PanDepth, an ultrafast and efficient genomic tool for coverage calculation.

Coverage quantification is required in many sequencing datasets within the field of genomics research. However, most existing tools fail to provide comprehensive statistical results and exhibit limited performance gains from multithreading. Here, we present PanDepth, an ultra-fast and efficient tool for calculating coverage and depth from sequencing alignments. PanDepth outperforms other tools in computation time and memory efficiency for both BAM and CRAM-format alignment files from sequencing data, regardless of read length. It employs chromosome parallel computation and optimized data structures, resulting in ultrafast computation speeds and memory efficiency. It accepts sorted or unsorted BAM and CRAM-format alignment files as well as GTF, GFF and BED-formatted interval files or a specific window size. When provided with a reference genome sequence and the option to enable GC content calculation, PanDepth includes GC content statistics, enhancing the accuracy and reliability of copy number variation analysis. Overall, PanDepth is a powerful tool that accelerates scientific discovery in genomics research.

Lysine 2-hydroxyisobutyrylation proteomics analyses reveal the regulatory mechanism of CaMYB61-CaAFR1 module in regulating stem development in Capsicum annuum L.

Plant stems constitute the most abundant renewable resource on earth. The function of lysine (K)-2-hydroxyisobutyrylation (Khib), a novel post-translational modification (PTM), has not yet been elucidated in plant stem development. Here, by assessing typical pepper genotypes with straight stem (SS) and prostrate stem (PS), we report the first large-scale proteomics analysis for protein Khib to date. Khib-modifications influenced central metabolic processes involved in stem development, such as glycolysis/gluconeogenesis and protein translation. The high Khib level regulated gene expression and protein accumulation associated with cell wall formation in the pepper stem. Specially, we found that CaMYB61 knockdown lines that exhibited prostrate stem phenotypes had high Khib levels. Most histone deacetylases (HDACs, e.g., switch-independent 3 associated polypeptide function related 1, AFR1) potentially function as the "erasing enzymes" involved in reversing Khib level. CaMYB61 positively regulated CaAFR1 expression to erase Khib and promote cellulose and hemicellulose accumulation in the stem. Therefore, we propose a bidirectional regulation hypothesis of "Khib modifications" and "Khib erasing" in stem development, and reveal a novel epigenetic regulatory network in which the CaMYB61-CaAFR1 molecular module participating in the regulation of Khib levels and biosynthesis of cellulose and hemicellulose for the first time.

Folate shapes plant root architecture by affecting auxin distribution.

Folate (vitamin B9) is important for plant root development, but the mechanism is largely unknown. Here we characterized a root defective mutant, folb2, in Arabidopsis, which has severe developmental defects in the primary root. The root apical meristem of the folb2 mutant is impaired, and adventitious roots are frequently found at the root-hypocotyl junction. Positional cloning revealed that a 61-bp deletion is present in the predicted junction region of the promoter and the 5' untranslated region of AtFolB2, a gene encoding a dihydroneopterin aldolase that functions in folate biosynthesis. This mutation leads to a significant reduction in the transcript level of AtFolB2. Liquid chromatography-mass spectrometry analysis showed that the contents of the selected folate compounds were decreased in folb2. Arabidopsis AtFolB2 knockdown lines phenocopy the folb2 mutant. On the other hand, the application of exogenous 5-formyltetrahydrofolic acid could rescue the root phenotype of folb2, indicating that the root phenotype is indeed related to the folate level. Further analysis revealed that folate could promote rootward auxin transport through auxin transporters and that folate may affect particular auxin/indole-3-acetic acid proteins and auxin response factors. Our findings provide new insights into the important role of folic acid in shaping root structure.

A mutation in a C2H2-type zinc finger transcription factor contributed to the transition toward self-pollination in cultivated tomato.

The degree of stigma exsertion has a major influence on self-pollination efficiency in tomato, and its improvement is essential for raising productivity and for fixing advantageous traits in cultivated tomato. To study the evolution of stigma exsertion degree in tomato, we searched for genes associated with this trait and other aspects of flower morphology, including the lengths of anthers, styles, and ovaries. We performed a genome-wide association on 277 tomato accessions and discovered a novel stigma exsertion gene (SE3.1). We reannotated the structure of the gene, which encodes a C2H2-type zinc finger transcription factor. A mutation of the lead single nucleotide polymorphism creates a premature termination codon in SE3.1 and an inserted stigma in cultivated tomatoes. SE3.1 is essential for the conversion of flush stigmas to inserted stigmas. This conversion has a major impact on the rate of self-fertilization. Intriguingly, we found that both SE3.1 and Style2.1 contribute to the transition from stigma exsertion to insertion during the domestication and improvement of tomato. Style2.1 controls the first step of exserted stigmas to flush stigmas, and SE3.1 controls the second step of flush stigmas to inserted stigmas. We provide molecular details for the two-step process that controls the transition from stigma exsertion to insertion, which is of great agronomic importance in tomato.

Critical roles of mitochondrial fatty acid synthesis in tomato development and environmental response.

Plant mitochondrial fatty acid synthesis (mtFAS) appears to be important in photorespiration based on the reverse genetics research from Arabidopsis (Arabidopsis thaliana) in recent years, but its roles in plant development have not been completely explored. Here, we identified a tomato (Solanum lycopersicum) mutant, fern-like, which displays pleiotropic phenotypes including dwarfism, yellowing, curly leaves, and increased axillary buds. Positional cloning and genetic and heterozygous complementation tests revealed that the underlying gene FERN encodes a 3-hydroxyl-ACP dehydratase enzyme involved in mtFAS. FERN was causally involved in tomato morphogenesis by affecting photorespiration, energy supply, and the homeostasis of reactive oxygen species. Based on lipidome data, FERN and the mtFAS pathway may modulate tomato development by influencing mitochondrial membrane lipid composition and other lipid metabolic pathways. These findings provide important insights into the roles and importance of mtFAS in tomato development.

Genome-wide association study reveals the genetic architecture of 27 agronomic traits in tomato.

Tomato (Solanum lycopersicum) is a highly valuable fruit crop, and yield is one of the most important agronomic traits. However, the genetic architecture underlying tomato yield-related traits has not been fully addressed. Based on ∼4.4 million single nucleotide polymorphisms obtained from 605 diverse accessions, we performed a comprehensive genome-wide association study for 27 agronomic traits in tomato. A total of 239 significant associations corresponding to 129 loci, harboring many previously reported and additional genes related to vegetative and reproductive development, were identified, and these loci explained an average of ∼8.8% of the phenotypic variance. A total of 51 loci associated with 25 traits have been under selection during tomato domestication and improvement. Furthermore, a candidate gene, Sl-ACTIVATED MALATE TRANSPORTER15, that encodes an aluminum-activated malate transporter was functionally characterized and shown to act as a pivotal regulator of leaf stomata formation, thereby affecting photosynthesis and drought resistance. This study provides valuable information for tomato genetic research and breeding.

Hair interacts with SlZFP8-like to regulate the initiation and elongation of trichomes by modulating SlZFP6 expression in tomato.

Trichomes are specialized glandular or non-glandular structures that provide physical or chemical protection against insect and pathogen attack. Trichomes in Arabidopsis have been extensively studied as typical non-glandular structures. By contrast, the molecular mechanism underlying glandular trichome formation and elongation remains largely unknown. We previously demonstrated that Hair is essential for the formation of type I and type VI trichomes. Here, we found that overexpression of Hair increased the density and length of tomato trichomes. Biochemical assays revealed that Hair physically interacts with its close homolog SlZFP8-like (SlZFP8L), and SlZFP8L also directly interacts with Woolly. SlZFP8L-overexpressing plants showed increased trichome density and length. We further found that the expression of SlZFP6, which encodes a C2H2 zinc finger protein, is positively regulated by Hair. Using chromatin immunoprecipitation, yeast one-hybrid, and dual-luciferase assays we identified that SlZFP6 is a direct target of Hair. Similar to Hair and SlZFP8L, the overexpression of SlZFP6 also increased the density and length of tomato trichomes. Taken together, our results suggest that Hair interacts with SlZFP8-like to regulate the initiation and elongation of trichomes by modulating SlZFP6 expression in tomato.

Transcriptomic and functional analyses uncover the regulatory role of lncRNA000170 in tomato multicellular trichome formation.

Trichomes are universal specific structures originating from nearly all terrestrial plants. Although quantities of long non-coding RNAs (lncRNAs) have been identified in many plant species, the role of lncRNAs in trichome formation still remains unknown. Here, we identified a total of 1303 lncRNAs in the young stems of woolly mutant LA3560 (Wo) and its non-woolly segregants (WT). Out of these lncRNAs, 86 lncRNAs were obviously upregulated in Wo and 110 lncRNAs were downregulated. We determined that seven lncRNAs were highly expressed in stem trichomes compared to trichome-free stems and several other tissues of LA3560 by a quantitative reverse transcriptase-polymerase chain reaction, including lncRNA000746, lncRNA000170, lncRNA000277, lncRNA000774, lncRNA000756, lncRNA000100, and lncRNA000898. Transgenic experiments revealed that overexpression of lncRNA000170 inhibited type I trichome formation on the lower stems of the adult transgenic plants. We further determined that lncRNA000170 was transcribed from the complementary strand of Solyc10g006360, for which expression can be induced by lncRNA000170 in its overexpression lines and woolly mutants. Solyc10g006360 overexpression also caused type I trichome decrease. In addition, several trichome regulators, such as Wo, H, SlCycB2, and SlCycB3, were markedly downregulated in lncRNA000170 overexpression lines. These findings demonstrate that lncRNA000170 may be involved in the regulatory pathway mediated by these trichome regulators.

Full-length mRNA sequencing and gene expression profiling reveal broad involvement of natural antisense transcript gene pairs in pepper development and response to stresses.

Pepper is an important vegetable with great economic value and unique biological features. In the past few years, significant development has been made toward understanding the huge complex pepper genome; however, pepper functional genomics has not been well studied. To better understand the pepper gene structure and pepper gene regulation, we conducted full-length mRNA sequencing by PacBio sequencing and obtained 57 862 high-quality full-length mRNA sequences derived from 18 362 previously annotated and 5769 newly detected genes. New gene models were built that combined the full-length mRNA sequences and corrected approximately 500 fragmented gene models from previous annotations. Based on the full-length mRNA, we identified 4114 and 5880 pepper genes forming natural antisense transcript (NAT) genes in-cis and in-trans, respectively. Most of these genes accumulate small RNAs in their overlapping regions. By analyzing these NAT gene expression patterns in our transcriptome data, we identified many NAT pairs responsive to a variety of biological processes in pepper. Pepper formate dehydrogenase 1 (FDH1), which is required for R-gene-mediated disease resistance, may be regulated by nat-siRNAs and participate in a positive feedback loop in salicylic acid biosynthesis during resistance responses. Several cis-NAT pairs and subgroups of trans-NAT genes were responsive to pepper pericarp and placenta development, which may play roles in capsanthin and capsaicin biosynthesis. Using a comparative genomics approach, the evolutionary mechanisms of cis-NATs were investigated, and we found that an increase in intergenic sequences accounted for the loss of most cis-NATs, while transposon insertion contributed to the formation of most new cis-NATs. OPEN RESEARCH BADGES: This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at http://bigd.big.ac.cn/gsa Accession number, CRA001412.

GREEN STRIPE, encoding methylated TOMATO AGAMOUS-LIKE 1, regulates chloroplast development and Chl synthesis in fruit.

Fruit development involves chloroplast development, carotenoid accumulation and fruit coloration. Although genetic regulation of fruit development has been extensively investigated, epigenetic regulation of fruit coloration remains largely unexplored. Here, we report a naturally occurring epigenetic regulation of TAGL1, and its impact on chloroplast development and fruit coloration. We used a genome-wide association study in combination with map-based cloning to identify the GREEN STRIPE (GS) locus, a methylated isoform of TAGL1 regulating diversified chloroplast development and carotenoid accumulation. Nonuniform pigmentation of fruit produced by GS was highly associated with methylation of the TAGL1 promoter, which is linked to a SNP at SL2.50ch07_63842838. High degrees of methylation of the TAGL1 promoter downregulated its expression, leading to green stripes. By contrast, low degrees of methylation led to light green stripes in gs. RNA-seq and ChIP collectively showed that the expression of genes involved with Chl synthesis and chloroplast development were significantly upregulated in green stripes relative to light green stripes. Quantitative PCR and dual luciferase assay confirmed that TAGL1 downregulates expression of SlMPEC, SlPsbQ, and SlCAB, and upregulates expression of PSY1 - genes which are associated with chloroplast development and carotenoid accumulation. Altogether, our findings regarding the GS locus demonstrate that naturally occurring methylation of TAGL1 has diverse effects on plastid development in fruit.

NADPH oxidases and the evolution of plant salinity tolerance.

Soil salinization is a major threat to global food security and the biodiversity of natural ecosystems. To adapt to salt stress, plants rely on ROS-mediated signalling networks that operate upstream of a broad array of physiological and genetic processes. A key player in ROS signalling is NADPH oxidase, a plasma-membrane-bound enzyme encoded by RBOH genes. In this study, we have conducted a comprehensive bioinformatic analysis of over 50 halophytic and glycophytic species to link the difference in the kinetics of ROS signalling between contrasting species with the abundance and/or structure of NADPH oxidases. The RBOH proteins were predicted in all the tested plant lineages except some algae species from the Rhodophyta, Chlorophyta and Streptophyta. Within the glycophytic group, the number of RBOH copies correlated negatively with salinity stress tolerance, suggesting that a reduction in the number of RBOH isoforms may be potentially related to the evolution of plant salinity tolerance. While halophytes did not develop unique protein families during evolution, they evolved additional phosphorylation target sites at the N-termini of NADPH oxidases, potentially modulating enzyme activity and allowing more control over their function, resulting in more efficient ROS signalling and adaptation to saline conditions.

Identification of drought-responsive microRNAs in tomato using high-throughput sequencing.

Drought is a major abiotic stress affecting crop productivity and quality. As a class of noncoding RNA, microRNA (miRNA) plays important roles in plant growth, development, and stress response. However, their response and roles in tomato drought stress is largely unknown. Here, by using high-throughput sequencing, we compared the miRNA profiles before and after drought treatment in two tomato genotypes: M82, a drought-sensitive cultivated tomato (Solanum lycopersicum), and IL2-5, a drought-tolerant introgression line derived from M82 and the tomato wild species S. pennellii (LA0716). A total of 108 conserved and 208 novel miRNAs were identified, among them, 32 and 68 were significantly changed in expression after stress. Further, 1936 putative target genes were predicted for those differentially-expressed miRNAs. Gene ontology and pathway analysis showed that many of the target genes were involved in stress resistance, such as genes in GO terms including response to stress, defense response, response to stimulus, phosphorylation, and signal transduction. Our results suggested that miRNAs play an essential role in the drought response of tomato. This work will help to further characterize specific miRNAs functioning in drought tolerance.

Profiling of drought-responsive microRNA and mRNA in tomato using high-throughput sequencing.

BACKGROUND: Abiotic stresses cause severe loss of crop production. Among them, drought is one of the most frequent environmental stresses, which limits crop growth, development and productivity. Plant drought tolerance is fine-tuned by a complex gene regulatory network. Understanding the molecular regulation of this polygenic trait is crucial for the eventual success to improve plant yield and quality. Recent studies have demonstrated that microRNAs play critical roles in plant drought tolerance. However, little is known about the microRNA in drought response of the model plant tomato. Here, we described the profiling of drought-responsive microRNA and mRNA in tomato using high-throughput next-generation sequencing. RESULTS: Drought stress was applied on the seedlings of M82, a drought-sensitive cultivated tomato genotype, and IL9-1, a drought-tolerant introgression line derived from the stress-resistant wild species Solanum pennellii LA0716 and M82. Under drought, IL9-1 performed superior than M82 regarding survival rate, H2O2 elimination and leaf turgor maintenance. A total of four small RNA and eight mRNA libraries were constructed and sequenced using Illumina sequencing technology. 105 conserved and 179 novel microRNAs were identified, among them, 54 and 98 were differentially expressed upon drought stress, respectively. The majority of the differentially-expressed conserved microRNAs was up-regulated in IL9-1 whereas down-regulated in M82. Under drought stress, 2714 and 1161 genes were found to be differentially expressed in M82 and IL9-1, respectively, and many of their homologues are involved in plant stress, such as genes encoding transcription factor and protein kinase. Various pathways involved in abiotic stress were revealed by Gene Ontology and pathway analysis. The mRNA sequencing results indicated that most of the target genes were regulated by their corresponding microRNAs, which suggested that microRNAs may play essential roles in the drought tolerance of tomato. CONCLUSION: In this study, numerous microRNAs and mRNAs involved in the drought response of tomato were identified using high-throughput sequencing, which will provide new insights into the complex regulatory network of plant adaption to drought stress. This work will also help to exploit new players functioning in plant drought-stress tolerance.

Design and Application of a High Sensitivity Piezoresistive Pressure Sensor for Low Pressure Conditions.

In this paper, a pressure sensor for low pressure detection (0.5 kPa-40 kPa) is proposed. In one structure (No. 1), the silicon membrane is partly etched to form a crossed beam on its top for stress concentration. An aluminum layer is also deposited as part of the beam. Four piezoresistors are fabricated. Two are located at the two ends of the beam. The other two are located at the membrane periphery. Four piezoresistors connect into a Wheatstone bridge. To demonstrate the stress concentrate effect of this structure, two other structures were designed and fabricated. One is a flat membrane structure (No. 2), the other is a structure with the aluminum beam, but without etched silicon (No. 3). The measurement results of these three structures show that the No.1 structure has the highest sensitivity, which is about 3.8 times that of the No. 2 structure and 2.7 times that of the No. 3 structure. They also show that the residual stress in the beam has some backside effect on the sensor performance.

Stem lodging Resistance-1 controls stem strength by positively regulating the biosynthesis of cell wall components in Capsicum annuum L.

Lodging presents a significant challenge in cultivating high-yield crops with extensive above-ground biomass, yet the molecular mechanisms underlying this phenomenon in the Solanaceae family remain largely unexplored. In this study, we identified a gene, CaSLR1 (Capsicum annuum Stem Lodging Resistance 1), which encodes a MYELOBLASTOSIS (MYB) family transcription factor, from a lodging-affected C. annuum EMS mutant. The suppression of CaSLR1 expression in pepper led to notable stem lodging, reduced thickness of the secondary cell wall, and decreased stem strength. A similar phenotype was observed in tomato with the knockdown of SlMYB61, the orthologous gene to CaSLR1. Further investigations demonstrated that CaNAC6, a gene involved in secondary cell wall (SCW) formation, is co-expressed with CaSLR1 and acts as a positive regulator of its expression, as confirmed through yeast one-hybrid, dual-luciferase reporter assays, and electrophoretic mobility shift assays. These findings elucidate the CaNAC6-CaSLR1 module that contributes to lodging resistance, emphasizing the critical role of CaSLR1 in the lodging resistance regulatory network.

GFI1B specifies developmental potential of innate lymphoid cell progenitors in the lungs.

Tissue-resident innate lymphoid cells (ILCs) play a vital role in the frontline defense of various tissues, including the lung. The development of type 2 ILCs (ILC2s) depends on transcription factors such as GATA3, RORα, GFI1, and Bcl11b; however, the factors regulating lung-resident ILC2s remain unclear. Through fate mapping analysis of the paralog transcription factors GFI1 and GFI1B, we show that GFI1 is consistently expressed during the transition from progenitor to mature ILC2s. In contrast, GFI1B expression is limited to specific subsets of bone marrow progenitors and lung-resident ILC progenitors. We found that GFI1B+ lung ILC progenitors represent a multi-lineage subset with tissue-resident characteristics and the potential to form lung-derived ILC subsets and liver-resident ILC1s. Loss of GFI1B in bone marrow progenitors led to the selective loss of lung-resident IL-18R+ ILCs and mature ILC2, subsequently preventing the emergence of effector ILCs that could protect the lung against inflammatory or tumor challenge.

PD-1 regulates ILC3-driven intestinal immunity and homeostasis.

Interleukin-(IL) 22 production by intestinal group 3 innate lymphoid cells (ILC3) is critical to maintain gut homeostasis. However, IL-22 needs to be tightly controlled; reduced IL-22 expression is associated with intestinal epithelial barrier defect while its overexpression promotes tumor development. Here, using a single-cell ribonucleic acid sequencing approach, we identified a core set of genes associated with increased IL-22 production by ILC3. Among these genes, programmed cell death 1 (PD-1), extensively studied in the context of cancer and chronic infection, was constitutively expressed on a subset of ILC3. These cells, found in the crypt of the small intestine and colon, displayed superior capacity to produce IL-22. PD-1 expression on ILC3 was dependent on the microbiota and was induced during inflammation in response to IL-23 but, conversely, was reduced in the presence of Notch ligand. PD-1+ ILC3 exhibited distinct metabolic activity with increased glycolytic, lipid, and polyamine synthesis associated with augmented proliferation compared with their PD-1- counterparts. Further, PD-1+ ILC3 showed increased expression of mitochondrial antioxidant proteins which enable the cells to maintain their levels of reactive oxygen species. Loss of PD-1 signaling in ILC3 led to reduced IL-22 production in a cell-intrinsic manner. During inflammation, PD-1 expression was increased on natural cytotoxicity receptor (NCR)- ILC3 while deficiency in PD-1 expression resulted in increased susceptibility to experimental colitis and failure to maintain gut barrier integrity. Collectively, our findings uncover a new function of the PD-1 and highlight the role of PD-1 signaling in the maintenance of gut homeostasis mediated by ILC3 in mice.

SlZF3 regulates tomato plant height by directly repressing SlGA20ox4 in the gibberellic acid biosynthesis pathway.

Plant height is an important target trait for crop genetic improvement. Our previous work has identified a salt-tolerant C2H2 zinc finger, SlZF3, and its overexpression lines also showed a semi-dwarf phenotype, but the molecular mechanism remains to be elucidated. Here, we characterized the dwarf phenotype in detail. The dwarfism is caused by a decrease in stem internode cell elongation and deficiency of bioactive gibberellic acids (GAs), and can be rescued by exogenous GA3 treatment. Gene expression assays detected reduced expression of genes in the GA biosynthesis pathway of the overexpression lines, including SlGA20ox4. Several protein-DNA interaction methods confirmed that SlZF3 can directly bind to the SlGA20ox4 promoter and inhibit its expression, and the interaction can also occur for SlKS and SlKO. Overexpression of SlGA20ox4 in the SlZF3-overexpressing line can recover the dwarf phenotype. Therefore, SlZF3 regulates plant height by directly repressing genes in the tomato GA biosynthesis pathway.

Metabolic features of innate lymphoid cells.

Innate and adaptive immune cells are found in distinct tissue niches where they orchestrate immune responses. This requires intrinsic and temporal metabolic adaptability to coordinately activate the immune response cascade. Dysregulation of this program is a key feature of immunosuppression. Direct or indirect metabolic immune cell reprogramming may offer new approaches to modulate immune cells behavior for therapy to overcome dysregulation. In this review, we explored how metabolism regulates lymphocytes beyond the classical T cell subsets. We focus on the innate lymphoid cell (ILC) family, highlighting the distinct metabolic characteristics of these cells, the impact of environmental factors, and the receptors that could alter immune cell functions through manipulation of metabolic pathways to potentially prevent or treat various diseases.