Upcoming progress of transcriptomics studies on plants: An overview

The widespread misuse of StringTie's gene identifier tags as de facto gene symbols does not allow consistent gene identification in published research

Current RNA sequencing techniques allow the characterization of novel genes and transcript isoforms, with StringTie being an effective and widely used tool for transcript assembly. In merge mode, StringTie assigns identifiers to putative genes, prefixed with "MSTRG" by default. These tags are sometimes used by authors as the designated name for genes or transcripts of high relevance in their work, even though they are unique and unambiguous only within the context of one analysis. In addition, when such identifiers are used, detailed genomic information is essential to identify the genes of interest clearly. In this report, we examined 161 studies that referred to a gene or transcript by its StringTie identifier in their title or abstract. Of these, only 41% provided sufficient information to clearly identify the gene(s) of interest and allow the reproducibility of the results and their comparison to further independent research. In light of this, we offer recommendations to address this issue and improve reporting standards.

Integrative multi-transcriptomic analysis uncovers core genes and potential defense mechanisms in rice-Magnoporthe oryzae interaction

KEY MESSAGE

Multiple transcriptomic comprehensive analyses highlight key genes and cast new light on multifaceted pathways that may be important arenas in rice innate immunity against Magnoporthe oryzae blast disease. Magnaporthe oryzae (MOR) poses a significant threat to rice production worldwide. However, defense mechanisms in rice against MOR remain inadequately defined. In this study, a multi-transcriptomic integrative analysis on 441 samples from diverse microarrays and RNA-seq sets was conducted to reveal critical factors in rice defense against MOR infection. A robust pattern of 3534 upregulated genes and 2920 repressed genes was commonly identified across all MOR-infected arrays and RNA-seq profiles. Interestingly, enrichment analysis revealed a consistent triggering of endoplasmic reticulum (ER)-related mechanisms and citric acid cycle (TCA) influx in rice response to MOR infection across all the transcriptome profiles, suggesting their critical role in modulating rice immunity against the pathogen. By contrast, chloroplast and photosynthesis pathways were frequently repressed across all the profiles. Among ER-related mechanisms, the phagosome pathway involved in the activation of NADPH oxidase was highly triggered in early response to MOR infection. Moreover, WGCNA analysis highlighted four key co-expressed gene modules and 80 significant hub genes associated with MOR infection. Among the core genes, Sec61 gene involved in the ER-translocation process was identified along with OsMFP (peroxisomal oxidation gene) and OSAHH gene (involved in cyclic-trans-methylation). Furthermore, MPK6, WRKY24, NUP35, and NPR1 genes were observed as core co-expressed genes, suggesting their significance in regulating rice immunity against MOR. Our findings elucidate key genes and multifaceted mechanisms in rice-MOR interaction, proposing new informative clues that can be exploited to improve rice resistance against blast disease.

Unveiling the spatiotemporal strategies of plants in response to biotic and abiotic stresses:A comprehensive review

Plant functions are governed by complex regulatory mechanisms that operate across diverse cell types in various tissues. However, the challenge of dissecting plant tissues has hindered the widespread application of single-cell technologies in plant research. Recent advancements in single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) have propelled the field forward. scRNA-seq enables the examination of gene expression at the single-cell level, while ST preserves the spatial context of cellular organization. While previous reviews have discussed the breakthroughs of scRNA-seq and ST in plants, none have comprehensively addressed the use of these technologies to study plant responses to environmental stress at the cellular level. This review provides an in-depth analysis of the development, advantages, and limitations of single-cell and spatial transcriptomics, highlighting their critical role in unraveling plant strategies for coping with biotic and abiotic stresses. We also explore the challenges and future prospects of integrating scRNA-seq and ST in plant research. Understanding cell-specific responses and the complex interactions between cellular entities within the plant under stress is essential for advancing our knowledge of plant biology.

Integrative physiological and transcriptomic analysis provides insights on the molecular basis of ABA-enhanced drought tolerance in pear (Pyrus betulaefolia)

BACKGROUND

Drought stress could suppress the carbon assimilation and limit nutrient uptake of pear plants, thus affecting their growth and severely impacting the quality and yield of pear fruit. ABA is a stress hormone and is reported to alleviate drought stress in numerous plants. However, whether and how ABA functions in the drought responses of pear plants is yet explored.

RESULTS

Here, to address this gap, pear seedlings (Pyrus betulaefolia) were used and subjected to PEG-induced drought conditions with or without additional ABA in various doses. The results showed that while drought caused severe leaf water loss and damage, applying ABA at 50 µM and 100 µM dramatically amended the phenomenon, as indicated by the markedly increased relative water content, and notably decreased relative electrolyte leakage and malondialdehyde content. Based on the results of RNA sequencing and related physiological indices, it was found that drought grossly disrupted chlorophyll synthesis and photosynthesis. It induced the over-production of reactive oxygen species (ROS) and broke the ROS homeostasis, despite the pronounced increases in ABA biosynthesis/content and signaling, flavonoid synthesis, and antioxidant enzyme activities, as well as sugar metabolism. However, ABA applications significantly elevated the expressions of genes in chlorophyll synthesis and photosynthesis, partially boosting the SPAD and Fv/Fm values. In addition, ABA treatments further prominently accelerate the synthesis processes of ABA, flavonoids, and antioxidant enzymes by up-regulating the corresponding genes, resulting in endogenous ABA accumulation and enzymatic activity improvement, thereby expediting the ROS scavenging. Of course, the sugar metabolism pathway was also outstandingly enhanced to balance the growth and stress response of pear seedlings. Moreover, through WGCNA analysis, the core turquoise module associated with ABA-attenuated drought stress was identified, and a portion of key transcription factors (TFs) and some hub genes were characterized, particularly for ERF, WRKY, MYB, bHLH, NAC in TFs, and CSP, COR, and DHN in hub genes. Overall, our study reveals that exogenous ABA could help pear plants to efficiently scavenge drought-induced ROS by improving their photosynthesis capacity, ABA accumulation, sugar catabolism, enzymatic antioxidant system, etc. These results will provide a scientific basis and practical direction for utilizing ABA to mitigate the adverse effects of water starvation resulting from the persistent high temperature on pear plants in summer.

CONCLUSION

50 µM and 100 µM ABA application ameliorated the drought damage in pear seedlings, and the working routes are associated with reinforcement in the photosystem, ABA biosynthesis and signaling, flavonoid accumulation, and sugar metabolism, as well as enzymatic activities in ROS scavenging. The relevant regulatory network is complex, primarily concerned with ERF, WRKY, MYB, bHLH, and NAC TFs, with a focus on the potential target genes named CSP, COR, and DHN.

Transcriptome Analysis Reveals the Role of Plant Hormone Signal Transduction Pathways in the Drought Stress Response of Hemerocallis middendorffii

Drought stress is a significant environmental factor that can impede plant growth and ornamental quality. Hemerocallis middendorffii, a drought-tolerant garden plant, has attracted attention for its ornamental value and application prospects. To investigate the molecular mechanism of drought stress resistance of H. middendorffii, this study employed 20% polyethylene glycol (PEG) 6000 to simulate drought stress. Leaves and roots of H. middendorfii were subjected to 24 h treatment and followed by transcriptome sequencing. Analysis revealed 8796 and 3401 differentially expressed genes (DEGs) in leaves and roots. The major biological processes and key molecular pathways activated under drought stress in H. middendorffii were revealed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The focus of this analysis was on the gene expression changes within plant hormone signal transduction pathway. Additionally, drought-associated transcription factor families such as AP2/ERF, WRKY, MYB, bHLH, NAC, and bZIP were identified among DEGs. Furthermore, potential regulatory relationships of the above transcription factors (TFs) with functional genes in the abscisic acid (ABA) and jasmonic acid (JA) signalling pathways were analysed using correlation network prediction. This research establishes the groundwork for subsequent exploration of drought-responsive gene expression and regulatory patterns in H. middendorfii and provides an importance for the systematic study of its drought-resistant molecular mechanism.

Huanglongbing as a Persistent Threat to Citriculture in Latin America

Citrus commercial species are the most important fruit crops in the world; however, their cultivation is seriously threatened by the fast dispersion of emerging diseases, including Huanglongbing (HLB) citrus greening. HLB disease is vectored by psyllid vectors and associated with phloem-limited α-proteobacteria belonging to the Candidatus Liberibacter genus. Climatic change and trade globalization have led to the rapid spread of HLB from its origin center in Southeast Asia, causing a great economic impact in the main production areas, including East Asia (China), the Mediterranean basin, North America (the United States), and Latin America (Brazil and Mexico). Despite important advances to understand the HLB epidemiology, Candidatus Liberibacter genetics, psyllid vector control, the molecular citrus-Candidatus Liberibacter interaction, and the development of integral disease management strategies, the study areas have been mostly restricted to high-tech-producing countries. Thus, in this review, we provide an overview of the epidemiology, distribution, genetic diversity, management aspects, and omics analysis of HLB in Latin America, where this information to date is limited.

Accelerating crop improvement via integration of transcriptome-based network biology and genome editing

MAIN CONCLUSION

Big data and network biology infer functional coupling between genes. In combination with machine learning, network biology can dramatically accelerate the pace of gene discovery using modern transcriptomics approaches and be validated via genome editing technology for improving crops to stresses. Unlike other living things, plants are sessile and frequently face various environmental challenges due to climate change. The cumulative effects of combined stresses can significantly influence both plant growth and yields. In navigating the complexities of climate change, ensuring the nourishment of our growing population hinges on implementing precise agricultural systems. Conventional breeding methods have been commonly employed; however, their efficacy has been impeded by limitations in terms of time, cost, and infrastructure. Cutting-edge tools focussing on big data are being championed to usher in a new era in stress biology, aiming to cultivate crops that exhibit enhanced resilience to multifactorial stresses. Transcriptomics, combined with network biology and machine learning, is proving to be a powerful approach for identifying potential genes to target for gene editing, specifically to enhance stress tolerance. The integration of transcriptomic data with genome editing can yield significant benefits, such as gaining insights into gene function by modifying or manipulating of specific genes in the target plant. This review provides valuable insights into the use of transcriptomics platforms and the application of biological network analysis and machine learning in the discovery of novel genes, thereby enhancing the understanding of plant responses to combined or sequential stress. The transcriptomics as a forefront omics platform and how it is employed through biological networks and machine learning that lead to novel gene discoveries for producing multi-stress-tolerant crops, limitations, and future directions have also been discussed.

Classification of and detection techniques for RNAi-induced effects in GM plants

RNA interference (RNAi) is a biotechnological tool used for gene silencing in plants, with both endogenous and exogenous applications. Endogenous approaches, such as host-induced gene silencing (HIGS), involve genetically modified (GM) plants, while exogenous methods include spray-induced gene silencing (SIGS). The RNAi mechanism hinges on the introduction of double-stranded RNA (dsRNA), which is processed into short interfering RNAs (siRNAs) that degrade specific messenger RNAs (mRNAs). However, unintended effects on non-target organisms and GM plants are a concern due to sequence homologies or siRNA-induced epigenetic changes. Regulatory bodies such as the EPA and EFSA emphasize the need for comprehensive risk assessments. Detecting unintended effects is complex, often relying on bioinformatic tools and untargeted analyses like transcriptomics and metabolomics, though these methods require extensive genomic data. This review aims to classify mechanisms of RNAi effects induced by short interfering RNA from different sources in plants and to identify technologies that can be used to detect these effects. In addition, practical case studies are summarized and discussed in which previously unintended RNAi effects in genetically modified plants have been investigated. Current literature is limited but suggests RNAi is relatively specific, with few unintended effects observed in GM crops. However, further studies are needed to fully understand and mitigate potential risks, particularly those related to transcriptional gene silencing (TGS) mechanisms, which are less predictable than post-transcriptional gene silencing (PTGS). Particularly the application of untargeted approaches such as small RNA sequencing and transcriptomics is recommended for thorough and comprehensive risk assessments.

GOLEM: A tool for visualizing the distribution of Gene regulatOry eLEMents within the plant promoters with a focus on male gametophyte

Gene expression regulation during tissue development is extremely complex. A key mechanism of gene regulation is the recognition of regulatory motifs, also known as cis-regulatory elements (CREs), by various proteins in gene promoter regions. Localization of these motifs near the transcription start site (TSS) or translation start site (ATG) is crucial for transcription initiation and rate. Transcription levels of individual genes, regulated by these motifs, can vary significantly across tissues and developmental stages, especially in processes like sexual reproduction. However, the precise localization and visualization of these motifs in relation to gene expression in specific tissues can be challenging. Here, we introduce a freely available tool called GOLEM (Gene regulatOry eLEMents; https://golem.ncbr.muni.cz), which enables users to precisely locate any motif of interest with respect to TSS or ATG within the relevant plant genomes across the plant Tree of Life (Chara, Marchantia, Physcomitrium, Azolla, Ceratopteris, Amborella, Oryza, Zea, Solanum and Arabidopsis). The visualization of the motifs is performed with respect to the transcript levels of particular genes in leaves and male reproductive tissues and can be compared with genome-wide distribution regardless of the transcription level. Additionally, genes with specific CREs at defined positions and high expression in selected tissues can be exported for further analysis. GOLEM's functionality is illustrated by its application to conserved motifs (e.g. TATA-box, ABRE, I-box, and TC-element), hormone-responsive elements (GCC-box, ARR10_binding motif), as well as to male gametophyte-related motifs (e.g., LAT52, MEF2, and DOF_core).

Transcriptomic analysis reveals potential roles of polyamine and proline metabolism in waterlogged peach roots inoculated with Funneliformis mosseae and Serendipita indica

Root-associated endophytic fungi can create symbiotic relationships with trees to enhance stress tolerance, but the underlying mechanisms, especially with regard to waterlogging tolerance, remain unclear. This study aimed to elucidate the effects of Funneliformis mosseae and Serendipita indica on the growth, root cross-section structure, and root transcriptional responses of peach under waterlogging stress, with a focus on polyamine and proline metabolism. Genes and transcription factors associated with secondary cell wall biosynthesis were selected, and their expression profiles were analyzed. Funneliformis mosseae significantly increased the height, stem diameter and leaf number of peach seedlings subjected to 2 weeks of waterlogging stress, whereas S. indica only significantly improved stem diameter. Both fungal species substantially increased root diameter, stele diameter, the number of late metaxylem inside the stele and late metaxylem diameter, thus improving aeration within inoculated roots under waterlogging stress. Transcriptomic analysis of waterlogged roots identified 5425 and 5646 differentially expressed genes following inoculation with F. mosseae and S. indica, respectively. The arginine and proline metabolism and arginine biosynthesis pathways were enriched following fungal inoculations. Both fungi reduced the conversion of glutamate and ornithine for proline synthesis. However, S. indica promoted peptide-to-proline conversion by up-regulating the expression of PIPs. Although both fungi promoted the expression of genes involved in arginine and ornithine synthesis pathway, only F. mosseae led to increased levels of arginine and ornithine. Additionally, F. mosseae promoted the accumulation of putrescine and maintained polyamine homeostasis by down-regulating PAO2 and SAMDC. Moreover, F. mosseae facilitated the metabolism of cadaverine. In conclusion, both F. mosseae and S. indica formed symbiotic relationships with peach plants, with F. mosseae primarily improving polyamine accumulation and S. indica predominantly facilitating proline accumulation for enhanced waterlogging resistance.

Rootstock Selection for Resisting Cucumber Fusarium Wilt in Hainan and Corresponding Transcriptome and Metabolome Analysis

Soilborne diseases are important problems in modern agricultural production. Fusarium oxysporum f. sp. cucumerinum (FOC) is one of the predominant soilborne pathogens threatening cucumber cultivation, especially in Hainan, China. This study assessed FOC-resistant rootstocks using incidence rate, disease severity index (DSI), and area under the disease severity index curve (AUDRC), revealing "JinJiaZhen (Mc-4)" as resistant and "JinGangZhuan 1901 (Mc-18)" as susceptible. Comprehensive transcriptome and metabolome analyses were conducted to investigate the defense mechanisms of these rootstocks, revealing key pathways, such as the mitogen-activated protein kinase (MAPK) signaling pathway, starch and sucrose metabolism, and phenylpropanoid biosynthesis, which are crucial for plant disease resistance. Additionally, the study compared the resistance mechanisms of two other rootstocks, Mc-4 and Mc-18, against FOC infection through transcriptomic and metabolomic analyses. Mc-4 exhibited a higher number of differentially expressed genes (DEGs) related to phenylpropanoid biosynthesis compared to Mc-18. Untargeted metabolomics identified 4093 metabolites, with phenylpropanoid biosynthesis, isoquinoline alkaloid biosynthesis, and porphyrin metabolism as primary annotated pathways. On the sixth day post-inoculation, when the number of DEGs and differentially accumulated metabolites (DAMs) was highest, phenylpropanoid biosynthesis emerged as a key pathway in Mc-4, with 37 DEGs and 8 DAMs identified. Notably, Mc-4 showed upregulated expression of genes encoding enzymes involved in phenylpropanoid biosynthesis and increased accumulation of related metabolites, such as coniferyl-aldehyde, coniferyl alcohol, and coniferyl acetate. These findings highlight the differential defense mechanisms between resistant and sensitive rootstocks and provide insights into plant-pathogen interactions. This study's results will contribute to the development of better and disease-free cucumber varieties, promoting sustainable agriculture.

De novo transcriptome profiling revealing genes involved in piperine biosynthetic pathway in Piper longum L

Piper longum, commonly known as long pepper, is highly valued for its bioactive alkaloid piperine, which has diverse pharmaceutical and culinary applications. In this study, we used high-throughput sequencing and de novo transcriptome assembly to analyze the transcriptomes of P. longum leaves, roots, and spikes. Our dataset consisted of 173,381 high-quality transcripts, with functional annotations highlighting key pathways involved in lysine biosynthesis and secondary metabolite production. We identified 8041 simple sequence repeats (SSRs), primarily trinucleotide repeats, adding valuable genetic markers. Additionally, we uncovered 21,235 transcription factors (TFs) across 65 families, including bHLH, NAC, and MYB, which are essential in regulating metabolism. KEGG pathway analysis categorized 4730 transcripts into 377 pathways, focusing on piperine biosynthesis, including phenylpropanoid and L-lysine metabolism. Our research identified 14 expressed genes encoding enzymes crucial for tropane, piperidine, and pyridine alkaloid biosynthesis, shedding light on piperine production mechanisms. High-performance liquid chromatography (HPLC) revealed varying piperine concentrations, with spikes showing the highest content, followed by roots and leaves. This comprehensive analysis of the P. longum transcriptome offers valuable insights into the genetics and regulatory networks underlying piperine biosynthesis, identifying molecular markers and genes that hold significant potential for enhancing the plant's biological and pharmaceutical applications.

Color-induced changes in Chrysanthemum morifolium: an integrative transcriptomic and metabolomic analysis of petals and non-petals

Chrysanthemum morifolium (CM), renowned for its diverse and vibrant varieties, holds significant ornamental and medicinal value. Despite this, the core regulatory mechanisms underlying its coloration, especially in non-petal tissues (i.e., the parts of CM that do not include petals, such as the reproductive tissues, receptacle and calyx), have been insufficiently studied. In this study, we performed transcriptomic and metabolomic analyses on yellow, gold, and white CM petals, as well as non-petal tissues, to investigate the molecular processes driving color variation. A total of 90 differential metabolites were identified, with flavonoids, their derivatives, and lipids emerging as the predominant components of the metabolic profile. At the transcriptional level, 38 pathways were significantly enriched based on the expression of differential genes. The combined metabolomic and transcriptomic analyses revealed that glycerophospholipid metabolism, primarily involving lipids, served as a key regulatory pathway for both petal and non-petal parts across different tissue colors. Notably, white CM exhibited marked differences from their gold and yellow counterparts at both the metabolic and transcriptional levels. These findings offer critical insights into the molecular mechanisms governing CM coloration and provide a foundation for optimizing future breeding efforts.

Transcriptome and Gene Expression Analysis Revealed CeNA1: A Potential New Marker for Somatic Embryogenesis in Common Centaury (Centaurium erythraea Rafn.)

Centaurium erythraea Rafn. is a medicinal plant used as a model for studying plant developmental processes due to its developmental plasticity and ease of manipulation in vitro. Identifying the genes involved in its organogenesis and somatic embryogenesis (SE) is the first step toward unraveling the molecular mechanisms underlying its morphogenic plasticity. Although SE is the most common method of centaury regeneration, the genes involved in this have not yet been identified. The aim of this study was to identify the differentially expressed genes (DEGs) during key stages of SE and organogenesis using transcriptome data, with a focus on novel SE-related genes. The transcriptomic analysis revealed a total of 4040 DEGs during SE and 12,708 during organogenesis. Gene Ontology (GO) annotation showed that the highest number of SE-related genes was involved in defense responses. The expression of fifteen selected SE-related candidate genes was assessed by RT-qPCR across nine centaury developmental stages, including embryogenic tissues. Notably, a newly reported transcript, named CeNA1, was specifically activated during embryogenic callus (ec) induction, making it a potential novel marker for early SE. These findings provide, for the first time, insight into SE-related transcriptional patterns, representing a step closer to uncovering the molecular basis of centaury's developmental plasticity.

Deciphering early responsive signature genes in rice blast disease: an integrated temporal transcriptomic study

Rice blast disease, caused by Magnaporthe oryzae, reigns as the top-most cereal killer, jeopardizing global food security. This necessitates the timely scouting of pathogen stress-responsive genes during the early infection stages. Thus, we integrated time-series microarray (GSE95394) and RNA-Seq (GSE131641) datasets to decipher rice transcriptome responses at 12- and 24-h post-infection (Hpi). Our analysis revealed 1580 differentially expressed genes (DEGs) overlapped between datasets. We constructed a protein-protein interaction (PPI) network for these DEGs and identified significant subnetworks using the MCODE plugin. Further analysis with CytoHubba highlighted eight plausible hub genes for pathogenesis: RPL8 (upregulated) and RPL27, OsPRPL3, RPL21, RPL9, RPS5, OsRPS9, and RPL17 (downregulated). We validated the expression levels of these hub genes in response to infection, finding that RPL8 exhibited significantly higher expression compared with other downregulated genes. Remarkably, RPL8 formed a distinct cluster in the co-expression network, whereas other hub genes were interconnected, with RPL9 playing a central role, indicating its pivotal role in coordinating gene expression during infection. Gene Ontology highlighted the enrichment of hub genes in the ribosome and protein translation processes. Prior studies suggested that plant immune defence activation diminishes the energy pool by suppressing ribosomes. Intriguingly, our study aligns with this phenomenon, as the identified ribosomal proteins (RPs) were suppressed, while RPL8 expression was activated. We anticipate that these RPs could be targeted to develop new stress-resistant rice varieties, beyond their housekeeping role. Overall, integrating transcriptomic data revealed more common DEGs, enhancing the reliability of our analysis and providing deeper insights into rice blast disease mechanisms.

Variability of plant transcriptomic responses under stress acclimation: a review from high throughput studies

Plant transcriptomes are complex entities shaped spatially and temporally by a multitude of stressors. The aim of this review was to summarize the most relevant transcriptomic responses to selected abiotic (UV radiation, chemical compounds, drought, suboptimal temperature) and biotic (bacteria, fungi, viruses, viroids) stress conditions in a variety of plant species, including model species, crops, and medicinal plants. Selected basic and applicative studies employing RNA-seq from various sequencing platforms and single-cell RNA-seq were involved. The transcriptomic responsiveness of various plant species and the diversity of affected gene families were discussed. Under stress acclimation, plant transcriptomes respond particularly dynamically. Stress response involved both distinct, but also similar gene families, depending on the species, tissue, and the quality and dosage of the stressor. We also noted the over-representation of transcriptomic data for some plant organs. Studies on plant transcriptomes allow for a better understanding of response strategies to environmental conditions. Functional analyses reveal the multitude of stress-affected genes as well as acclimatory mechanisms and suggest metabolome diversity, particularly among medicinal species. Extensive characterization of transcriptomic responses to stress would result in the development of new cultivars that would cope with stress more efficiently. These actions would include modern methodological tools, including advanced genetic engineering, as well as gene editing, especially for the expression of selected stress proteins in planta and for metabolic modifications that allow more efficient synthesis of secondary metabolites.

Omics-Driven Strategies for Developing Saline-Smart Lentils: A Comprehensive Review

A number of consequences of climate change, notably salinity, put global food security at risk by impacting the development and production of lentils. Salinity-induced stress alters lentil genetics, resulting in severe developmental issues and eventual phenotypic damage. Lentils have evolved sophisticated signaling networks to combat salinity stress. Lentil genomics and transcriptomics have discovered key genes and pathways that play an important role in mitigating salinity stress. The development of saline-smart cultivars can be further revolutionized by implementing proteomics, metabolomics, miRNAomics, epigenomics, phenomics, ionomics, machine learning, and speed breeding approaches. All these cutting-edge approaches represent a viable path toward creating saline-tolerant lentil cultivars that can withstand climate change and meet the growing demand for high-quality food worldwide. The review emphasizes the gaps that must be filled for future food security in a changing climate while also highlighting the significant discoveries and insights made possible by omics and other state-of-the-art biotechnological techniques.

Transcriptomic Analysis Provides New Insights into the Tolerance Mechanisms of Green Macroalgae Ulva prolifera to High Temperature and Light Stress

Our research focused on understanding the genetic mechanisms that contribute to the tolerance of Ulva prolifera (Chlorophyta), a marine macroalgae, to the combined stress of high temperature and high light intensity. At the mRNA level, the up-regulated DEGs showed enrichment in pathways related to ribosomes, proteasomes, and peroxisomes. The spliceosome pathway genes were found to be vital for U. prolifera's ability to adapt to various challenging situations in all the comparison groups. In response to elevated temperature and light intensity stress, there was a significant increase in genes and pathways related to ribosomes, proteasomes, and peroxisomes, whereas autophagy showed an increase in response to stress after 24 h, but not after 48 h. These findings provide novel insights into how U. prolifera adapts to elevated temperature and light stress.

Epigenetics and plant hormone dynamics: a functional and methodological perspective

Plant hormones, pivotal regulators of plant growth, development, and response to environmental cues, have recently emerged as central modulators of epigenetic processes governing gene expression and phenotypic plasticity. This review addresses the complex interplay between plant hormones and epigenetic mechanisms, highlighting the diverse methodologies that have been harnessed to decipher these intricate relationships. We present a comprehensive overview to understand how phytohormones orchestrate epigenetic modifications, shaping plant adaptation and survival strategies. Conversely, we explore how epigenetic regulators ensure hormonal balance and regulate the signalling pathways of key plant hormones. Furthermore, our investigation includes a search for novel genes that are regulated by plant hormones under the control of epigenetic processes. Our review offers a contemporary overview of the epigenetic-plant hormone crosstalk, emphasizing its significance in plant growth, development, and potential agronomical applications.

RNA-Seq and WGCNA Analyses Reveal Key Regulatory Modules and Genes for Salt Tolerance in Cotton

The problem of soil salinization has seriously hindered agricultural development. Cotton is a pioneering salinity-tolerant crop, so harvesting its key salinity-tolerant genes is important for improving crop salt tolerance. In this study, we analyzed changes in the transcriptome expression profiles of the salt-tolerant cultivar Lu Mian 28 (LM) and the salt-sensitive cultivar Zhong Mian Suo 12 (ZMS) after applying salt stress, and we constructed weighted gene co-expression networks (WGCNA). The results indicated that photosynthesis, amino acid biosynthesis, membrane lipid remodeling, autophagy, and ROS scavenging are key pathways in the salt stress response. Plant-pathogen interactions, plant hormone signal transduction, the mitogen-activated protein kinase (MAPK) signaling pathway, and carotenoid biosynthesis are the regulatory networks associated with these metabolic pathways that confer cotton salt tolerance. The gene-weighted co-expression network was used to screen four modules closely related to traits, identifying 114 transcription factors, including WRKYs, ERFs, NACs, bHLHs, bZIPs, and MYBs, and 11 hub genes. This study provides a reference for acquiring salt-tolerant cotton and abundant genetic resources for molecular breeding.

Unlocking the Transcriptional Reprogramming Repertoire between Variety-Dependent Responses of Grapevine Berries to Infection by Aspergillus carbonarius

Aspergillus carbonarius causes severe decays on berries in vineyards and is among the main fungal species responsible for grape contamination by ochratoxin A (OTA), which is the foremost mycotoxin produced by this fungus. The main goal of this study was to investigate at the transcriptome level the comparative profiles between two table grape varieties (Victoria and Fraoula, the white and red variety, respectively) after their inoculation with a virulent OTA-producing A. carbonarius strain. The two varieties revealed quite different transcriptomic signatures and the expression profiles of the differential expressed genes (DEGs) highlighted distinct and variety-specific responses during the infection period. The significant enrichment of pathways related to the modulation of transcriptional dynamics towards the activation of defence responses, the triggering of the metabolic shunt for the biosynthesis of secondary metabolites, mainly phenylpropanoids, and the upregulation of DEGs encoding phytoalexins, transcription factors, and genes involved in plant-pathogen interaction and immune signaling transduction was revealed in an early time point in Fraoula, whereas, in Victoria, any transcriptional reprogramming was observed after a delay. However, both varieties, to some extent, also showed common expression dynamics for specific DEG families, such as those encoding for laccases and stilbene synthases. Jasmonate (JA) may play a critical modulator role in the defence machinery as various JA-biosynthetic DEGs were upregulated. Along with the broader modulation of the transcriptome that was observed in white grape, expression profiles of specific A. carbonarius genes related to pathogenesis, fungal sporulation, and conidiation highlight the higher susceptibility of Victoria. Furthermore, the A. carbonarius transcriptional patterns directly associated with the regulation of the pathogen OTA-biosynthesis gene cluster were more highly induced in Victoria than in Fraoula. The latter was less contaminated by OTA and showed substantially lower sporulation. These findings contribute to uncovering the interplay beyond this plant-microbe interaction.

Urban Air Pollution and Plant Tolerance: Omics Responses to Ozone, Nitrogen Oxides, and Particulate Matter

Urban air pollution is a crucial global challenge, mainly originating from urbanization and industrial activities, which are continuously increasing. Vegetation serves as a natural air filter for air pollution, but adverse effects on plant health, photosynthesis, and metabolism can occur. Recent omics technologies have revolutionized the study of molecular plant responses to air pollution, overcoming previous limitations. This review synthesizes the latest advancements in molecular plant responses to major air pollutants, emphasizing ozone (O3), nitrogen oxides (NOX), and particulate matter (PM) research. These pollutants induce stress responses common to other abiotic and biotic stresses, including the activation of reactive oxygen species (ROSs)-scavenging enzymes and hormone signaling pathways. New evidence has shown the central role of antioxidant phenolic compound biosynthesis, via the phenylpropanoid pathway, in air pollution stress responses. Transcription factors like WRKY, AP2/ERF, and MYB, which connect hormone signaling to antioxidant biosynthesis, were also affected. To date, research has predominantly focused on laboratory studies analyzing individual pollutants. This review highlights the need for comprehensive field studies and the identification of molecular tolerance traits, which are crucial for the identification of tolerant plant species, aimed at the development of sustainable nature-based solutions (NBSs) to mitigate urban air pollution.

Multi-Omics Approaches in Oil Palm Research: A Comprehensive Review of Metabolomics, Proteomics, and Transcriptomics Based on Low-Temperature Stress

Oil palm (Elaeis guineensis Jacq.) is a typical tropical oil crop with a temperature of 26-28 °C, providing approximately 35% of the total world's vegetable oil. Growth and productivity are significantly affected by low-temperature stress, resulting in inhibited growth and substantial yield losses. To comprehend the intricate molecular mechanisms underlying the response and acclimation of oil palm under low-temperature stress, multi-omics approaches, including metabolomics, proteomics, and transcriptomics, have emerged as powerful tools. This comprehensive review aims to provide an in-depth analysis of recent advancements in multi-omics studies on oil palm under low-temperature stress, including the key findings from omics-based research, highlighting changes in metabolite profiles, protein expression, and gene transcription, as well as including the potential of integrating multi-omics data to reveal novel insights into the molecular networks and regulatory pathways involved in the response to low-temperature stress. This review also emphasizes the challenges and prospects of multi-omics approaches in oil palm research, providing a roadmap for future investigations. Overall, a better understanding of the molecular basis of the response of oil palm to low-temperature stress will facilitate the development of effective breeding and biotechnological strategies to improve the crop's resilience and productivity in changing climate scenarios.

Deciphering the Interaction between Coniella granati and Pomegranate Fruit Employing Transcriptomics

Pomegranate fruit dry rot is caused by Coniella granati, also referred as Pilidiella granati. In order to decipher the induced responses of mature pomegranates inoculated with the pathogen, an RNA-seq analysis was employed. A high number of differentially expressed genes (DEGs) were observed through a three-time series inoculation period. The transcriptional reprogramming was time-dependent, whereas the majority of DEGs were suppressed and the expression patterns of specific genes may facilitate the pathogen colonization at 1 day after inoculation (dai). In contrast, at 2 dai and mainly thereafter at 3 dai, defense responses were partially triggered in delay. Particularly, DEGs were mainly upregulated at the latest time point. Among them, specific DEGs involved in cell wall modification and degradation processes, pathogen recognition and signaling transduction cascades, activation of specific defense and metabolite biosynthesis-related genes, as well in induction of particular families of transcriptional factors, may constitute crucial components of a defense recruiting strategy employed by pomegranate fruit upon C. granati challenge. Overall, our findings provide novel insights to the compatible interaction of pomegranates-C. granati and lay the foundations for establishing integrated pest management (IPM) strategies involving advanced approaches, such as gene editing or molecular breeding programs for disease resistance, according to European Union (EU) goals.

Cutting-edge plant natural product pathway elucidation

Plant natural products (PNPs) play important roles in plant physiology and have been applied across diverse fields of human society. Understanding their biosynthetic pathways informs plant evolution and meanwhile enables sustainable production through metabolic engineering. However, the discovery of PNP biosynthetic pathways remains challenging due to the diversity of enzymes involved and limitations in traditional gene mining approaches. In this review, we will summarize state-of-the-art strategies and recent examples for predicting and characterizing PNP biosynthetic pathways, respectively, with multiomics-guided tools and heterologous host systems and share our perspectives on the systematic pipelines integrating these various bioinformatic and biochemical approaches.

Duckweed: Beyond an Efficient Plant Model System

Duckweed (Lemnaceae) rises as a crucial model system due to its unique characteristics and wide-ranging utility. The significance of physiological research and phytoremediation highlights the intricate potential of duckweed in the current era of plant biology. Special attention to duckweed has been brought due to its distinctive features of nutrient uptake, ion transport dynamics, detoxification, intricate signaling, and stress tolerance. In addition, duckweed can alleviate environmental pollutants and enhance sustainability by participating in bioremediation processes and wastewater treatment. Furthermore, insights into the genomic complexity of Lemnaceae species and the flourishing field of transgenic development highlight the opportunities for genetic manipulation and biotechnological innovations. Novel methods for the germplasm conservation of duckweed can be adopted to preserve genetic diversity for future research endeavors and breeding programs. This review centers around prospects in duckweed research promoting interdisciplinary collaborations and technological advancements to drive its full potential as a model organism.

Molecular Mechanism of Exogenous ABA to Enhance UV-B Resistance in Rhododendron chrysanthum Pall. by Modulating Flavonoid Accumulation

With the depletion of the ozone layer, the intensity of ultraviolet B (UV-B) radiation reaching the Earth's surface increases, which in turn causes significant stress to plants and affects all aspects of plant growth and development. The aim of this study was to investigate the mechanism of response to UV-B radiation in the endemic species of Rhododendron chrysanthum Pall. (R. chrysanthum) in the Changbai Mountains and to study how exogenous ABA regulates the response of R. chrysanthum to UV-B stress. The results of chlorophyll fluorescence images and OJIP kinetic curves showed that UV-B radiation damaged the PSII photosystem of R. chrysanthum, and exogenous ABA could alleviate this damage to some extent. A total of 2148 metabolites were detected by metabolomics, of which flavonoids accounted for the highest number (487, or 22.67%). KEGG enrichment analysis of flavonoids that showed differential accumulation by UV-B radiation and exogenous ABA revealed that flavonoid biosynthesis and flavone and flavonol biosynthesis were significantly altered. GO analysis showed that most of the DEGs produced after UV-B radiation and exogenous ABA were distributed in the cellular process, cellular anatomical entity, and catalytic activity. Network analysis of key DFs and DEGs associated with flavonoid synthesis identified key flavonoids (isorhamnetin-3-O-gallate and dihydromyricetin) and genes (TRINITY_DN2213_c0_g1_i4-A1) that promote the resistance of R. chrysanthum to UV-B stress. In addition, multiple transcription factor families were found to be involved in the regulation of the flavonoid synthesis pathway under UV-B stress. Overall, R. chrysanthum actively responded to UV-B stress by regulating changes in flavonoids, especially flavones and flavonols, while exogenous ABA further enhanced its resistance to UV-B stress. The experimental results not only provide a new perspective for understanding the molecular mechanism of the response to UV-B stress in the R. chrysanthum, but also provide a valuable theoretical basis for future research and application in improving plant adversity tolerance.

Mapping and Omics Integration: Towards Precise Rice Disease Resistance Breeding

Rice (Oryza sativa), as a staple crop feeding a significant portion of the global population, particularly in Asian countries, faces constant threats from various diseases jeopardizing global food security. A precise understanding of disease resistance mechanisms is crucial for developing resilient rice varieties. Traditional genetic mapping methods, such as QTL mapping, provide valuable insights into the genetic basis of diseases. However, the complex nature of rice diseases demands a holistic approach to gain an accurate knowledge of it. Omics technologies, including genomics, transcriptomics, proteomics, and metabolomics, enable a comprehensive analysis of biological molecules, uncovering intricate molecular interactions within the rice plant. The integration of various mapping techniques using multi-omics data has revolutionized our understanding of rice disease resistance. By overlaying genetic maps with high-throughput omics datasets, researchers can pinpoint specific genes, proteins, or metabolites associated with disease resistance. This integration enhances the precision of disease-related biomarkers with a better understanding of their functional roles in disease resistance. The improvement of rice breeding for disease resistance through this integration represents a significant stride in agricultural science because a better understanding of the molecular intricacies and interactions underlying disease resistance architecture leads to a more precise and efficient development of resilient and productive rice varieties. In this review, we explore how the integration of mapping and omics data can result in a transformative impact on rice breeding for enhancing disease resistance.

High-throughput sequencing-based analysis of the composition and diversity of the endophyte community in roots of Stellera chamaejasme

Stellera chamaejasme (S. chamaejasme) is an important medicinal plant with heat-clearing, detoxifying, swelling and anti-inflammatory effects. At the same time, it is also one of the iconic plants of natural grassland degradation in northwest China, playing a key role in the invasion process. Plant endophytes live in healthy plant tissues and can synthesize substances needed for plant growth, induce disease resistance in host plants, and enhance plant resistance to environmental stress. Therefore, studying the root endophytes of S. chamaejasme is of great significance for mining beneficial microbial resources and biological prevention and control of S. chamaejasme. This study used Illumina MiSeq high-throughput sequencing technology to analyze the composition and diversity of endophytes in the roots of S. chamaejasme in different alpine grasslands (BGC, NMC and XGYZ) in Tibet. Research results show that the main phylum of endophytic fungi in the roots of S. chamaejasme in different regions is Ascomycota, and the main phyla of endophytic bacteria are Actinobacteria, Proteobacteria and Firmicutes (Bacteroidota). Overall, the endophyte diversity of the NMC samples was significantly higher than that of the other two sample sites. Principal coordinate analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA) results showed significant differences in the composition of endophytic bacterial and fungal communities among BGC, NMC and XGYZ samples. Co-occurrence network analysis of endophytes showed that there were positive correlations between fungi and some negative correlations between bacteria, and the co-occurrence network of bacteria was more complex than that of fungi. In short, this study provides a vital reference for further exploring and utilizing the endophyte resources of S. chamaejasme and an in-depth understanding of the ecological functions of S. chamaejasme endophytes.

Comparative Metabolomics and Transcriptome Studies of Two Forms of Rhododendron chrysanthum Pall. under UV-B Stress

Rhododendron chrysanthum Pall. (R. chrysanthum), a plant with UV-B resistance mechanisms that can adapt to alpine environments, has gained attention as an important plant resource with the ability to cope with UV-B stress. In this experiment, R. chrysanthums derived from the same origin were migrated to different culture environments (artificial climate chamber and intelligent artificial incubator) to obtain two forms of R. chrysanthum. After UV-B irradiation, 404 metabolites and 93,034 unigenes were detected. Twenty-six of these different metabolites were classified as UV-B-responsive metabolites. Glyceric acid is used as a potential UV-B stress biomarker. The domesticated Rhododendron chrysanthum Pall. had high amino acid and SOD contents. The study shows that the domesticated Rhododendron chrysanthum Pall. has significant UV-B resistance. The transcriptomics results show that the trends of DEGs after UV-B radiation were similar for both forms of R. chrysanthum: cellular process and metabolic process accounted for a higher proportion in biological processes, cellular anatomical entity accounted for the highest proportion in the cellular component, and catalytic activity and binding accounted for the highest proportion in the molecular function category. Through comparative study, the forms of metabolites resistant to UV-B stress in plants can be reflected, and UV-B radiation absorption complexes can be screened for application in future specific practices. Moreover, by comparing the differences in response to UV-B stress between the two forms of R. chrysanthum, references can be provided for cultivating domesticated plants with UV-B stress resistance characteristics. Research on the complex mechanism of plant adaptation to UV-B will be aided by these results.

Insights into the Transcriptional Reprogramming of Peach Leaves Inoculated with Taphrina deformans

The dimorphic fungus Taphrina deformans is the causal agent of peach leaf curl disease, which affects leaves, flowers, and fruits. An RNA-seq approach was employed to gain insights into the transcriptional reprogramming of a peach cultivar during leaf inoculation with the yeast phase of the fungus across a compatible interaction. The results uncovered modulations of specific peach differentially expressed genes (DEGs) in peaches and pathways related to either the induction of host defense responses or pathogen colonization and disease spread. Expression profiles of DEGs were shown to be highly time-dependent and related to the presence of the two forms of the fungal growth, the inoculated yeast form and the later biotrophic phase during mycelial development. In parallel, this differential reprogramming was consistent with a diphasic detection of fungal load in the challenged leaves over the 120 h after inoculation (HAI) period. Leaf defense responses either occurred during the early yeast phase inoculation at 24 HAI, mediated primarily by cell wall modification processes, or more pronouncedly during the biotrophic phase at 72 HAI, as revealed by the activation of DEGs related to pathogen perception, signaling transduction, and secondary metabolism towards restraining further hypha proliferation. On the contrary, the expression patterns of specific DEGs at 120 HAI might further contribute to host susceptibility. These findings will further allow us to elucidate the molecular responses beyond the peach-T. deformans interaction.

Genome-wide identification of GA2ox genes family and analysis of PbrGA2ox1-mediated enhanced chlorophyll accumulation by promoting chloroplast development in pear

BACKGROUND

Chlorophyll (Chl) is an agronomic trait associated with photosynthesis and yield. Gibberellin 2-oxidases (GA2oxs) have previously been shown to be involved in Chl accumulation. However, whether and how the PbrGA2ox proteins (PbrGA2oxs) mediate Chl accumulation in pear (Pyrus spp.) is scarce.

RESULTS

Here, we aimed to elucidate the role of the pear GA2ox gene family in Chl accumulation and the related underlying mechanisms. We isolated 13 PbrGA2ox genes (PbrGA2oxs) from the pear database and identified PbrGA2ox1 as a potential regulator of Chl accumulation. We found that transiently overexpressing PbrGA2ox1 in chlorotic pear leaves led to Chl accumulation, and PbrGA2ox1 silencing in normal pear leaves led to Chl degradation, as evident by the regreening and chlorosis phenomenon, respectively. Meanwhile, PbrGA2ox1-overexpressing (OE) tobacco plants discernably exhibited Chl built-up, as evidenced by significantly higher Pn and Fv/Fm. In addition, RNA sequencing (RNA-seq), physiological and biochemical investigations revealed an increase in abscisic acid (ABA), methyl jasmonate (MeJA), and salicylic acid (SA) concentrations and signaling pathways; a marked elevation in reducing and soluble sugar contents; and a marginal decline in the starch and sucrose levels in OE plants. Interestingly, PbrGA2ox1 overexpression did not prominently affect Chl synthesis. However, it indeed facilitated chloroplast development by increasing chloroplast number per cell and compacting the thylakoid granum stacks. These findings might jointly contribute to Chl accumulation in OE plants.

CONCLUSION

Overall, our results suggested that GA2oxs accelerate Chl accumulation by stimulating chloroplast development and proved the potential of PbrGA2ox1 as a candidate gene for genetically breeding biofortified pear plants with a higher yield.

An assessment of AcquireX and Compound Discoverer software 3.3 for non-targeted metabolomics

We used the Exploris 240 mass spectrometer for non-targeted metabolomics on Saccharomyces cerevisiae strain BY4741 and tested AcquireX software for increasing the number of detectable compounds and Compound Discoverer 3.3 software for identifying compounds by MS2 spectral library matching. AcquireX increased the number of potentially identifiable compounds by 50% through six iterations of MS2 acquisition. On the basis of high-scoring MS2 matches made by Compound Discoverer, there were 483 compounds putatively identified from nearly 8000 candidate spectra. Comparisons to 20 amino acid standards, however, revealed instances whereby compound matches could be incorrect despite strong scores. Situations included the candidate with the top score not being the correct compound, matching the same compound at two different chromatographic peaks, assigning the highest score to a library compound much heavier than the mass for the parent ion, and grouping MS2 isomers to a single parent ion. Because the software does not calculate false positive and false discovery rates at these multiple levels where such errors can propagate, we conclude that manual examination of findings will be required post software analysis. These results will interest scientists who may use this platform for metabolomics research in diverse disciplines including medical science, environmental science, and agriculture.

Recent advances in plant translational genomics for crop improvement

The growing population, climate change, and limited agricultural resources put enormous pressure on agricultural systems. A plateau in crop yields is occurring and extreme weather events and urbanization threaten the livelihood of farmers. It is imperative that immediate attention is paid to addressing the increasing food demand, ensuring resilience against emerging threats, and meeting the demand for more nutritious, safer food. Under uncertain conditions, it is essential to expand genetic diversity and discover novel crop varieties or variations to develop higher and more stable yields. Genomics plays a significant role in developing abundant and nutrient-dense food crops. An alternative to traditional breeding approach, translational genomics is able to improve breeding programs in a more efficient and precise manner by translating genomic concepts into practical tools. Crop breeding based on genomics offers potential solutions to overcome the limitations of conventional breeding methods, including improved crop varieties that provide more nutritional value and are protected from biotic and abiotic stresses. Genetic markers, such as SNPs and ESTs, contribute to the discovery of QTLs controlling agronomic traits and stress tolerance. In order to meet the growing demand for food, there is a need to incorporate QTLs into breeding programs using marker-assisted selection/breeding and transgenic technologies. This chapter primarily focuses on the recent advances that are made in translational genomics for crop improvement and various omics techniques including transcriptomics, metagenomics, pangenomics, single cell omics etc. Numerous genome editing techniques including CRISPR Cas technology and their applications in crop improvement had been discussed.

Variability in Leaf Color Induced by Chlorophyll Deficiency: Transcriptional Changes in Bamboo Leaves

The diversity of leaf characteristics, particularly leaf color, underscores a pivotal area of inquiry within plant science. The synthesis and functionality of chlorophyll, crucial for photosynthesis, largely dictate leaf coloration, with varying concentrations imparting different shades of green. Complex gene interactions regulate the synthesis and degradation of chlorophyll, and disruptions in these pathways can result in abnormal chlorophyll production, thereby affecting leaf pigmentation. This study focuses on Bambusa multiplex f. silverstripe, a natural variant distinguished by a spectrum of leaf colors, such as green, white, and green-white, attributed to genetic variations influencing gene expression. By examining the physiological and molecular mechanisms underlying chlorophyll anomalies and genetic factors in Silverstripe, this research sheds light on the intricate gene interactions and regulatory networks that contribute to leaf color diversity. The investigation includes the measurement of photosynthetic pigments and nutrient concentrations across different leaf color types, alongside transcriptomic analyses for identifying differentially expressed genes. The role of key genes in pathways such as ALA biosynthesis, chlorophyll synthesis, photosynthesis, and sugar metabolism is explored, offering critical insights for advancing research and plant breeding practices.

Multi-omics-driven advances in the understanding of triacylglycerol biosynthesis in oil seeds

Vegetable oils are rich sources of polyunsaturated fatty acids and energy as well as valuable sources of human food, animal feed, and bioenergy. Triacylglycerols, which are comprised of three fatty acids attached to a glycerol backbone, are the main component of vegetable oils. Here, we review the development and application of multiple-level omics in major oilseeds and emphasize the progress in the analysis of the biological roles of key genes underlying seed oil content and quality in major oilseeds. Finally, we discuss future research directions in functional genomics research based on current omics and oil metabolic engineering strategies that aim to enhance seed oil content and quality, and specific fatty acids components according to either human health needs or industrial requirements.

Transcriptome data reveals the conservation genetics of Cypripedium forrestii, a plant species with extremely small populations endemic to Yunnan, China

The Cypripedium forrestii is an orchid species with extremely small populations (PSESP) in Yunnan, China. C. forrestii is range-restricted and less-studied than many orchid species, and it is exposed to various threats to its survival. We investigated its potential habitats and collected 52 samples from eight locations, as well as two outgroup species for reference. We developed genetic markers (SNPs) for C. forrestii based on transcriptome sequencing (RNA-seq) data, and analyzed the genetic diversity, population structure, gene flow and demographic history of C. forrestii in detail. C. forrestii is a taxonomically independent species to protect. We found that the genetic diversity of C. forrestii was very low (1.7e-4) compared with other endangered species. We identified three genetic clusters, and several populations with distinct genetic backgrounds. Most genetic diversity was found within sampling sites (87.87%) and genetic clusters (91.39%). Gene flow has been greatly limited over the most recent generations, probably due to geographical distance, historical climate change and habitat fragmentation. We also detected a severe bottleneck event brought about by the recent population constraints. These factors, together with its reproductive characteristics, contribute to the population fragmentation and low genetic diversity of C. forrestii. Based on our findings, we suggest an integrative conservation strategy to protect and recover the genetic diversity of C. forrestii and a further comprehensive study of its ecological traits in the future.

Diosgenin biosynthesis investigation in medicinal herb (Tribulus terrestris) by transcriptome analysis

Next-generation sequencing (NGS) has revolutionized the analysis of specific genes, pathways, and their regulation in various species. Tribulus terrestris L., an annual medicinal herb of Zygophyllaceae family, has gained significant attention due to its diverse medicinal properties, including anti-inflammatory, antimicrobial, and anti-cancer effects. Diosgenin, a steroidal saponin, is the major bioactive compound responsible for the medicinal importance of T. terrestris. However, there is a paucity of information regarding the genes involved in the diosgenin biosynthetic pathway in T. terrestris. To address this gap, this study aimed to identify candidate genes associated with diosgenin biosynthesis through whole transcriptome profiling. A total of ∼7.9 GB of data, comprising 482 million reads, was obtained and assembled into 148,871 unigenes. Subsequently, functional annotations were assigned to 50 % of the unigenes using sequence similarity searches against the NCBI non-redundant (NR), Uniprot, KEGG, Pfam, GO, and COG databases, primarily based on Gene Ontology and KEGG-KAAS pathways. The majority of unigenes associated with the biosynthesis of the steroidal diosgenin backbone exhibited up-regulation in the fruit, leaf, and root tissues, except the SQE gene in root. The differential expression of selected genes was further validated through quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, the study identified 21,026 unigenes related to transcription factors and 15,551 unigenes containing simple sequence repeats (SSR). Notably, di-nucleotide SSR motifs exhibited a high repeat frequency. These findings greatly enhance our understanding of the diosgenin biosynthesis pathway and provide a basis for future research in molecular investigation and metabolic engineering, specifically for boosting diosgenin content.

Abscisic Acid Affects Phenolic Acid Content to Increase Tolerance to UV-B Stress in Rhododendron chrysanthum Pall

The presence of the ozone hole increases the amount of UV radiation reaching a plant's surface, and UV-B radiation is an abiotic stress capable of affecting plant growth. Rhododendron chrysanthum Pall. (R. chrysanthum) grows in alpine regions, where strong UV-B radiation is present, and has been able to adapt to strong UV-B radiation over a long period of evolution. We investigated the response of R. chrysanthum leaves to UV-B radiation using widely targeted metabolomics and transcriptomics. Although phytohormones have been studied for many years in plant growth and development and adaptation to environmental stresses, this paper is innovative in terms of the species studied and the methods used. Using unique species and the latest research methods, this paper was able to add information to this topic for the species R. chrysanthum. We treated R. chrysanthum grown in a simulated alpine environment, with group M receiving no UV-B radiation and groups N and Q (externally applied abscisic acid treatment) receiving UV-B radiation for 2 days (8 h per day). The results of the MN group showed significant changes in phenolic acid accumulation and differential expression of genes related to phenolic acid synthesis in leaves of R. chrysanthum after UV-B radiation. We combined transcriptomics and metabolomics data to map the metabolic regulatory network of phenolic acids under UV-B stress in order to investigate the response of such secondary metabolites to stress. L-phenylalanine, L-tyrosine and phenylpyruvic acid contents in R. chrysanthum were significantly increased after UV-B radiation. Simultaneously, the levels of 3-hydroxyphenylacetic acid, 2-phenylethanol, anthranilate, 2-hydroxycinnamic acid, 3-hydroxycinnamic acid, α-hydroxycinnamic acid and 2-hydroxy-3-phenylpropanoic acid in this pathway were elevated in response to UV-B stress. In contrast, the study in the NQ group found that externally applied abscisic acid (ABA) in R. chrysanthum had greater tolerance to UV-B radiation, and phenolic acid accumulation under the influence of ABA also showed greater differences. The contents of 2-phenylethanol, 1-o-p-coumaroyl-β-d-glucose, 2-hydroxy-3-phenylpropanoic acid, 3-(4-hydroxyphenyl)-propionic acid and 3-o-feruloylquinic ac-id-o-glucoside were significantly elevated in R. chrysanthum after external application of ABA to protect against UV-B stress. Taken together, these studies of the three groups indicated that ABA can influence phenolic acid production to promote the response of R. chrysanthum to UV-B stress, which provided a theoretical reference for the study of its complex molecular regulatory mechanism.

Transcriptome and miRNAs Profiles Reveal Regulatory Network and Key Regulators of Secondary Xylem Formation in "84K" Poplar

Secondary xylem produced by stem secondary growth is the main source of tree biomass and possesses great economic and ecological value in papermaking, construction, biofuels, and the global carbon cycle. The secondary xylem formation is a complex developmental process, and the underlying regulatory networks and potential mechanisms are still under exploration. In this study, using hybrid poplar (Populus alba × Populus glandulosa clone 84K) as a model system, we first ascertained three representative stages of stem secondary growth and then investigated the regulatory network of secondary xylem formation by joint analysis of transcriptome and miRNAs. Notably, 7507 differentially expressed genes (DEGs) and 55 differentially expressed miRNAs (DEMs) were identified from stage 1 without initiating secondary growth to stage 2 with just initiating secondary growth, which was much more than those identified from stage 2 to stage 3 with obvious secondary growth. DEGs encoding transcription factors and lignin biosynthetic enzymes and those associated with plant hormones were found to participate in the secondary xylem formation. MiRNA-target analysis revealed that a total of 85 DEMs were predicted to have 2948 putative targets. Among them, PagmiR396d-PagGRFs, PagmiR395c-PagGA2ox1/PagLHW/PagSULTR2/PagPolyubiquitin 1, PagmiR482d-PagLAC4, PagmiR167e-PagbHLH62, and PagmiR167f/g/h-PagbHLH110 modules were involved in the regulating cambial activity and its differentiation into secondary xylem, cell expansion, secondary cell wall deposition, and programmed cell death. Our results give new insights into the regulatory network and mechanism of secondary xylem formation.

Application of Multi-Perspectives in Tea Breeding and the Main Directions

Tea plants are an economically important crop and conducting research on tea breeding contributes to enhancing the yield and quality of tea leaves as well as breeding traits that satisfy the requirements of the public. This study reviews the current status of tea plants germplasm resources and their utilization, which has provided genetic material for the application of multi-omics, including genomics and transcriptomics in breeding. Various molecular markers for breeding were designed based on multi-omics, and available approaches in the direction of high yield, quality and resistance in tea plants breeding are proposed. Additionally, future breeding of tea plants based on single-cellomics, pangenomics, plant-microbe interactions and epigenetics are proposed and provided as references. This study aims to provide inspiration and guidance for advancing the development of genetic breeding in tea plants, as well as providing implications for breeding research in other crops.