Isolation and functional analysis of OsAOS1 promoter for resistance to Nilaparvata lugens Stål infestation in rice.

Insect pests have a great impact on the yield and quality of crops. Insecticide applications are an effective method of pest control, however, they also have adverse effects on the environment. Using insect-inducible promoters to drive insect-resistant genes in transgenic crops is a potential sustainable pest management strategy, but insect-inducible promoters have been rarely reported. In this study, we found rice allene oxide synthase gene (AOS, LOC_Os03g12500) can be highly upregulated following brown planthopper (Nilaparvata lugens Stål, BPH) infestation. Then, we amplified the promoter of OsAOS1 and the ß- glucuronidase reporter gene was used to analyze the expression pattern of the promoter. Through a series of 5' truncated assays, three positive regulatory regions in response to BPH infestation in the promoter were identified. The transgenic plants, P1R123-min 35S and P1TR1-min 35S promoter-driven snowdrop lectin (Galanthus nivalis agglutinin, GNA) gene, demonstrated the highest expression levels of GNA and lowest BPH survival. Our work identified a BPH-inducible promoter and three positive regions within it. Transgenic rice with GNA driven by OsAOS1 promoter and positive regions exhibited an expected lethal effect on BPH. This study proved the application potential of BPH-inducible promoter and provided a novel path for the selection of insect-resistant tools in the future.

Paspalines C-D and Paxillines B-D: New Indole Diterpenoids from Penicillium brefeldianum WZW-F-69.

Five new indole diterpenoids named paspaline C-D (1-2) and paxilline B-D (3-5), as well as eleven known analogues (6-16), were identified from fungus Penicillium brefeldianum strain WZW-F-69, which was isolated from an abalone aquaculture base in Fujian province, China. Their structures were elucidated mainly through 1D- and 2D-NMR spectra analysis and ECD comparison. Compound 1 has a 6/5/5/6/6/8 hexacyclic ring system bearing 2,2-dimethyl-1,3-dioxocane, which is rare in natural products. Compound 2 has an unusual open F-ring structure. The cytotoxic activities against 10 cancer cell lines and antimicrobial activities against model bacteria and fungi of all compounds were assayed. No compound showed antimicrobial activity, but at a concentration of 1 µM, compounds 1 and 6 exhibited the highest inhibition rates of 71.2% and 83.4% against JeKo-1 cells and U2OS cells, respectively.

Pentacyclic Cytochalasins and Their Derivatives from the Endophytic Fungus Phomopsis sp. xz-18.

Eight new cytochalasins 1-8 and ten known analogs 9-18 were isolated from the endophytic fungus Phomopsis sp. xz-18. The planar structures of the cytochalasins were determined by HR-ESI-MS and NMR analysis. Compounds 1, 2, 9 and 10 were 5/6/6/7/5-fused pentacyclic cytochalasins; compounds 3 and 4 had conjugated diene structures in the macrocycle; and compound 6 had a ß,γ-unsaturated ketone. The absolute configuration of 6 was confirmed for the first time by the octant rule. The acid-free purification process proved that the pentacyclic system was a natural biosynthetic product and not an acid-mediated intramolecular cyclized artifact. The new compounds did not exhibit activities against human cancer cell lines in cytotoxicity bioassays or antipathogenic fungal activity, but compounds 1, 3 and 4 showed moderate antibacterial activity in disk diffusion assays.

Prediction of spatial distribution characteristics of ecosystem functions based on a minimum data set of functional traits of desert plants.

The relationship between plant functional traits and ecosystem function is a hot topic in current ecological research, and community-level traits based on individual plant functional traits play important roles in ecosystem function. In temperate desert ecosystems, which functional trait to use to predict ecosystem function is an important scientific question. In this study, the minimum data sets of functional traits of woody (wMDS) and herbaceous (hMDS) plants were constructed and used to predict the spatial distribution of C, N, and P cycling in ecosystems. The results showed that the wMDS included plant height, specific leaf area, leaf dry weight, leaf water content, diameter at breast height (DBH), leaf width, and leaf thickness, and the hMDS included plant height, specific leaf area, leaf fresh weight, leaf length, and leaf width. The linear regression results based on the cross-validations (FTEIW - L, FTEIA - L, FTEIW - NL, and FTEIA - NL) for the MDS and TDS (total data set) showed that the R2 (coefficients of determination) for wMDS were 0.29, 0.34, 0.75, and 0.57, respectively, and those for hMDS were 0.82, 0.75, 0.76, and 0.68, respectively, proving that the MDSs can replace the TDS in predicting ecosystem function. Then, the MDSs were used to predict the C, N, and P cycling in the ecosystem. The results showed that non-linear models RF and BPNN were able to predict the spatial distributions of C, N and P cycling, and the distributions showed inconsistent patterns between different life forms under moisture restrictions. The C, N, and P cycling showed strong spatial autocorrelation and were mainly influenced by structural factors. Based on the non-linear models, the MDSs can be used to accurately predict the C, N, and P cycling, and the predicted values of woody plant functional traits visualized by regression kriging were closer to the kriging results based on raw values. This study provides a new perspective for exploring the relationship between biodiversity and ecosystem function.

Cloning of the promoter of rice brown planthopper feeding-inducible gene OsTPS31 and identification of related cis-regulatory elements.

BACKGROUND: Brown planthopper (BPH; Nilaparvata lugens) is one of the most serious pests of rice in the world. Insect-resistant genetic engineering is a very effective technology to control BPH. The promoters and cis-regulatory elements inducible by plant-feeding insects are critical for genetic engineering of insect-resistant crops. RESULTS: In this study, we cloned a promoter Ptps31 and a 7 bp cis-regulatory sequence that up-regulated downstream genes induced by BPH feeding. The promoter of OsTPS31 (Ptps31) unresponsive to physical damage but responsive to BPH feeding was cloned and functionally verified. The results showed that expression of the OsBPH14 gene driven by the promoter region from -510 to -246 bp in rice could significantly improve the resistance to BPH. The promoter region from -376 to -370 bp (TAGTGTC) was identified as a cis-regulatory sequence related to BPH feeding induction of downstream gene expression. CONCLUSION: The findings provide a new promoter and a new cis-regulatory sequence tool for the research on and application of rice BPH resistance genes, as well as a new perspective for functional analysis of the OsTPS31 gene. © 2023 Society of Chemical Industry.

Exploring Diversity through Dimerization in Natural Products by a Rational Tandem Mass-Based Molecular Network Strategy.

The step- and atom-efficient dimerization strategy is frequently used in nature to build structural complexity and diversity. We propose the rationale and structural features of the versatile monomers that are responsible for "diversity through dimerization". Using 5-FAM-maleimide combined with a UHPLC-MS/MS-FBMN workflow, we successfully identified a diverse set of dimeric natural products from fungus Panus rudis F01315, in which all four complex 4'5-ring scaffolds are derived from one monomeric epoxyquinol and endowed with functional diversity.

RT-PCR demonstrates superior sensitivity and specificity in detecting the five neuroblastoma genes compared to the flow cytometry method for measurable residual disease.

Background: Exploring sensitive prognostic methods for patients with relapsed or refractory neuroblastoma (NB) is critical. The five NB genes (NB5) share a common trait: they are highly expressed in NB. Previous studies have identified their expression levels as markers for guiding micrometastasis. This study aimed to explore whether an improved NB5 detection method is superior to flow cytometry for predicting NB metastasis, measurable residual disease (MRD), and prognosis, and whether this result could serve as an independent factor to influence progression-free survival (PFS). Methods: We utilized reverse transcriptase polymerase chain reaction (RT-PCR) to assess the expression of NB5 (CHGA, DCX, DDC, PHOX2B, and TH) in bone marrow (BM), peripheral blood (PB), or cerebrospinal fluid (CSF) samples collected from 71 patients. The correlation between gene expression changes and clinical characteristics, as well as survival rates, based on 113 detections were analyzed. The NB5 detection results' sensitivity and specificity in all 71 patients collected from six research centers with a median follow-up of 14 months were assessed. Results: PB specimens showed 100% concordance with the BM specimens in terms of positive results. Furthermore, the BM specimens exhibited an additional 45.455% (5/11) positive results compared to the 34.091% (30/88) of PB specimens. The BM specimens were positive for NB5 assay, which was significantly higher than the positive results of flow cytometric MRD (15/88, 17.045%). NB5 was mainly expressed in newly diagnosed patients (P=0.043) and positive patients with flow cytometric MRD (P<0.001) or BM morphology (P<0.001). Positive rates of droplet digital PCR (ddPCR) were consistent with those of quantitative RT-PCR (qRT-PCR) in BM (13/18, 72.222%). However, in PB, the positive rate of ddPCR (2/5, 40.000%) was higher than that of qRT-PCR. A total of 38 specimens (BM, PB, CSF) were detected as positive under qRT-PCR. Among the positive results, the analysis revealed a significant difference between the CHGA and TH in pairwise comparisons (P=0.005). PFS analysis showed that among MRD-negative patients, the survival time of the NB5-positive group was significantly lower than that of NB5-negative group (27.408±10.791 vs. 35.961±3.084 months; P=0.034), and in the Cox regression model, risk stratification based on NB5 expression level was an independent prognostic factor for relapsed or refractory disease [95% confidence interval (CI):1.020 to 9.099, hazard ratio (HR) =3.046, P=0.046]. Combining the follow-up results, we found that the sensitivity and specificity of NB5 detection were both 100%. Conclusions: In our study, the improved NB5 detection method showed significantly higher sensitivity in assessing tumor relapse or residual disease compared to flow cytometric MRD. Moreover, it provided a more accurate assessment of treatment efficacy and prognosis. These findings support NB5 detection as an effective method for further stratification and monitoring of patients with relapsed or refractory NB.

Comparative transcriptome analysis of defense response of rice to Nilaparvata lugens and Chilo suppressalis infestation.

The brown planthopper (BPH, Nilaparvata lugens) and striped stem borer (SSB, Chilo suppressalis) are two of the most devastating insect pests in rice, causing significant losses of rice yield. Plants evolve multiple defense responses in the process of coexisting with pests. According to different pest infestation, the plants selectively activate related pathways and downstream gene expression. However, there are very few reports of differences in defense signaling pathways after rice was attacked by BPH or SSB. We determined the transcriptional responses of rice infested with BPH and SSB for 3 and 6 h using Illumina sequencing. By comparing the difference in gene changes caused by BPH and SSB infestation in rice, multiple signal pathways and gene expression patterns, including phytohormones, secondary metabolites, plant-pathogen interaction, reactive oxygen species, defense response, transcription factors, protease inhibitor and chitinase were found significantly different. Our results provide a basis for further exploring the molecular mechanism of rice defense response caused by BPH and SSB infestation, which will add to further understanding the interactions between plants and insects, and could provide valuable resources that could be applied in insect-resistant crop breeding.

Cloning and functional identification of a Chilo suppressalis-inducible promoter of rice gene, OsHPL2.

BACKGROUND: Promoters play a key role in driving insect-resistant genes during breeding of transgenic plants. In current transgenic procedures for breeding rice resistance to striped stem borer (Chilo suppressalis Walker, SSB), the constitutive promoter is used to drive the insect-resistant gene. To reduce the burden of constitutive promoters on plant growth, isolation and identification of insect-inducible promoters are particularly important. However, few promoters are induced specifically by insect feeding. RESULTS: We found rice hydroperoxide lyase gene (OsHPL2) (LOC_Os02g12680) was upregulated after feeding by SSB. We subsequently cloned the promoter of OsHPL2 and analysed its expression pattern using the ß-glucuronidase (GUS) reporter gene. Histochemical assays and quantitative analyses of GUS activity confirmed that P HPL2 :GUS was activated by SSB, but did not respond to brown planthopper (Nilaparvata lugens Stål, BPH) infestation, mechanical wounding or phytohormone treatments. A series of 5' truncated assays were conducted and three positive regulatory regions (-1452 to -1213, -903 to -624, and -376 to -176) induced by SSB infestation were identified. P2R123-min 35S and P2TR2-min 35S promoters linked with cry1C of transgenic plants showed the highest levels of Cry1C protein expression and SSB larval mortality. CONCLUSION: We identified an SSB-inducible promoter and three positive internal regions. Transgenic rice plants with the OsHPL2 promoter and its positive regions driving cry1C exhibited the expected larvicidal effect on SSB. Our study is the first report of an SSB-inducible promoter that could be used as a potential resource for breeding insect-resistant transgenic crops. © 2020 Society of Chemical Industry.