, the seedlings grew slowly and turned red at later stage. Under all 3 abiotic stresses, the chlorophyll content in seedlings significantly decreased, while the MDA content significantly increased; The activity of SOD and CAT showed a trend of increasing first and then decreasing. Transcriptome analysis revealed that DEGs were mainly involved in carbohydrate and amino acid metabolism, phenylpropanoid biosynthesis, and flavonoid synthesis metabolism. Metabolomic analysis found unique DAMs under 3 stress treatments. The combined analysis of transcriptome and metabolome showed that the changing patterns of DEGs and DAMs in primary and secondary metabolism were consistent: carbohydrate were significantly accumulated under low temperature stress; amino acids showed the most significant changes under salt stress. The variation pattern of secondary metabolism was similar under both drought and salt stress, while anthocyanin accumulation was the most obvious only under low temperature stress. CONCLUSION:Our study provides insightful information about the different mechanisms that L. gmelinii seedlings employ in response to drought, low temperature or salt stress.

Leaf senescence is essential for the growth and development of deciduous trees in the next season. Larix gmelinii, a deciduous coniferous tree, exhibits its most distinctive feature by turning yellow in the autumn and eventually shedding its leaves, resulting in significant changes in its appearance during the fall. Lysine acetylation plays an important role in diverse cellular processes; however, limited knowledge is available regarding acetylations in the needle senescence of L. gmelinii. In this study, the proteomics and acetylated modification omics of two phenotypic leaves, yellow and green (senescent and non-senescent) needles, were analyzed before autumn defoliation. In total, 5022 proteins and 4469 unique acetylation sites in 2414 lysine acylated proteins were identified, and this resulted in the discovery of 1335 differentially expressed proteins (DEPs) and 605 differentially expressed acetylated proteins (DAPs) in yellow versus green needles. There are significant differences between the proteome and acetylome; only 269 proteins were found to be DEP and DAP, of which 136 proteins were consistently expressed in both the DEP and DAP, 91 proteins were upregulated, and 45 proteins were down-regulated. The DEPs participate in the metabolism of starch and sucrose, while the DAPs are involved in glycolysis and the tricarboxylic acid cycle. Among them, DEPs underwent significant changes in glycolysis and citric acid cycling. Most of the enzymes involved in glycolysis and the citrate cycle were acetylated. DAPs were down-regulated in glycolysis and up-regulated in the citrate cycle. In all, the results of this study reveal the important role of lysine acetylation in the senescence of L. gmelinii needles and provide a new perspective for understanding the molecular mechanism of leaf senescence and tree seasonal growth.

Ratoon rice represents a viable means to enhance rice production efficiency in terms of both area and time. Nonetheless, the development of specific varieties tailored for ratoon rice has been hindered by the complexity of trait considerations required during breeding/screening processes. A pivotal step towards advancing ratoon rice breeding programs involves reducing the dimensionality of selection traits. In this study, we performed a comprehensive analysis exploring whether the yield of the main crop could serve as a predictor for ratoon crop yield, thereby simplifying the selection process. Our findings revealed significant variability in the rice yields of both main and ratoon crops, with the ratoon crop yield averaging 51% of the main crop. Importantly, the correlation between grain yields of the main and ratoon crops did not deviate from the identity line, substantiating the feasibility of predicting ratoon crop yield based on the main crop yield. The number of panicles in the ratoon crops was found to be closely linked to that of the main crop; however, the size values of the panicles in the ratoon crops exhibited less of a dependency on the main crop’s panicle size. Additionally, a general decrease in grain weight was observed in the ratoon crops compared to the main crop. In summary, this study elucidates a pathway for the simplification of selection traits, thereby enhancing the efficiency of breeding high-yielding ratoon rice varieties, with the ultimate aim of fostering the sustainable development of ratoon rice.

To elucidate the genetic factors contributing to melon resistance against Phelipanche aegyptiaca and comprehend the role of differentially resistant materials in responding to changes in P aegyptiaca parasitisation, we investigated the P. aegyptiaca-resistant line K16 and the susceptible line K27. The parasitism rate of P aegyptiaca was assessed at 25 days. Results revealed significant differences in parasitisation rates between K16 (15.35%) and K27 (34.2%). We compared inoculated K16 and K27 to their respective controls through transcriptome analysis and contrasted inoculated K16 with inoculated K27. Eight hundred eighteen genes exhibited differential expression across all comparisons. Gene Ontology (GO) functional enrichment analysis revealed that differentially expressed genes were significantly enriched in nitrate transport and assimilation, cellular components, extracellular regions, binding and enzyme activities. KEGG pathway enrichment underscored the importance of phytohormone signaling, phenylpropanoid biosynthesis, linolenic acid and linoleic acid metabolism, cyanoamino acid metabolism and nitrogen metabolism in the interaction between melon and P. aegyptiaca. . Nine genes potentially associated with P. aegyptiaca resistance were identified, encoding cytochrome protein P450, peroxidases, P-glucosidase, acyltransferase family proteins, histidine phosphotransfer protein, and D-type cyclins. This study aims to provide insights into the mechanism of P aegyptiaca parasitism on melons and offers implications for breeding resistant varieties.

Strong early growth vigor is an essential target in both direct seeded rice breeding and high-yielding rice breeding for rice varieties with relatively short growth duration in the double-cropping region. Shoot dry weight (SDW) is one of the important traits associated with early growth vigor, and breeders have been working to improve this trait. Finding stable QTLs or functional genes for SDW is crucial for improving the early growth vigor by implementing molecular breeding in rice. Here, a genome-wide association analysis revealed that the QTL for SDW, qSDW-5, was stably detected in the three cultivation methods commonly used in production practice. Through gene-based haplotype analysis of the annotated genes within the putative region of qSDW-5, and validated by gene expression and knockout transgenic experiments, LOC_Os05g09520, which is identical to the reported GW5/GSE5 controlling grain width (GW) and thousand grain weight (TGW) was identified as the causal gene for qSDW-5. Five main haplotypes of LOC_Os05g09520 were identified in the diverse international rice collection used in this study and their effects on SDW, GW and TGW were analyzed. Phenotypic comparisons of the major haplotypes of LOC_Os05g09520 in the three subpopulations (indica, japonica and aus) revealed the same patterns of wider GW and higher TGW along with higher SDW. Furtherly, the haplotype analysis of 138 rice varieties/lines widely used in southern China showed that 97.8% of the cultivars/lines carry Hap2LOC_Os05g09520. These results not only provide a promising gene source for the molecular breeding of rice varieties with strong early growth vigor, but also elucidate the effect of the LOC_Os05g09520 haplotypes on SDW, GW, and TGW in rice. Importantly, this study provides direct genetic evidence that these three traits are significantly correlated, and suggests a breeding strategy for developing high-yielding and slender grain-shaped indica cultivars with strong early growth vigor.

Understanding the evolutionary forces in speciation is a central goal in evolutionary biology. Asian cultivated rice has two subspecies, indica and japonica, but the underlying mechanism of the partial reproductive isolation between them remains obscure. Here we show a presence-absence variation (PAV) at the Se locus functions as an indica-japonica reproductive barrier by causing hybrid sterility (HS) in indica-japonica crosses. The locus comprises two adjacent genes: ORF3 encodes a sporophytic pollen killer, whereas ORF4 protects pollen in a gametophytic manner. In F1 of indica-japonica crosses, pollen with the japonica haplotype, which lacks the sequence containing the protective ORF4, is aborted due to the pollen-killing effect of ORF3 from indica. Evolutionary analysis suggests ORF3 is a gene associated with the Asian cultivated rice species complex, and the PAV has contributed to the reproductive isolation between the two subspecies of Asian cultivated rice. Our analyses provide perspectives on rice inter-subspecies post-zygotic isolation, and will promote efforts to overcome reproductive barriers in indica-japonica hybrid rice breeding.

Although germin-like proteins (GLPs) have been demonstrated to participate in plant biotic stress responses, their specific functions in rice disease resistance are still largely unknown. Here, we report the identification and characterization of OsGLP3-7, a member of the GLP family in rice. Expression of OsGLP3-7 was significantly induced by pathogen infection, jasmonic acid (JA) treatment, and hydrogen peroxide (H2O2) treatment. OsGLP3-7 was highly expressed in leaves and sublocalized in the cytoplasm. Overexpression of OsGLP3-7 increased plant resistance to leaf blast, panicle blast, and bacterial blight, whereas disease resistance in OsGLP3-7 RNAi silenced plants was remarkably compromised, suggesting this gene is a positive regulator of disease resistance in rice. Further analysis showed that OsGLP3-7 has superoxide dismutase (SOD) activity and can influence the accumulation of H2O2 in transgenic plants. Many genes involved in JA and phytoalexin biosynthesis were strongly induced, accompanied with elevated levels of JA and phytoalexins in OsGLP3-7-overexpressing plants, while expression of these genes was significantly suppressed and the levels of JA and phytoalexins were reduced in OsGLP3-7 RNAi plants compared with control plants, both before and after pathogen inoculation. Moreover, we showed that OsGLP3-7-dependent phytoalexin accumulation may, at least partially, be attributed to the elevated JA levels observed after pathogen infection. Taken together, our results indicate that OsGLP3-7 positively regulates rice disease resistance by activating JA and phytoalexin metabolic pathways, thus providing novel insights into the disease resistance mechanisms conferred by GLPs in rice.

Genome-wide association mapping revealed a novel QTL for shoot length across multiple environments. Its causal gene, LOC_Os01g68500, was identified firstly through gene-based haplotype analysis, gene expression and knockout transgenic verification. Strong seedling vigor is an important breeding target for rice varieties used in direct seeding. Shoot length (SL) is one of the important traits associated with seedling vigor characterized by rapid growth of seedling, which enhance seedling emergence. Therefore, mining genes for SL and conducting molecular breeding help to develop varieties for direct seeding. However, few QTLs for SL have been fine mapped or cloned so far. In this study, a genome-wide association study of SL was performed in a diverse rice collection consisting of 391 accessions in two years, using phenotypes generated by different cultivation methods according to the production practice, and a total of twenty-four QTLs for SL were identified. Among them, the novel QTL qSL-1f on chromosome 1 could be stably detected across all three cultivation methods in the whole population and indica subpopulation. Through gene-based haplotype analysis of the annotated genes within the putative region of qSL-1f, and validated by gene expression and knockout transgenic experiments, LOC_Os01g68500 (i.e., Os01g0913100 in RAP-DB) was identified as the causal gene for SL, which has a single-base variation (C-to-A transversion) in its CDS region, resulting in the significant difference in SL of rice. LOC_Os01g68500 encodes a DUF538 (Domain of unknown function) containing protein, and the function of DUF538 protein gene on rice seedling growth is firstly reported in this study. These results provide a new clue for exploring the molecular mechanism regulating SL, and promising gene source for the molecular breeding in rice.

High-salinity and blast disease are two major stresses that cause dramatic yield loss in rice production. GF14 (14-3-3) genes have been reported to play important role in biotic and abiotic stresses in plants. However, the roles of OsGF14C remain unknown. To understand the functions and regulatory mechanisms of OsGF14C in regulating salinity tolerance and blast resistance in rice, we have conducted OsGF14C-overexpressing transgenic experiments in the present study. Our results showed that overexpression of OsGF14C enhanced salinity tolerance but reduced blast resistance in rice. The enhanced salinity tolerance is related to the reduction of methylglyoxal and Na+ uptake instead of exclusion or compartmentation and the negative role of OsGF14C in blast resistance is associated with the suppression of OsGF14E, OsGF14F and PR genes. Our results together with the results from the previous studies suggest that the lipoxygenase gene LOX2 which is regulated by OsGF14C may play roles in coordinating salinity tolerance and blast resistance in rice. The current study for the first time revealed the possible roles of OsGF14C in regulating salinity tolerance and blast resistance in rice, and laid down a foundation for further functional study and crosstalk regulation between salinity and blast resistance in rice.

Caragana korshinskii is a deciduous shrub with large eco-economic value and strong tolerance to abiotic stresses. However, the shortage of reliable genetic transformation technology severely hinders its research on stress tolerance mechanisms and stress-resistant gene mining and application. In this study, the embryonic tip of the C. korshinskii seedling was used as the initiating explant to get regenerated plant through the direct organogenesis pathway, which significantly shortened the culture cycle and set the foundation for investigation of Agrobacterium-mediated genetic transformation. Our results suggest that the embryonic tip possesses robust meristem capacity and is an efficient method for transgenic breeding. This research provides a technical basis for asexual reproduction, molecular breeding, and gene function investigation in C. korshinskii by establishing, for the first time, an effective in vitro regeneration system and an Agrobacterium-mediated stable genetic transformation system utilizing the embryonic tip of C. korshinskii as explants.

Abstract Drought, which can induce osmotic stress, is the leading environmental constraint on crop productivity. Plants in both agricultural and natural settings have developed various mechanisms to cope with drought stress. The identification of genes associated with drought stress tolerance and understanding the underlying regulatory mechanisms are prerequisites for developing molecular manipulation strategies to address this issue. Here, we reported that the G-BOX FACTOR 14-3-3f (14-3-3 protein OsGF14f) positively modulates osmotic stress tolerance in rice (Oryza sativa). OsGF14f transgenic lines had no obvious change in crucial agronomic traits including yield and plant height. OsGF14f is transcriptionally induced by PEG treatment, and in rice, overexpression or knockout of this gene leads to enhanced or weakened osmotic stress tolerance, respectively. Furthermore, OsGF14f positively regulates abscisic acid (ABA) responses by interacting with the core ABA-responsive transcription factor BASIC LEUCINE ZIPPER 23 (OsbZIP23) to enhance its transcriptional regulation activity toward downstream target genes. Further genetic analysis showed that OsGF14f is required for the full function of OsbZIP23 in rice osmotic response, and OsGF14f-mediated osmotic stress tolerance partially depends on OsbZIP23. Interestingly, OsGF14f is a direct target gene of OsbZIP23. Taken together, our findings reveal a genetic and molecular framework by which the OsGF14f–OsbZIP23 complex modulates rice osmotic response, providing targets for developing drought-tolerant crops.

Low temperature germination (LTG) is a key agronomic trait in rice (Oryza sativa L.). However, the genetic basis of natural variation for LTG is largely unknown. Here, a genome-wide association study (GWAS) was performed using 276 accessions from the 3,000 Rice Genomes (3K-RG) project with 497 k single nucleotide polymorphisms (SNPs) to uncover potential genes for LTG in rice. In total, 37 quantitative trait loci (QTLs) from the 6th day (D6) to the 10th day (D10) were detected in the full population, overlapping with 12 previously reported QTLs for LTG. One novel QTL, namely qLTG1-2, was found stably on D7 in both 2019 and 2020. Based on two germination-specific transcriptome datasets, 13 seed-expressed genes were isolated within a 200 kb interval of qLTG1-2. Combining with haplotype analysis, a functional uncharacterized gene, LOC_Os01g23580, and a seed germination-associated gene, LOC_Os01g23620 (OsSar1a), as promising candidate genes, both of which were significantly differentially expressed between high and low LTG accessions. Collectively, the candidate genes with favorable alleles may be useful for the future characterization of the LTG mechanism and the improvement of the LTG trait in rice breeding.

The head milled rice rate (HMRR) is the most important trait of milling quality, which affects the final yield and quality of rice. However, few genes related to HMRR have been identified and the regulatory mechanism of HMRR remains elusive. In this study, we performed a comparative analysis integrating the transcriptome sequencing of developing seeds at the grain-filling stage and a metabolome analysis of brown rice between two groups of accessions with contrasting performances in HMRR. A total of 768 differentially expressed genes (DEGs) were identified between the transcriptome profiles of low-HMRR and high-HMRR accessions. In comparison to the high-HMRR accessions, 655 DEGs were up-regulated in the low-HMRR accessions, which was 4.79 folds higher than the number of down-regulated genes. These up-regulated DEGs were enriched in various metabolic and biosynthetic processes, oxidation reduction, phosphorylation, ion transport and ATP-related processes. However, the 113 down-regulated DEGs in the low-HMRR accessions were concentrated in carbohydrate metabolic processes, cell-death-related processes and defense response. Among the 30 differential metabolites, 20 and 10 metabolites were down-/up-regulated, respectively, in the accessions with low HMRR. In addition, 10 differential metabolites, including five metabolites of the shikimate pathway and five metabolites of the pyruvate pathway, were integrated into two separate pathways, starting from sucrose. Our global analysis of HMRR provides an invaluable resource for a better understanding of the molecular mechanism underlying the genetic regulation of HMRR.