Genome-wide analysis of the MATE gene family in potato

Genome-wide identification and characterization of DTX family genes highlighting their locations, functions, and regulatory factors in banana (Musa acuminata)

The detoxification efflux carriers (DTX) are a significant group of multidrug efflux transporter family members that play diverse functions in all kingdoms of living organisms. However, genome-wide identification and characterization of DTX family transporters have not yet been performed in banana, despite its importance as an economic fruit plant. Therefore, a detailed genome-wide analysis of DTX family transporters in banana (Musa acuminata) was conducted using integrated bioinformatics and systems biology approaches. In this study, a total of 37 DTX transporters were identified in the banana genome and divided into four groups (I, II, III, and IV) based on phylogenetic analysis. The gene structures, as well as their proteins' domains and motifs, were found to be significantly conserved. Gene ontology (GO) annotation revealed that the predicted DTX genes might play a vital role in protecting cells and membrane-bound organelles through detoxification mechanisms and the removal of drug molecules from banana cells. Gene regulatory analyses identified key transcription factors (TFs), cis-acting elements, and post-transcriptional regulators (miRNAs) of DTX genes, suggesting their potential roles in banana. Furthermore, the changes in gene expression levels due to pathogenic infections and non-living factor indicate that banana DTX genes play a role in responses to both biotic and abiotic stresses. The results of this study could serve as valuable tools to improve banana quality by protecting them from a range of environmental stresses.

Identification and analysis of MATE protein family in Gleditsia sinensis

Many studies have shown that multidrug and toxic compound extrusion (MATE) is a new secondary transporter family that plays a key role in secondary metabolite transport, the transport of plant hormones and disease resistance in plants. However, detailed information on this family in Gleditsia sinensis has not yet been reported. In the present study, a total of 45 GsMATE protein members were identified and analysed in detail, including with gene classification, phylogenetic evaluation and conserved motif determination. Phylogenetic analysis showed that GsMATE proteins were divided into six subfamilies. Additionally, in order to understand these members' regulatory roles in growth and development in G. sinensis , the GsMATEs expression profiles in different tissues and different developmental stages of thorn were examined in transcriptome data. The results of this study demonstrated that the expression of all MATE genes varies in roots, stems and leaves. Notably, the expression levels of GsMATE26 , GsMATE32 and GsMATE43 differ most in the early stages of thorn development, peaking at higher levels than in later stages. Our results provide a foundation for further functional characterisation of this important class of transporter family in G. sinensis .

Genome-Wide Identification, Expression Analysis under Abiotic Stress and Co-Expression Analysis of MATE Gene Family in Torreya grandis

The multidrug and toxin efflux (MATE) family participates in numerous biological processes and plays important roles in abiotic stress responses. However, information about the MATE family genes in Torreya grandis remains unclear. In this study, our genome-wide investigation identified ninety MATE genes in Torreya grandis, which were divided into five evolutionary clades. TgMATE family members are located on eleven chromosomes, and a total of thirty TgMATEs exist in tandem duplication. The promoter analysis showed that most TgMATEs contain the cis-regulatory elements associated with stress and hormonal responses. In addition, we discovered that most TgMATE genes responded to abiotic stresses (aluminum, drought, high temperatures, and low temperatures). Weighted correlation network analysis showed that 147 candidate transcription factor genes regulated the expression of 14 TgMATE genes, and it was verified through a double-luciferase assay. Overall, our findings offer valuable information for the characterization of the TgMATE gene mechanism in responding to abiotic stress and exhibit promising prospects for the stress tolerance breeding of Torreya grandis.

Genome-wide identification and expression pattern analysis of the MATE gene family in carmine radish (Raphanus sativus L.)

Carmine radish (Raphanus sativus L.) is famousforcontaininganaturalredpigment(redradishpigment) that grown in Fuling, Chongqing City, China. MATE (multidrug and toxic compound extrusion), as an integral member of the multidrug efflux transporter family, has various functions in plants. However, noinformationhasbeenavailableaboutcharacteristicsoftheMATEgenefamily in carmine radish. In this study, total of 85 candidate MATE gene family members classifiedinto 4 groups were identified and foundtobewidelyandrandomlydistributedindifferent genome. Synteny analysis revealed that twenty-one segmental and ten tandem duplications acted as important regulators for the expansion of RsMATE genes. The Ka/Ks ratios of RsMATE indicated that RsMATE may have undergone intense purification in the radish genome. Cis-acting element analysis of RsMATE in the promoter region indicated that RsMATE were mainly related to the abiotic stress response and phytohormone. Quantitative real-time polymerase chain reaction (qRT-PCR) showed that RsMATE40-b, RsMATE16-b and RsMATE13-a genes were significantly expressed under ABA (abscisic acid) and NaCl stress treatments respectively. In addition, the expression patterns of fifteen key RsMATE genes were investigated in 'XCB' (Xichangbai) and 'HX' (Hongxin) roots under Cadmium (Cd) stress for different treatment times using qRT-PCR, of those, RsMATE49-b, RsMATE33 and RsMATE26 transcripts were strongly altered at different time points in XCB responsive to Cd stress,compared to HX. This study will provide valuable insights for studying the functional characterization of the MATE gene in carmine radish and other plants.

Genome wide identification and characterization of MATE family genes in mangrove plants

Multidrug and Toxic Compound Extrusion (MATE) proteins are essential transporters that extrude metabolites and participate in plant development and cellular detoxification. MATE transporters, which play crucial roles in the survival of mangrove plants under highly challenged environments, by specialized salt extrusion mechanisms, are mined from their genomes and reported here for the first time. Through homology search and domain prediction in the genome assemblies of Avicennia marina, Bruguiera sexangula, Ceriops zippeliana, Kandelia obovata, Rhizophora apiculata and Ceriops tagal, 74, 68, 66, 66, 63 and 64 MATE proteins, respectively were identified. The phylogenetic analysis divided the identified proteins into five major clusters and following the clustering pattern of the functionally characterized proteins, functions of the transporters in each cluster were predicted. Amino acid sequences, exon-intron structure, motif details and subcellular localization pattern for all the 401 proteins are described. The custom designed repeat masking libraries generated for each of these genomes, which will be of extensive use for the researchers worldwide, are also provided in this paper. This is the first study on the MATE genes in mangroves and the results provide comprehensive information on the molecular mechanisms enabling the survival of mangroves under hostile conditions.

Heavy metal and metalloid toxicity in horticultural plants: Tolerance mechanism and remediation strategies

Heavy metal/metalloids (HMs) are among the primary soil pollutants that limit crop production worldwide. Plants grown in HM contaminated soils exhibit reduced growth and development, resulting in a decrease in crop production. The exposure to HMs induces plant oxidative stress due to the formation of free radicals, which alter plant morphophysiological and biochemical mechanisms at cellular and tissue levels. When exposed to HM toxicity, plants evolve sophisticated physiological and cellular defense strategies, such as sequestration and transportation of metals, to ensure their survival. Plants also have developed efficient strategies by activating signaling pathways, which induce the expression of HM transporters. Plants either avoid the uptake of HMs from the soil or activate the detoxifying mechanism to tolerate HM stress, which involves the production of antioxidants (enzymatic and non-enzymatic) for the scavenging of reactive oxygen species. The metal-binding proteins including phytochelatins and metallothioneins also participate in metal detoxification. Furthermore, phytohormones and their signaling pathways also help to regulate cellular activities to counteract HM stress. The excessive levels of HMs in the soil can contribute to plant morpho-physiological, biochemical, and molecular alterations, which have a detrimental effect on the quality and productivity of crops. To maintain the commercial value of fruits and vegetables, various measures should be considered to remove HMs from the metal-polluted soils. Bioremediation is a promising approach that involves the use of tolerant microorganisms and plants to manage HMs pollution. The understanding of HM toxicity, signaling pathways, and tolerance mechanisms will facilitate the development of new crop varieties that help in improving phytoremediation.

Circadian Rhythm Regulates Reactive Oxygen Species Production and Inhibits Al-Induced Programmed Cell Death in Peanut

Peanut is among the most important oil crops in the world. In the southern part of China, peanut is highly produced; however, the arable land is acidic. In acidic soils, aluminum (Al) inhibits plant growth and development by changing the properties of the cell wall and causing the disorder of the intracellular metabolic process. Circadian rhythm is an internal mechanism that occurs about every 24 h and enables plants to maintain internal biological processes with a daily cycle. To investigate the effect of photoperiod and Al stress on the Al-induced programmed cell death (PCD), two peanut varieties were treated with 100 μM AlCl₃ under three photoperiodic conditions (8/16, SD; 12/12, ND; 16/8 h, LD). The results show that Al toxicity was higher in ZH2 than in 99-1507 and higher under LD than under SD. Root length decreased by 30, 37.5, and 50% in ZH2 and decreased by 26.08, 34.78, and 47.82% in 99-1507 under SD, ND, and LD, respectively, under Al stress. Photoperiod and Al induced cell death and ROS production. MDA content, PME activity, and LOX activity increased under SD, ND, and LD, respectively, under Al stress both in ZH2 and 99-1507. APX, SOD, CAT, and POD activities were higher under SD, ND, and LD, respectively. Al stress increased the level of AhLHY expression under SD and ND but decreased it under LD in both ZH2 and 99-1507. Contrastingly, AhSTS expression levels increased exponentially and were higher under SD, LD, and ND, respectively, under Al stress. Our results will be a useful platform to research PCD induced by Al and gain new insights into the genetic manipulation of the circadian clock for plant stress response.

Genome-Wide Analysis of Multidrug and Toxic Compound Extruction Transporters in Grape

Grape (Vitis vinifera L.) is an important fruit crop in the world. It is used as a table grape and is also used for raisin and wine production. Grape berries accumulate secondary metabolites, such as anthocyanins, tannins, and resveratrol, which are known as functional compounds for human health. Multidrug and toxic compound extrusion transporter (MATEs) transport secondary metabolites. MATEs also transport other solutes, including organic acids, and toxic xenobiotics, depending on cation gradient and play various roles in plants. MATE comprises 300-500 amino acid residues and possesses a MATE domain and 8-12 transmembrane domains. In the present study, 59 MATE genes were identified in the grape genome, and phylogenetic analysis revealed the presence of four groups of grape MATEs (Group 1-4). Their information, such as gene structures, protein motifs, predicted subcellular localizations, and gene IDs of four genome annotations, that is, CRIBI v1, CRIBI v2, Genoscope, and Vcost v3, were annotated. The transport substrates and physiological functions of grape MATEs were estimated based on their homology with the analyzed MATEs in other plant species. Group 1 may transport toxic compounds and alkaloids, Group 2 may transport polyphenolic compounds, Group 3 may transport organic acids, and Group 4 may transport plant hormones related to signal transduction. In addition to the known anthocyanin transporters, VvMATE37 and VvMATE39, a novel anthocyanin transporter, VvMATE38 in Group 2, was suggested as a key transporter for anthocyanin accumulation in grape berry skin. VvMATE46, VvMATE47, and VvMATE49 in Group 3 may contribute to Al³⁺ detoxification and Fe²⁺/Fe³⁺ translocation via organic acid transport. This study provides helpful and fundamental information for grape MATE studies and resolves the confusion of gene IDs in different genome annotations.

A Systematic Phylogenomic Classification of the Multidrug and Toxic Compound Extrusion Transporter Gene Family in Plants

Multidrug and toxic compound extrusion (MATE) transporters comprise a multigene family that mediates multiple functions in plants through the efflux of diverse substrates including organic molecules, specialized metabolites, hormones, and xenobiotics. MATE classification based on genome-wide studies remains ambiguous, likely due to a lack of large-scale phylogenomic studies and/or reference sequence datasets. To resolve this, we established a phylogeny of the plant MATE gene family using a comprehensive kingdom-wide phylogenomic analysis of 74 diverse plant species. We identified more than 4,000 MATEs, which were classified into 14 subgroups based on a systematic bioinformatics pipeline using USEARCH, blast+ and synteny network tools. Our classification was performed using a four-step process, whereby MATEs sharing ≥ 60% protein sequence identity with a ≤ 1E-05 threshold at different sequence lengths (either full-length, ≥ 60% length, or ≥ 150 amino acids) or retaining in the similar synteny blocks were assigned to the same subgroup. In this way, we assigned subgroups to 95.8% of the identified MATEs, which we substantiated using synteny network clustering analysis. The subgroups were clustered under four major phylogenetic groups and named according to their clockwise appearance within each group. We then generated a reference sequence dataset, the usefulness of which was demonstrated in the classification of MATEs in additional species not included in the original analysis. Approximately 74% of the plant MATEs exhibited synteny relationships with angiosperm-wide or lineage-, order/family-, and species-specific conservation. Most subgroups evolved independently, and their distinct evolutionary trends were likely associated with the development of functional novelties or the maintenance of conserved functions. Together with the systematic classification and synteny network profiling analyses, we identified all the major evolutionary events experienced by the MATE gene family in plants. We believe that our findings and the reference dataset provide a valuable resource to guide future functional studies aiming to explore the key roles of MATEs in different aspects of plant physiology. Our classification framework can also be readily extendable to other (super) families.

Microbial resistance: The role of efflux pump superfamilies and their respective substrates

The microorganism resistance to antibiotics has become one of the most worrying issues for science due to the difficulties related to clinical treatment and the rapid spread of diseases. Efflux pumps are classified into six groups of carrier proteins that are part of the different types of mechanisms that contribute to resistance in microorganisms, allowing their survival. The present study aimed to carry out a bibliographic review on the superfamilies of carriers in order to understand their compositions, expressions, substrates, and role in intrinsic resistance. At first, a search for manuscripts was carried out in the databases Medline, Pubmed, ScienceDirect, and Scielo, using as descriptors: efflux pump, expression, pump inhibitors and efflux superfamily. For article selection, two criteria were taken into account: for inclusion, those published between 2000 and 2020, including textbooks, and for exclusion, duplicates and academic collections. In this research, 139,615 published articles were obtained, with 312 selected articles and 7 book chapters that best met the aim. From the comprehensive analysis, it was possible to consider that the chromosomes and genetic elements can contain genes encoding efflux pumps and are responsible for multidrug resistance. Even though this is a well-explored topic in the scientific community, understanding the behavior of antibiotics as substrates that increase the expression of pump-encoding genes has challenged medicine. This review study succinctly summarizes the most relevant features of these systems, as well as their contribution to multidrug resistance.

Genome-wide investigation and comparative analysis of MATE gene family in Rosaceae species and their regulatory role in abiotic stress responses in Chinese pear (Pyrus bretschneideri)

The Multidrug and Toxic Compound Extrusion (MATE) protein belongs to a secondary transporter gene family, which plays a primary role in transporting many kinds of substrates such as organic compounds, secondary metabolites, and phytohormones. MATE protein members exist in both prokaryotes and eukaryotes. However, evolution and comprehensive analysis of the MATE genes has not been performed in Rosaceae species. In the present study, a total of 404 MATEs genes were identified from six Rosaceae genomes (Prunus avium, Pyrus bretschneideri, Prunus persica, Fragaria vesca, Prunus mume, and Malus domestica) and classified into eight main subfamilies (I-VII) based on structural and phylogenetic analysis. Microcollinearity analysis showed that whole-genome duplication events might play a vital role in the expansion of the MATE genes family. The Ka/Ks analysis, chromosomal localization, subcellular localization, and molecular characteristics (length, weight, and pI) were performed using various bioinformatics tools. Furthermore, different subfamilies have different introns-exons structures, cis-acting elements, and conserved motifs analysis, indicating functional divergence in the MATE family. Subsequently, RNA-seq analysis and real-time qRT-PCR were conducted during Chinese pear fruit development. Moreover, PbMATE genes were significantly expressed under hormonal treatments of MeJA (methyl jasmonate), SA (salicylic acid), and ABA (abscisic acid). Overall, our results provide helpful insights into the functions, expansion complexity, and evolutions of the MATE genes in Chinese pear and five Rosaceae species.

ATP-binding cassette transporters expression profiling revealed its role in the development and regulating stress response in Solanum tuberosum

The ATP-binding cassette (ABC) transporter gene family plays a vital role in substance transportation, including secondary metabolites, and phytohormones across membranous structures. It is still uncovered in potato (Solanum tuberosum), grown worldwide as a 3^rd important food crop. The current study identified a total of 54 Stabc genes in potato genome. The accumulative phylogenetic tree of Stabc with arabidopsis, divided into eight groups (ABCA to ABCH). ABCG was the most prominent group covering 90% of Stabc genes, followed by ABCB group. The number and architecture of exon-intron varied from gene to gene. In addition, the presence of stress-responsive elements in the regulatory regions depicted their role in environmental stress. Furthermore, the tissue-specific and stress-specific expression profiling of Stabc genes and their validation through real-time-qPCR analysis revealed their role in development and stress. The presented results provided useful information for further functional analysis of Stabc genes and can also use as a reference study for other important crops.

Genome-wide identification, characterization and expression analysis of MATE family genes in apple (Malus × domestica Borkh)

BACKGROUND

As an important group of the multidrug efflux transporter family, the multidrug and toxic compound extrusion (MATE) family has a wide range of functions and is distributed in all kingdoms of living organisms. However, only two MATE genes in apple have been analyzed and genome-wide comprehensive analysis of MATE family is needed.

RESULTS

In this study, a total of 66 MATE (MdMATE) candidates encoding putative MATE transporters were identified in the apple genome. These MdMATE genes were classified into four groups by phylogenetic analysis with MATE genes in Arabidopsis. Synteny analysis reveals that whole genome duplication (WGD) and segmental duplication events played a major role in the expansion of MATE gene family in apple. MdMATE genes show diverse expression patterns in different tissues/organs and developmental stages. Analysis of cis-regulatory elements in MdMATE promoter regions indicates that the function of MdMATE genes is mainly related to stress response. Besides, the changes of gene expression levels upon different pathogen infections reveal that MdMATE genes are involved in biotic stress response.

CONCLUSIONS

In this work, we systematically identified MdMATE genes in apple genome using a set of bioinformatics approaches. Our comprehensive analysis provided valuable resources for improving disease resistance in apple and further functional characterization of MATE genes in other species.

Genome-Wide Identification of MATE Gene Family in Potato (Solanum tuberosum L.) and Expression Analysis in Heavy Metal Stress

A genome-wide identification and expression analysis of multidrug and toxic compound extrusion (MATE) gene family in potato was carried out to explore the response of MATE proteins to heavy meta stress. In this study, we identified 64 MATE genes from potato genome, which are located on 12 chromosomes, and are divided into I–IV subfamilies based on phylogenetic analysis. According to their order of appearance on the chromosomes, they were named from StMATE1–64. Subcellular location prediction showed that 98% of them are located on the plasma membrane as transporters. Synteny analysis showed that five pairs of collinearity gene pairs belonged to members of subfamily I and subfamily II had two pairs indicating that the duplication is of great significance to the evolution of genes in subfamilies I and II. Gene exon–intron structures and motif composition are more similar in the same subfamily. Every StMATE gene contained at least one cis-acting element associated with regulation of hormone transport. The relative expression levels of eight StMATE genes were significantly upregulated under Cu²⁺ stress compared with the non-stress condition (0 h). After Cd²⁺ stress for 24 h, the expression levels of StMATE33 in leaf tissue were significantly increased, indicating its crucial role in the process of Cd²⁺ stress. Additionally, StMATE18/60/40/33/5 were significantly induced by Cu²⁺ stress, while StMATE59 (II) was significantly induced by Ni²⁺ stress. Our study initially explores the biological functions of StMATE genes in the regulation of heavy metal stress, further providing a theoretical basis for studying the subsequent molecular mechanisms in detail.

Genome-wide identification and expression analysis of detoxification efflux carriers (DTX) genes family under abiotic stresses in flax

The detoxification efflux carriers (DTX)/multidrug and toxic compound extrusion (MATE) transporters encompass an ancient gene family of secondary transporters involved in the process of plant detoxification. A genome-wide analysis of these transporters was carried out in order to better understand the transport of secondary metabolites in flaxseed genome (Linum usitassimum). A total of 73 genes coding for DTX/MATE transporters were identified. Gene structure, protein domain and motif organization were found to be notably conserved over the distinct phylogenetic groups, showing the evolutionary significant role of each class. Gene ontology (GO) annotation revealed a link to transporter activities, response to stimulus and localizations. The presence of various hormone and stress-responsive cis-regulatory elements in promoter regions could be directly correlated with the alteration of their transcripts. Tertiary structure showed conservation for pore size and constrains in the pore, which indicate their involvement in the exclusion of toxic substances from the cell. MicroRNA target analysis revealed that LuDTXs genes were targeted by different classes of miRNA families. Twelve LuDTX genes were chosen for further quantitative real-time polymerase chain reaction analysis in response to cold, salinity and cadmium stress at 0, 6, 12 and 24 hours after treatment. Altogether, the identified members of the DTX gene family, their expression profile, phylogenetic and miRNAs analysis might provide opportunities for future functional validation of this important gene family in flax.

Identification and Expression of the Multidrug and Toxic Compound Extrusion (MATE) Gene Family in Capsicum annuum and Solanum tuberosum

Multidrug and Toxic Compound Extrusion (MATE) proteins are essential transporters that extrude metabolites and participate in plant development and the detoxification of toxins. Little is known about the MATE gene family in the Solanaceae, which includes species that produce a broad range of specialized metabolites. Here, we identified and analyzed the complement of MATE genes in pepper (Capsicum annuum) and potato (Solanum tuberosum). We classified all MATE genes into five groups based on their phylogenetic relationships and their gene and protein structures. Moreover, we discovered that tandem duplication contributed significantly to the expansion of the pepper MATE family, while both tandem and segmental duplications contributed to the expansion of the potato MATE family, indicating that MATEs took distinct evolutionary paths in these two Solanaceous species. Analysis of ω values showed that all potato and pepper MATE genes experienced purifying selection during evolution. In addition, collinearity analysis showed that MATE genes were highly conserved between pepper and potato. Analysis of cis-elements in MATE promoters and MATE expression patterns revealed that MATE proteins likely function in many stages of plant development, especially during fruit ripening, and when exposed to multiple stresses, consistent with the existence of functional differentiation between duplicated MATE genes. Together, our results lay the foundation for further characterization of pepper and potato MATE gene family members.

A Genome-Wide Survey of MATE Transporters in Brassicaceae and Unveiling Their Expression Profiles under Abiotic Stress in Rapeseed

The multidrug and toxic compound extrusion (MATE) protein family is important in the export of toxins and other substrates, but detailed information on this family in the Brassicaceae has not yet been reported compared to Arabidopsis thaliana. In this study, we identified 57, 124, 81, 85, 130, and 79 MATE genes in A. thaliana, Brassica napus, Brassica oleracea, Brassica rapa, Brassica juncea, and Brassica nigra, respectively, which were unevenly distributed on chromosomes owing to both tandem and segmental duplication events. Phylogenetic analysis showed that these genes could be classified into four subgroups, shared high similarity and conservation within each group, and have evolved mainly through purifying selection. Furthermore, numerous B. napusMATE genes showed differential expression between tissues and developmental stages and between plants treated with heavy metals or hormones and untreated control plants. This differential expression was especially pronounced for the Group 2 and 3 BnaMATE genes, indicating that they may play important roles in stress tolerance and hormone induction. Our results provide a valuable foundation for the functional dissection of the different BnaMATE homologs in B. napus and its parental lines, as well as for the breeding of more stress-tolerant B. napus genotypes.

A Genomic and Transcriptomic Overview of MATE, ABC, and MFS Transporters in Citrus sinensis Interaction with Xanthomonas citri subsp. citri

The multi-antimicrobial extrusion (MATE), ATP-binding cassette (ABC), and major facilitator superfamily (MFS) are the main plant transporters families, playing an essential role in the membrane-trafficking network and plant-defense mechanism. The citrus canker type A (CC), is a devastating disease caused by Xanthomonas citri subsp. citri (Xac), affecting all citrus species. In this work, we performed an in silico analysis of genes and transcripts from MATE, ABC, and MFS families to infer the role of membrane transporters in Citrus-Xac interaction. Using as reference, the available Citrus sinensis genome and the citrus reference transcriptome from CitrusKB database, 67 MATE, 91 MFS, and 143 ABC genes and 82 MATE, 139 MFS, and 226 ABC transcripts were identified and classified into subfamilies. Duplications, alternative-splicing, and potentially non-transcribed transporters' genes were revealed. Interestingly, MATE I and ABC G subfamilies appear differently regulated during Xac infection. Furthermore, Citrus spp. showing distinct levels of CC susceptibility exhibited different sets of transporters transcripts, supporting dissimilar molecular patterns of membrane transporters in Citrus-Xac interaction. According to our findings, 4 MATE, 10 ABC, and 3 MFS are potentially related to plant-defense mechanisms. Overall, this work provides an extensive analysis of MATE, ABC, and MFS transporters' in Citrus-Xac interaction, bringing new insights on membrane transporters in plant-pathogen interactions.

Understanding the Composition, Biosynthesis, Accumulation and Transport of Flavonoids in Crops for the Promotion of Crops as Healthy Sources of Flavonoids for Human Consumption

Flavonoids are a class of polyphenolic compounds that naturally occur in plants. Sub-groups of flavonoids include flavone, flavonol, flavanone, flavanonol, anthocyanidin, flavanol and isoflavone. The various modifications on flavonoid molecules further increase the diversity of flavonoids. Certain crops are famous for being enriched in specific flavonoids. For example, anthocyanins, which give rise to a purplish color, are the characteristic compounds in berries; flavanols are enriched in teas; and isoflavones are uniquely found in several legumes. It is widely accepted that the antioxidative properties of flavonoids are beneficial for human health. In this review, we summarize the classification of the different sub-groups of flavonoids based on their molecular structures. The health benefits of flavonoids are addressed from the perspective of their molecular structures. The flavonoid biosynthesis pathways are compared among different crops to highlight the mechanisms that lead to the differential accumulation of different sub-groups of flavonoids. In addition, the mechanisms and genes involved in the transport and accumulation of flavonoids in crops are discussed. We hope the understanding of flavonoid accumulation in crops will guide the proper balance in their consumption to improve human health.