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Light serves as one of the major environmental signals that stimulates anthocyanin biosynthesis in higher plants. In this study, we demonstrate that AtGLK2, an Arabidopsis nuclear GARP transcription factor, plays a positive role in the regulation of anthocyanin biosynthesis. The disruption of AtGLK2 decreased the anthocyanin contents in Arabidopsis seedlings, whereas the overexpression of AtGLK2 resulted in significant enhancements to the accumulation of anthocyanin. Gene expression analysis demonstrated that the expression of late biosynthetic genes in the anthocyanin biosynthetic pathway was dramatically reduced in glk2 but elevated in AtGLK2-overexpressing seedlings. It was found that the disruption of AtHY5 decreased the expression of AtGLK2 and that AtGLK2 exhibited light-responsive expression patterns in an AtHY5-dependent manner. Further studies demonstrated that AtHY5-mediated light signaling is required for AtGLK2-regulated anthocyanin accumulation and photosynthetic development. Moreover, AtGLK2 and AtMYBL2 antagonistically regulate the expression of anthocyanin biosynthetic genes and the subsequent anthocyanin accumulation process. Taken together, our data reveal that AtGLK2 positively regulates anthocyanin biosynthesis through AtHY5-mediated light signaling in Arabidopsis.

Here, we identified sequence variations of CYP72A69 and UGT73F4 genes from the Sojeongja and Haepum cultivars, and revealed that accumulation patterns of soyasaponin Aa and Ab were different in the Sojeongja and Haepum cultivars. Several genes related in soyasaponin biosynthetic pathway showed significant changes in their expression patterns in two soybean cultivars and soyasaponin contents were also altered under several abiotic stress conditions, albeit no significant correlations between soyasaponin contents and biosynthetic gene expression were observed. We also demonstrated that UGT73F4 gene could be responsible for biosynthesis of soyasaponin Aa in the Socheongja by investigating gene expression and soyasaponin accumulations. Our results provide a molecular basis to improve the commercial properties of soyasaponin in Korean domestic soybean cultivars.

The transgene‐directed accumulation of non‐native omega‐3 long chain polyunsaturated fatty acids in the seed oil of Camelina sativa (Camelina) was evaluated in the field, in distinct geographical and regulatory locations. A construct, DHA2015.1, containing an optimal combination of biosynthetic genes, was selected for experimental field release in the UK, USA and Canada, and the accumulation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) determined. The occurrence of these fatty acids in different triacylglycerol species was monitored and found to follow a broad trend irrespective of the agricultural environment. This is a clear demonstration of the stability and robust nature of the transgenic trait for omega‐3 long chain polyunsaturated fatty acids in Camelina. Examination of non‐seed tissues for the unintended accumulation of EPA and DHA failed to identify their presence in leaf, stem, flower, anther or capsule shell material, confirming the seed‐specific accumulation of these novel fatty acids. Collectively, these data confirm the promise of GM plant‐based sources of so‐called omega‐3 fish oils as a sustainable replacement for oceanically derived oils.

Anthocyanins confer the wide range of colors for plants and also play beneficial health roles as potentially protective factors against heart disease and cancer. Brassica juncea is cultivated as an edible oil resource and vegetable crop worldwide, thus elucidating the anthocyanin biosynthetic pathway would be helpful to improve the nutritional quality of Brassica juncea through the breeding and cultivating of high anthocyanin content varieties. Herein, 129 genes in B. juncea were identified as orthologs of 41 anthocyanin biosynthetic genes (ABGs) in Arabidopsis thaliana by comparative genomic analyses. The B. juncea ABGs have expanded by whole genome triplication and subsequent allopolyploidizatoin, but lost mainly during the whole genome triplication between B. rapa/B. nigra and A. thaliana, rather than the allopolyploidization process between B. juncea and B. rapa/B. nigra, leading to different copy numbers retention of A. thaliana homologous genes. Although the overall expansion levels ABGs were similar to the whole genome, more negative regulatory genes were retained in the anthocyanin biosynthesis regulatory system. Transcriptional analysis of B. juncea with different anthocyanin accumulation showed that BjDFR, BjTT19, BjTT8 are significantly up-regulated in plants with purple leaves as compared with green leaves. The overexpression of BjTT8 and these target genes which were involved in late anthocyanin biosynthesis and transport might account for increasing levels of anthocyanin accumulation in purple leaves. Our results could promote the understanding of the genetic mechanism of anthocyanin biosynthesis in B. juncea.

Drought-tolerant rootstocks have been used to improve production efficiency of graft-propagated crops. Kiwifruit is a high-valued fruit crop of the world. Drought stress widely occurs in many of kiwifruit-growing regions including China. The present study used micrografting for evaluation of drought tolerance in four kiwifruit cultivars micrografted on the drought-tolerant rootstock MX1. When stressed by PEG-induced drought, the micrografted kiwifruit cultivars showed significant differences in accumulation of ROS (O2·− and H2O2), physiological metabolism (total soluble sugar, total soluble protein and free proline), activities of antioxidants (SOD and CAT), endogenous ABA levels and expression levels of ABA biosynthetic genes (DREB1 and DREB2). Drought tolerance of the micrografts varied with the four kiwifruit cultivars, with the highest and lowest drought tolerance found in ‘Yuxiang’ and ‘Hayward’, respectively. Micrografting provides an alternative strategy for fast and efficient evaluation of drought tolerance of plant cultivars, thus assisting sustainable development of production of the graft-propagated plant species. In vitro micrografting provided a fast and efficient approach to evaluate drought tolerance of kiwifruit, and has potential applications to other graft-propagated plant species.

Cherry tomatoes are highly nutritious, flavory with a pleasant taste and are becoming increasingly popular to the consumers. The cherry tomato cv. ‘Minichal’ produced some dwarf plants along with normal plants. Lignin, a phenolic biopolymer is the key component of cell walls in plants. Here, we analyzed lignin biosynthesis-related genes in leaves, inflorescences and fruits of dwarf and normal cherry tomato plants by reverse-transcription quantitative PCR (RT-qPCR). Among analyzed genes, SlCCOAOMT1, SlCCOAOMT2, SlCCOAOMT3, SlF5H, and SlCOMT showed significantly higher expressions, in leaf and inflorescence of dwarf plants compared with the normal plants, while SlPAL1 showed a significantly higher expression only in the leaves. On the contrary, SlHCT and SlC3H showed significantly lower expression levels in the leaves and inflorescences of dwarf plants compared with normal ones. The results suggest that SlHCT and SlC3H might have an impact on the dwarf cherry tomato plants.

Improving the quality of life and human health has a timely demand for the ample supply of fruits with high quality. Apple is one of the most consumed fruit in daily life. Facilitating the coloration of the apple with a simple and available method is important to their timely supply. We propose for the first time that utilizing photocatalytic nanoparticles facilitates the coloration of apple. The photocatalytic nanoparticles with the size of ∼18 nm can effectively promote the utilization of ultraviolet irradiation of the apple skin. The photocatalytic nanoparticles treatment remarkably upregulates the expression of the anthocyanin biosynthetic genes in apple skin, in which MdDFR is even more than 26 times that of the control fruits. The area and color examination indicates that the coloration efficiency of photocatalytic treated apples is as twice that of the control samples. This work provides an available nanomaterial to accelerate the coloration of fruit skin and proposes a new application of photocata...

In Nigeria and many other developing countries of the world, the incidence of mycotoxin- contamination of foods and food products has attracted attention and stirred a lot of concern for food safety. This work aims at detection of aflatoxigenic and ochratoxigenic synthetic genes from fungal isolates of palm oil as a veritable means for the evaluation of foods for possible mycotoxin contamination. In this study, fungal isolates from palm oil samples collected from the five states of South-east geopolitical zone in Nigeria were screened for aflatoxin and ochratoxin biosynthetic genes using Multiplex Polymerase Chain Reaction (mPCR). The assay relied on three sets of primers that amplify aflatoxgenic Aspergillus, ochratoxigenic Aspergillus and Penicillium species under optimized PCR conditions. Optimum multiplex PCR assay was standardized for simultaneous detection of toxigenic Aspergillus and ochratoxin producing Penicillium species targeting AflR, AflS and pks genes involved in aflatoxin and ochratoxin metabolic pathways respectively. AflR primer pair gave specific amplification for aflatoxigenic A. flavus but did not give amplification for A. niger and P. chrysogenum. While AflS and pks gave amplification for only aflatoxigenic and ochratoxigenic A. niger and P. chrysogenum. In the evaluation and monitoring of mycotoxin-producing fungi during the processing of food and feed commodities, Multiplex PCR approach could be a veritable tool to supplement the conventional analytical techniques.

3-Deoxyanthocyanidins are a rare type of anthocyanins that are present in mosses, ferns, and some flowering plants. They are water-soluble pigments and impart orange-red and blue-violet color to plants and play a role as phytoalexins against microbial infection and environmental stress. In contrast to anthocyanins, the lack of a hydroxyl group at the C-3 position confers unique chemical and biochemical properties. They are potent natural antioxidants with a number of potential health benefits including cancer prevention. 3-Deoxyanthocyanidin pigments have attracted much attention in the food industry as natural food colorants, mainly due to their higher stability during processing and handling conditions compared with anthocyanins. They are also photochromic compounds capable of causing a change in "perceived" color, when exposed to UV light, which can be used to design novel foods and beverages. Due to their interesting properties and potential industrial applications, great efforts have been made to synthesize these compounds. For biosynthesis, researchers have discovered the 3-deoxyanthocyanidin biosynthetic pathway and their biosynthetic genes. For chemical synthesis, advances have been made to synthesize the compounds in a simpler and more efficient way as well as looking for its novel derivative with enhanced coloration properties. This review summarizes the developments in the research on 3-deoxyanthocyanidin as a colorant, from natural sources to chemical syntheses and from health benefits to applications and future prospects, providing comprehensive insights into this group of interesting compounds.

Abscisic acid (ABA) is one of the main participants in the regulation of plant responses to water deficiency. Knowledge of the ABA signal transduction pathways in gymnosperms is rather limited, especially in comparison with those in angiosperms. Seedlings of Scots pine and Norway spruce are known for their contrasting behaviour strategies under water deficit. To characterize the possible role of ABA in these differences, ABA dynamics were investigated under conditions of water deficit in seedlings of these two species. The content of ABA and its catabolites was followed in the roots and needles of seedlings of Pinus sylvestris and Picea abies under conditions of polyethylene glycol (PEG)-induced water deficiency (−0.15 and −0.5 MPa) for 10 days. The expression of the main genes for ABA-biosynthetic enzymes was also analysed. ABA showed more pronounced stress-dependent dynamics in pine roots than in spruce roots, whereas in needles, the response was greater for spruce than pine. The ABA increase during drought was mainly due to de novo synthesis and the shift in the balance between ABA synthesis and catabolism towards synthesis. The ABA-glucosyl ester did not serve as a reserve for the release of free ABA under water deficiency. The expression levels of the main ABA biosynthetic genes showed a weak or no correlation with changes in ABA content under water stress, i.e., the ABA content in the seedlings of both species was not directly linked to the transcript levels of the main ABA biosynthetic genes. Less-pronounced stress-induced changes in ABA in pine needles than in spruce needles may be related to pine seedlings having a less conservative strategy of growth and maintenance of water balance under water deficit.

Aflatoxins residues in different poultry products were determined using HPLC technique and the expression of biosynthetic nor-1 gene of these aflatoxins by PCR assay. 90 different chicken products were analyzed for presence of aflatoxins (AFB1, AFB2, AFG1 and AFG2) using highly accurate, robust, selective, sensitive and precise HPLC-FLD assay. Incidence of aflatoxins in examined samples showed that the level of AFB1, AFB2 and AFG2 were 10 % for each and of AFG1 was 16.7%. The highest aflatoxins levels of analyzed samples were found in the liver. Expression of nor-1 gene of aflatoxins in polluted poultry products by PCR assay. A Real time PCR (RT-PCR) technique was applied to detect the gene expression of structural nor-1, which catalyzed the first step in the biosynthetic pathway of aflatoxins. The obtained results showed a very strong relationship between the presences of aflatoxins biosynthetic genes as analyzed by multiplex PCR and aflatoxins determination by HPLC/FLD.

Wild and cultivated rice show a significant difference in anthocyanin biosynthesis in the leaf. The regulation system of anthocyanin biosynthesis in rice leaf and the causal mechanism of the difference in this biosynthesis between wild and cultivated rice remain largely unknown. In this study, a genome-wide association study and transcriptome analysis were performed to identify the determinant factors and dissect the regulatory system for anthocyanin biosynthesis in rice leaves. OsC1, OsRb and OsDFR were identified as the determinants of anthocyanin biosynthesis in rice leaves. Artificial selection of certain null mutations of OsC1 and OsRb was the main causal mechanism underlying the loss of anthocyanin pigmentation in most cultivated rice. OsP1 and the MYB-bHLH-WD40 complexes regulate anthocyanin biosynthetic genes in rice leaves with partial functional overlap. OsP1 specifically activates upstream biosynthetic genes (OsCHS, OsCHI and OsF3'H) for anthocyanin biosynthesis, whereas the ternary MYB-bHLH-WD40 complex activates all anthocyanin biosynthetic genes including OsCHS, OsCHI, OsF3'H, OsF3H, OsDFR and OsANS. OsC1 and OsRb are tissue-specific regulators that do not influence anthocyanin biosynthesis in the pericarp. Our results reveal the determinant factors, regulatory system and domestication of anthocyanin biosynthesis in rice leaves, and show the potential of engineering anthocyanin biosynthesis in rice.

Nuts, such as peanut, almond, and chestnut, are valuable food crops for humans being important sources of fatty acids, vitamins, minerals, and polyphenols. Polyphenols, such as flavonoids, stilbenoids, and hydroxycinnamates, represent a group of plant-specialized (secondary) metabolites which are characterized as health-beneficial antioxidants within the human diet as well as physiological stress protectants within the plant. In food chemistry research, a multitude of polyphenols contained in culinary nuts have been studied leading to the identification of their chemical properties and bioactivities. Although functional elucidation of the biosynthetic genes of polyphenols in nut species is crucially important for crop improvement in the creation of higher-quality nuts and stress-tolerant cultivars, the chemical diversity of nut polyphenols and the key biosynthetic genes responsible for their production are still largely uncharacterized. However, current technical advances in whole-genome sequencing have facilitated that nut plant species became model plants for omics-based approaches. Here, we review the chemical diversity of seed polyphenols in majorly consumed nut species coupled to insights into their biological activities. Furthermore, we present an example of the annotation of key genes involved in polyphenolic biosynthesis in peanut using comparative genomics as a case study outlining how we are approaching omics-based approaches of the nut plant species.

Terrestrial animals, especially insects, contain various carotenoids that show structural diversity. These animals accumulated carotenoids derived from plants and other animals and modified them through metabolic reactions. Therefore, most of the carotenoids found in terrestrial animals originated from plants. Conversely, recent investigation revealed that some species of aphids and spider mites synthesized carotenoid themselves by carotenoid biosynthetic genes, which were horizontally transferred from fungi. In this chapter, carotenoids in terrestrial animals are described from the viewpoints of natural product chemistry, metabolism, food chain, and chemosystematics.

Global climate change and the industrial revolution have increased the concentration of tropospheric ozone, a photochemical air pollutant that can negatively affect plant growth and crop production. In the present study, we investigated the effects of O3 on the metabolites and transcripts of tartary buckwheat. A total of 36 metabolites were identified by gas chromatography coupled with time-of-flight mass spectrometry, and principal component analysis was performed to verify the metabolic differences between nontreated and O3-treated tartary buckwheat. The content of threonic acid increased after 2 days of the O3 treatment, whereas it decreased after 4 days of exposure, after which it gradually increased until the eighth day of exposure. In addition, the levels of most metabolites decreased significantly after the O3 treatment. On the contrary, the levels of two anthocyanins, cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside, increased more than 11.36- and 11.43-fold, respectively, after the O3 treatment. To assess the effect of O3 on the genomic level, we analyzed the expression of anthocyanin biosynthesis pathway genes in O3-treated and nontreated buckwheat using quantitative real-time reverse transcription polymerase chain reaction (PCR). We found that the expression of all anthocyanin pathway genes increased significantly in the O3-treated buckwheat compared to that in the nontreated buckwheat. Altogether, our results suggested that O3 affected the transcripts and metabolites of tartary buckwheat, which would eventually cause phenotypic changes in plants.

Paeonia ostii seeds were identified as novel sources of edible plant oil with a high proportion of α-linolenic acid, a type of n-3 fatty acid with many health benefits. Due to the unreliability of seed oil content and quality, it is necessary to discover the mechanism underlying lipid biosynthesis in Paeonia ostii seeds. This study aimed to identify the key genes involved in lipid biosynthesis in Paeonia ostii seeds by analyzing the relationship among the seed characteristics and the expression patterns of lipid genes in Paeonia ostii during seed development. Preliminary research on Paeonia ostii seed development was carried out from 10 days after pollination until maturity, focusing on phenology, oil content and lipid profiles. In addition, we investigated the spatiotemporal expression of 36 lipid biosynthetic genes in Paeonia ostii by using quantitative real-time PCR. The results suggested that the development of Paeonia ostii seeds from pollination to maturity could be divided into three periods. The 36 lipid genes showed various spatiotemporal expression patterns and five gene groups with distinct temporal patterns during seed development were identified by clustering analysis of expression data. Furthermore, the relationships between gene expression and lipid/fatty acid accumulation and some candidate key lipid genes were discussed. This study provided the global patterns of fatty acid and lipid biosynthesis-related gene expression, which are critical to understanding the molecular basis of lipid biosynthesis and identifying the lipid accumulation rate-limiting genes during seed development.

Penicillium verrucosum is responsible for ochratoxin A (OTA) contamination of temperate cereals during harvesting and storage. Inoculum comes from soil and crop debris. This study examined the effect of temperature (25 vs 30 °C), CO2 (400 vs 1000 ppm) and matric and solute stress (-2.8 vs -7.0 MPa) on (i) growth, (ii) key OTA biosynthetic genes and (iii) OTA production on a milled wheat substrate. Growth was generally faster under matric than solute stress at 25 °C, regardless of CO2 concentrations. At 30 °C, growth of P. verrucosum was significantly reduced under solute stress in both CO2 treatments, with no growth observed at -2.8 MPa (=0.98 water activity, aw) and 1000 ppm CO2. Overall, the growth patterns under solute stress was slower in elevated CO2 than under matric stress conditions when compared with existing conditions. The otapksPV gene expression was increased under elevated CO2 levels in matric stress treatments. There was fewer effects on the otanrpsPV biosynthetic gene. This pattern was paralleled with the production of OTA under these conditions. This suggest that P. verrucosum is able to actively grow and survive in both soil and on crop debris under three way interacting climate-related abiotic factors. This resilience suggests that they would still be able to pose an OTA contamination risk in temperate cereals post-harvest.

The widely application of metallic oxide nanoparticles (NPs) has led to an increase in their accumulation in farmland. Previous studies have found that the metallic oxide NPs have negative effect on plants development and growth. Nonetheless, the underlying mechanism of response to metallic oxide NPs in rice remains elusive. In this study, we show that rice FT-INTERACTING PROTEIN 7 (OsFTIP7) plays an essential role in NPs of CuO and ZnO-mediated physiological and biochemical changes in rice. Loss of function of OsFTIP7 reduced the toxicity of the NPs of CuO and ZnO to the seedlings by accumulating more biomass and chlorophyll contents. Furthermore, after high exposure to metallic oxide NPs, more indole-3-acetic acid (IAA) were determined in Osftip7 with higher expression of auxin biosynthetic genes than the control seedlings. What's more, IAA-treated seedlings displayed the similar phenotype as Osftip7 under high concentrations of NPs of CuO and ZnO. Taken together, the results substantiate that OsFTIP7 is involved in metallic oxide nanoparticle-mediated physiological and biochemical changes by negatively regulating auxin biosynthesis in rice.

Plants count on ecological services provided by pollinators or seed-dispersal animals through attracting them with volatile compounds from reproductive organs. On the other hand, volatiles from vegetative organs, such as leaves, stems, and roots, doesn’t seem to have the same function despite the organs have abilities to form, emit, and in some cases, accumulate volatiles. In most cases, vegetative plant volatiles are to defend against organisms that eat plants. Plants have acquired several sophisticated ways to make their ability to form volatiles effective against attackers. This chapter gives updates of current knowledge of biosynthetic pathways for green leaf volatiles, volatile terpenes, and phenylpropanoid volatiles, in vegetative organs. The production of volatile compounds at the level sufficient for efficient defense requires appropriate transcriptional/posttranscriptional regulation of biosynthetic pathways and/or transport and deposition of final products on the accurate tissues/cells/subcellular compartments. The precise mechanism of regulation has become clear gradually but steadily. An array of findings about the mechanism obtained so far has significantly contributed to our understanding of evolution of the biosynthetic genes, tissue-localized production, and a glycosylated storage form for vegetative volatiles.

Watercress (Nasturtium officinale R. Br.) is a cruciferous plant consumed by people worldwide. This vegetable contains numerous health-benefiting compounds; however, gene information and metabolomic profiling of individual parts for this plant species are scarce. In this study, we investigated the expression patterns of phenylpropanoid biosynthetic genes and the content of phenylpropanoids in different parts of watercress. We identified 11 genes encoding enzymes related to the phenylpropanoid biosynthetic pathway and analyzed the expression patterns of these genes in the leaves, stems, roots, flowers, and seeds of watercress. The result showed that most of the genes were expressed at the highest levels in the flowers. HPLC analysis performed in samples from these same parts revealed the presence of seven phenylpropanoid-derived compounds. The content of total phenylpropanoids was the highest in flowers, followed by that in the leaves, whereas the lowest level was generally detected in the stems. Rutin was the most abundant phenylpropanoid in all plant segments, while quercetin was detected only in the flowers and roots. This study provides useful information for further molecular and functional research involving N. officinale and closely related species. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-020-02244-y) contains supplementary material, which is available to authorized users.

Citrus plants are challenged by a broad diversity of abiotic and biotic stresses, which definitely alter their growth, development, and productivity. In order to survive the various stressful conditions, citrus plants relay on multi-layered adaptive strategies, among which is the accumulation of stress-associated metabolites that play vital and complex roles in citrus defensive responses. These metabolites included amino acids, organic acids, fatty acids, phytohormones, polyamines (PAs), and other secondary metabolites. However, the contribution of PAs pathways in citrus defense responses is poorly understood. In this review article, we will discuss the recent metabolic, genetic, and molecular evidence illustrating the potential roles of PAs in citrus defensive responses against biotic and abiotic stressors. We believe that PAs-based defensive role, against biotic and abiotic stress in citrus, is involving the interaction with other stress-associated metabolites, particularly phytohormones. The knowledge gained so far about PAs-based defensive responses in citrus underpins our need for further genetic manipulation of PAs biosynthetic genes to produce transgenic citrus plants with modulated PAs content that may enhance the tolerance of citrus plants against stressful conditions. In addition, it provides valuable information for the potential use of PAs or their synthetic analogs and their emergence as a promising approach to practical applications in citriculture to enhance stress tolerance in citrus plants.

In this research, we compared the phenotypical characters, total anthocyanins content, total phenols content, and antioxidant activity of red-fleshed apple cultivars &lsquo, XJ4&prime, &lsquo, QN-5&prime, DH&rsquo, and &lsquo, HX1&prime, at three fruit developmental stages. A further flavonoids metabolites study was conducted in &lsquo, We found broader variation of total anthocyanins content in the peel of the four cultivars, which might result in larger differences of free radicals scavenging rate. The most significant difference in fruit phenotype, anthocyanins content, and DPPH scavenging rate was observed between &lsquo, at mature stage. Therefore, the flavonoids metabolites of &lsquo, at mature stage were compared to unveil the details of anthocyanins compounds. The unique compounds pelargonidin 3-O-&beta, D-glucoside and cyanidin-3-O-malonylhexoside were detected only in peel and flesh of &lsquo, but not in &lsquo, which might contribute to the purple peel and dark-red flesh color of &lsquo, Significantly decreased upstream metabolites in the early biosynthetic genes regulated domain were found only in &lsquo, peel but not in the flesh. This might explain why the anthocyanins content in &lsquo, peel was decreased largely at the mature stage. Taken together, our findings will give some insight into the metabolites study in flavonoid biosynthetic pathway of red-fleshed apple.

Flavonoids represent a large diverse group of natural products that are used as a traditional medicine against various infectious diseases. They possess many biological activities including antimicrobial, antioxidant, anti-inflammatory, anti-cancer and anti-diabetic activities. Commercially, flavonoids are mainly obtained from plants, however, several challenges are faced during their extraction. Microorganisms have been known as natural sources of a wide range of bioactive compounds including flavonoids. Actinobacteria are the most prolific group of microorganisms for the production of bioactive secondary metabolites, thus facilitating the production of flavonoids. The screening programs for bioactive compounds revealed the potential application of actinobacteria to produce flavonoids with interesting biological activities, especially anticancer activities. Since marine actinobacteria are recognized as a potential source of novel anticancer agents, they are highly expected to be potential producers of anticancer flavonoids with unusual structures and properties. In this review, we highlight the production of flavonoids by actinobacteria through classical fermentation, engineering of plant biosynthetic genes in a recombinant actinobacterium and the de novo biosynthesis approach. Through these approaches, we can control and improve the production of interesting flavonoids or their derivatives for the treatment of cancer.

Metabolomics has become an integral part of a broad understanding of the plant phenome. It involves large-scale quantitative and qualitative analyses of metabolites present in plant tissues. Metabolomics can generally be divided into targeted and non-targeted analyses. Every year, new tools are developed and used to better understand unknown metabolomes. These tools help to identify new metabolites but also increase our understanding of biosynthetic pathways that were inexplicable using only genomics data. This article reviews existing and new metabolomics tools and their integrated utility in the discovery of plant biosynthetic genes. It covers literature and data from approximately 2010–19. This article provides a basis for an average reader to understand how plant metabolites are identified, validated, and used to understand their biosynthetic origin using integrated genomics, transcriptomics, and metabolomics.

Graphical abstract, Highlights • UPLC-SEC used as a novel tool for biopolymer characterisation. • Faster analysis time and higher resolution than existing techniques. • Potential for high throughput screening of starch fine structure., Starch has a complex molecular structure, with properties dependent on the relative chain lengths and branching structure of its constituent molecules, which varies due to polymorphisms in starch biosynthetic genes, as well as environmental factors. Here we present the application of ultra-high performance size exclusion chromatography to the separation of starch chains from plant seeds. Several methods, have been used to analyse chain length distributions in starch, all with limitations in terms of analysis time, sample preparation and molecular weight range. Here we demonstrate that chain length distributions can be obtained with dramatically reduced analysis time using ultra-high performance size exclusion chromatography. The method may also show improvements in resolution of some fine structural features. Understanding links between starch fine structure and biosynthetic genes will allow bioengineering of starches with tailored properties. This technique may have application to the size separation and resolution of a range of biopolymers of value to the food, drink and pharmaceutical industries.

Environmental changes resulted in a variety of stresses in plants of which heavy metal stress holds important position, affect the growth and development and trigger a series of morphological, physiological, biochemical and molecular changes in plants. When exposed heavy metal stress, the complex dynamickinetics of polyamine biosynthesis was observed. Polyamines are small organic polycations present in all organisms and have a leading role in signaling, plant growth and development and deliver tolerance to a cultivar against stresses. High accumulation of polyamines (putrescine, spermidine and spermine) in plantsduring heavy metal stress has been well reported and is correlated with increased tolerance to different plants under stressed condition. Genetic engineering of polyamine biosynthetic genes in crop plants is the way to create resistance heavy metal toxicity.

Sunlight influences many morphological, biochemical and molecular changes in fruits and the most important is color change associated with the development of pigments. The exposure to sunlight influences the anthocyanin content of the fruit peel. With the aim to understand the influence of bagging of fruits on the mango peel color, anthocyanin and expression of anthocyanin biosynthetic genes, an experiment was conducted by covering fruits of red colored cv. ‘Lily’ with muslin cloth. The observations were recorded for fruits of control (non-bagged) and fruits developing in shade. In bagged fruits, the color of peel changed towards lightness and yellowness. The reduction in anthocyanin was observed up to 17 times in bagged and shaded fruits. We also observed the down-regulation of all anthocyanin biosynthetic genes in fruits under bagged and shaded conditions. This study reports the influence of bagging and shade on anthocyanin biosynthetic genes and subsequent change in the color of fruit peel.

Specialized secondary metabolites serve not only to protect plants against abiotic and biotic challenges, but have also been used extensively by humans to combat diseases. Due to the great importance of medicinal plants for health, we need to find new and sustainable ways to improve the production of the specialized metabolites. In addition to direct extraction, recent progress in metabolic engineering of plants offers an alternative supply option. We argue that metabolic engineering for producing the secondary metabolites in plants may have distinct advantages over microbial production platforms, and thus propose new approaches of plant metabolic engineering, which are inspired by an ancient Chinese irrigation system. Metabolic engineering strategies work at three levels: introducing biosynthetic genes, using transcription factors, and improving metabolic flux including increasing the supply of precursors, energy, and reducing power. In addition, recent progress in biotechnology contributes markedly to better engineering, such as the use of specific promoters and the deletion of competing branch pathways. We propose that next-generation plant metabolic engineering will improve current engineering strategies, for the purpose of producing valuable metabolites in plants on industrial scales.

A new series comprising phenylacetyl-homoserine lactones (HSLs), caffeoyl-HSL and feruloyl-HSL, was biologically synthesized using an artificial de novo biosynthetic pathway. We developed an Escherichia coli system containing artificial biosynthetic pathways that yield phenylacetyl-HSLs from simple carbon sources. These artificial biosynthetic pathways contained the LuxI-type synthase gene (rpaI) in addition to caffeoyl-CoA and feruloyl-CoA biosynthetic genes, respectively. Finally, the yields for caffeoyl-HSL and feruloyl-HSL were 97.1 ± 10.3 and 65.2 ± 5.7 mg/l, respectively, by tyrosine-overproducing E. coli with a L-methionine feeding strategy. In a quorum sensing (QS) competition assay, feruloyl-HSL and p-coumaroyl-HSL antagonized the QS receptor TraR in Agrobacterium tumefaciens NT1, whereas caffeoyl-HSL did not.

Cotton seeds are important for the yield of fiber, oil, and protein. Previous studies have shown that phytosterols play important roles in fiber growth. However, the functions of phytosterols in cotton seed development remain to be elucidated. In this study, we detected the phytosterol content of cotton seeds at various developmental stages by gas chromatography–mass spectrometry (GC–MS). We found that the contents of sitosterol and campesterol were higher in the stages from 5 to 25 days post-anthesis (DPA) and decreased rapidly after 25 DPA. Moreover, the ratio of campesterol to sitosterol was low before 15 DPA and high at 20 and 25 DPA. During the early developmental stages of cotton seeds, sitosterol and campesterol are the predominant phytosterols, and the sitosterol content is much higher than that of campesterol. In addition, we found that most phytosterol biosynthetic genes were highly expressed in 10-DPA and/or 20-DPA seeds by qRT-PCR, which was consistent with the phytosterol content in cotton seeds. When the cotton bud was treated with the sterol biosynthesis inhibitors tridemorph and fenpropimorph, the growth of cotton seeds was retarded. Moreover, overexpression of the phytosterol biosynthetic gene GhSMT2−1 significantly increased the size and weight of cotton seeds. These results indicate that phytosterols indeed participate in the regulation of cotton seed development.

Twenty Aspergillus niger strains were isolated from peanuts and 14 strains were able to completely inhibit AFB1 production with co-cultivation. By using a Spin-X centrifuge system, it was confirmed that there are some soluble signal molecules or antibiotics involved in the inhibition by A. niger, although they are absent during the initial 24h of A. flavus growth when it is sensitive to inhibition. In A. flavus, 19 of 20 aflatoxin biosynthetic genes were down-regulated by A. niger. Importantly, the expression of aflS was significantly down-regulated, resulting in a reduction of AflS/AflR ratio. The results suggest that A. niger could directly inhibit AFB1 biosynthesis through reducing the abundance of aflS to aflR mRNAs. Interestingly, atoxigenic A. flavus JZ2 and GZ15 effectively degrade AFB1. Two new metabolites were identified and the key toxic lactone and furofuran rings both were destroyed and hydrogenated, meaning that lactonase and reductase might be involved in the degradation process.

In the present study, efforts were made to determine effect of different light wavelengths on carotenoid biosynthesis in Scutellaria baicalensis, a promising traditional herbal medicine used in North America and Asia. The variation in the transcriptional level of carotenoid biosynthesis genes and carotenoid contents in the callus was analyzed after exposure to light from red (wavelength, 660 nm), blue (wavelength, 470 nm), or white (wavelength, 380 nm) light-emitting diodes. The transcription levels of phytoene synthase (SbPSY), ξ-carotene desaturase (SbZDS), β-ring carotene hydroxylase (SbCHXB), and zeaxanthin epoxidase (SbZEP) were upregulated on exposure to all three lights, with the greatest increase in expression observed upon exposure to blue light. In contrast, the transcriptional levels of two carotenoid cleavage dioxygenases (SbCCD1 and SbCCD4) decreased under all three light treatments. Increased production of zeaxanthin, β-carotene, and 9-cis-β-carotene was observed on exposure to all 3 lights. The total carotenoid production rose by 27.35% under blue light treatment, while the white and red lights did not have any considerable effect. Our findings may establish new approaches for increasing carotenoid production in S. baicalensis as well as in other plants.

This review analyzes the advances in understanding the natural signaling pathways and environmental factors regulating stilbene biosynthesis. We also discuss the studies reporting on stilbene content and repertoire in plants. Stilbenes, including the most-studied stilbene resveratrol, are a family of phenolic plant secondary metabolites that have been the subject of intensive research due to their valuable pharmaceutical effects and contribution to plant disease resistance. Understanding the natural mechanisms regulating stilbene biosynthesis in plants could be useful for both the development of new plant protection strategies and for commercial stilbene production. In this review, we focus on the environmental factors and cell signaling pathways regulating stilbene biosynthesis in plants and make a comparison with the regulation of flavonoid biosynthesis. This review also analyzes the recent data on stilbene biosynthetic genes and summarizes the available studies reporting on both stilbene content and stilbene composition in different plant families.

Vitamin E refers to four tocopherols and four tocotrienols that are exclusively synthesized by photosynthetic organisms. While α-tocopherol is the most potent vitamin E compound, it is not the main form consumed since the composition of most major crops is dominated by γ-tocopherol. Nutritional studies show that populations of developed countries do not consume enough vitamin E and that a large proportion of individuals exhibit plasma α-tocopherol deficiency. Following the identification of vitamin E biosynthetic genes, several strategies including metabolic engineering, classic breeding and mutation breeding, have been undertaken to improve the vitamin E content of crops. In addition to providing crops in which vitamin E content is enhanced, these studies are revealing the bottlenecks limiting its biosynthesis.

Chlorophyll (Chl) biosynthesis requires highly efficient metabolic regulation during chloroplast biogenesis in angiosperms. The intermediates of Chl biosynthesis and Chls are easily activated by li...

Current understanding of the role of plant hormones during cereal grain filling is confounded by contradictory reports on hormone production that is based on poor methodology. We report here on the accurate measurement of indole-3-acetic acid (IAA) and abscisic acid (ABA) by combined liquid chromatography-tandem mass spectrometry in multiple reaction-monitoring mode with heavy isotope labelled internal standards. ABA and IAA contents of superior versus inferior rice grains (ABA maxima 159 ng g–1 FW and 109 ng g–1 FW, IAA maxima 2 µg g–1 FW and 1.7 µg g–1 FW respectively) correlated with the expression of biosynthetic genes and with grain fill. Results confirm that grain ABA is produced primarily by OsNCED2(5), but suggest that ABA import and metabolism also play important roles in ABA regulation. The IAA content of grains is primarily influenced by OsYUC9 and OsYUC11. However, the distinct expression profile of OsYUC12 suggests a specific role for IAA produced by this enzyme. Co-expression of OsYUC12 with OsIAA29 indicates their involvement in a common signalling pathway. Co-expression and cis-element analysis identified several aleurone-specific transcriptional regulators as well as glutelin as strong candidates for detailed investigation for direct regulation by the auxin-signalling pathway.

Background: Pueraria candollei var. mirifica , a Thai medicinal plant used traditionally as a rejuvenating herb, is known as a rich source of phytoestrogens, including isoflavonoids and the highly estrogenic miroestrol and deoxymiroestrol. Although these active constituents in P. candollei var. mirifica have been known for some time, actual knowledge regarding their biosynthetic genes remains unknown. Results: A de novo transcriptome analysis was conducted using combined P. candollei var. mirifica tissues of young leaves, mature leaves, tuberous cortices, and cortex-excised tubers.A total of 166,923 contigs was assembled for functional annotation using protein databases and as a library for identification of genes that are potentially involved in the biosynthesis of isoflavonoids and miroestrol. Twenty-one differentially expressed genes from four separate libraries were identified as candidatesinvolved in these biosyntheticpathways, and their respective expressions were validated by quantitative real-time reverse transcription polymerase chain reaction. Notably, isoflavonoid profiling generated by LC-MS/MS was positively correlated with expression levels of isoflavonoid biosynthetic genes across the four types of tissues. Moreover, we identified R2R3 MYB transcription factors that may be involved in the regulation of isoflavonoid biosynthesis in P. candollei var. mirifica . To confirm the function of a key-isoflavone biosynthetic gene, P. candollei var. mirifica isoflavone synthase identified in our library was transiently co-expressed with an Arabidopsis MYB12 transcription factor ( At MYB12) in Nicotiana benthamiana leaves. Remarkably, the combined expression of these proteins ledto the production of the isoflavone genistein. Conclusions: Our results provide compelling evidence regarding the integration of transcriptome and metabolome as a powerful tool for unraveling biosynthetic pathways in plants.

Ochratoxin A (OTA) is a potent pentaketide nephrotoxin widely contaminating food and feed products (grains, legumes, coffee, dried fruits, meat derived products, beer and wine). OTA is the primary mycotoxin risk in wine and dried vine fruits. The contamination of grapes and wine is strongly related to climatic conditions during cultivation. There is little information on the impact that climate change environmental fluxes may have on fungal colonization and ochratoxin A contamination of grapes. It has been suggested that the Mediterranean region is a hot spot for the impact of climate change scenarios with temperatures expected to increase by +2-5°C and CO2 to double or triple (400 ppm vs 800/1200 ppm) in the medium term. The northern region of Apulia, in the south of Italy, is normally considered to be an area where the risk of OTA in vineyards is relatively low. This study has examined the effect of i) increased temperature in the alternating day/night cycle (15-28°C vs 18-34°C), ii) existing and predicted CO2 concentrations (400 vs 1000 ppm), iii) conditions where water is freely available or drought stress is imposed (0.99 vs 0.93 aw ) in A. carbonarius strains (ITEM 7444, ITEM 5010 and B7), grown on grape-based matrices, by analysis of growth rate, OTA production and expression of key toxin biosynthetic genes. The results showed that in both non-stressed aw and drought stressed conditions the effect of elevated CO2 (1000 ppm) caused a general positive stimulation of growth rates at both the temperature cycles. Furthermore, while differences in the alternating day/night temperatures at 400 ppm and 0.99 aw did not result in any variation in OTA production, elevated CO2 condition (1000 ppm) was observed to stimulate OTA production especially at the 15-28°C cycle. These results were confirmed by gene expression analysis showing higher expression levels of OTA related genes at higher CO2 concentration. This study showed for the first time that elevated CO2 concentrations under different fluxes in day/night temperatures in the Mediterranean region may result in an increasing of OTA risk contamination in the production chain, being grapes destined for wine production less resilient under climate change scenarios.

Carrot is considered one of the leading horticultural crops in the world in terms of its nutritional value, health benefits, and unique flavor based on its high content of carotenoids and volatile aroma compounds. Terpenes such as monoterpenes and sesquiterpenes represent some of the predominant volatile compounds that contribute to carrot aroma and flavor. Variation of terpene composition based on genotypic differences or environmental factors has significant effects on taste perception by consumers and, therefore, is a critical quality attribute for carrot breeders and growers. Surprisingly, little is known about the biosynthesis of volatile terpenes in carrots and the various enzymes involved in their formation. In this chapter, we provide an overview of volatile terpene sampling and terpene diversity in different D. carota genotypes. Facilitated by the recent elucidation of the carrot genome, we further describe and discuss latest findings of the function of genes and enzymes in the terpene synthase family involved in the biosynthesis of carrot terpene volatiles.

The involvement of ethylene gas in the ripening of peach fruit is a symbolic phenomenon that has a place in the history of research on plant hormones. It is well documented that fruit ripening is developmentally regulated and affected by environmental factors such as temperature and light. Blue light has been shown to induce pigment synthesis in postharvest fruit. However, information on its effect on fruit ripening is still limited. This study aimed to investigate the effect of light-emitting diode blue light treatment at 40 μmol m−2 s−1 on fruit ripening, ethylene biosynthesis and signalling in postharvest peaches during storage at 10 °C. Blue light exposure induced fruit ripening as expressed by the enhanced decline of fruit firmness and increases in skin colour parameters, which was associated with the increase in ethylene production because of the up-regulated expression of PpLOXs and ethylene biosynthetic genes such as PpACO1 and PpACS3. Meanwhile, six genes in relation to ethylene perception and signalling were also investigated using real-time PCR. Among them, blue light treatment significantly inhibited expression of PpERS1 and enhanced transcript levels of PpEIN2, PpEIL1, PpEIL2 and PpERF2, which led to an induction ethylene signalling pathway and resulted in turn into the promotion of ethylene production and fruit softening in postharvest peaches. Compared to control fruit stored at darkness, higher expression level of ethylene biosynthetic and signalling genes in blue light exposed peaches could be beneficial for its ethylene production and consequently fruit ripening.

Anthocyanin biosynthesis exhibits a rhythmic oscillation pattern in some plants. To investigate the correlation between the oscillatory regulatory network and anthocyanin biosynthesis in pear, the anthocyanin accumulation and the expression patterns of anthocyanin late biosynthetic genes (ALBGs) were investigated in fruit skin of &lsquo, Red Zaosu&rsquo, (Pyrus bretschneideri Rehd.). The anthocyanin accumulated mainly during the night over three continuous days in the fruit skin, and the ALBGs&rsquo, expression patterns in &lsquo, fruit skin were oscillatory. However, the expression levels of typical anthocyanin-related transcription factors did not follow this pattern. Here, we found that the expression patterns of four PbREVEILLEs (PbRVEs), members of a class of atypical anthocyanin-regulated MYBs, were consistent with those of ALBGs in &lsquo, fruit skin over three continuous days. Additionally, transient expression assays indicated that the four PbRVEs promoted anthocyanin biosynthesis by regulating the expression of the anthocyanin biosynthetic genes encoding dihydroflavonol-4-reductase (DFR) and anthocyanidin synthase (ANS) in red pear fruit skin, which was verified using a dual-luciferase reporter assay. Moreover, a yeast one-hybrid assay indicated that PbRVE1a, 1b and 7 directly bound to PbDFR and PbANS promoters. Thus, PbRVEs promote anthocyanin accumulation at night by up-regulating the expression levels of PbDFR and PbANS in &lsquo, fruit skin.

Covering: 1960s to end of August 2018 Plant glandular trichomes (GTs) are adaptive structures that are well known as "phytochemical factories" due to their impressive capacity to biosynthesize and store large quantities of specialized natural products. The natural products in GTs are chemically diverse and mostly function as defense chemicals, therefore GTs are frequently regarded as "the first defense line" of plants against biotic and abiotic stresses. More importantly, many GT natural products are commercially desirable, thanks to their significant biological activities, thus attracting extensive interest in their biosynthesis. Consequently, it is well known that plant GTs are not only important reservoirs of biologically active natural products but are also a valuable bank of novel biosynthetic genes and enzymes. The non-volatile or oxygenated natural products in plant GTs, which need longer biosynthetic pathways and more energy from the plants, are of particular interest due to their more extensive biological activities and high commercial value. This review mainly focuses on these non-volatile natural products in plant GTs, including their chemistry, biological activities and biosynthesis. The methods employed for investigating natural products and their biosynthesis in plant GTs are also comprehensively discussed.

Sacred lotus (Nelumbo nucifera Gaertn.) is an ancient aquatic plant used throughout Asia for its nutritional and medicinal properties. Benzylisoquinoline alkaloids (BIAs), mostly within the aporphine and bisbenzylisoquinoline structural categories, are among the main bioactive constituents in the plant. The alkaloids of sacred lotus exhibit promising anti-cancer, anti-arrhythmic, anti-HIV, and anti-malarial properties. Despite their pharmacological significance, BIA metabolism in this non-model plant has not been extensively investigated. In this review, we examine the diversity of BIAs in sacred lotus, with an emphasis on the distinctive stereochemistry of alkaloids found in this species. Additionally, we discuss our current understanding of the biosynthetic genes and enzymes involved in the formation of 1-benzylisoquinoline, aporphine, and bisbenzylisoquinoline alkaloids in the plant. We conclude that a comprehensive functional characterization of alkaloid biosynthetic enzymes using both in vitro and in vivo methods is required to advance our limited knowledge of BIA metabolism in the sacred lotus.

The methylated flavone tricin has been associated with numerous health benefits, including reductions in intestinal and colon cancers in animal models. Tricin is found in a wide range of plant species and in many different tissues. However, whole cereal grains, such as rice, barley, oats, and wheat, are the only food sources of tricin, which is located in the bran portion of the grain. Variation in tricin levels was found in bran from rice genotypes with light brown, brown, red, and purple pericarp color, with the purple pericarp genotypes having the highest levels of tricin. Here, we analyzed tricin and tricin derivative levels in developing pericarp and embryo samples of a purple pericarp genotype, IAC600, that had high tricin and tricin derivative levels in the bran, and a light brown pericarp genotype, Cocodrie, that had no detectable tricin or tricin derivatives in the bran. Tricin and tricin derivatives were detected in both the pericarp and embryo of IAC600 but only in the embryo of Cocodrie. The purple pericarp rice had higher total levels of free tricin plus tricin derivatives than the light brown pericarp rice. When expressed on a per grain basis, most of the tricin component of IAC600 was in the pericarp. In contrast, Cocodrie had no detectable tricin in the pericarp samples but did have detectable chrysoeriol, a precursor of tricin, in the pericarp samples. We also used RNA-Seq analysis of developing pericarp and embryo samples of the two cultivars to compare the expression of genes involved in the flavonoid biosynthetic pathway. The results presented here suggest that understanding the basis of tricin accumulation in rice pericarp may lead to an approach to increasing tricin levels in whole grain rice. From analysis of gene expression levels in the pericarp samples it appears that regulation of the flavone specific genes is independent of regulation of the anthocyanin biosynthetic genes. It therefore may be feasible to develop brown pericarp rice cultivars that accumulate tricin in the pericarp.

The accumulation of beneficial biochemical compounds in different parts of pomegranate ( Punica granatum L.) fruit determines fruit quality and highly depends on environmental conditions. We investigated the effects of agro-climatic conditions on major biochemical compounds and on the expression of major anthocyanin biosynthetic genes in the peels and arils of a yellow-peeled and pink-ariled pomegranate cultivar in three agro-climatologically different locations in Sri Lanka. Drier and warmer climates promoted the accumulation of the measured biochemical compounds, i.e. total phenolic content (TPC), antioxidant capacity (AOX), and α, β, and total punicalagin, in both peels and arils compared to wetter and cooler climates. Pomegranate DFR, F3H, and ANS transcripts in both peels and arils showed higher relative expression in hotter and drier regions, compared to those grown in cooler and wetter conditions. Therefore, growing pomegranates in drier and warmer environments maximizes the production of beneficial biochemical compounds and associated gene expression in pomegranate fruit.

Pakchoi (Brassica rapa subsp. chinensis) is cultivated for its nutritional value, particularly with regard to vitamins, minerals and dietary fibers. However, limited metabolic information is available on the phyto-nutritional traits of pakchoi. Our GC-TOF MS analysis showed that green pakchoi has higher contents of carbon metabolism-associated metabolites such as sugars, sugar derivatives and inositol, while purple pakchoi has higher levels of nitrogen metabolism-associated metabolites such as amino acids and amino acid derivatives. To compare the content and composition of secondary metabolites in green and purple pakchoi, we analyzed phenylpropanoid-derived compounds and anthocyanins in mature leaves using an HPLC-UV system. This analysis identified 9 phenylpropanoid-derived compounds and 12 anthocyanins in the mature leaves of green and purple pakchoi. The level of rutin was significantly higher in purple pakchoi compared with green pakchoi, consistent with the expression of phenylpropanoid biosynthetic genes in the two pakchoi cultivars. The data obtained from this comprehensive metabolic profiling would be helpful to improve our understanding of the nutritional values of pakchoi cultivars as food sources.

Seed germination plays important roles in the establishment of seedlings and their subsequent growth; however, seed germination is inhibited by salinity, and the inhibitory mechanism remains elusive. Our results indicate that NaCl treatment inhibits rice seed germination by decreasing the contents of bioactive gibberellins (GAs), such as GA1 and GA4, and that this inhibition can be rescued by exogenous bioactive GA application. To explore the mechanism of bioactive GA deficiency, the effect of NaCl on GA metabolic gene expression was investigated, revealing that expression of both GA biosynthetic genes and GA-inactivated genes was up-regulated by NaCl treatment. These results suggest that NaCl-induced bioactive GA deficiency is caused by up-regulated expression of GA-inactivated genes, and the up-regulated expression of GA biosynthetic genes might be a consequence of negative feedback regulation of the bioactive GA deficiency. Moreover, we provide evidence that NaCl-induced bioactive GA deficiency inhibits rice seed germination by decreasing α-amylase activity via down-regulation of α-amylase gene expression. Additionally, exogenous bioactive GA rescues NaCl-inhibited seed germination by enhancing α-amylase activity. Thus, NaCl treatment reduces bioactive GA content through promotion of bioactive GA inactivation, which in turn inhibits rice seed germination by decreasing α-amylase activity via down-regulation of α-amylase gene expression.

Anthocyanins are the resultant end-point metabolites of phenylapropanoid/flavonoid (F/P) pathway which is regulated at transcriptional level via a series of structural genes. Identifying the key genes and their potential interactions can provide us with the clue for novel points of intervention for improvement of the trait in strawberry. We profiled the expressions of putative regulatory and biosynthetic genes of cultivated strawberry in three developmental and characteristically colored stages of fruits of contrastingly anthocyanin rich cultivars: Tokun, Maehyang and Soelhyang. Besides FaMYB10, a well-characterized positive regulator, FaMYB5, FabHLH3 and FabHLH3-delta might also act as potential positive regulators, while FaMYB11, FaMYB9, FabHLH33 and FaWD44-1 as potential negative regulators of anthocyanin biosynthesis in these high-anthocyanin cultivars. Among the early BGs, Fa4CL7, FaF3H, FaCHI1, FaCHI3, and FaCHS, and among the late BGs, FaDFR4-3, FaLDOX, and FaUFGT2 showed significantly higher expression in ripe fruits of high anthocyanin cultivars Maehyang and Soelhyang. Multivariate analysis revealed the association of these genes with total anthocyanins. Increasingly higher expressions of the key genes along the pathway indicates the progressive intensification of pathway flux leading to final higher accumulation of anthocyanins. Identification of these key genetic determinants of anthocyanin regulation and biosynthesis in Korean cultivars will be helpful in designing crop improvement programs.

Plants synthesize volatile compounds to attract pollinators. The volatiles emitted by flowers are often complex mixtures of organic compounds; pollinators are capable of distinctly recognizing different volatile compounds. Plants also produce volatile compounds to protect themselves against herbivores and pathogens. Some of the volatile compounds produced in floral and vegetative tissues are toxic to insects and microbes. To adapt changes in the environment, plants have evolved the ability to synthesize a unique set of volatiles. Intensive studies have identified and characterized the enzymes responsible for the formation of plant volatiles. In particular, many biosynthetic genes have been isolated and their enzymatic functions have been proposed. This review describes how plants have evolved the biosynthetic pathways leading to the formation of green leaf volatiles and phenylpropene volatiles.

An actinomycete strain, CB-75, was isolated from the soil of a diseased banana plantation in Hainan, China. Based on phenotypic and molecular characteristics, and 99.93% sequence similarity with Streptomyces spectabilis NBRC 13424 (AB184393), the strain was identified as Streptomyces sp. This strain exhibited broad-spectrum antifungal activity against 11 plant pathogenic fungi. Type I polyketide synthase (PKS-I) and non-ribosomal peptide synthetase (NRPS) were detected, which were indicative of the antifungal compounds that Streptomyces sp. CB-75 could produce. An ethyl acetate extract from the strain exhibited the lowest minimum inhibitory concentration (MIC) against Colletotrichum musae (ATCC 96167) (0.78 μg/ml) and yielded the highest antifungal activity against Colletotrichum gloeosporioides (ATCC 16330) (50.0 μg/ml). Also, spore germination was significantly inhibited by the crude extract. After treatment with the crude extract of Streptomyces sp. CB-75 at the concentration 2 × MIC, the pathogenic fungi showed deformation, shrinkage, collapse, and tortuosity when observed by scanning electron microscopy (SEM). By gas chromatography-mass spectrometry (GC-MS) of the crude extract, 18 chemical constituents were identified; (Z)-13-docosenamide was the major constituent. Pot experiments showed that the incidence of banana seedlings was reduced after using Streptomyces sp. CB-75 treatment. The disease index was 10.23, and the prevention and control effect was 83.12%. Furthermore, Streptomyces sp. CB-75 had a growth-promoting effect on banana plants. The chlorophyll content showed 88.24% improvement, the leaf area, root length, root diameter, plant height, and stem showed 88.24, 90.49, 136.17, 61.78, and 50.98% improvement, respectively, and the shoot fresh weight, root fresh weight, shoot dry weight, and root dry weight showed 82.38, 72.01, 195.33, and 113.33% improvement, respectively, compared with treatment of fermentation broth without Streptomyces sp. CB-75. Thus, Streptomyces sp. CB-75 is an important microbial resource as a biological control against plant pathogenic fungi and for promoting banana growth.