Functional genomics encompasses diverse disciplines in molecular biology and bioinformatics to comprehend the blueprint, regulation, and expression of genetic elements that define the physiology of an organism. The deluge of sequencing data in the postgenomics era has demanded the involvement of computer scientists and mathematicians to create algorithms, analytical software, and databases for the storage, curation, and analysis of biological big data. In this chapter, we discuss on the concept of functional genomics in the context of systems biology and provide examples of its application in human genetic disease studies, molecular crop improvement, and metagenomics for antibiotic discovery. An overview of transcriptomics workflow and experimental considerations is also introduced. Lastly, we present an in-house case study of transcriptomics analysis of an aromatic herbal plant to understand the effect of elicitation on the biosynthesis of volatile organic compounds.
This chapter introduces different aspects of bioinformatics with a brief discussion in the systems biology context. Example applications in network pharmacology of traditional Chinese medicine, systems metabolic engineering, and plant genome-scale modelling are described. Lastly, this chapter concludes on how bioinformatics helps to integrate omics data derived from various studies described in previous chapters for a holistic understanding of secondary metabolite production in P. minus.
The generation of microplastics (MPs) has increased recently and become an emerging issue globally. Due to their long-term durability and capability of traveling between different habitats in air, water, and soil, MPs presence in freshwater ecosystem threatens the environment with respect to its quality, biotic life, and sustainability. Although many previous works have been undertaken on the MPs pollution in the marine system recently, none of the study has covered the scope of MPs pollution in the freshwater. To consolidate scattered knowledge in the literature body into one place, this work identifies the sources, fate, occurrence, transport pathways, and distribution of MPs pollution in the aquatic system with respect to their impacts on biotic life, degradation, and detection techniques. This article also discusses the environmental implications of MPs pollution in the freshwater ecosystems. Certain techniques for identifying MPs and their limitations in applications are presented. Through a literature survey of over 276 published articles (2000-2023), this study presents an overview of solutions to the MP pollution, while identifying research gaps in the body of knowledge for further work. It is conclusive from this review that the MPs exist in the freshwater due to an improper littering of plastic waste and its degradation into smaller particles. Approximately 15-51 trillion MP particles have accumulated in the oceans with their weight ranging between 93,000 and 236,000 metric ton (Mt), while about 19-23 Mt of plastic waste was released into rivers in 2016, which was projected to increase up to 53 Mt by 2030. A subsequent degradation of MPs in the aquatic environment results in the generation of NPs with size ranging from 1 to 1000 nm. It is expected that this work facilitates stakeholders to understand the multi-aspects of MPs pollution in the freshwater and recommends policy actions to implement sustainable solutions to this environmental problem.
The carnivorous plants of genus Nepenthes produce unique pitchers containing secretory glands, which secrete proteins into the digestive fluid. We investigated protein profile in the pitcher fluid during the first three days of opening to understand carnivory trait of Nepenthes × ventrata. The proteome analysis of pitcher fluid from N. × ventrata was performed by label-free quantitative liquid chromatography mass spectrometry (nLC-MS/MSALL). Raw MS data have been deposited to the ProteomeXchange with identifier PXD007251. This dataset allows the identification and quantification of proteins from pitcher fluids to elucidate proteins involved in carnivory physiology of Nepenthes species.
Mitragyna speciosa is a psychoactive plant known as "ketum" in Malaysia and "kratom" in Thailand. This plant is distinctly known to produce two important alkaloids, namely mitragynine (MG) and 7-hydroxymitragynine (7-OH-MG) that can bind to opioid receptors [1]. MG was reported to exhibit antidepressant properties in animal studies [2]. These compounds were also proposed to have the potential to replace opioid analgesics with much lower risks of side effects [3]. To date, there are only over 40 metabolites identified in M. speciosa [4,5]. To obtain a more complete profile of secondary metabolites in ketum, we performed metabolomics study using mature leaves of the green M. speciosa variety. The leaf samples were extracted using methanol prior to liquid chromatography-electrospray ionization-time of flight-mass spectrometry (LC-ESI-TOF-MS) analysis. This data can be useful to for the identification of unknown metabolites that are associated with alkaloid biosynthesis pathway in M. speciosa.
Hybridisation plays a significant role in the evolution and diversification of plants. Hybridisation among Nepenthes species is extensive, either naturally or man-made. To investigate the effects of hybridisation on the chemical compositions, we carried out metabolomics study on pitcher tissue of Nepenthes ampullaria, Nepenthes rafflesiana and their hybrid, Nepenthes × hookeriana. Pitcher samples were harvested and extracted in methanol:chloroform:water via sonication-assisted extraction before analysed using LC-TOF-MS. MS data were analysed using XCMS online version 2.2.5. This is the first MS data report towards the profiling, identification and comprehensive comparison of metabolites present in Nepenthes species.
The dataset presented in this article describes microarray experiment of Auxin-binding protein 57, Abp57-overexpressing transgenic rice. The gene expression profiles were generated using Affymetrix GeneChip® Rice (Cn) Gene 1.0 ST Arrays. Total RNA from seedlings tissue of transgenic rice and wildtype, which serve as control were used as starting materials for microarray experiment. Detailed experimental methods and data analysis were described here. The raw and normalized microarray data were deposited into Gene Expression Omnibus (GEO) under accession number GSE99055.
Expansin increases cell wall extensibility to allow cell wall loosening and cell expansion even in the absence of hydrolytic activity. Previous studies showed that excessive overexpression of expansin gene resulted in defective growth (Goh et al., 2014; Rochange et al., 2001) [1,2] and altered cell wall chemical composition (Zenoni et al., 2011) [3]. However, the molecular mechanism on how the overexpression of non-enzymatic cell wall protein expansin can result in widespread effects on plant cell wall and organ growth remains unclear. We acquired transcriptomic data on previously reported transgenic Arabidopsis line (Goh et al., 2014) [1] to investigate the effects of overexpressing a heterologus cucumber expansin gene (CsEXPA1) on the global gene expression pattern during early and late phases of etiolated hypocotyl growth.
Mangosteen (Garcinia mangostana L.) has exceptional potential for commercial and pharmaceutical applications due to its delicious fruit and medicinal properties. Nevertheless, the molecular mechanism of mangosteen seed development is poorly understood. In this study, we performed transcriptomic analysis of four seed developmental stages; eight, ten, twelve and fourteen weeks after anthesis. Illumina HiSeq™ 4000 sequencer was used to generate raw data of approximately 68 Gb in size. From 451,495,326 raw reads, 406,143,756 clean reads were obtained. The raw data were uploaded to SRA database and the BioProject ID is PRJNA395504. These data provide the basis for further exploration and understanding of the molecular mechanism in mangosteen seed development.
Vibriosis disease by Vibrio spp. greatly reduced productivity of aquaculture, such as brown-marbled grouper (Epinephelus fuscoguttatus), which is an economically important fish species in Malaysia. Preventive measures and immediate treatment are critical to reduce the mortality of E. fuscoguttatus from vibriosis. To investigate the molecular mechanisms associated with immune response and host-bacteria interaction, a transcriptomic analysis was performed to compare between healthy and Vibrio-infected groupers. This permits the discovery of immune-related genes, specifically the resistance genes upon infection. Herein, we provide the raw transcriptome data from Illumina HiSeq. 4000 that have been deposited into NCBI SRA database with the BioProject accession number PRJNA396437. A total of 493,403,076 raw sequences of 74.5 Gb were obtained. Trimming of the raw data produced 437,186,232 clean reads of ~58 Gb. These datasets will be useful to elucidate the defence mechanisms of E. fuscoguttatus against Vibrio vulnificus infection for future development of effective prevention and treatment of vibriosis.
Proteomics is often hindered by the lack of protein sequence database particularly for non-model species such as Persicaria minor herbs. An integrative approach called proteomics informed by transcriptomics is possible [1], in which translated transcriptome sequence database is used as the protein sequence database. In this current study, the proteome profile were profiled using SWATH-MS technology complemented with documented transcriptome profiling [2], the first such report in this tropical herb. The plant was also elicited using a phytohormone, methyl jasmonate (MeJA) and protein changes were elucidated using label-free quantification of SWATH-MS to understand the role of such signal molecule in this herbal species. The mass spectrometry proteomics data was deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD005749. This data article refers to the article entitled "Proteomics (SWATH-MS)-informed by transcriptomics approach of Persicaria minor leaves upon methyl jasmonate elicitation" [3].
Nepenthes is a genus comprising carnivorous tropical pitcher plants that have evolved trapping organs at the tip of their leaves for nutrient acquisition from insect trapping. Recent studies have applied proteomics approaches to identify proteins in the pitcher fluids for better understanding the carnivory mechanism, but protein identification is hindered by limited species-specific transcriptomes for Nepenthes. In this study, the proteomics informed by transcriptomics (PIT) approach was utilized to identify and compare proteins in the pitcher fluids of Nepenthes ampullaria, Nepenthes rafflesiana, and their hybrid Nepenthes × hookeriana through PacBio isoform sequencing (Iso-Seq) and liquid chromatography-mass spectrometry (LC-MS) proteomic profiling. We generated full-length transcriptomes from all three species of 80,791 consensus isoforms with an average length of 1,692 bp as a reference for protein identification. The comparative analysis found that transcripts and proteins identified in the hybrid N. × hookeriana were more resembling N. rafflesiana, both of which are insectivorous compared with omnivorous N. ampullaria that can derive nutrients from leaf litters. Previously reported hydrolytic proteins were detected, including proteases, glucanases, chitinases, phosphatases, nucleases, peroxidases, lipid transfer protein, thaumatin-like protein, pathogenesis-related protein, and disease resistance proteins. Many new proteins with diverse predicted functions were also identified, such as amylase, invertase, catalase, kinases, ligases, synthases, esterases, transferases, transporters, and transcription factors. Despite the discovery of a few unique enzymes in N. ampullaria, we found no strong evidence of adaptive evolution to produce endogenous enzymes for the breakdown of leaf litter. A more complete picture of digestive fluid protein composition in this study provides important insights on the molecular physiology of pitchers and carnivory mechanism of Nepenthes species with distinct dietary habits.
Hybridization is key to the evolution and diversity of plants in nature. Nepenthaceae comprises a family of diverse tropical carnivorous pitcher plant species with extensive hybridization. However, there is no study to date on the metabolite expression of hybrids in this family. We performed a non-targeted metabolomics analysis of the pitchers of two Nepenthes species with different dietary habits, namely, the semi-detritivorous N. ampullaria and carnivorous N. rafflesiana with their hybrid (N. × hookeriana) for a comparative study. The whole-pitcher samples were extracted in methanol:chloroform:water (3:1:1) via sonication-assisted extraction and analyzed using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) followed by data analysis to profile chemical compositions. A total of 1,441 metabolite features were profiled from the three species in which 43.3% of features in the hybrid samples were not found in either of its parents. The partial least squares discriminant analysis (PLS-DA) found 324 metabolite features with variable in projection (VIP) values greater than one in which 55 features were statistically significant. This showed that the hybrid is closer to N. rafflesiana, which is consistent to the previous study on gene and protein expressions. A total of 105 metabolites were putatively identified with manual searches using public metabolite databases. Phenols were detected to be the most abundant secondary metabolites due to a high flavonoid content, especially in N. rafflesiana. The most abundant feature 476.3s:449.102 was found to be the most significant VIP for distinguishing between the three species as a chemical marker. This is the first study comparing metabolites in the carnivory organs of different Nepenthes species with comprehensive profiling and putative identification. The differential metabolite compositions in the pitchers of different species might have ecological implications with the hybrid showing intermediate phenotype between the parents as well as manifesting unique metabolites. However, there is no clear evidence of metabolites related to the differences in dietary habits between the hybrid and the two parent species.
Across all facets of biology, the rapid progress in high-throughput data generation has enabled us to perform multi-omics systems biology research. Transcriptomics, proteomics, and metabolomics data can answer targeted biological questions regarding the expression of transcripts, proteins, and metabolites, independently, but a systematic multi-omics integration (MOI) can comprehensively assimilate, annotate, and model these large data sets. Previous MOI studies and reviews have detailed its usage and practicality on various organisms including human, animals, microbes, and plants. Plants are especially challenging due to large poorly annotated genomes, multi-organelles, and diverse secondary metabolites. Hence, constructive and methodological guidelines on how to perform MOI for plants are needed, particularly for researchers newly embarking on this topic. In this review, we thoroughly classify multi-omics studies on plants and verify workflows to ensure successful omics integration with accurate data representation. We also propose three levels of MOI, namely element-based (level 1), pathway-based (level 2), and mathematical-based integration (level 3). These MOI levels are described in relation to recent publications and tools, to highlight their practicality and function. The drawbacks and limitations of these MOI are also discussed for future improvement toward more amenable strategies in plant systems biology.
Polygonum minus is an herbal plant that grows in Southeast Asian countries and traditionally used as medicine. This plant produces diverse secondary metabolites such as phenolic compounds and their derivatives, which are known to have roles in plant abiotic and biotic stress responses. Methyl jasmonate (MeJA) is a plant signaling molecule that triggers transcriptional reprogramming in secondary metabolism and activation of defense responses against many biotic and abiotic stresses. However, the effect of MeJA elicitation on the genome-wide expression profile in the leaf tissue of P. minus has not been well-studied due to the limited genetic information. Hence, we performed Illumina paired-end RNA-seq for de novo reconstruction of P. minus leaf transcriptome to identify differentially expressed genes (DEGs) in response to MeJA elicitation. A total of 182,111 unique transcripts (UTs) were obtained by de novo assembly of 191.57 million paired-end clean reads using Trinity analysis pipeline. A total of 2374 UTs were identified to be significantly up-/down-regulated 24 h after MeJA treatment. These UTs comprising many genes related to plant secondary metabolite biosynthesis, defense and stress responses. To validate our sequencing results, we analyzed the expression of 21 selected DEGs by quantitative real-time PCR and found a good correlation between the two analyses. The single time-point analysis in this work not only provides a useful genomic resource for P. minus but also gives insights on molecular mechanisms of stress responses in P. minus.
Mangosteen (Garcinia mangostana Linn.) is a tropical tree mainly found in South East Asia and considered as "the queen of fruits". The asexually produced fruit is dark purple or reddish in color, with white flesh which is slightly acidic with sweet flavor and a pleasant aroma. The purple pericarp tissue is rich in xanthones which are useful for medical purposes. We performed the first genome sequencing of this commercially important fruit tree to study its genome composition and attempted draft genome assembly. Raw reads of the DNA sequencing project have been deposited to SRA database with the accession number SRX1426419.
Carnivorous plants have the ability to capture and digest insects for nutrients, which allows them to survive in land deprived of nitrogenous nutrients. Nepenthes spp. are one of the carnivorous plants, which uniquely produce pitcher from the tip of an elongated leaf. This study provides the first transcriptome resource from pitcher of a Nepenthes ventricosa × Nepenthes alata hybrid, Nepenthes × ventrata to understand carnivory mechanism in Nepenthes spp., as well as in other carnivorous species. Raw reads and the transcriptome assembly project have been deposited to SRA database with the accession numbers SRX1389337 (day 0 control), SRX1389392 (day 3 longevity), and SRX1389395 (day 3 chitin-treated).
Polygonum minus plant is rich in secondary metabolites, especially terpenoids and flavonoids. Present study generates transcriptome resource for P. minus to decipher its secondary metabolite biosynthesis pathways. Raw reads and the transcriptome assembly project have been deposited at GenBank under the accessions SRX313492 (root) and SRX669305 (leaf) respectively.
Rafflesia cantleyi, known as one of the world's largest flowers, is a specialised holoparasite due to dramatic morphological modifications. It possesses highly reduced vegetative structure and only appears as a flower for sexual reproduction. Moreover, it has an unusual life cycle in that its floral bud development takes up to nine months. In order to fully understand the highly modified floral organ structure and long life cycle of R. cantleyi, we used Illumina sequencing technology (HiSeq) for sequence generation followed by de novo assembly of sequence reads. We obtained the RNA-seq data from three different stages of floral bud, representing the early, mid and advanced developmental stages. These data are available via BioProject accession number PRJNA378435. More than 10.3 Gb raw sequence data were generated, corresponding to 102,203,042 raw reads. Following removal of low-quality reads and trimming of adapter sequences, a total of 91,638,836 reads were obtained. De novo assembly of these sequences using Trinity resulted in 89,690 unique transcripts with an N50 of 1653 bp. The obtained transcriptomic data will be useful for further study to understand the molecular interactions that result in R. cantleyi floral development.