Flavonoids and Other Phenolic Compounds for Physiological Roles, Plant Species Delimitation, and Medical Benefits: A Promising View.

Flavonoids and other phenolic constituents are a large group of plant metabolites that have long attracted interest from researchers worldwide due to their functions in plant physiology, as well as their huge number of benefits for human health and well-being. This review attempts to reveal a promising view of the major physiological roles of flavonoids and other phenolic phytochemical molecules, e.g.

Telomere-to-telomere genome assembly of an allotetraploid pernicious weed, Echinochloa phyllopogon.

Echinochloa phyllopogon is an allotetraploid pernicious weed species found in rice fields worldwide that often exhibit resistance to multiple herbicides. An accurate genome sequence is essential to comprehensively understand the genetic basis underlying the traits of this species. Here, the telomere-to-telomere genome sequence of E.

Syntenic analysis of ACCase loci and target-site-resistance mutations in cyhalofop-butyl resistant Echinochloa crus-galli var. crus-galli in Japan.

Background: Recently, suspected cyhalofop-butyl-resistant populations of allohexaploid weed Echinochloa crus-galli var. crus-galli were discovered in rice fields in Aichi Prefecture, Japan. Analyzing the target-site ACCase genes of cyhalofop-butyl helps understand the resistance mechanism.

Transcriptionally linked simultaneous overexpression of P450 genes for broad-spectrum herbicide resistance.

Broad-spectrum herbicide resistance (BSHR), often linked to weeds with metabolism-based herbicide resistance, poses a threat to food production. Past studies have revealed that overexpression of catalytically promiscuous enzymes explains BSHR in some weeds; however, the mechanism of BSHR expression remains poorly understood. Here, we investigated the molecular basis of high-level resistance to diclofop-methyl in BSHR late watergrass (Echinochloa phyllopogon) found in the United States, which cannot be solely explained by the overexpression of promiscuous cytochrome P450 monooxygenases CYP81A12/21.

Comparison of herbicide specificity of CYP81A cytochrome P450s from rice and a multiple-herbicide resistant weed, Echinochloa phyllopogon.

Background: CYP81A cytochrome P450s (CYP81As) play a key role in herbicide detoxification in Poaceae plants. Crop CYP81As confer natural tolerance to multiple herbicides, whereas CYP81As in weeds disrupt herbicide action. Identifying differences in CYP81A herbicide specificity between crops and weeds could provide valuable information for controlling weeds.

Investigation of clomazone-tolerance mechanism in a long-grain cultivar of rice.

Background: Clomazone is a potent herbicide for controlling weeds that have evolved resistance to other herbicides due to its unique mode of action. Clomazone is used in rice cultivation, but is limited to long-grain cultivars because other cultivars are highly sensitive to it. In this study, we investigated the mechanism of clomazone tolerance in a long-grain cultivar.

Precision genome editing in plants via gene targeting and subsequent break-induced single-strand annealing.

Genome editing via artificial nucleases such as CRISPR/Cas9 has become popular in plants now. However, small insertions or deletions are major mutations and nucleotide substitutions rarely occur when DNA cleavage is induced. To induce nucleotide substitutions, a base editor utilizing dead or nickase-type Cas9 fused with deaminase have been developed.

Cytochrome P450-mediated herbicide metabolism in plants: current understanding and prospects.

Cytochrome P450s (P450s) have been at the center of herbicide metabolism research as a result of their ability to endow selectivity in crops and resistance in weeds. In the last 20 years, ≈30 P450s from diverse plant species have been revealed to possess herbicide-metabolizing function, some of which were demonstrated to play a key role in plant herbicide sensitivity. Recent research even demonstrated that some P450s from crops and weeds metabolize numerous herbicides from various chemical backbones, which highlights the importance of P450s in the current agricultural systems.

Characterization of the acetolactate synthase gene family in sensitive and resistant biotypes of two tetraploid Monochoria weeds, M. vaginalis and M. korsakowii.

Monochoria vaginalis and M. korsakowii are allotetraploid noxious weeds in rice cultivation. Occurrences of resistance to acetolactate synthase (ALS)-inhibiting herbicides have been reported in these weeds in Japan since the 1990s.

Functional characterization of cytochrome P450 CYP81A subfamily to disclose the pattern of cross-resistance in Echinochloa phyllopogon.

CYP81A P450s armor Echinochloa phyllopogon against diverse and several herbicide chemistries. CYP81A substrate preferences can be a basis for cross-resistance prediction and management in E. phyllopogon and other related species.

Quinclorac resistance in Echinochloa phyllopogon is associated with reduced ethylene synthesis rather than enhanced cyanide detoxification by β-cyanoalanine synthase.

Background: Multiple herbicide resistant Echinochloa phyllopogon exhibits resistance to the auxin herbicide quinclorac. Previous research observed enhanced activity of the cyanide-detoxifying enzyme β-cyanoalanine synthase (β-CAS) and reduced ethylene production in the resistant line, suggesting β-CAS-mediated cyanide detoxification and insensitivity to quinclorac stimulation as the resistance mechanisms. To investigate the molecular mechanisms of quinclorac resistance, we characterized the β-CAS genes alongside plant transformation studies.

Role of CYP81A cytochrome P450s in clomazone metabolism in Echinochloa phyllopogon.

Clomazone is a herbicide used in the cultivation of numerous crops due to its unique site of action and effectiveness on weeds. The differences in clomazone susceptibility among plants have been attributed to the differences in their complex clomazone metabolic pathways that are not fully understood. We previously identified two CYP81A cytochrome P450 monooxygenases that metabolize five chemically unrelated herbicides in multiple-herbicide resistant Echinochloa phyllopogon.

CYP81A P450s are involved in concomitant cross-resistance to acetolactate synthase and acetyl-CoA carboxylase herbicides in Echinochloa phyllopogon.

Californian populations of Echinochloa phyllopogon have evolved multiple-herbicide resistance (MHR), posing a threat to rice production in California. Previously, we identified two CYP81A cytochrome P450 genes whose overexpression is associated with resistance to acetolactate synthase (ALS) inhibitors from two chemical groups. Resistance mechanisms to other herbicides remain unknown.

Copy Number Variation in Acetolactate Synthase Genes of Thifensulfuron-Methyl Resistant (Shortawn Foxtail) Accessions in Japan.

Severe infestations of (shortawn foxtail), a noxious weed in wheat and barley cropping systems in Japan, can occur even after application of thifensulfuron-methyl, a sulfonylurea (SU) herbicide. In the present study, nine accessions of growing in a single wheat field were tested for sensitivity to thifensulfuron-methyl. Seven of the nine accessions survived application of standard field rates of thifensulfuron-methyl, indicating that severe infestations likely result from herbicide resistance.

Multiple-herbicide resistance in Echinochloa crus-galli var. formosensis, an allohexaploid weed species, in dry-seeded rice.

Biotypes of Echinochloa crus-galli var. formosensis with resistance to cyhalofop-butyl, an acetyl-CoA carboxylase (ACCase) inhibitor, have been found in dry-seeded rice fields in Okayama, Japan. We collected two lines with suspected resistance (Ecf27 and Ecf108) from dry-seeded rice fields and investigated their sensitivity to cyhalofop-butyl and other herbicides.

Cytochrome P450 CYP81A12 and CYP81A21 Are Associated with Resistance to Two Acetolactate Synthase Inhibitors in Echinochloa phyllopogon.

Previous studies have demonstrated multiple herbicide resistance in California populations of Echinochloa phyllopogon, a noxious weed in rice (Oryza sativa) fields. It was suggested that the resistance to two classes of acetolactate synthase-inhibiting herbicides, bensulfuron-methyl (BSM) and penoxsulam (PX), may be caused by enhanced activities of herbicide-metabolizing cytochrome P450. We investigated BSM metabolism in the resistant (R) and susceptible (S) lines of E.

A novel rice cytochrome P450 gene, CYP72A31, confers tolerance to acetolactate synthase-inhibiting herbicides in rice and Arabidopsis.

Target-site and non-target-site herbicide tolerance are caused by the prevention of herbicide binding to the target enzyme and the reduction to a nonlethal dose of herbicide reaching the target enzyme, respectively. There is little information on the molecular mechanisms involved in non-target-site herbicide tolerance, although it poses the greater threat in the evolution of herbicide-resistant weeds and could potentially be useful for the production of herbicide-tolerant crops because it is often involved in tolerance to multiherbicides. Bispyribac sodium (BS) is an herbicide that inhibits the activity of acetolactate synthase.

Cytochrome P450 genes induced by bispyribac-sodium treatment in a multiple-herbicide-resistant biotype of Echinochloa phyllopogon.

Background: Incremental herbicide metabolism by cytochrome P450 monooxygenases (P450s) has been proposed as the basis for resistance to bispyribac-sodium (bispyribac) in a multiple-herbicide-resistant biotype of Echinochloa phyllopogon. Upon exposure to bispyribac, strong induction of bispyribac-metabolising P450 activity has been reported in the resistant line, indicating that P450s induced by bispyribac are involved in the bispyribac resistance.

Results: A polymerase chain reaction (PCR)-based cloning strategy was used to isolate 39 putative P450 genes from the bispyribac-resistant line of E.

Isolation and expression of genes for acetolactate synthase and acetyl-CoA carboxylase in Echinochloa phyllopogon, a polyploid weed species.

Background: Target-site resistance is the major cause of herbicide resistance to acetolactate synthase (ALS)- and acetyl-CoA carboxylase (ACCase)-inhibiting herbicides in arable weeds, whereas non-target-site resistance is rarely reported. In the Echinochloa phyllopogon biotypes resistant to these herbicides, target-site resistance has not been reported, and non-target-site resistance is assumed to be the basis for resistance. To explore why target-site resistance had not occurred, the target-site genes for these herbicides were isolated from E.

Concentration-dependent dual effects of hydrogen peroxide on insulin signal transduction in H4IIEC hepatocytes.

Background: Oxidative stress induced by the accumulation of reactive oxygen species (ROS) has a causal role in the development of insulin resistance, whereas ROS themselves function as intracellular second messengers that promote insulin signal transduction. ROS can act both positively and negatively on insulin signaling, but the molecular mechanisms controlling these dual actions of ROS are not fully understood.

Methodology/principal Findings: Here, we directly treated H4IIEC hepatocytes with hydrogen peroxide (H2O2), a representative membrane-permeable oxidant and the most abundant ROS in cells, to identify the key factors determining whether ROS impair or enhance intracellular insulin signaling.