Isoflavone Reductase Research Articles

Biochemical characterization of HcrF from Limosilactobacillus fermentum, a NADH-dependent 2-ene reductase with activity on hydroxycinnamic acids.

In fermented plant foods, phenolic compounds are metabolized by 2-ene reductases, which reduce double bonds adjacent to an aromatic rings in phytochemicals including hydroxycinnamic acids, isoflavones, and flavones. Only few 2-ene reductases of lactic acid bacteria were characterized, including the hydrocinnamic reductases HcrB and Par1, and the daidzein reductase of Lactococcus lactis. This study aimed to characterize HcrF, a homologue of HcrB, in Limosilactobacillus fermentum. HcrF was purified after cloning in Escherichia coli and purification by affinity chromatography. HcrF was optimally active at 30 - 40°C and pH 7.0 and required both FMN and NADH as co-factors. Ferulic, caffeic, p-coumaric and sinapic acids but not trans-cinnamic acids were reduced to dihydro derivatives. The maximum reaction velocity Vmax of HcrF was highest for ferulic acid. On a phylogenetic tree of 2-ene reductases, HcrF clustered most closely with the hydroxycinnamic acid reductase HcrB of Lactiplantibacillus plantarum. The hydroxycinnamic acid reductase Par1 of Furfurilactobacillus milii and flavone or isoflavone reductases were only distantly related to HcrF. In summary, current knowledge does not allow to predict the substrate specificity of 2-ene reductases on the basis of the protein sequence; this study adds HcrF to the short list of enzymes with known substrate specificity.

Heat-induced modulation of flavonoid biosynthesis via a LhMYBC2-Mediated regulatory network in oriental hybrid lily

Global warming significantly threatens crop production, and adversely affects plant physiology due to rising temperatures. Oriental hybrid lily, an ornamental plant of economic importance, experiences flower color changes in response to elevated temperatures. Anthocyanins belong to a subgroup of flavonoids and are the primary pigments responsible for the coloration of oriental hybrid lily petals. However, the regulatory mechanisms governing flavonoid biosynthesis under high temperature conditions in lilies remain poorly understood. In this study, we revealed the altered metabolite profiles in flavonoid biosynthesis using quasi-targeted metabolomic and transcriptomic analyses. Isoflavonoids accumulate substantially under high temperature conditions, whereas the accumulation of anthocyanin decreases. The expression of the isoflavone reductase gene (LhIFR) and the transcription factor LhMYBC2 were upregulated in response to high temperatures. The LhMYBC2 protein, which belongs to Subgroup 4-AtMYB4, competes with the anthocyanin positive regulator LhMYBA1 for the LhTT8 partner, thereby repressing the formation of a positively regulated transcription complex. Heterologous overexpression of LhMYBC2 in tobacco led to reduced anthocyanin accumulation and increased isoflavonoid accumulation, corroborating its role in inhibiting anthocyanin biosynthesis. This study proposes a regulatory model wherein LhMYBC2 acts as a mediator of flavonoid biosynthesis, influencing the coloration of lily flowers under high-temperature stress. These findings deepen our understanding of the metabolic and transcriptional responses of lily to heat stress and underscore the potential role of LhMYBC2 in mitigating anthocyanin accumulation.

Shotgun proteomics and in silico analysis of potential allergens in mature seeds and sprouts of purple winged bean

Winged bean (Psophocarpus tetragonolobus (L.) DC.) is a tropical legume crop found in Southeast Asian countries including Thailand. The mature seeds have high protein content and have been targeted as a protein source, and germination has been used to increase the value of nutrition. We used nanoLC/timsTOF Pro 2 combined with PEAKS® studio Xpro software to explore the proteomes of mature seeds and sprouts of purple winged bean. This study is the first report on the allergenic proteins in mature seeds and sprouts of purple winged bean. In silico analysis using Allergen Nomenclature search and the Allermatchtm program, 37 allergens were found. Conglutin beta 5 and late embryogenesis abundant protein (3 and D-29) were identified only in mature seeds, while 4 types of major pollen allergen Bet V, profilin and isoflavone reductase, were identified only in sprouts. Examples of allergens in both samples include basic 7S globulin, beta-conglycinin alpha/beta subunit (1,2), convicilin, defensin-like protein, 7 types of non-specific lipid-transfer protein, P24 oleosin isoform B. Since food allergy and airway allergy are found in sprouts, we used shotgun proteomics and in silico analysis for detecting the profiles of allergens. With regards to food safety, purple winged beans may also induce cross-reactivity in patients who are allergic to peanuts or other legumes. Therefore, identifying the proteomes and potential allergens in mature seeds and sprouts of purple winged beans could assist researchers in studying plant-based food safety.

Comprehensive in silico characterization of soybean (Glycine max L.) isoflavone reductase genes and their expressions in response to spermidine and ultrasonication

Soybean (Glycine max L.) is a globally important industrial legume crop that provides several important dietary components but faces growth challenges under various stresses, that cause production and economic losses. Isoflavone reductase (IFR) is a key gene involved in isoflavonoid biosynthesis and response to plant growth and stresses. However, IFR genes remain unexplored in the soybean genome. In this study, 37 IFR genes were identified and comprehensively characterized for the first time in the soybean genome. All GmIFR proteins contained NmrA conserved domains with diverse physicochemical properties including 1 to 9 motifs, and 1 to 10 exons. Chromosomal distribution revealed 11 GmIFR genes located on chromosomes 1 and 11. Cis-element analysis unveiled GmIFR genes role in phytohormones and stress responses. Synteny analysis identified 13 segmental and 2 tandem GmIFR duplicates under purifying selection. Additionally, 118 gma-miRNAs from 76 families were identified to be targeting all 37 GmIFR genes. Potential transcription factors including ERF, MYB, Dof, BBR-BPC, and bHLHs were predicted and visualized in a network interacting with GmIFR genes. The annotation results exhibit that GmIFR genes were highly related to the biosynthesis of metabolites, phenylpropanoid pathway, and response to stresses. FPKM expression data highlighted the significant upregulation of GmIFR genes in soybean tissues under different stress conditions. qRT-PCR results exhibited that most GmIFR genes, mainly GmIFR9/17 and GmIFR36 were highly upregulated in soybean cotyledon followed by hypocotyl and root tissues under spermidine and ultrasonication treatments than control, suggesting their key role in growth and developmental processes in soybean. These findings laid the foundation for further functional studies of GmIFR genes to elucidate their contributions to soybean improvement under adverse conditions.

Identification and analysis of isoflavone reductase gene family in Gossypium hirsutum L.

Isoflavone reductase (IFR) is a key enzyme controlling isoflavone synthesis and widely involved in response to various stresses. In this study, the IFR genes in four Gossypium species and other 7 species were identified and analyzed in the whole genome, and the physicochemical properties, gene structures, cis-acting elements, chromosomal locations, collinearity relationships and expression patterns of IFR genes were systematically analyzed. 28, 28, 14 and 15 IFR genes were identified in Gossypium hirsutum, Gossypium barbadense, Gossypium arboreum and Gossypium raimondii, respectively, which were divided into five clades according to the evolutionary tree and gene structure. Collinear analysis showed that segmental duplication and whole genome duplication were the main driving forces in the process of evolution, and most genes underwent pure selection. Gene structure analysis showed that IFR gene family was relatively conserved. Cis-element analysis of promoter showed that most GhIFR genes contain cis-elements related to abiotic stresses and plant hormones. Analysis of GhIFR gene expression under different stresses showed that GhIFR genes were involved in the response to drought, salt, heat and cold stresses through corresponding network mechanisms, especially GhIFR9A. Phenotypic analysis after silencing GhIFR9A gene by VIGS was shown that GhIFR9A gene was involved in the response to salt stress. This study laid a foundation for the subsequent functional study of cotton IFR genes.

Exogenous melatonin stimulated isoflavone biosynthesis in NaCl-stressed germinating soybean (Glycine max L.)

Melatonin (MT) has gained increasing attention due to its pleiotropic effects. In this study, the function of exogenous MT on the response to NaCl stress and isoflavone biosynthesis in germinating soybeans was investigated. Results showed the exogenous MT (100 μM) application neutralised the negative effects of NaCl stress (60 mM), induced sprout growth, biomass and fluorescence intensity of intracellular free calcium, decreased malondialdehyde, H2O2 content and fluorescence intensity of O2•-, and enhanced superoxide dismutase, catalase and peroxidas activities of germinating soybeans. Meanwhile, total flavonoids and different forms of isoflavone content were enhanced by MT application, not only companied by the up-regulated relative gene expression of cinnamic acid 4-hydroxylase chalcone reductase, chalcone isomerase 1A, isoflavone reductase and isoflavone synthase 1 that involved in isoflavone biosynthesis, but also increased activities of phenylalanine ammonia lyase and 4-coumarate coenzyme A ligase. Given the evidence from the present study, it's proposed that the exogenous MT could relieve NaCl stress and stimulate isoflavone biosynthesis in germinating soybeans.

Melatonin mediates isoflavone accumulation in germinated soybeans (Glycine max L.) under ultraviolet-B stress

Soybean germination under ultraviolet-B (UV–B) radiation stress is a common and effective way to enrich the isoflavone content of sprouts. However, the growth and biomass of germinated soybeans are significantly suppressed using this method. Melatonin (MT), a novel plant biostimulant, not only plays a vital protective role in responses to various abiotic stresses but also regulates the accumulation of secondary metabolites. In the present study, the effects of exogenous MT on the growth and isoflavone metabolism of germinating soybeans exposed to UV-B stress were investigated. Compared to UV-B stress, the application of exogenous MT (25 μM) significantly increased sprout length, fresh weight, Ca2+ influx, and peroxidase activity; markedly decreased the content of malondialdehyde and H2O2 and the fluorescence intensity of H2O2 and O2•-; but had no noticeable effect on the activity of superoxide dismutase and catalase during germination. Moreover, the content of total flavonoids and isoflavone monomers (including daidzein, genistein, daidzin, glycitin and genistin) in 4-day-old germinated soybeans was significantly enhanced by MT application under UV-B stress and was not only companied by dramatically increased phenylalanine ammonia lyase activity, but also by markedly increased relative expression levels of phenylalanine ammonia lyase1, chalcone synthase, isoflavone reductase and flavanone 3-hydroxylase that are involved in the isoflavone biosynthesis pathway. The inhibitory effects of UV-B stress on the growth and biomass of germinated soybeans were alleviated with exogenous MT. MT enhanced the content of total flavonoids and isoflavone monomers under UV-B stress by increasing the activity and relative gene expression level of critical isoflavone biosynthesis-related enzymes.

Changes in biochemistry and cellular ultrastructure support different resistance mechanisms to Phytophthora sojae in nonhost common bean and host soybean

AbstractPhytophthora root and stem rot of soybean caused by Phytophthora sojae is a destructive disease affecting soybean production worldwide. In nature, soybean is the only economically important cultivated host of P. sojae. The aim of this study was to explain different resistance mechanisms to P. sojae in nonhost common bean and host soybean as a basis for the control of Phytophthora root and stem rot of soybean via nonhost resistance. Observations and measurements of disease resistance‐related variables showed slight differences in structural and biochemical resistance mechanisms between common bean and soybean. P. sojae infection induced a stronger hypersensitive response in nonhost common bean than in host resistant soybean. Moreover, phytoalexin phaseollidin synthesis‐related vestitone reductase gene was extremely highly up‐regulated, and phytoalexin glyceollin synthesis‐related isoflavone reductase gene was slightly less up‐regulated in common bean than in soybean, which resulted in a higher level of phaseollidin and a lower level of glyceollin in common bean. Phaseollidin had stronger inhibitory effects on mycelial growth and oospore formation of P. sojae than glyceollin, and more cell wall depositions and callose accumulated in common bean, which are probably related to the stronger resistance of nonhost common bean to P. sojae.

VviAGL11 self-regulates and targets hormone- and secondary metabolism-related genes during seed development.

VviAGL11, the Arabidopsis SEEDSTICK homolog, has been proposed to have a causative role in grapevine stenospermocarpy. An association between a mutation in the coding sequence (CDS) and the seedless phenotype was reported, however, no working mechanisms have been demonstrated yet. We performed a deep investigation of the full VviAGL11 gene sequence in a collection of grapevine varieties belonging to several seedlessness classes that revealed three different promoter-CDS combinations. By investigating the expression of the three VviAGL11 alleles, and by evaluating their ability to activate the promoter region, we observed that VviAGL11 self-activates in a specific promoter-CDS combination manner. Furthermore, by transcriptomic analyses on ovule and developing seeds in seeded and seedless varieties and co-expression approaches, candidate VviAGL11 targets were identified and further validated through luciferase assay and in situ hybridization. We demonstrated that VviAGL11 Wild Type CDS activates Methyl jasmonate esterase and Indole-3-acetate beta-glucosyltransferase, both involved in hormone signaling and Isoflavone reductase, involved in secondary metabolism. The dominant-negative effect of the mutated CDS was also functionally ectopically validated in target induction. VviAGL11 was shown to co-localize with its targets in the outer seed coat integument, supporting its direct involvement in seed development, possibly by orchestrating the crosstalk among MeJA, auxin, and isoflavonoids synthesis. In conclusion, the VviAGL11 expression level depends on the promoter-CDS allelic combination, and this will likely affect its ability to activate important triggers of the seed coat development. The dominant-negative effect of the mutated VviAGL11 CDS on the target genes activation was molecularly validated. A new regulatory mechanism correlating VviAGL11 haplotype assortment and seedlessness class in grapevine is proposed.

A Potential Role of Coumestrol in Soybean Leaf Senescence and Its Interaction With Phytohormones.

Coumestrol is a natural organic compound synthesized in soy leaves and functions as a phytoalexin. The coumestrol levels in plants are reported to increase upon insect attack. This study investigates the correlation between coumestrol, senescence, and the effect of phytohormones on the coumestrol levels in soybean leaves. Our analysis involving high-performance liquid chromatography and 2-D gel electrophoresis indicated a significant difference in the biochemical composition of soybean leaves at various young and mature growth stages. Eight chemical compounds were specifically detected in young leaves (V1) only, whereas three different coumestans isotrifoliol, coumestrol, and phaseol were detected only in mature, yellow leaves of the R6 and R7 growth stage. MALDI-TOF-MS analysis was used to identify two proteins 3,9 -dihydroxypterocarpan 6A-monooxygenase (CYP93A1) and isoflavone reductase homolog 2 (IFR2) only in mature leaves, which are key components of the coumestrol biosynthetic pathway. This indicates that senescence in soybean is linked to the accumulation of coumestrol. Following the external application of coumestrol, the detached V1-stage young leaves turned yellow and showed an interesting development of roots at the base of the midrib. Additionally, the application of phytohormones, including SA, methyl jasmonate (MeJA), and ethephon alone and in various combinations induced yellowing within 5 days of the application with a concomitant significant increase in endogenous coumestrol accumulation. This was also accompanied by a significant increase in the expression of genes CYP81E28 (Gm08G089500), CYP81E22 (Gm16G149300), GmIFS1, and GmIFS2. These results indicate that various coumestans, especially coumestrol, accumulate during leaf maturity, or senescence in soybean.

A short-chain dehydrogenase/reductase (SDR) detection for the Isoflavone reductase gene in Bulbophyllum and other orchids

Bulbophyllum, the largest genus in Orchidaceae, is known for being rich in phenolic compounds. In this study, the polyphenol and antioxidant content of four Bulbophyllum species was compared to that of a Dendrobium sp. control. The transcript levels of eight genes involved in flavonoid biosynthesis and oxidative stress responses were then determined to identify correlations with flavonoid and antioxidant content. A positive correlation between flavonoid content and transcription level of isoflavone reductase (IFR), belonging to the short-chain dehydrogenase/reductase (SDR) superfamily, was observed in leaf and pseudobulb tissue of the orchids. IFR showed an extraordinarily high level of gene expression (max. 118-fold) in the pseudobulb tissue of Bulbophyllum species compared with that in the same tissue in several species of Dendrobium. A pair of primers derived from two conserved regions within the sequences of related SDRs (IFR, eugenol synthase, and phenylcoumaran benzylic ether reductase) from Dendrobium spp., Paphiopedilum sp., Phaseolus sp., Phoenix sp., Striga sp., and Vanda sp. were used to attain a full-length IFR from four Bulbophyllum spp., three Dendrobium spp. and one Vanda sp. The phylogenetic relationships of those SDRs reported in the NCBI database showed distinctive clusters between the closely related SDRs of each genus in the Orchidaceae, and the distantly related clusters of the other plant SDRs. This work describes an easy method for the quick detection and isolation of IFRs in Bulbophyllum and other orchid species.

The Induction of the Isoflavone Biosynthesis Pathway Is Associated with Resistance to Common Bacterial Blight in Phaseolus vulgaris L.

Xanthomonas axonopodis infects common bean (Phaseolus vulgaris L.) causing the disease common bacterial blight (CBB). The aim of this study was to investigate the molecular and metabolic mechanisms underlying CBB resistance in P. vulgaris. Trifoliate leaves of plants of a CBB-resistant P. vulgaris recombinant inbred line (RIL) and a CBB-susceptible RIL were inoculated with X. axonopodis or water (mock treatment). Leaves sampled at defined intervals over a 48-h post-inoculation (PI) period were monitored for alterations in global transcript profiles. A total of 800 genes were differentially expressed between pathogen and mock treatments across both RILs; approximately half were differentially expressed in the CBB-resistant RIL at 48 h PI. Notably, there was a 4- to 32-fold increased transcript abundance for isoflavone biosynthesis genes, including several isoflavone synthases, isoflavone 2′-hydroxylases and isoflavone reductases. Ultra-high performance liquid chromatography-tandem mass spectrometry assessed leaf metabolite levels as a function of the PI period. The concentrations of the isoflavones daidzein and genistein and related metabolites coumestrol and phaseollinisoflavan were increased in CBB-resistant RIL plant leaves after exposure to the pathogen. Isoflavone pathway transcripts and metabolite profiles were unaffected in the CBB-susceptible RIL. Thus, induction of the isoflavone pathway is associated with CBB-resistance in P. vulgaris.

Elevated CO2 modulates the effect of heat stress responses in Triticum aestivum by differential expression of isoflavone reductase-like (IRL) gene.

Two wheat genotypes forming high and low biomass (HB and LB), exhibiting differential expression of an isoflavone reductase-like (IRL) gene, and resulting in contrasting grain yield under heat stress field conditions, were analyzed in detail for their responses under controlled heat and elevated CO2 conditions. Significant differences in IRL expression between the two lines were hypothesized to be the basis of their differential performance under the tested conditions and their stress tolerance potential. By a holistic approach integrating advanced cell physiological phenotyping of the antioxidative and phytohormone system in spikes and leaves with measurements of ecophysiological and agronomic traits, the genetic differences of the genotypes in IRL expression were assessed. In response to heat and elevated CO2, the two genotypes showed opposite regulation of IRL expression, which was associated with cytokinin concentration, total flavonoid contents, activity of superoxide dismutase, antioxidant capacity and photosynthetic rate in leaves and cytokinin concentration and ascorbate peroxidase activity in spikes. Our study showed that IRL expression is associated with wheat yield performance under heat stress at anthesis, mediated by diverse physiological mechanisms. Hence, based on our results, the IRL gene is a promising candidate for developing genetic markers for breeding heat-tolerant wheat.

Genetic Diversity and Sequences Analysis from Elaeis guineensis Jacq. Infected with Ganoderma boninense

Early screening tests on the seedling phase of Elaeis guineensis would have a significant effect on diminishing the time and the resources needed to increase variations in the oil palm breeding program to resistance Ganoderma. This research was conducted to evaluate the genetic diversity and heterozygosity among eight populations of E. guineensis Jacq. Seedlings and matures using the molecular of variant loci analysis to an early screening. PCR and GenAlEx studied the method of genetic diversity and oil palm resistance genes. The results showed the microsatellite markers (EgIFR, Eg001, Eg002, and Eg003) pattern in the DNA and protein-encoding in the oil palm seedlings' root tissue to Ganoderma resistance played a potential early screening role in material planting. The polymorphic information content (PIC) values were identified as 0.655-0.998. The means number of allele distribution in each population and loci showed Ho = 0.48. The mean of heterozygosity was found in 0.67 level. The analysis molecular of variance (AMOVA) showed a significant variability by 45% among individuals and 53% within individuals in the population. A total of 92 data sequences were identified and available on the NCBI database. They have a similarity from proteins, i.e., isoflavone reductase, polyadenylated, heat shock cognate, and thaumatin. The highest total score was showed 117, and the similarity was identified at 100%. Furthermore, the phylogenetic clusters were distinct between the seedling and mature based on the same gene and protein. This study suggested the markers and proteins important to E. guineensis against Ganoderma boninense.

Predicted of isoflavone reductase protein from oil palm and date palm using of PHYRE2 and SWISS-MODEL software

Plants contained a large number of proteins homologous to isoflavone reductase. Two palmae tree genes, c2qx7A and 1qyc1B, encoding isoflavone reductase-like proteins had been previously identified from their unique expression patterns. To gain insight into the possibility of protein modeling of isoflavone reductase, we compared in detail the build models of protein by PHYRE2 and SWISS-MODEL software. The oil palm showed a higher in sequence identity, sequence similarity, coverage, and Qmean compared to date palm. Homology modelling showed that 294 residue (97% of the amino acid sequence) had been modelling with 100.0% confidence by the single highest scoring template for both oil palm and date palm using PHYRE2. This coverage was higher than the SWISS-MODEL predicted (80% and 77%). The c2qx7A image patterns were not similar to 1qyc1B. The c2qx7A image patterns were not similar to 1qyc1B, suggesting that different protein functions in the response for each plant.

Proteomic analyses unraveling water stress response in two Eucalyptus species originating from contrasting environments for aridity.

Eucalyptus are widely cultivated in several regions of the world due to their adaptability to different climatic conditions and amenable to tree breeding programs. With changes in environmental conditions pointing to an increase in aridity in many areas of the globe, the demand for genetic materials that adapt to this situation is required. Therefore, the aim of this work was to identify contrasting differences between two Eucalyptus species under water stress through the identification of differentially abundant proteins. For this, total protein extraction was proceeded from leaves of both species maintained at 40 and 80% of field capacity (FC). The 80% FC water regime was considered as the control and the 40% FC, severe water stress. The proteins were separated by 2-DE with subsequent identification of those differentially abundant by liquid nanocromatography coupled to high resolution MS (Q-Exactive). Comparative proteomics allowed to identify four proteins (ATP synthase gamma and alpha, glutamine synthetase and a vacuolar protein) that were more abundant in drought-tolerant species and simultaneously less abundant or unchanged in the drought- sensitive species, an uncharacterized protein found exclusively in plants under drought stress and also 10 proteins (plastid-lipid, ruBisCO activase, ruBisCO, protease ClpA, transketolase, isoflavone reductase, ferredoxin-NADP reductase, malate dehydrogenase, aminobutyrate transaminase and sedoheptulose-1-bisphosphatase) induced exclusively in the drought-tolerant species in response to water stress. These results suggest that such proteins may play a crucial role as potential markers of water stress tolerance through the identification of species-specific proteins, and future targets for genetic engineering.

Yeast extract elicited isoflavonoid accumulation and biosynthetic gene expression in Pueraria candollei var. mirifica cell cultures

Yeast extract (YE) has emerged as a potent biotic elicitor that can induce plant defense responses, leading to enhanced phytoalexin accumulation. Increased production of two isoflavones—daidzein and genistein—that are widely used in pharmaceutical industries was elicited using YE in suspension cell cultures of Pueraria candollei var. mirifica. Compared with the controls, cells treated with 2 mg/L YE for 21 days produced 11-fold increased amounts of daidzein and genistein in the suspension cultures (5.12 and 0.34 mg/g dry weight (DW), respectively). Furthermore, YE treatment significantly upregulated isoflavonoid biosynthesis, as revealed via gene expression studies. In particular, among genes involved in daidzein and genistein biosynthesis, the isoflavone synthase and isoflavone reductase genes were significantly upregulated and the chalcone isomerase and 2,7,4′-trihydroxyisoflavanone dehydratase genes were significantly downregulated; moreover, these changes were associated with the accumulation of these two isoflavones in suspension cell cultures. Overall, the results obtained in this study both emphasize the utility of YE for enhancing the in vitro production of the two bioactive isoflavones examined for pharmaceutical and nutraceutical utilization and advance our understanding of their biosynthesis in response to YE elicitation. Yeast extract modulated the expression of genes involved in isoflavonoid biosynthesis in suspension cultures of P. candollei var. mirifica cells.

Mitigation of Cd toxicity by Mn in young plants of cacao, evaluated by the proteomic profiles of leaves and roots.

Cd is a non-essential metal and highly toxic to plants, animals and humans, even at very low concentrations. Cd has been found in cocoa beans and in their products, as in the case of chocolate. Mn plays an important role in photosynthetic and can interact with Cd and attenuate its toxic effects on plants. The objective of this work was to evaluate the mechanisms of Mn response in the mitigation of Cd toxicity in young plants of the CCN 51 cacao genotype submitted to 0.8 mmol Cd kg-1, 1.6 mmol Mn kg-1 or the combination of 0.4 mmol Cd kg-1 + 0.8 mmol Mn kg-1 soil, together with the control treatment (without addition of Cd and Mn in soil), by means of analysis of changes in the profile of exclusive proteins (EP) and differentially accumulated proteins (DAP). Leaf and root proteins were extracted and quantified from the different treatments, followed by proteomic analysis. About eight DAP and 38 EP were identified in leaves, whereas in roots 43 DAP and 21 EP were identified. Some important proteins induced in the presence of Cd and repressed in the presence of Cd + Mn or vice versa, were ATPases, isoflavone reductase, proteasome and chaperonin. It was concluded that proteins involved in oxidoreduction and defense and stress response processes, in addition to other processes, were induced in the presence of Cd and repressed in the presence of Cd + Mn. This demonstrated that Mn was able to mitigate the toxic effects of Cd on young plants of the CCN 51 cocoa genotype.

Evolution of a Novel and Adaptive Floral Scent in Wild Tobacco.

Many plants emit diverse floral scents that mediate plant-environment interactions and attain reproductive success. However, how plants evolve novel and adaptive biosynthetic pathways for floral volatiles remains unclear. Here, we show that in the wild tobacco, Nicotiana attenuata, a dominant species-specific floral volatile (benzyl acetone, BA) that attracts pollinators and deters florivore is synthesized by phenylalanine ammonia-lyase 4 (NaPAL4), isoflavone reductase 3 (NaIFR3), and chalcone synthase 3 (NaCHAL3). Transient expression of NaFIR3 alone in N.attenuata leaves is sufficient and necessary for ectopic foliar BA emissions, and coexpressing NaIFR3 with NaPAL4 and NaCHAL3 increased the BA emission levels. Independent changes in transcription of NaPAL4 and NaCHAL3 contributed to intraspecific variations of floral BA emission. However, among species, the gain of expression of NaIFR3 resulted in the biosynthesis of BA, which was only found in N.attenuata. This study suggests that novel metabolic pathways associated with adaptation can arise via reconfigurations of gene expression.

Host Alternative NADH:Ubiquinone Oxidoreductase Serves as a Susceptibility Factor to Promote Pathogenesis of Rhizoctonia solani in Plants

Phytopathogens have evolved mechanisms to utilize host genes (commonly known as susceptibility factors) to promote their pathogenesis. Rhizoctonia solani is a highly destructive fungal pathogen of various plants, including rice. We previously reported rice genes that were differentially regulated during R. solani pathogenesis. In this study, we analyzed the role of tomato homologs of two rice genes, isoflavone reductase (IFR) and alternative NADH:ubiquinone oxidoreductase (NUOR), as potential susceptibility factors for R. solani. Virus-induced gene silencing of NUOR in tomato resulted in compromised susceptibility against R. solani, whereas IFR-silenced plants demonstrated susceptibility similar to that of control plants. NUOR silencing in tomato led to homogenous accumulation of reactive oxygen species (optimum range) upon R. solani infection. In addition, the expression and enzyme activity of some host defense and antioxidant genes was enhanced, whereas H2O2 content, lipid peroxidation, and electrolyte leakage were reduced in NUOR-silenced plants. Similarly, transient silencing of OsNUOR provided tolerance against R. solani infection in rice. Overall, the data presented in this study suggest that NUOR serves as a host susceptibility factor to promote R. solani pathogenesis.