ResNetKhib: a novel cell type-specific tool for predicting lysine 2-hydroxyisobutylation sites via transfer learning.

Lysine 2-hydroxyisobutylation (Khib), which was first reported in 2014, has been shown to play vital roles in a myriad of biological processes including gene transcription, regulation of chromatin functions, purine metabolism, pentose phosphate pathway and glycolysis/gluconeogenesis. Identification of Khib sites in protein substrates represents an initial but crucial step in elucidating the molecular mechanisms underlying protein 2-hydroxyisobutylation. Experimental identification of Khib sites mainly depends on the combination of liquid chromatography and mass spectrometry. However, experimental approaches for identifying Khib sites are often time-consuming and expensive compared with computational approaches. Previous studies have shown that Khib sites may have distinct characteristics for different cell types of the same species. Several tools have been developed to identify Khib sites, which exhibit high diversity in their algorithms, encoding schemes and feature selection techniques. However, to date, there are no tools designed for predicting cell type-specific Khib sites. Therefore, it is highly desirable to develop an effective predictor for cell type-specific Khib site prediction. Inspired by the residual connection of ResNet, we develop a deep learning-based approach, termed ResNetKhib, which leverages both the one-dimensional convolution and transfer learning to enable and improve the prediction of cell type-specific 2-hydroxyisobutylation sites. ResNetKhib is capable of predicting Khib sites for four human cell types, mouse liver cell and three rice cell types. Its performance is benchmarked against the commonly used random forest (RF) predictor on both 10-fold cross-validation and independent tests. The results show that ResNetKhib achieves the area under the receiver operating characteristic curve values ranging from 0.807 to 0.901, depending on the cell type and species, which performs better than RF-based predictors and other currently available Khib site prediction tools. We also implement an online web server of the proposed ResNetKhib algorithm together with all the curated datasets and trained model for the wider research community to use, which is publicly accessible at https://resnetkhib.erc.monash.edu/.

OsMADS5 interacts with OsSPL14/17 to inhibit rice root elongation by restricting cell proliferation of root meristem under ammonium supply.

Nitrogen (N) is a vital major nutrient for rice (Oryza sativa). Rice responds to different applications of N by altering its root morphology, including root elongation. Although ammonium ( NH 4 + ) is the primary source of N for rice, NH 4 + is toxic to rice roots and inhibits root elongation. However, the precise molecular mechanism that NH 4 + -inhibited root elongation of rice is not well understood. Here, we identified a rice T-DNA insert mutant of OsMADS5 with a longer seminal root (SR) under sufficient N conditions. Reverse-transcription quantitative PCR analysis revealed that the expression level of OsMADS5 was increased under NH 4 + compared with NO 3 - supply. Under NH 4 + conditions, knocking out OsMADS5 (cas9) produced a longer SR, phenocopying osmads5, while there was no significant difference in SR length between wild-type and cas9 under NO 3 - supply. Moreover, OsMADS5-overexpression plants displayed the opposite SR phenotype. Further study demonstrated that enhancement of OsMADS5 by NH 4 + supply inhibited rice SR elongation, likely by reducing root meristem activity of root tip, with the involvement of OsCYCB1;1. We also found that OsMADS5 interacted with OsSPL14 and OsSPL17 (OsSPL14/17) to repress their transcriptional activation by attenuating DNA binding ability. Moreover, loss of OsSPL14/17 function in osmads5 eliminated its stimulative effect on SR elongation under NH 4 + conditions, implying OsSPL14/17 may function downstream of OsMADS5 to mediate rice SR elongation under NH 4 + supply. Overall, our results indicate the existence of a novel modulatory pathway in which enhancement of OsMADS5 by NH 4 + supply represses the transcriptional activities of OsSPL14/17 to restrict SR elongation of rice.

Upland rice genomic signatures of adaptation to drought resistance and navigation to molecular design breeding.

Upland rice is a distinctive drought-aerobic ecotype of cultivated rice highly resistant to drought stress. However, the genetic and genomic basis for the drought-aerobic adaptation of upland rice remains largely unclear due to the lack of genomic resources. In this study, we identified 25 typical upland rice accessions and assembled a high-quality genome of one of the typical upland rice varieties, IRAT109, comprising 384 Mb with a contig N50 of 19.6 Mb. Phylogenetic analysis revealed upland and lowland rice have distinct ecotype differentiation within the japonica subgroup. Comparative genomic analyses revealed that adaptive differentiation of lowland and upland rice is likely attributable to the natural variation of many genes in promoter regions, formation of specific genes in upland rice, and expansion of gene families. We revealed differentiated gene expression patterns in the leaves and roots of the two ecotypes and found that lignin synthesis mediated by the phenylpropane pathway plays an important role in the adaptive differentiation of upland and lowland rice. We identified 28 selective sweeps that occurred during domestication and validated that the qRT9 gene in selective regions can positively regulate drought resistance in rice. Eighty key genes closely associated with drought resistance were appraised for their appreciable potential in drought resistance breeding. Our study enhances the understanding of the adaptation of upland rice and provides a genome navigation map of drought resistance breeding, which will facilitate the breeding of drought-resistant rice and the "blue revolution" in agriculture.

Pseudomonas hefeiensis sp. nov., isolated from the rhizosphere of multiple cash crops in China.

Three bacterial strains, FP250T, FP821, and FP53, were isolated from the rhizosphere soil of oilseed rape, licorice, and habanero pepper in Anhui Province, Xinjiang Uygur Autonomous Region, and Jiangsu Province, PR China, respectively. All strains were shown to grow at 4-37 °C and pH 6.0-9.0, and in the presence of 0-4.0 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences or housekeeping genes (16S rRNA, gyrB, rpoB, and rpoD) and phylogenomic analysis showed that strains FP250T, FP821, and FP53 belong to the genus Pseudomonas, and are closely related to Pseudomonas kilonensis DSM 13647T, Pseudomonas brassicacearum JCM 11938T, Pseudomonas viciae 11K1T, and Pseudomonas thivervalensis DSM 13194T. The DNA G+C content of strain FP205T was 59.8 mol%. The average nucleotide identity and digital DNA-DNA hybridization values of strain FP205T with the most closely related strain were 93.2 % and 51.4 %, respectively, which is well below the threshold for species differentiation. Strain FP205T contained summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) as major fatty acids, and diphosphatidylglycerol along with phosphatidylethanolamine and aminophospholipid as major polar lipids. The predominant isoprenoid quinone was ubiquinone-9. Based on these phenotypic, phylogenetic, and chemotaxonomic results, strain FP205T represents a novel species of the genus Pseudomonas, for which the name Pseudomonas hefeiensis sp. nov. is proposed. The type strain is FP205T (=ACCC 62447T=JCM 35687T).

iFeatureOmega: an integrative platform for engineering, visualization and analysis of features from molecular sequences, structural and ligand data sets.

The rapid accumulation of molecular data motivates development of innovative approaches to computationally characterize sequences, structures and functions of biological and chemical molecules in an efficient, accessible and accurate manner. Notwithstanding several computational tools that characterize protein or nucleic acids data, there are no one-stop computational toolkits that comprehensively characterize a wide range of biomolecules. We address this vital need by developing a holistic platform that generates features from sequence and structural data for a diverse collection of molecule types. Our freely available and easy-to-use iFeatureOmega platform generates, analyzes and visualizes 189 representations for biological sequences, structures and ligands. To the best of our knowledge, iFeatureOmega provides the largest scope when directly compared to the current solutions, in terms of the number of feature extraction and analysis approaches and coverage of different molecules. We release three versions of iFeatureOmega including a webserver, command line interface and graphical interface to satisfy needs of experienced bioinformaticians and less computer-savvy biologists and biochemists. With the assistance of iFeatureOmega, users can encode their molecular data into representations that facilitate construction of predictive models and analytical studies. We highlight benefits of iFeatureOmega based on three research applications, demonstrating how it can be used to accelerate and streamline research in bioinformatics, computational biology, and cheminformatics areas. The iFeatureOmega webserver is freely available at http://ifeatureomega.erc.monash.edu and the standalone versions can be downloaded from https://github.com/Superzchen/iFeatureOmega-GUI/ and https://github.com/Superzchen/iFeatureOmega-CLI/.

Natural variation in MORE GRAINS 1 regulates grain number and grain weight in rice.

Grain yield is determined mainly by grain number and grain weight. In this study, we identified and characterized MORE GRAINS1 (MOG1), a gene associated with grain number and grain weight in rice (Oryza sativa L.), through map-based cloning. Overexpression of MOG1 increased grain yield by 18.6%-22.3% under field conditions. We determined that MOG1, a bHLH transcription factor, interacts with OsbHLH107 and directly activates the expression of LONELY GUY (LOG), which encodes a cytokinin-activating enzyme and the cell expansion gene EXPANSIN-LIKE1 (EXPLA1), positively regulating grain number per panicle and grain weight. Natural variations in the promoter and coding regions of MOG1 between Hap-LNW and Hap-HNW alleles resulted in changes in MOG1 expression level and transcriptional activation, leading to functional differences. Haplotype analysis revealed that Hap-HNW, which results in a greater number and heavier grains, has undergone strong selection but has been poorly utilized in modern lowland rice breeding. In summary, the MOG1-OsbHLH107 complex activates LOG and EXPLA1 expression to promote cell expansion and division of young panicles through the cytokinin pathway, thereby increasing grain number and grain weight. These findings suggest that Hap-HNW could be used in strategies to breed high-yielding temperate japonica lowland rice.

E3 ubiquitin ligase OsPIE3 destabilises the B-lectin receptor-like kinase PID2 to control blast disease resistance in rice.

Previous studies have reported that PID2, which encodes a B-lectin receptor-like kinase, is a key gene in the resistance of rice to Magnaporthe oryzae strain ZB15. However, the PID2-mediated downstream signalling events remain largely unknown. The U-box E3 ubiquitin ligase OsPIE3 (PID2-interacting E3) was isolated and confirmed to play key roles in PID2-mediated rice blast resistance. Yeast two-hybrid analysis showed that the armadillo repeat region of OsPIE3 is required for its interaction with PID2. Further investigation demonstrated that OsPIE3 can modify the subcellular localisation of PID2, thus promoting its nuclear recruitment from the plasma membrane for protein degradation in the ubiquitin-proteasome system. Site-directed mutagenesis of a conserved cysteine site (C230S) within the U-box domain of OsPIE3 reduces PID2 translocation and ubiquitination. Genetic analysis suggested that OsPIE3 loss-of-function mutants exhibited enhanced resistance to M. oryzae isolate ZB15, whereas mutants with overexpressed OsPIE3 exhibited reduced resistance. Furthermore, the OsPIE3/PID2-double mutant displayed a similar blast phenotype to that of the PID2 single mutant, suggesting that OsPIE3 is a negative regulator and functions along with PID2 in blast disease resistance. Our findings confirm that the E3 ubiquitin ligase OsPIE3 is necessary for PID2-mediated rice blast disease resistance regulation.

BPB1 regulates rice (Oryza sative L.) panicle length and panicle branch development by promoting lignin and inhibiting cellulose accumulation.

Panicle structure is one of the most important agronomic traits directly related to rice yield. This study identified a rice mutant basal primary branch 1 (bpb1), which exhibited a phenotype of reduced panicle length and arrested basal primary branch development. In addition, lignin content was found to be increased while cellulose content was decreased in bpb1 young panicles. Map-based cloning methods characterized the gene BPB1, which encodes a peptide transporter (PTR) family transporter. Phylogenetic tree analysis showed that the BPB1 family is highly conserved in plants, especially the PTR2 domain. It is worth noting that BPB1 is divided into two categories based on monocotyledonous and dicotyledonous plants. Transcriptome analysis showed that BPB1 mutation can promote lignin synthesis and inhibit cellulose synthesis, starch and sucrose metabolism, cell cycle, expression of various plant hormones, and some star genes, thereby inhibiting rice panicle length, resulting in basal primary branch development stagnant phenotypes. In this study, BPB1 provides new insights into the molecular mechanism of rice panicle structure regulation by BPB1 by regulating lignin and cellulose content and several transcriptional metabolic pathways. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01389-x.

Mapping of qChalk1 controlling grain chalkiness in japonica rice.

BACKGROUND: Rice grain chalkiness is an undesirable characteristic that affects grain quality. The aim of this study was to map QTLs controlling grain chalkiness in japonica rice. METHODS AND RESULTS: In this study, two japonica rice cultivars with similar grain shapes but different grain chalkiness rates were crossed and the F2 and BC1F2 populations were subjected to QTL-seq analysis to map the QTLs controlling the grain chalkiness rate. QTL-seq analysis revealed SNP index differences on chromosome 1 in both of the segregating populations. Using polymorphic markers between the two parents, QTL mapping was conducted on 213 individual plants in the BC1F2 population. QTL mapping confined a QTL controlling grain chalkiness, qChalk1, to a 1.1 Mb genomic region on chromosome 1. qChalk1 explained 19.7% of the phenotypic variation. CONCLUSION: A QTL controlling grain chalkiness qChalk1 was detected in both F2 and BC1F2 segregating populations by QTL-Seq and QTL mapping methods. This result would be helpful for further cloning of the genes controlling grain chalkiness in japonica rice.

Regulation of OsPIL15 on rice quality.

The phytochrome-interacting factor-like gene OsPIL15 negatively regulates grain size and 1000-grain weight, but its regulatory effect on rice quality traits is unknown. Here, knock-down, knock-out, and over-expression of OsPIL15 transgenic rice lines were used to investigate the effects of OsPIL15 on rice yield and quality traits. The results showed that knock-down or knock-out of OsPIL15 increased grain length and width, chalkiness, amylose content, glutenin and globulin content, and total protein content but reduced amylopectin content, total starch content, prolamin and albumin content, and gel consistency. Over-expression of OsPIL15 showed the opposite results, except for the reduction of prolamin content. Although OsPIL15 changed the grain size and weight, it had no effect on grain length/width ratio, brown rice rate, and milled rice rate. KEGG pathway enrichment analysis of differentially expressed genes between transgenic lines and wild type showed that OsPIL15 mainly regulated genes related to ribosome, metabolic pathways, and biosynthesis of secondary metabolites. Gene expression analysis showed that RNAi transgenic lines decreased OsCIN2 and OsSUS1 expression and increased OsGBSSI, OsSSI, OsAPGL2, and OsAPGL3 expression level, while over-expression of OsPIL15 increased OsCIN2, OsSUS1, OsSUS6, and OsSSI and decreased OsSSIIa, OsSSIIc, and OsAPGL2 expression level. These results revealed that OsPIL15 plays an important role in rice grain development. In addition to grain shape, OsPIL15 also regulates chalkiness, starch content, protein content, and gel consistency. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01311-x.

The basic helix-loop-helix transcription factor, OsPIL15, regulates grain size via directly targeting a purine permease gene OsPUP7 in rice.

As members of the basic helix-loop-helix transcription factor families, phytochrome-interacting factors regulate an array of developmental responses ranging from seed germination to plant growth. However, little is known about their roles in modulating grain development. Here, we firstly analyzed the expression pattern of rice OsPIL genes in grains and found that OsPIL15 may play an important role in grain development. We then generated knockout (KO) OsPIL15 lines in rice using CRISPR/Cas9 technology, the silencing expression of OsPIL15 led to increased numbers of cells, which thus enhanced grain size and weight. Moreover, overexpression and suppression of OsPIL15 in the rice endosperm resulted in brown rice showing grain sizes and weights that were decreased and increased respectively. Further studies indicated that OsPIL15 binds to N1-box (CACGCG) motifs of the purine permease gene OsPUP7 promoter. Measurement of isopentenyl adenosine, a bioactive form of cytokinin (CTK), revealed increased contents in the OsPIL15-KO spikelets compared with the wild-type. Overall, our results demonstrate a possible pathway whereby OsPIL15 directly targets OsPUP7, affecting CTK transport and thereby influencing cell division and subsequent grain size. These findings provide a valuable insight into the molecular functions of OsPIL15 in rice grains, highlighting a useful genetic improvement leading to increased rice yield.

miR1432-OsACOT (Acyl-CoA thioesterase) module determines grain yield via enhancing grain filling rate in rice.

Rice grain filling rate contributes largely to grain productivity and accumulation of nutrients. MicroRNAs (miRNAs) are key regulators of development and physiology in plants and become a novel key target for engineering grain size and crop yield. However, there is little studies, so far, showing the miRNA regulation of grain filling and rice yield, in consequence. Here, we show that suppressed expression of rice miR1432 (STTM1432) significantly improves grain weight by enhancing grain filling rate and leads to an increase in overall grain yield up to 17.14% in a field trial. Molecular analysis identified rice Acyl-CoA thioesterase (OsACOT), which is conserved with ACOT13 in other species, as a major target of miR1432 by cleavage. Moreover, overexpression of miR1432-resistant form of OsACOT (OXmACOT) resembled the STTM1432 plants, that is, a large margin of an increase in grain weight up to 46.69% through improving the grain filling rate. Further study indicated that OsACOT was involved in biosynthesis of medium-chain fatty acids. In addition, RNA-seq based transcriptomic analyses of transgenic plants with altered expression of miR1432 demonstrated that downstream genes of miR1432-regulated network are involved in fatty acid metabolism and phytohormones biosynthesis and also overlap with the enrichment analysis of co-expressed genes of OsACOT, which is consistent with the increased levels of auxin and abscisic acid in STTM1432 and OXmACOT plants. Overall, miR1432-OsACOT module plays an important role in grain filling in rice, illustrating its capacity for engineering yield improvement in crops.

Suppression of microRNA159 impacts multiple agronomic traits in rice (Oryza sativa L.).

BACKGROUND: microRNAs (miRNAs) are important regulators in plant growth and development. miR159 is a conserved miRNA among different plant species and has various functions in plants. Studies on miR159 are mostly done on model plant, Arabidopsis thaliana. In rice, studies on miR159 were either based upon genome-wide expression analyses focused upon responses to different nitrogen forms and abiotic stress or upon phenotypic studies of transgenic plants overexpressing its precursor. STTM (Short Tandem Target Mimic) is an effective tool to block the activity of endogenous mature miRNA activity in plant. Therefore, specific roles of miR159 in rice could be explored by down regulating miR159 through STTM. RESULTS: In this study, expression of mature miR159 was successfully suppressed by STTM which resulted in the increased expressions of its two targets genes, OsGAMYB and OsGAMYBL1 (GAMYB-LIKE 1). Overall, STTM159 plants exhibited short stature along with smaller organ size and reduction in stem diameter, length of flag leaf, main panicle, spikelet hulls and grain size. Histological analysis of stem, leaf and mature spikelet hull showed the reduced number of small vascular bundles (SVB), less number of small veins (SV) between two big veins (LV) and less cell number in outer parenchyma. Gene Ontology (GO) enrichment analysis of differentially expressed genes between wild type plants and STTM159 transgenic plants showed that genes involved in cell division, auxin, cytokinin (CK) and brassinosteroids (BRs) biosynthesis and signaling are significantly down-regulated in STTM159 plants. CONCLUSION: Our data suggests that in rice, miR159 positively regulates organ size, including stem, leaf, and grain size due to the promotion of cell division. Further analysis from the RNA-seq data showed that the decreased cell divisions in STTM159 transgenic plants may result, at least partly from the lower expression of the genes involved in cell cycle and hormone homeostasis, which provides new insights of rice miR159-specific functions.

qRT9, a quantitative trait locus controlling root thickness and root length in upland rice.

Breeding for strong root systems is an important strategy for improving drought avoidance in rice. To clone genes responsible for strong root traits, an upland rice introgression line IL392 with thicker and longer roots than the background parent lowland rice Yuefu was selected. A quantitative trait locus (QTL), qRT9, controlling root thickness and root length was detected under hydroponic culture using 203 F(2:3) populations derived from a cross between Yuefu and IL392. The qRT9 locus explained 32.5% and 28.1% of the variance for root thickness and root length, respectively. Using 3185 F2 plants, qRT9 was ultimately narrowed down to an 11.5 kb region by substitution mapping. One putative basic helix-loop-helix (bHLH) transcription factor gene, LOC_Os09g28210 (named OsbHLH120), is annotated in this region. Sequences of OsbHLH120 in 11 upland rice and 13 lowland rice indicated that a single nucleotide polymorphism (SNP) at position 82 and an insertion/deletion (Indel) at position 628-642 cause amino acid changes and are conserved between upland rice and lowland rice. Phenotypic analysis indicated that the two polymorphisms were significantly associated with root thickness and root length under hydroponic culture. Quantitative real-time PCR showed that OsbHLH120 was strongly induced by polyethylene glycol (PEG), salt, and abscisic acid, but higher expression was present in IL392 roots than in Yuefu under PEG and salt stress. The successfully isolated locus, qRT9, enriches our knowledge of the genetic basis for drought avoidance and provides an opportunity for breeding drought avoidance varieties by utilizing valuable genes in the upland rice germplasm.

Differentially expressed microRNA cohorts in seed development may contribute to poor grain filling of inferior spikelets in rice.

BACKGROUND: The inferior spikelets are defined to be those at portions where the grains receive less photosynthetic products during the seed development. The typical inferior spikelets are physically located on the proximal secondary branches in a rice panicle and traditionally characterized by a later flowering time and a slower grain-filling rate, compared to those so-called superior spikelets. Grains produced on the inferior spikelets are consequently under-developed and lighter in weight than those formed on the superior spikelets. MicroRNAs (miRNAs) are recognized as key players in regulating plant development through post-transcriptional gene regulations. We previously presented the evidence that miRNAs may influence grain-filling rate and played a role in determining the grain weight and yield in rice. RESULTS: In this study, further analyses of the expressed small RNAs in superior and inferior spikelets were conducted at five distinct developmental stages of grain development. Totally, 457 known miRNAs and 13 novel miRNAs were analyzed, showing a differential expression of 141 known miRNAs between superior and inferior spikelets with higher expression levels of most miRNAs associated with the superior than the inferior spikelets during the early stage of grain filling. Genes targeted by those differentially expressed miRNAs (i.e. miR156, miR164, miR167, miR397, miR1861, and miR1867) were recognized to play roles in multiple developmental and signaling pathways related to plant hormone homeostasis and starch accumulation. CONCLUSIONS: Our data established a complicated link between miRNA dynamics and the traditional role of hormones in grain filling and development, providing new insights into the widely accepted concepts of the so-called superior and inferior spikelets in rice production.

Phenotypic and Genomic Characterization of Pseudomonas wuhanensis sp. nov., a Novel Species with Promising Features as a Potential Plant Growth-Promoting and Biocontrol Agent.

Plant growth-promoting rhizobacterial strain FP607T was isolated from the rhizosphere of beets in Wuhan, China. Strain FP607T exhibited significant antagonism toward several phytopathogenic bacteria, indicating that FP607T may produce antimicrobial metabolites and has a stronger biocontrol efficacy against plant pathogens. Growth-promoting tests showed that FP607T produced indole-3-acetic acid (IAA), NH3, and ferritin. The genome sequence of strain FP607T was 6,590,972 bp long with 59.0% G + C content. The optimum temperature range was 25-30 °C, and the optimum pH was 7. The cells of strain FP607T were Gram-negative, short, and rod-shaped, with polar flagella. The colonies on the King's B (KB) agar plates were light yellow, smooth, and circular, with regular edges. A phylogenetic analysis of the 16S rRNA sequence and a multilocus sequence analysis (MLSA) showed that strain FP607T was most closely related to the type of strain Pseudomonas farris SWRI79T. Based on a polyphasic taxonomic approach, strain FP607T was identified as a novel species within the genus Pseudomonas, for which the name Pseudomonas wuhanensis sp. nov. was proposed. The type of strain used was FP607T (JCM 35688, CGMCC 27743, and ACCC 62446).

Natural product guvermectin inhibits guanosine 5'-monophosphate synthetase and confers broad-spectrum antibacterial activity.

Bacterial diseases caused substantial yield losses worldwide, with the rise of antibiotic resistance, there is a critical need for alternative antibacterial compounds. Natural products (NPs) from microorganisms have emerged as promising candidates due to their potential as cost-effective and environmentally friendly bactericides. However, the precise mechanisms underlying the antibacterial activity of many NPs, including Guvermectin (GV), remain poorly understood. Here, we sought to explore how GV interacts with Guanosine 5'-monophosphate synthetase (GMPs), an enzyme crucial in bacterial guanine synthesis. We employed a combination of biochemical and genetic approaches, enzyme activity assays, site-directed mutagenesis, bio-layer interferometry, and molecular docking assays to assess GV's antibacterial activity and its mechanism targeting GMPs. The results showed that GV effectively inhibits GMPs, disrupting bacterial guanine synthesis. This was confirmed through drug-resistant assays and direct enzyme inhibition studies. Bio-layer interferometry assays demonstrated specific binding of GV to GMPs, with dependency on Xanthosine 5'-monophosphate. Site-directed mutagenesis identified key residues crucial for the GV-GMP interaction. This study elucidates the antibacterial mechanism of GV, highlighting its potential as a biocontrol agent in agriculture. These findings contribute to the development of novel antibacterial agents and underscore the importance of exploring natural products for agricultural disease management.

Diverse interactions of five core type III effectors from Ralstonia solanacearum with plants.

Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type III effectors (T3Es) to cause disease. In this study, we isolate a pathogenic R. solanacearum strain named P380 from tomato rhizosphere. Five out of 12 core T3Es of strain P380 are introduced into Pseudomonas syringae DC3000D36E separately to determine their functions in interacting with plants. DC3000D36E that harbors each effector suppresses FliC-triggered Pti5 and ACRE31 expression, ROS burst, and callose deposition. RipAE, RipU, and RipW elicit cell death as well as upregulate the MAPK cascades in Nicotiana benthamiana. The derivatives RipC1ΔDXDX(T/V) and RipWΔDKXXQ but not RipAEK310R fail to suppress ROS burst. Moreover, RipAEK310R and RipWΔDKXXQ retain the cell death elicitation ability. RipAE and RipW are associated with salicylic acid and jasmonic acid pathways, respectively. RipAE and RipAQ significantly promote the propagation of DC3000D36E in plants. The five core T3Es localize in diverse subcellular organelles of nucleus, plasma membrane, endoplasmic reticulum, and Golgi network. The suppressor of G2 allele of Skp1 is required for RipAE but not RipU-triggered cell death in N. benthamiana. These results indicate that the core T3Es in R. solanacearum play diverse roles in plant-pathogen interactions.

An Open Dataset of Annotated Metaphase Cell Images for Chromosome Identification.

Chromosomes are a principal target of clinical cytogenetic studies. While chromosomal analysis is an integral part of prenatal care, the conventional manual identification of chromosomes in images is time-consuming and costly. This study developed a chromosome detector that uses deep learning and that achieved an accuracy of 98.88% in chromosomal identification. Specifically, we compiled and made available a large and publicly accessible database containing chromosome images and annotations for training chromosome detectors. The database contains five thousand 24 chromosome class annotations and 2,000 single chromosome annotations. This database also contains examples of chromosome variations. Our database provides a reference for researchers in this field and may help expedite the development of clinical applications.

Pseudomonas syringae Type III Secretion Protein HrpP Manipulates Plant Immunity To Promote Infection.

The bacterial plant pathogen Pseudomonas syringae deploys a type III secretion system (T3SS) to deliver effector proteins into plant cells to facilitate infection, for which many effectors have been characterized for their interactions. However, few T3SS Hrp (hypersensitive response and pathogenicity) proteins from the T3SS secretion apparatus have been studied for their direct interactions with plants. Here, we show that the P. syringae pv. tomato DC3000 T3SS protein HrpP induces host cell death, suppresses pattern-triggered immunity (PTI), and restores the effector translocation ability of the hrpP mutant. The hrpP-transgenic Arabidopsis lines exhibited decreased PTI responses to flg22 and elf18 and enhanced disease susceptibility to P. syringae pv. tomato DC3000. Transcriptome analysis reveals that HrpP sensing activates salicylic acid (SA) signaling while suppressing jasmonic acid (JA) signaling, which correlates with increased SA accumulation and decreased JA biosynthesis. Both yeast two-hybrid and bimolecular fluorescence complementation assays show that HrpP interacts with mitogen-activated protein kinase kinase 2 (MKK2) on the plant membrane and in the nucleus. The HrpP truncation HrpP1-119, rather than HrpP1-101, retains the ability to interact with MKK2 and suppress PTI in plants. In contrast, HrpP1-101 continues to cause cell death and electrolyte leakage. MKK2 silencing compromises SA signaling but has no effect on cell death caused by HrpP. Overall, our work highlights that the P. syringae T3SS protein HrpP facilitates effector translocation and manipulates plant immunity to facilitate bacterial infection. IMPORTANCE The T3SS is required for the virulence of many Gram-negative bacterial pathogens of plants and animals. This study focuses on the sensing and function of the T3SS protein HrpP during plant interactions. Our findings show that HrpP and its N-terminal truncation HrpP1-119 can interact with MKK2, promote effector translocation, and manipulate plant immunity to facilitate bacterial infection, highlighting the P. syringae T3SS component involved in the fine-tuning of plant immunity.