Chromosomal-level genome assembly and annotation of the tropical sea cucumber Holothuria scabra.

Holothuria scabra, a commercially valuable yet ecologically vulnerable tropical holothuroid, has experienced a severe decline in its wild populations, especially in China. Genomic resources are crucial for the development of effective genomic breeding projects and stock conservation strategies to restore these natural populations. Until now, a high-quality, chromosome-level reference genome for H. scabra has not been available. Here, we employed Oxford Nanopore and Hi-C sequencing technologies to assemble and annotate a high-quality, chromosome-level reference genome of H. scabra. The final genome comprised 31 scaffolds with a total length of 1.19 Gb and a scaffold N50 length of 53.52 Mb. Remarkably, 1,191.67 Mb (99.95%) of the sequences were anchored to 23 pseudo-chromosomes, with the longest one spanning 79.75 Mb. A total of 34,418 protein-coding genes were annotated in the final genome, with BUSCO analysis revealing 98.01% coverage of metazoa_odb10 genes, marking a significant improvement compared to the previous report. These chromosome-level sequences and annotations will provide an essential genomic basis for further investigation into molecular breeding and conservation management of H. scabra.

Transfer learning enables identification of multiple types of RNA modifications using nanopore direct RNA sequencing.

Nanopore direct RNA sequencing (DRS) has emerged as a powerful tool for RNA modification identification. However, concurrently detecting multiple types of modifications in a single DRS sample remains a challenge. Here, we develop TandemMod, a transferable deep learning framework capable of detecting multiple types of RNA modifications in single DRS data. To train high-performance TandemMod models, we generate in vitro epitranscriptome datasets from cDNA libraries, containing thousands of transcripts labeled with various types of RNA modifications. We validate the performance of TandemMod on both in vitro transcripts and in vivo human cell lines, confirming its high accuracy for profiling m6A and m5C modification sites. Furthermore, we perform transfer learning for identifying other modifications such as m7G, Ψ, and inosine, significantly reducing training data size and running time without compromising performance. Finally, we apply TandemMod to identify 3 types of RNA modifications in rice grown in different environments, demonstrating its applicability across species and conditions. In summary, we provide a resource with ground-truth labels that can serve as benchmark datasets for nanopore-based modification identification methods, and TandemMod for identifying diverse RNA modifications using a single DRS sample.

Silencing Ditylenchus destructor cathepsin L-like cysteine protease has negative pleiotropic effect on nematode ontogenesis.

Ditylenchus destructor is a migratory plant-parasitic nematode that severely harms many agriculturally important crops. The control of this pest is difficult, thus efficient strategies for its management in agricultural production are urgently required. Cathepsin L-like cysteine protease (CPL) is one important protease that has been shown to participate in various physiological and pathological processes. Here we decided to characterize the CPL gene (Dd-cpl-1) from D. destructor. Analysis of Dd-cpl-1 gene showed that Dd-cpl-1 gene contains a signal peptide, an I29 inhibitor domain with ERFNIN and GNFD motifs, and a peptidase C1 domain with four conserved active residues, showing evolutionary conservation with other nematode CPLs. RT-qPCR revealed that Dd-cpl-1 gene displayed high expression in third-stage juveniles (J3s) and female adults. In situ hybridization analysis demonstrated that Dd-cpl-1 was expressed in the digestive system and reproductive organs. Silencing Dd-cpl-1 in 1-cell stage eggs of D. destructor by RNAi resulted in a severely delay in development or even in abortive morphogenesis during embryogenesis. The RNAi-mediated silencing of Dd-cpl-1 in J2s and J3s resulted in a developmental arrest phenotype in J3 stage. In addition, silencing Dd-cpl-1 gene expression in female adults led to a 57.43% decrease in egg production. Finally, Dd-cpl-1 RNAi-treated nematodes showed a significant reduction in host colonization and infection. Overall, our results indicate that Dd-CPL-1 plays multiple roles in D. destructor ontogenesis and could serve as a new potential target for controlling D. destructor.

Root hairs facilitate rice root penetration into compacted layers.

Compacted soil layers adversely affect rooting depth and access to deeper nutrient and water resources, thereby impacting climate resilience of crop production and global food security. Root hair plays well-known roles in facilitating water and nutrient acquisition. Here, we report that root hair also contributes to root penetration into compacted layers. We demonstrate that longer root hair, induced by elevated auxin response during a root compaction response, improves the ability of rice roots to penetrate harder layers. This compaction-induced auxin response in the root hair zone is dependent on the root apex-expressed auxin synthesis gene OsYUCCA8 (OsYUC8), which is induced by compaction stress. This auxin source for root hair elongation relies on the auxin influx carrier AUXIN RESISTANT 1 (OsAUX1), mobilizing this signal from the root apex to the root hair zone. Mutants disrupting OsYUC8 and OsAUX1 genes exhibit shorter root hairs and weaker penetration ability into harder layers compared with wild type (WT). Root-hair-specific mutants phenocopy these auxin-signaling mutants, as they also exhibit an attenuated root penetration ability. We conclude that compaction stress upregulates OsYUC8-mediated auxin biosynthesis in the root apex, which is subsequently mobilized to the root hair zone by OsAUX1, where auxin promotes root hair elongation, improving anchorage of root tips to their surrounding soil environment and aiding their penetration ability into harder layers.

Long-term outcomes of endovascular therapy for right subclavian artery occlusive lesions: A multi-center experience.

OBJECTIVE: To review our multi-institutional experience with endovascular therapy for right subclavian artery occlusive disease and to evaluate the long-term outcomes. METHODS: We retrospectively evaluated all patients with right subclavian artery stenosis and occlusive disease who underwent endovascular therapy between March 2014 and September 2022 at two institutions. Patient baseline demographics, lesion characteristics, treatment strategies, and in-hospital and follow-up outcomes were prospectively collected and retrospectively analyzed. RESULTS: Between March 2014 and September 2022, 73 patients underwent endovascular treatment at the two institutions. The dominant cause of lesions in this cohort was atherosclerosis. Three different types of lesions were summarized, and the corresponding endovascular strategies were performed. 66 patients (90.4%) underwent successful endovascular treatment, and 62 patients (84.9%) underwent balloon-expandable stent deployment. The mean perioperative in-hospital stay was 4.0 days (range, 3-6 days). Two patients died due to myocardial infarction, and one died of cerebral hemorrhage resulting from a traffic accident within 30 days of the intervention. The median follow-up time was 31.6 months (range, 12-96 months). No complications, including death, stroke, stent fractures, or migration, were noted in any patient during the follow-up period. The overall complication rate was 7/73 (9.6%), and 5/7 (6.9%) of the complications required reintervention. CONCLUSIONS: Endovascular treatment of right subclavian artery lesions is safe, effective, and technically achievable. The reasonable use of balloon-expandable stents can achieve satisfactory outcomes with accurate orientation and promising patency.

Ethylene regulates auxin-mediated root gravitropic machinery and controls root angle in cereal crops.

Root angle is a critical factor in optimising the acquisition of essential resources from different soil depths. The regulation of root angle relies on the auxin-mediated root gravitropism machinery. While the influence of ethylene on auxin levels is known, its specific role in governing root gravitropism and angle remains uncertain, particularly when Arabidopsis (Arabidopsis thaliana) core ethylene signaling mutants show no gravitropic defects. Our research, focusing on rice (Oryza sativa L.) and maize (Zea mays), clearly reveals the involvement of ethylene in root angle regulation in cereal crops through the modulation of auxin biosynthesis and the root gravitropism machinery. We elucidated the molecular components by which ethylene exerts its regulatory effect on auxin biosynthesis to control root gravitropism machinery. The ethylene-insensitive mutants ethylene insensitive2 (osein2) and ethylene insensitive like1 (oseil1), exhibited substantially shallower crown root angle compared to the wild type. Gravitropism assays revealed reduced root gravitropic response in these mutants. Hormone profiling analysis confirmed decreased auxin levels in the root tips of the osein2 mutant, and exogenous auxin (NAA) application rescued root gravitropism in both ethylene-insensitive mutants. Additionally, the auxin-biosynthetic mutant mao hu zi10 (mhz10)/tryptophan aminotransferase2 (ostar2) showed impaired gravitropic response and shallow crown root angle phenotypes. Similarly, maize ethylene-insensitive mutants (zmein2) exhibited defective gravitropism and root angle phenotypes. In conclusion, our study highlights that ethylene controls the auxin-dependent root gravitropism machinery to regulate root angle in rice and maize, revealing a functional divergence in ethylene signaling between Arabidopsis and cereal crops. These findings contribute to a better understanding of root angle regulation and have implications for improving resource acquisition in agricultural systems.

Identification and characterization of the Remorin gene family in Saccharum and the involvement of ScREM1.5e-1/-2 in SCMV infection on sugarcane.

Introduction: Remorins (REMs) are plant-specific membrane-associated proteins that play important roles in plant-pathogen interactions and environmental adaptations. Group I REMs are extensively involved in virus infection. However, little is known about the REM gene family in sugarcane (Saccharum spp. hyrid), the most important sugar and energy crop around world. Methods: Comparative genomics were employed to analyze the REM gene family in Saccharum spontaneum. Transcriptomics or RT-qPCR were used to analyze their expression files in different development stages or tissues under different treatments. Yeast two hybrid, bimolecular fluorescence complementation and co-immunoprecipitation assays were applied to investigate the protein interaction. Results: In this study, 65 REMs were identified from Saccharum spontaneum genome and classified into six groups based on phylogenetic tree analysis. These REMs contain multiple cis-elements associated with growth, development, hormone and stress response. Expression profiling revealed that among different SsREMs with variable expression levels in different developmental stages or different tissues. A pair of alleles, ScREM1.5e-1/-2, were isolated from the sugarcane cultivar ROC22. ScREM1.5e-1/-2 were highly expressed in leaves, with the former expressed at significantly higher levels than the latter. Their expression was induced by treatment with H2O2, ABA, ethylene, brassinosteroid, SA or MeJA, and varied upon Sugarcane mosaic virus (SCMV) infection. ScREM1.5e-1 was localized to the plasma membrane (PM), while ScREM1.5e-2 was localized to the cytoplasm or nucleus. ScREM1.5e-1/-2 can self-interact and interact with each other, and interact with VPgs from SCMV, Sorghum mosaic virus, or Sugarcane streak mosaic virus. The interactions with VPgs relocated ScREM1.5e-1 from the PM to the cytoplasm. Discussion: These results reveal the origin, distribution and evolution of the REM gene family in sugarcane and may shed light on engineering sugarcane resistance against sugarcane mosaic pathogens.

Genetic regulation of the root angle in cereals.

The root angle plays a critical role in efficiently capturing nutrients and water from different soil layers. Steeper root angles enable access to mobile water and nitrogen from deeper soil layers, whereas shallow root angles facilitate the capture of immobile phosphorus from the topsoil. Thus, understanding the genetic regulation of the root angle is crucial for breeding crop varieties that can efficiently capture resources and enhance yield. Moreover, this understanding can contribute to developing varieties that effectively sequester carbon in deeper soil layers, supporting global carbon mitigation efforts. Here we review and consolidate significant recent discoveries regarding the molecular components controlling root angle in cereal crop species and outline the remaining research gaps in this field.

MicroRNA sequencing analysis reveals immune responses in hepatopancreas of Fenneropenaeus penicillatus under white spot syndrome virus infection.

White Spot Disease is one of the most harmful diseases of the red tail shrimp, which can cause devastating economic losses due to the highest mortality up to 100% within a few days. MicroRNAs (miRNAs) are large class of small noncoding RNAs with the ability to post-transcriptionally repress the translation of target mRNAs. MiRNAs are considered to have a significant role in the innate immune response of crustaceans, particularly in relation to antiviral defense mechanisms. Numerous crustacean miRNAs have been verified to be required in host immune defense against viral infection, however, till present, the miRNAs functions of F. penicillatus defense WSSV infection have not been studied yet. Here in this study, for the first time, miRNAs involved in the F. penicillatus immune defense against WSSV infection were identified using high-throughput sequencing platform. A total of 432 miRNAs were obtained including 402 conserved miRNAs and 30 novel predicted miRNAs. Comparative analysis between the WSSV-challenged group and the control group revealed differential expression of 159 microRNAs in response to WSSV infection. Among these, 48 were up-regulated and 111 were down-regulated. Ten candidate MicroRNAs associated with immune activities were randomly selected for qRT-PCR analysis, which confirming the expression profiling observed in the MicroRNA sequencing data. As a result, most differentially expressed miRNAs were down-regulated lead to increase the expression of various target genes that mediated immune reaction defense WSSV infection, including genes related to signal transduction, Complement and coagulation cascade, Phagocytosis, and Apoptosis. Furthermore, the genes expression of the key members in Toll and Imd signaling pathways and apoptotic signaling were mediated by microRNAs to activate host immune responses including apoptosis against WSSV infection. These results will help to understand molecular defense mechanism against WSSV infection in F. penicillatus and to develop an effective WSSV defensive strategy in shrimp farming.

Manganese-oxide-supported gold catalyst derived from metal-organic frameworks for trace PCl3 oxidation in an organic system.

Polysilicon is widely used in the field of semiconductors and solar energy. Trichlorosilane feedstocks that are used to produce polysilicon in the mainstream production process contain PCl3 impurities that have adverse effects on the quality of the polysilicon. Traditional methods for dephosphorization cannot achieve the effect of complete removal, whereas oxidizing PCl3 to POCl3 in the presence of oxygen for removal via adsorption is a promising and appealing route for establishing a dephosphorization process; it has a high phosphorous removal rate due to the strong Lewis-base property of POCl3 in comparison with PCl3. In this work, we synthesized an active catalyst with an active interface between Au nanoparticles (NPs) and a manganese-oxide support (Mn3O4) by calcination of a corresponding composite, where Au NPs were embedded uniformly in a metal-organic framework (MOF). The catalyst shows a significantly active catalytic performance for trace PCl3 oxidation in an organic system that is an imitation of a trichlorosilane system, with a 99.13% yield of POCl3 in an 80 °C and 0.6 MPa reaction environment. The structure-performance-mechanism analysis shows that the possible reaction and catalytic mechanism is PCl3 oxidation by interface lattice oxygens, which bridge the Au NPs and the support, in a Mars van Krevelen (MvK) process; this process was promoted by the interaction between the Au NPs and Mn3O4 in terms of charge transfer and chemical potential changes. This work provides an effective way to dephosphorize trichlorosilane feedstocks in the polysilicon industry and gives guidance for constructing an efficient catalyst via the study of the structure and mechanism.

Sugarcane mosaic virus employs 6K2 protein to impair ScPIP2;4 transport of H2O2 to facilitate virus infection.

Sugarcane mosaic virus (SCMV), one of the main pathogens causing sugarcane mosaic disease, is widespread in sugarcane (Saccharum spp. hybrid) planting areas and causes heavy yield losses. RESPIRATORY BURST OXIDASE HOMOLOG (RBOH) NADPH oxidases and plasma membrane intrinsic proteins (PIPs) have been associated with the response to SCMV infection. However, the underlying mechanism is barely known. In the present study, we demonstrated that SCMV infection upregulates the expression of ScRBOHs and the accumulation of hydrogen peroxide (H2O2), which inhibits SCMV replication. All eight sugarcane PIPs (ScPIPs) interacted with SCMV-encoded protein 6K2, whereby two PIP2s (ScPIP2;1 and ScPIP2;4) were verified as capable of H2O2 transport. Furthermore, we revealed that SCMV-6K2 interacts with ScPIP2;4 via transmembrane domain 5 to interfere with the oligomerization of ScPIP2;4, subsequently impairing ScPIP2;4 transport of H2O2. This study highlights a mechanism adopted by SCMV to employ 6K2 to counteract the host resistance mediated by H2O2 to facilitate virus infection and provides potential molecular targets for engineering sugarcane resistance against SCMV.

MicroRNA sequencing analysis reveals injury-induced immune responses of Scylla paramamosain against cheliped autotomy.

During pond culture or intensive culture system of crabs (mainly Eriocheir sinensis, Portunus trituberculatus and Scylla paramamosain), high-density farming has typically contributed to a higher limb autotomy level in juvenile animals, especially in S. paramamosain which has a high level of cannibalism. Due to the high limb autotomy level, the survival and growth rates in S. paramamosain farming are restricted, which limit the growth of the mud crab farming industry. MicroRNAs (miRNAs) are small noncoding RNAs that regulate a series of biological processes including innate immune responses by post-transcriptional suppression of their target genes. MiRNAs are believed to be crucial for innate immune process of host wound healing. Many miRNAs have been verified to be required in host immune responses to repair wound and to defense pathogen after tissue damage. However, to our best knowledge, the miRNAs functions of crustacean innate immune reactions against injury induced by limb autotomy have not been studied yet. Here in this study, for the first time, miRNAs involved in the S. paramamosain immune reactions against injury induced by cheliped autotomy were obtained by high-throughput sequencing. A total of 575 miRNAs (518 known miRNAs and 57 novel predicted miRNAs) were obtained, of which 141 differentially expressed microRNAs (93 up-regulated microRNAs and 48 down-regulated microRNAs) were revealed to be modified against cheliped autotomy, and the qPCR results of randomly selected miRNAs confirmed the expression patterns in the miRNAs sequencing data. Numerous immune-related target genes associated with innate immune system were mediated by miRNAs to induce host humoral immune and cellular immune defense to minimize acute physical damage. Furthermore, the genes expression in hemolymph coagulation and melanization pathways, as well as Toll and Imd signaling pathways were mediated by miRNAs to activate host immune responses including melanization and antimicrobial peptides for rapid wound healing and killing invaded pathogens. These results will help to understand injury-induced immune responses in crabs and to develop an effective control strategy of autotomy rate in crabs farming.

MiR-452-5p facilitates retinoblastoma cell growth and invasion via the SOCS3/JAK2/STAT3 pathway.

Retinoblastoma (RB) is an intraocular tumor in children. Accumulated evidence confirms that microRNAs (miRNAs) exert critical functions in RB. This research aimed to investigate the miR-452-5p function in RB. MiR-452-5p expressions in RB were tested with quantitative real-time polymerase chain reaction (PCR). MiR-452-5p functions in RB were evaluated via Cell Counting Kit-8, 5-Ethynyl-2'-deoxyuridine assay, flow cytometry, Western blot, and Transwell. MiR-452-5p mechanism in RB was assessed using bioinformatics software Starbase and dual-luciferase reporter gene assay. Meanwhile, miR-452-5p function in RB in vivo was examined by constructing tumor xenografts in nude mice, immunohistochemistry, and Western blot assays. MiR-452-5p was overexpressed in RB tissues and cells, and miR-452-5p expression was positively correlated with RB clinicopathology including the Largest tumor base (mm) and Differentiation. Functionally, miR-452-5p knockdown restrained RB cell proliferation, invasion, epithelial-mesenchymal transition (EMT), and facilitated cell apoptosis. Mechanistically, suppressors of cytokine signaling (SOCS3) knockdown restored the inhibitory effects of miR-452-5p knockdown on RB cells. Meanwhile, in vivo studies further corroborated that miR-452-5p knockdown reduced RB tumor growth, EMT, and accelerated apoptosis in vivo. Also, miR-452-5p knockdown increased SOCS3 protein levels, and decreased phosphorylated Janus kinase 2/Janus kinase 2 (JAK2), phosphorylated signal transducer and activator of transcription 3/signal transducer and activator of transcription 3 (STAT3) in vivo. MiR-452-5p accelerated RB cell growth and invasion by SOCS3/JAK2/STAT3.

Nuclear export of pre-60S particles through the nuclear pore complex.

The nuclear pore complex (NPC) is the bidirectional gate that mediates the exchange of macromolecules or their assemblies between nucleus and cytoplasm1-3. The assembly intermediates of the ribosomal subunits, pre-60S and pre-40S particles, are among the largest cargoes of the NPC and the export of these gigantic ribonucleoproteins requires numerous export factors4,5. Here we report the cryo-electron microscopy structure of native pre-60S particles trapped in the channel of yeast NPCs. In addition to known assembly factors, multiple factors with export functions are also included in the structure. These factors in general bind to either the flexible regions or subunit interface of the pre-60S particle, and virtually form many anchor sites for NPC binding. Through interactions with phenylalanine-glycine (FG) repeats from various nucleoporins of NPC, these factors collectively facilitate the passage of the pre-60S particle through the central FG repeat network of the NPC. Moreover, in silico analysis of the axial and radial distribution of pre-60S particles within the NPC shows that a single NPC can take up to four pre-60S particles simultaneously, and pre-60S particles are enriched in the inner ring regions close to the wall of the NPC with the solvent-exposed surface facing the centre of the nuclear pore. Our data suggest a translocation model for the export of pre-60S particles through the NPC.

LINC00294/miR-620/MKRN2 axis provides biomarkers and negatively regulates malignant progression in colorectal carcinoma.

BACKGROUND: Colorectal carcinoma (CRC) ranks the third most frequent malignancy worldwide. Makorin RING zinc finger-2 (MKRN2) has been identified as a tumor suppressor in CRC, and the bioinformatics prediction indicated that some non-coding RNAs (ncRNAs) that directly or indirectly regulate MKRN2 might play critical roles in CRC progression. This study aimed to analyze the regulatory effect of LINC00294 on CRC progression, and to explore the underlying mechanisms by assessing miR-620 and MKRN2. The potential prognostic value of the ncRNAs and MKRN2 was also investigated. METHODS: The expression of LINC00294, MKRN2, miR-620 was examined by qRT-PCR. Cell counting kit-8 assay was used to assess the proliferation of CRC cells. Transwell assay was used to evaluate the migration, invasion of CRC cells. Kaplan-Meier method and log-rank test were used to perform comparative analysis of overall survival in CRC patients. RESULTS: Lower expression of LINC00294 was observed in both CRC tissues and cell lines. In CRC cells, LINC00294 overexpression inhibited cell proliferation, migration and invasion, but these effects were directly reversed by the overexpression of miR-620, which was demonstrated as a target of LINC00294. Additionally, MKRN2 was found to be a target gene of miR-620, and might mediate the regulatory function of LINC00294 in CRC progression. In CRC patients, low LINC00294, MKRN2 and high miR-620 expression was associated poor overall survival of CRC. CONCLUSIONS: LINC00294/miR-620/MKRN2 axis had the potential to provide prognostic biomarkers for CRC patients, and negatively regulated the malignant progression of CRC cells, including proliferation, migration and invasion.

Ability of three-dimensional 3-Tesla ultrashort echo time magnetic resonance imaging to display the morphological characteristics of pulmonary nodules: a sensitivity analysis.

Background: Radiation-free lung cancer screening will reduce/eliminate radiation exposure in the diagnosis and follow-up of patients with lung cancer. Methods: This was a prospective study. The participants were recruited using convenience sampling. A total of 36 patients with pulmonary nodules [patients with single or multiple pulmonary nodules >4 and <30 mm on their pulmonary computed tomography (CT) scans] who were admitted to Fudan University Zhongshan Hospital's Xiamen branch were enrolled; they underwent a CT scan and a free-breathing ultrashort time-of-echo (UTE) sequence scan using a 3-Tesla (T) magnetic resonance imaging (MRI) scanner. The CT examinations were regarded as the reference standard. Patients had an interval time of <3 days between their CT and MRI examinations. Two reviewers with more than 10 years' experience in the diagnosis of pulmonary nodules identified the numbers and morphological features of the pulmonary nodules. Results: Among the 36 patients, 46 nodules were detected on CT images, 45 of which were also detected on UTE images (a detection rate of 97.6%). The detection rate for lobulation using UTE-MRI was 96.9%; however, the difference compared with the rate for the CT images was not statistically significant (P>0.05). In terms of confounding lesions (confounding lesions indicate that the patient has malignant tumours, benign nodules or inoperable nodules), the UTE-MRI method had a higher detection rate than the CT method, and the difference was significant (P<0.05). The probability of malignant lesions was found to be higher in confounding lesions than in homogeneous lesions. In terms of pleural traction, the UTE-MRI method demonstrated a higher detection rate (120%) than the CT method, but the difference was not statistically significant (P>0.05). In terms of spiculation, the UTE-MRI method demonstrated a lower detection rate (81.8%) than the CT method, although the difference was not statistically significant (P>0.05). Conclusions: Overall, 3-T UTE-MRI imaging has a high detection rate for pulmonary nodules >4 mm and is similar to that of conventional CT imaging. The method can be used for radiation-free lung cancer screening and follow-up examinations to reduce/eliminate both repeat CT examinations and radiation damage.

First Report of Lasiodiplodia theobromae Causing Brown Leaf Spot on Bruguiera gymnorrhiza in China.

Bruguiera gymnorrhiza (Linn.) Sav. is a dominant tree species of mangrove forests in tropical coastal areas of China. This species is commonly used for the greening of tidal flats and seawalls in tropical and subtropical regions (Allen, & Duke 2000). A survey that was conducted from August to September 2020, in the mangrove national nature reserve at Zhanjiang, Guangdong Province, South China. Brown leaf spot symptoms were observed on Bruguiera gymnorrhiza and disease incidence was over 10% (200 investigated trees). Symptomatic small spots initially appeared at the middle or edges of leaves, enlarged irregularly, and developed into brown necrotic spots with dying curly edges. The color of the lesion's center changed to dark brown or gray. To identify the causative agent, twenty diseased leaves were sampled for pathogen isolation. Affected foliar tissues cut into 5 × 5 mm pieces, disinfected in 75% ethanol for 2 mins, rinsed in sterile distilled water, and then air dried under a sterilized filter paper. Leaf pieces were plated onto potato dextrose agar (PDA) in Petri dishes and then incubated at 28°C in darkness for 3-5 days. Hyphal tips of fungal colonies growing from the tissue pieces were subcultured onto fresh PDA to obtain pure single hyphae cultures. The fungal colonies were initially composed of white aerial mycelia, but turned gray after 7 days. Immature conidia were hyaline, subovoid, and aseptate while mature conidia becoming dark brown, one-septate with longitudinal stripes, the length/width ratio is 19.98 to 29.50 µm (average 24.37 µm; n = 50) × 11.99 to 14.45 µm (average 13.09 µm; n = 50). On the basis of morphological features all isolates were identified as Lasiodiplodia theobromae (Pat.) Griffon & Maubl (Alves et al. 2008). For DNA-based identification, the internal transcribed spacer (ITS) region gene and fragment of elongation factor 1-alpha (EF1-α) gene of the three isolates were amplified and sequenced following the methods described in a previous study (White et al. 1990, Carbone & Kohn 1999). The obtained sequences of ITS and EF1-α were deposited in GenBank with accession numbers OK644200 and OL345571. The BLAST results showed at least 99.60% similarity with the sequences of Lasiodiplodia theobromae (ITS, MT644474.1 [99.79%]; EF1-a, MK961975.1 [99.60%]). To fulfill Koch's postulates, PDA plugs with actively growing mycelium of the isolates were inoculated on the leaves of Bruguiera gymnorrhiza plants that were wounded by using a sterilized needle or scalpel. Inoculated leaves were covered with sterilized wet cotton, and the plants were kept at 28°C and 80% relative humidity. The inoculated plants showed leaf spot symptoms that were similar to those previously observed in the field after 1-2 days, whereas control leaves remained healthy. Lasiodiplodia theobromae was consistently isolated from inoculated leaves again. Lasiodiplodia theobromae (Botryosphaeriaceae) is a plurivorous pathogen in a wide variety of hosts, mostly prevalent in tropical and subtropical climate regions. It has been previously reported to cause brown leaf spot on Broussonetia papyrifera (Luo et al. 2020), foliar diseases on Camellia oleifera (Zhu et al. 2014) and Kadsura longipedunculata (Fan et al. 2020). To our knowledge, this is the first report of Lasiodiplodia theobromae causing brown leaf spot on Bruguiera gymnorrhiza plants in China and worldwide. Our findings will help to make management strategies for control of this disease on Bruguiera gymnorrhiza.

Roles of auxin response factors in rice development and stress responses.

Auxin signalling plays a key role in various developmental processes ranging from embryogenesis to senescence in plants. Auxin response factor (ARF), a key component of auxin signalling, functions by binding to auxin response element within promoter of auxin response genes, activating or repressing the target genes. Increasing evidences show that ARFs are crucial for plant response to stresses. This review summarises the recent advance on the functions and their regulatory pathways of rice ARFs in development and responding to stresses. The importance of OsARFs is demonstrated by their roles in triggering various physiological, biochemical and molecular reactions to resist adverse environmental conditions. We also describe the transcriptional and post-transcriptional regulation of OsARFs, and discuss the major challenges in this area.

Structure of the Acidobacteria homodimeric reaction center bound with cytochrome c.

Photosynthesis converts light energy to chemical energy to fuel life on earth. Light energy is harvested by antenna pigments and transferred to reaction centers (RCs) to drive the electron transfer (ET) reactions. Here, we present cryo-electron microscopy (cryo-EM) structures of two forms of the RC from the microaerophilic Chloracidobacterium thermophilum (CabRC): one containing 10 subunits, including two different cytochromes; and the other possessing two additional subunits, PscB and PscZ. The larger form contained 2 Zn-bacteriochlorophylls, 16 bacteriochlorophylls, 10 chlorophylls, 2 lycopenes, 2 hemes, 3 Fe4S4 clusters, 12 lipids, 2 Ca2+ ions and 6 water molecules, revealing a type I RC with an ET chain involving two hemes and a hybrid antenna containing bacteriochlorophylls and chlorophylls. Our results provide a structural basis for understanding the excitation energy and ET within the CabRC and offer evolutionary insights into the origin and adaptation of photosynthetic RCs.