The RNA binding protein EHD6 recruits the m6A reader YTH07 and sequesters OsCOL4 mRNA into phase-separated ribonucleoprotein condensates to promote rice flowering.

N6-Methyladenosine (m6A) is one of the most abundant modifications of eukaryotic mRNA, but its comprehensive biological functionality remains further exploration. In this study, we identified and characterized a new flowering-promoting gene, EARLY HEADING DATE6 (EHD6), in rice. EHD6 encodes an RNA recognition motif (RRM)-containing RNA binding protein that is localized in the non-membranous cytoplasm ribonucleoprotein (RNP) granules and can bind both m6A-modified RNA and unmodified RNA indiscriminately. We found that EHD6 can physically interact with YTH07, a YTH (YT521-B homology) domain-containing m6A reader. We showed that their interaction enhances the binding of an m6A-modified RNA and triggers relocation of a portion of YTH07 from the cytoplasm into RNP granules through phase-separated condensation. Within these condensates, the mRNA of a rice flowering repressor, CONSTANS-like 4 (OsCOL4), becomes sequestered, leading to a reduction in its protein abundance and thus accelerated flowering through the Early heading date 1 pathway. Taken together, these results not only shed new light on the molecular mechanism of efficient m6A recognition by the collaboration between an RNA binding protein and YTH family m6A reader, but also uncover the potential for m6A-mediated translation regulation through phase-separated ribonucleoprotein condensation in rice.

RGA1 regulates grain size, rice quality and seed germination in the small and round grain mutant srg5.

BACKGROUND: Generating elite rice varieties with high yield and superior quality is the main goal of rice breeding programs. Key agronomic traits, including grain size and seed germination characteristics, affect the final yield and quality of rice. The RGA1 gene, which encodes the α-subunit of rice G-protein, plays an important role in regulating rice architecture, seed size and abiotic stress responses. However, whether RGA1 is involved in the regulation of rice quality and seed germination traits is still unclear. RESULTS: In this study, a rice mutant small and round grain 5 (srg5), was identified in an EMS-induced rice mutant library. Systematic analysis of its major agronomic traits revealed that the srg5 mutant exhibited a semi-dwarf plant height with small and round grain and reduced panicle length. Analysis of the physicochemical properties of rice showed that the difference in rice eating and cooking quality (ECQ) between the srg5 mutant and its wild-type control was small, but the appearance quality was significantly improved. Interestingly, a significant suppression of rice seed germination and shoot growth was observed in the srg5 mutant, which was mainly related to the regulation of ABA metabolism. RGA1 was identified as the candidate gene for the srg5 mutant by BSA analysis. A SNP at the splice site of the first intron disrupted the normal splicing of the RGA1 transcript precursor, resulting in a premature stop codon. Additional linkage analysis confirmed that the target gene causing the srg5 mutant phenotype was RGA1. Finally, the introduction of the RGA1 mutant allele into two indica rice varieties also resulted in small and round rice grains with less chalkiness. CONCLUSIONS: These results indicate that RGA1 is not only involved in the control of rice architecture and grain size, but also in the regulation of rice quality and seed germination. This study sheds new light on the biological functions of RGA1, thereby providing valuable information for future systematic analysis of the G-protein pathway and its potential application in rice breeding programs.

Heat-Resistant Inbred Lines Coordinate the Heat Response Gene Expression Remarkably in Maize (Zea mays L.).

High temperatures are increasingly becoming a prominent environmental factor accelerating the adverse influence on the growth and development of maize (Zea mays L.). Therefore, it is critical to identify the key genes and pathways related to heat stress (HS) tolerance in maize. Great challenges have been faced in dissecting genetic mechanisms and uncovering master genes for HS tolerance. Here, Z58D showed more thermotolerance than AF171 at the seedling stage with a lower wilted leaf rate and H2O2 accumulation under HS conditions. Transcriptomic analysis identified 3006 differentially expressed genes (DEGs) in AF171 and 4273 DEGs in Z58D under HS treatments, respectively. Subsequently, GO enrichment analysis showed that commonly upregulated genes in AF171 and Z58D were significantly enriched in the following biological processes, including protein folding, response to heat, response to temperature stimulus and response to hydrogen peroxide. Moreover, the comparison between the two inbred lines under HS showed that response to heat and response to temperature stimulus were significantly over-represented for the 1234 upregulated genes in Z58D. Furthermore, more commonly upregulated genes exhibited higher expression levels in Z58D than AF171. In addition, maize inbred CIMBL55 was verified to be more tolerant than B73, and more commonly upregulated genes also showed higher expression levels in CIMBL55 than B73 under HS. These consistent results indicate that heat-resistant inbred lines may coordinate the remarkable expression of genes in order to recover from HS. Additionally, 35 DEGs were conserved among five inbred lines via comparative transcriptomic analysis. Most of them were more pronounced in Z58D than AF171 at the expression levels. These candidate genes may confer thermotolerance in maize.

STING signaling in islet macrophages impairs insulin secretion in obesity.

The innate immune regulator stimulator of interferon genes (STING) mediates self-DNA sensing and leads to the induction of type I interferons and inflammatory cytokines, which promotes the progression of various inflammatory and autoimmune diseases. Innate immune system plays a critical role in regulating obesity-induced islet dysfunction, whereas the potential effect of STING signaling is not fully understood. Here, we demonstrate that STING is mainly expressed and activated in islet macrophages upon high-fat diet (HFD) feeding. Sting-/- alleviates HFD-induced islet inflammation by inhibiting the expression of pro-inflammatory cytokines and the infiltration of macrophages. Mechanically, palmitic acid incubation promotes mitochondrial DNA leakage into the cytosol and subsequently activates STING pathway in macrophages. Additionally, STING activation in macrophages impairs glucose-stimulated insulin secretion by mediating the engulfment of ß cell insulin secretory granules. Pharmacologically inhibiting STING activation enhances insulin secretion to control hyperglycemia. Together, our results reveal a regulatory mechanism in controlling the islet inflammation and insulin secretion in diet--induced obesity and suggest that selective blocking of the STING activation may be a promising strategy for treating type 2 diabetes.

Investigating the influence of primary uterine tumor site on pelvic and para-aortic lymph node metastatic pattern and evaluating the risk factors for lymph node metastases in endometrial carcinoma: A retrospective study.

To assess the metastatic pattern in pelvic and para-aortic lymph nodes in relation with the primary uterine tumor site and to evaluate risk factors for lymph node metastases. 212 patients with endometrial cancer who underwent surgical treatment from December 2014 to December 2019 were selected. The clinical and pathological data were retrospectively analyzed. The factors and uterine primary tumor site related to lymph node metastasis were analyzed by univariate and multivariate analysis. Among the 212 patients with endometrial cancer, 17 cases had lymph node metastasis, and thus the metastasis rate was 8.02%. Univariate analysis revealed that lymph node metastasis was significantly correlated with Federation of Gynecology and Obstetrics stage, depth of myometrial invasion, tumor size, pathological grade, and lymphovascular space invasion (P < .05) and was not correlated with age, pathological type, and cervical involvement (P > .05). Primary uterine tumor site (fundus, horns, body or lower uterine segment) with or without cervical involvement was associated with different lymph nodes' metastatic sites. The lymph node metastatic pathways of endometrial cancer mainly include obturator lymph nodes and para-aortic lymph nodes, and skip metastasis may occur; endometrial carcinoma may jump and metastasize to para-aortic lymph nodes, specially when the lesion is located in the uterine fundus and uterine horns (cornua of uterus); there is a significant correlation between the location of lymph node metastasis and the location of primary uterine malignant tumor.

ESCRT-III component OsSNF7.2 modulates leaf rolling by trafficking and endosomal degradation of auxin biosynthetic enzyme OsYUC8 in rice.

The endosomal sorting complex required for transport (ESCRT) is highly conserved in eukaryotic cells and plays an essential role in the biogenesis of multivesicular bodies and cargo degradation to the plant vacuole or lysosomes. Although ESCRT components affect a variety of plant growth and development processes, their impact on leaf development is rarely reported. Here, we found that OsSNF7.2, an ESCRT-III component, controls leaf rolling in rice (Oryza sativa). The Ossnf7.2 mutant rolled leaf 17 (rl17) has adaxially rolled leaves due to the decreased number and size of the bulliform cells. OsSNF7.2 is expressed ubiquitously in all tissues, and its protein is localized in the endosomal compartments. OsSNF7.2 homologs, including OsSNF7, OsSNF7.3, and OsSNF7.4, can physically interact with OsSNF7.2, but their single mutation did not result in leaf rolling. Other ESCRT complex subunits, namely OsVPS20, OsVPS24, and OsBRO1, also interact with OsSNF7.2. Further assays revealed that OsSNF7.2 interacts with OsYUC8 and aids its vacuolar degradation. Both Osyuc8 and rl17 Osyuc8 showed rolled leaves, indicating that OsYUC8 and OsSNF7.2 function in the same pathway, conferring leaf development. This study reveals a new biological function for the ESCRT-III components, and provides new insights into the molecular mechanisms underlying leaf rolling.

Electrical Impedance Analysis for Lung Cancer: A Prospective, Multicenter, Blind Validation Study.

Hypothesis: Patients with cancer have different impedances or conductances than patients with benign normal tissue; thus, we can apply electrical impedance analysis (EIA) to identify patients with cancer. Method: To evaluate EIA's efficacy and safety profile in diagnosing pulmonary lesions, we conducted a prospective, multicenter study among patients with pulmonary lesions recruited from 4 clinical centers (Zhongshan Hospital Ethics Committee, Approval No. 2015-16R and 2017-035(3). They underwent EIA to obtain an Algorithm Composite Score or 'Prolung Index,' PI. The classification threshold of 29 was first tested in an analytical validation set of 144 patients and independently validated in a clinical validation set of 418 patients. The subject's final diagnosis depended on histology and a 2-year follow-up. Results: In total, 418 patients completed the entire protocol for clinical validation, with 186 true positives, 145 true negatives, 52 false positives, and 35 false negatives. The sensitivity, specificity, and diagnostic yield were 84% (95% CI 79.3%-89.0%), 74% (95% CI 67.4%-79.8%), and 79% (95%CI 75.3%-83.1%), respectively, and did not differ according to age, sex, smoking history, body mass index, or lesion types. The sensitivity of small lesions was comparable to that of large lesions (p = 0.13). Four hundred eighty-four patients who underwent the analysis received a safety evaluation. No adverse events were considered to be related to the test. Conclusion: Electrical impedance analysis is a safe and efficient tool for risk stratification of pulmonary lesions, especially for patients with a suspicious lung lesion.

Convergent selection of a WD40 protein that enhances grain yield in maize and rice.

A better understanding of the extent of convergent selection among crops could greatly improve breeding programs. We found that the quantitative trait locus KRN2 in maize and its rice ortholog, OsKRN2, experienced convergent selection. These orthologs encode WD40 proteins and interact with a gene of unknown function, DUF1644, to negatively regulate grain number in both crops. Knockout of KRN2 in maize or OsKRN2 in rice increased grain yield by ~10% and ~8%, respectively, with no apparent trade-offs in other agronomic traits. Furthermore, genome-wide scans identified 490 pairs of orthologous genes that underwent convergent selection during maize and rice evolution, and these were enriched for two shared molecular pathways. KRN2, together with other convergently selected genes, provides an excellent target for future crop improvement.

Circ_0020123 promotes NSCLC tumorigenesis via up-regulating KIAA1522 expression through miR-940.

Circ_0020123 was highly expressed in NSCLC tissues and cell lines, and knockdown of circ_0020123 abolished cell growth, migration and invasion in vitro and hindered tumor growth in nude mice. Mechanically, circ_0020123 directly targeted miR-940, and KIAA1522 was a target of miR-940. Thereafter, a series of rescue experiments showed that circ_0020123 served its biological functions by miR-940/KIAA1522 axis. In all, circ_0020123 acted as an oncogene to promote the tumorigenesis of NSCLC via miR-940/KIAA1522 axis, suggesting a potential therapeutic target for NSCLC treatment.

Enhancing the HSV-1-mediated antitumor immune response by suppressing Bach1.

BACKGROUND: In 2015, herpes simplex virus 1 (HSV-1)-derived talimogene laherparepvec (T-VEC) was the first oncolytic virus approved by the US Food and Drug Administration as a therapeutic agent for cancer treatment. However, its antitumor application is limited to local treatment of melanoma, and there is a lack of understanding of the mechanisms underlying the regulation of HSV-1 replication in cancer cells and the associated antitumor immunity. We hypothesized that increasing the replication capacity of HSV-1 in tumor cells would enhance the antitumor effect of this virus. METHODS: We systematically identified IFN-stimulated genes induced by HSV-1 by performing functional screens and clarified the mechanism by which BACH1 acts against HSV-1. Then, we tested the effect of BACH1 deficiency on immunogenic cell death induced by HSV-1. Furthermore, we investigated the antitumor effect of BACH1 deficiency on HSV-1 in MCA205 and B16 murine tumor models. RESULTS: We identified eight IFN-stimulated genes (ISGs) controlling HSV-1 replication, among which BTB and CNC homology 1 (BACH1) suppressed HSV-1 replication by inhibiting the transcription of ICP4, ICP27, and UL39. Loss of Bach1 function not only increased HSV-1 proliferation but also promoted HSV-1-induced cell apoptosis, HMGB1 secretion, and calreticulin exposure in tumor cells. More importantly, hemin, an FDA-approved drug known to downregulate BACH1, significantly enhanced HSV-1-mediated antitumor activity with increased T lymphocyte infiltration at the tumor site. CONCLUSIONS: Our studies uncovered a novel antiviral activity of BACH1 and provided a new strategy for improving the clinical efficiency of the oncolytic virus HSV-1.

Indocyanine green near-infrared imaging-guided lymph node dissection during oesophageal cancer surgery: A single-centre experience.

Objective: This study aimed to investigate the feasibility of using indocyanine green (ICG) near-infrared (NIR) imaging during lymphadenectomy for oesophageal cancer. Methods: Eighty-seven patients with primary oesophageal cancer were enrolled in this study. All the enrolled patients received an endoscopic injection of ICG between 40 min and 23 h before surgery. Nodal dissection during surgery was performed under fluorescence imaging visualisation, with the NIR signal shown in purple. ICG+ or ICG- nodes were recorded station by station and were microscopically evaluated. Results: Endoscopic peritumoral ICG injection was successfully performed in all patients. Major post-surgery complications included wound infection, pleural effusion, dysphonia, pneumonia and anastomotic fistula. No patients experienced ICG-related adverse events. A total of 2,584 lymph nodes were removed, and the mean number of lymph nodes for each patient was 29.70 ± 9.24. Most of the removed nodes (97.83%) were ICG+, and 3.32% of the ICG+ nodes were metastatic. No metastatic nodes were ICG- or belonged to an ICG- lymph node station. The time from ICG injection to surgery did not affect the number of harvested lymph nodes. Conclusions: The use of ICG-NIR imaging during oesophageal cancer surgery can enhance the visualisation of lymph nodes during surgery. It is a feasible, safe and helpful technique for lymphadenectomy.

Competing endogenous RNA network for esophageal cancer progression.

BACKGROUND: Esophageal cancer (ESCA) constitutes one of the most common cancers worldwide. The identification of potential biomarkers is important to improving the diagnostic accuracy and treatment efficiency for patients with ESCA. In this study, we aimed to identify biomarkers related to ESCA progression through a comprehensive analysis of long non-coding RNAs (lncRNAs), microRNA (miRNAs), and mRNA expression profiles in ESCA. METHODS: Differentially expressed lncRNAs, miRNAs, and mRNAs (DElncRNAs, DEmiRNAs, and DEmRNAs, respectively) in ESCA samples compared with normal controls were obtained. A competing endogenous RNA (ceRNA) network consisting of interacting DElncRNAs, DEmiRNAs, and DEmRNAs was constructed using a combination of the miRCode and TargetScan databases. Relationships between RNAs in the ceRNA network and overall survival in patients with EC were explored through another independent ESCA dataset from The Cancer Genome Atlas. RESULTS: A total of 1,014 DElncRNAs, 3,677 DEmRNAs, and 35 DEmiRNAs were identified in ESCA samples compared with normal samples. Functional enrichment analysis indicated that the DEmRNAs were involved in cell activity, inflammatory response, and oxygen metabolism-related biological processes. A ceRNA network containing 5 DEmiRNAs, 582 DEmRNAs and 764 DElncRNAs was obtained. In the survival analysis, 39 genes were found to be significantly associated with overall survival in patients with EC, including GOLGA7, NFYB, TOP1, and TMTC3. CONCLUSIONS: Our study constructed a ceRNA network for ESCA for the first time, which will be helpful for the disease's diagnosis and treatment.

Comparative transcriptome profiling and co-expression network analysis uncover the key genes associated withearly-stage resistance to Aspergillus flavus in maize.

BACKGROUND: The fungus Aspergillus flavus (A. flavus) is a serious threat to maize (Zea mays) production worldwide. It causes considerable yield and economic losses, and poses a health risk to humans and livestock due to the high toxicity of aflatoxin. However, key genes and regulatory networks conferring maize resistance to A. flavus are not clear, especially at the early stage of infection. Here, we performed a comprehensive transcriptome analysis of two maize inbred lines with contrasting resistance to A. flavus infection. RESULTS: The pairwise comparisons between mock and infected kernels in each line during the first 6 h post inoculation (hpi) showed that maize resistance to A. flavus infection was specific to the genotype and infection stage, and defense pathways were strengthened in the resistant line. Further comparison of the two maize lines revealed that the infection-induced up-regulated differentially expressed genes (DEGs) in the resistant line might underlie the enhanced resistance. Gene co-expression network analysis by WGCNA (weighted gene co-expression network analysis) identified 7 modules that were significantly associated with different infection stages, and 110 hub genes of these modules. These key regulators mainly participate in the biosynthesis of fatty acid and antibiotics. In addition, 90 candidate genes for maize resistance to A. flavus infection and/or aflatoxin contamination obtained in previous studies were confirmed to be differentially expressed between the resistant and susceptible lines within the first 6 hpi. CONCLUSION: This work unveiled more A. flavus resistance genes and provided a detailed regulatory network of early-stage resistance to A. flavus in maize.

Analysis of serum cfDNA concentration and integrity before and after surgery in patients with lung cancer.

The content and integrity of cell-free DNA (cfDNA) before and after surgery in patients with lung cancer were determined to investigate its clinical significance.   Peripheral blood was collected from 120 patients with lung cancer who were treated in our hospital from March 2016 to November 2018, including 50 cases before operation and 70 cases after operation. 60   healthy subjects served as controls. Quantitative PCR was used to determine the cfDNA level of each group. The relationship between cfDNA levels and the clinical features of lung cancer patients was determined. Receiver Operating Curves were used to determine the sensitivity and specificity of cfDNA, CEA, NSE and CYFRA21-1 in lung cancer.  The concentration and integrity of cfDNA before surgery in patients with lung cancer were significantly higher than those after surgery and those in healthy control group. The cfDNA concentration in patients with lung cancer after surgery was significantly higher than that in the control group, but there was no statistical difference in cfDNA integrity between the two groups. There was no significant correlation between cfDNA concentration/integrity and gender, age, tumor type, tumor stage, and expressions of CA199, CA125, and CA153 in patients with lung cancer before or after surgery. However, there were significant correlations between the expression levels of CEA, NSE, and CYFRA21-1 and cfDNA concentration. The expression levels of CEA and CYFRA21-1 were significantly correlated with cfDNA integrity before surgery, while the correlations were not significant after surgery.  The concentration and integrity of cfDNA increased significantly in serum of lung cancer patients. The concentration and integrity of cfDNA in patients with lung cancer after surgery were significantly lower than those before surgery. Thus, cfDNA has high application value in the diagnosis and evaluation of lung cancer.

Genetic determinants controlling maize rubisco activase gene expression and a comparison with rice counterparts.

BACKGROUND: Rubisco activase (RCA) regulates the activity of Rubisco and is a key enzyme of photosynthesis. RCA expression was widely reported to affect plant photosynthesis and crop yield, but the molecular basis of natural variation in RCA expression in a wide range of maize materials has not been fully elucidated. RESULTS: In this study, correlation analysis in approximately 200 maize inbred lines revealed a significantly positive correlation between the expression of maize RCA gene ZmRCAß and grain yield. A genome-wide association study revealed both cis-expression quantitative trait loci (cis-eQTLs) and trans-eQTLs underlying the expression of ZmRCAß, with the latter playing a more important role. Further allele mining and genetic transformation analysis showed that a 2-bp insertion and a 14-bp insertion in the promoter of ZmRCAß conferred increased gene expression. Because rice is reported to have higher RCA gene expression than does maize, we subsequently compared the genetic factors underlying RCA gene expression between maize and rice. The promoter activity of the rice RCA gene was shown to be stronger than that of the maize RCA gene, suggesting that replacing the maize RCA gene promoter with that of the rice RCA gene would improve the expression of RCA in maize. CONCLUSION: Our results revealed two DNA polymorphisms regulating maize RCA gene ZmRCAß expression, and the RCA gene promoter activity of rice was stronger than that of maize. This work increased understanding of the genetic mechanism that underlies RCA gene expression and identify new targets for both genetic engineering and selection for maize yield improvement.

OsVIN2 encodes a vacuolar acid invertase that affects grain size by altering sugar metabolism in rice.

KEY MESSAGE: OsVIN2, a vacuolar invertase, affects grain size and yield by altering sugar composition, transport, and starch accumulation in rice. Grain size, a major determinant of rice yield, is influenced by many developmental and environmental factors. Sugar metabolism plays vital roles in plant development. However, the way in which sugar metabolism affects rice grain size remains largely elusive. In this study, we characterized the small grain-size rice mutant sgs1. Histological analyses showed that reduced spikelet hull and endosperm size results from decreased cell size rather than cell number. Map-based cloning and complementation tests revealed that a DaiZ7 transposon insertion in a vacuolar invertase gene OsVIN2 is responsible for the mutant phenotype. Subcellular distribution and biochemical analysis indicated that OsVIN2 is located in the vacuolar lumen, and that its sucrose hydrolysis activity is maintained under acidic conditions. Furthermore, an altered sugar content with increased sucrose and decreased hexose levels, as well as changes in invertase and sucrose synthase activities, sugar transport gene expression, and starch constitution in sgs1 implies that OsVIN2 affects sucrose metabolism, including sugar composition, transport, and conversion from the source to the sink organs. Collectively, OsVIN2 is involved in sugar metabolism, and thus regulates grain size; our findings provide insights into grain development and also suggest a potential strategy to improve grain quality and yield in rice.

Post-transcriptional regulation of Ghd7 protein stability by phytochrome and OsGI in photoperiodic control of flowering in rice.

Rice (Oryza sativa) is a facultative short-day (SD) plant, flowering early under SD and late under long-day (LD) conditions. Ghd7 is a major regulator of flowering time in rice, which strongly delays flowering under LD. Induction of Ghd7 expression by phytochromes has been shown to contribute to photoperiodic regulation of flowering in rice. Here, we show that Ghd7 also is regulated by phytochromes at a post-transcriptional level. We found that constitutive expression of Ghd7 delays flowering in the wild-type (WT) background, but not in the se5 mutant background (deficient in functional phytochromes) under LD and that Ghd7 protein fails to accumulate in the se5 mutant. We also found that co-expressing OsGIGANTEA (OsGI) with Ghd7 causes reduced accumulation of Ghd7 protein and partially suppresses the delayed flowering phenotype in the WT background, suggesting that phytochromes and OsGI play antagonist roles in regulating Ghd7 protein stability and flowering time. We show that OsPHYA, OsPHYB and OsGI could directly interact with Ghd7. Interestingly, OsPHYA and OsPHYB could inhibit the interaction between OsGI and Ghd7, thus helping to stabilize Ghd7 protein. Our results revealed a new level of Ghd7 regulation by phytochromes and OsGI in photoperiodic control of flowering in rice.

Early heading 7 interacts with DTH8, and regulates flowering time in rice.

KEY MESSAGE: EH7/Ghd7 interacts with DTH8, and regulates heading date by controlling the expression of Ehd1 in rice. Heading date, or flowering time, an important agronomic trait, influences regional adaptability and yield of crops. Many genes related to heading date in rice have been identified, and a preliminary regulatory network has been established, but the relationships between proteins involved are poorly understood. We identified a flowering suppressor EH7 (Early heading 7) that represses flowering under long-day (LD) conditions. The eh7 allele caused earlier heading, shorter plant height and less grain per main panicle than did the wild type (WT), but the tiller number and 1000-grain weight were not significantly affected under natural long-day conditions. Biochemical assays showed that EH7 interacts with DTH8. Quantitative PCR showed that EH7 inhibited heading date by downregulating the expression of Ehd1, Hd3a and RFT1. We propose that EH7 interacts with DTH8 to control flowering time by regulating the expression of Ehd1, Hd3a and RFT1.

OsLOX2, a rice type I lipoxygenase, confers opposite effects on seed germination and longevity.

Rice production and seed storage are confronted with grain deterioration and loss of seed viability. Some members of the lipoxygenase (LOX) family function in degradation of storage lipids during the seed germination, but little is known about their influence on seed longevity during storage. We characterized the role of rice OsLOX2 gene in seed germination and longevity via over-expression and knock-down approaches. Abundant expression of OsLOX2 was detected in panicles, roots, and stems, but not in leaves. Moreover, OsLOX2 was highly induced during germination. OsLOX2 protein, located in the cytoplasm, showed a wide range of temperature adaptation (20-50 °C) and a substrate preference to linoleic acid. Lines over-expressing OsLOX2 showed accelerated seed germination under normal condition and lower seed viability after accelerated aging. RNA interference (RNAi) of OsLOX2 caused delayed germination and enhanced seed longevity. RNAi lines with strongly repressed OsLOX2 activity completely lost the capability of germination after accelerated aging. More lipid hydroperoxide were found in OE15 than the control, but less in RNAi lines than in the WT Nipponbare. Therefore, OsLOX2 acts in opposite directions during seed germination and longevity during storage. Appropriate repression of the OsLOX2 gene may delay the aging process during the storage without compromising germination under normal conditions.