Transcriptomic-Proteomic Analysis Revealed the Regulatory Mechanism of Peanut in Response to Fusarium oxysporum.

Peanut Fusarium rot, which is widely observed in the main peanut-producing areas in China, has become a significant factor that has limited the yield and quality in recent years. It is highly urgent and significant to clarify the regulatory mechanism of peanuts in response to Fusarium oxysporum. In this study, transcriptome and proteome profiling were combined to provide new insights into the molecular mechanisms of peanut stems after F. oxysporums infection. A total of 3746 differentially expressed genes (DEGs) and 305 differentially expressed proteins (DEPs) were screened. The upregulated DEGs and DEPs were primarily enriched in flavonoid biosynthesis, circadian rhythm-plant, and plant-pathogen interaction pathways. Then, qRT-PCR analysis revealed that the expression levels of phenylalanine ammonia-lyase (PAL), chalcone isomerase (CHI), and cinnamic acid-4-hydroxylase (C4H) genes increased after F. oxysporums infection. Moreover, the expressions of these genes varied in different peanut tissues. All the results revealed that many metabolic pathways in peanut were activated by improving key gene expressions and the contents of key enzymes, which play critical roles in preventing fungi infection. Importantly, this research provides the foundation of biological and chemical analysis for peanut disease resistance mechanisms.

A Magnetic Reduced Graphene Oxide Nanocomposite: Synthesis, Characterization, and Application for High-Efficiency Detoxification of Aflatoxin B1.

(1) Background: Safety problems associated with aflatoxin B1 (AFB1) contamination have always been a major threat to human health. Removing AFB1 through adsorption is considered an attractive remediation technique. (2) Methods: To produce an adsorbent with a high AFB1 adsorption efficiency, a magnetic reduced graphene oxide composite (Fe3O4@rGO) was synthesized using one-step hydrothermal fabrication. Then, the adsorbent was characterized using a series of techniques, such as SEM, TEM, XRD, FT-IR, VSM, and nitrogen adsorption-desorption analysis. Finally, the effects of this nanocomposite on the nutritional components of treated foods, such as vegetable oil and peanut milk, were also examined. (3) Results: The optimal synthesis conditions for Fe3O4@rGO were determined to be 200 °C for 6 h. The synthesis temperature significantly affected the adsorption properties of the prepared material due to its effect on the layered structure of graphene and the loading of Fe3O4 nanoparticles. The results of various characterizations illustrated that the surface of Fe3O4@rGO had a two-dimensional layered nanostructure with many folds and that Fe3O4 nanoparticles were distributed uniformly on the surface of the composite material. Moreover, the results of isotherm, kinetic, and thermodynamic analyses indicated that the adsorption of AFB1 by Fe3O4@rGO conformed to the Langmuir model, with a maximum adsorption capacity of 82.64 mg·g-1; the rapid and efficient adsorption of AFB1 occurred mainly through chemical adsorption via a spontaneous endothermic process. When applied to treat vegetable oil and peanut milk, the prepared material minimized the loss of nutrients and thus preserved food quality. (4) Conclusions: The above findings reveal a promising adsorbent, Fe3O4@rGO, with favorable properties for AFB1 adsorption and potential for food safety applications.

First Report of Root Rot Caused by Macrophomina phaseolina in Peanut Shandong Province, China.

Peanut (Arachis hypogaea L.) is a widely grown oilseed crop of great agricultural importance worldwide. In July 2022, disease symptoms were observed on peanut roots in Laixi (36º85' N, 120º54' E), Shandong Province, China. About 25% of the plants showed various symptoms, including stem and root rot and blackening, microsclerotia on the stem, yellowing and wilting of leaves, and even death. Twenty diseased plants were collected to confirm the pathogen. Symptomatic roots were cut into small pieces, disinfested with 75% ethanol for 1 min and 0.5% NaClO for 2 min, rinsed three times with sterile water, dried on sterile filter paper, and then spread on potato dextrose agar (PDA) supplemented with 100 µg/mL chloramphenicol and incubated at 25°C in the dark. At the beginning of growth, the fungus formed sparse, white mycelia, which white, then darkened with age and microsclerotia were formed in the medium after 5 days. The mycelium aggregated into black, round to oblong or irregularly shaped microsclerotia 84 to 163 µm long and 54 to 125 µm wide (n=40). These morphological characteristics were consistent with the description of Macrophomina phaseolina (Holliday and Punithalingam, 1970). Molecular identification was performed by sequencing the internal transcribed spacer (ITS) region with ITS1 and ITS4 and translation elongation factor 1-alpha (TEF) with EF1-728F/EF1-986R (Glass and Donaldson 1995) of a representative isolate SXY183. ITS (OR056369) and TEF (OR098356) of SXY183 showed 100% and 97.74% similarity with M. phaseolina (KF951622, KF951997), respectively. Phylogenetic analysis was performed using Neighbor-Joining (NJ) analysis based on the gene sequences of ITS and TEF. The fungus was identified as M. phaseolina based on molecular analysis and morphological characteristics. The pathogenicity of a representative isolate (SXY183) was tested on peanuts under greenhouse conditions. Two-week-old peanut (Huayu No. 9115) seedlings were inoculated with a mycelial plug (8 mm diameter) at the root base of each plant and cultured in a greenhouse (30°C during the day and 25°C at night, a 12-h photoperiod, and 80% RH). Ten plants were inoculated with a plug of non-colonized PDA as a control. Brown lesions were observed on the stem and root of all inoculated seedlings 7 days after inoculation, but not on the control plants. The experiment was repeated three times. M. phaseolina was re-isolated from the symptomatic root and confirmed based on morphological characteristics and DNA sequence analysis of ITS and TEF. M. phaseolina is a soil-borne fungus that is distributed worldwide and has a broad host range. Disease agent has previously been reported on several host plants such as adzuki bean, faba bean, watermelon, Plukenetia volubilis, Atractylodes lancea and Curcuma longa in China (Cai et al., 2020; Sun et al. 2016; Sun et al., 2019; Sun et al., 2020; Wang et al., 2020; Wu et al., 2022). However, this is the first report in which M. phaseolina was found to cause peanut root rot in Shandong Province, China. Our report will provide important information for studying the epidemiology and management of this disease.

Proteoform characterization based on top-down mass spectrometry.

Proteins are dominant executors of living processes. Compared to genetic variations, changes in the molecular structure and state of a protein (i.e. proteoforms) are more directly related to pathological changes in diseases. Characterizing proteoforms involves identifying and locating primary structure alterations (PSAs) in proteoforms, which is of practical importance for the advancement of the medical profession. With the development of mass spectrometry (MS) technology, the characterization of proteoforms based on top-down MS technology has become possible. This type of method is relatively new and faces many challenges. Since the proteoform identification is the most important process in characterizing proteoforms, we comprehensively review the existing proteoform identification methods in this study. Before identifying proteoforms, the spectra need to be preprocessed, and protein sequence databases can be filtered to speed up the identification. Therefore, we also summarize some popular deconvolution algorithms, various filtering algorithms for improving the proteoform identification performance and various scoring methods for localizing proteoforms. Moreover, commonly used methods were evaluated and compared in this review. We believe our review could help researchers better understand the current state of the development in this field and design new efficient algorithms for the proteoform characterization.

Pseudomonas laoshanensis sp. nov., isolated from peanut field soil.

A novel Gram-stain-negative, aerobic strain, designated Y22T, was isolated from peanut field soil in Laoshan Mountain in China. Cells of strain Y22T were rod-shaped and motile by a single flagellum. The strain was found to be oxidase- and catalase-positive. 16S rRNA gene sequence based on phylogenetic analysis indicated that strain Y22T belonged to the genus Pseudomonas, and showed the highest 16S rRNA gene sequence similarity of 99.0% to Pseudomonas pelagia JCM 15562T, followed by Pseudomonas salina JCM 19469T (98.4%), Pseudomonas sabulinigri JCM 14963T (97.9%), Pseudomonas bauzanensis CGMCC 1.9095T (97.6%) and Pseudomonas litoralis KCTC23093T (97.5%). The phylogenetic analysis based on multilocus sequence analyses with concatenated 16S rRNA, gyrB, rpoD and rpoB genes indicated that strain Y22T belonged to Pseudomonas pertucinogena lineage. The average nucleotide identity scores between strain Y22T and closely related species were 74.6-82.8%, and the Genome-to-Genome Distance Calculator scores were 16.4-44.9%. The predominant cellular fatty acids of strain Y22T were C18:1ω7c (29.6%), C17:0 cyclo (17.5%) and summed feature 3 (C16:1ω7c and/or C16:1ω6c) (17.4%). The genomic DNA G+C content was 57.9 mol%. On the basis of phenotypic characteristics, phylogenetic analyses and in silico DNA-DNA relatedness, a novel species, Pseudomonas laoshanensis sp. nov. is proposed. The type strain is Y22T (= JCM 32580T = KCTC 62385T = CGMCC 1.16552T).

El factor de transcripción bZIP Afap1 afecta al estrés oxidativo y la biosíntesis de aflatoxinas en Aspergillus flavus / The bZIP transcription factor Afap1 mediates the oxidative stress response and aflatoxin biosynthesis in Aspergillus flavus

Abstract Aflatoxin is a carcinogenic secondary metabolite produced mainly by Aspergillus flavus and Aspergillus parasiticus, which can seriously endanger the health of humans and animals. Oxidative stress is a common defense response, and it is known that reactive oxygen species (ROS) can induce the synthesis of a series of secondary metabolites, including aflatoxin. By using mutants lacking the afap 1 gene, the role of afap 1 gene in oxidative stress and aflatoxin synthesis was assessed. The growth of the mutant strains was significantly inhibited by the increase in the concentration of H2O2, inhibition was complete at 40mmol/l. However, in the quantitative analysis by HPLC, the concentration of AFB1 increased with the increased H 2O 2 until 10mmol/l. Following an analysis based on the information provided by the NCBI BLAST analysis, it was assumed that Afap1, a basic leucine zipper (bZIP) transcription factor, was associated with the oxidative stress in this fungus. Treatment with 5mmol/l H 2O 2 completely inhibited the growth of the mutant strains in afap 1 but did not affect the growth of the CA14PTs strain (non-mutant strain). In addition, the concentration of AFB 1 in the mutant strains was approximately V of that observed in the CA14PTs strain. These results suggested that Afap1 plays a key role in the regulation of oxidative stress and aflatoxin production in A. flavus. ©2018 Published by Elsevier España, S.L.U. on behalf of Asociación Argentina de Microbiología. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/ licenses/by-nc-nd/4.0/).

Resumen La aflatoxina es un metabolito secundario cancerígeno producido principalmente por Aspergillus flavus y Aspergillus parasiticus, que pone en riesgo grave a la salud de los humanos y los animales. El estrés oxidativo es una respuesta de defensa común, y es sabido que las especies reactivas de oxígeno (ROS) pueden inducir la síntesis de una serie de metabolitos secundarios, incluida la aflatoxina. Empleando mutantes carentes del gen afap1 se evaluó el papel de Afap1 en el estrés oxidativo y la síntesis de aflatoxinas. El crecimiento de las cepas mutadas se vio significativamente inhibido con el aumento de la concentración de H 2O 2, la inhibición fue completa a 40mmol/l. Sin embargo, en el análisis cuantitativo por HPLC, la concentración de la aflatoxina AFBi aumentó con el aumento de la concentración de H 2O 2 hasta 10mmol/l. Tras un análisis apoyado en la información provista por la herramienta NCBI BLAST, se supuso que Afap1, un factor de transcripción de la cremallera de leucina básica (bZIP), estaba asociado con el estrés oxidativo en este hongo. El tratamiento con 5mmol/l de H 2O 2 inhibió completamente el crecimiento de las cepas mutantes en afap1, pero no afectó el crecimiento de la cepa CA14PTs (cepa no mutada). Además, la concentración de AFB 1 en las cepas mutadas fue de aproximadamente 1/4 de la observada en CA14PTs. Estos resultados sugieren que Afap1 juega un papel clave en la regulación del estrés oxidativo y la producción de aflatoxinas en A. flavus.

The bZIP transcription factor Afap1 mediates the oxidative stress response and aflatoxin biosynthesis in Aspergillus flavus.

Aflatoxin is a carcinogenic secondary metabolite produced mainly by Aspergillus flavus and Aspergillus parasiticus, which can seriously endanger the health of humans and animals. Oxidative stress is a common defense response, and it is known that reactive oxygen species (ROS) can induce the synthesis of a series of secondary metabolites, including aflatoxin. By using mutants lacking the afap 1 gene, the role of afap1 gene in oxidative stress and aflatoxin synthesis was assessed. The growth of the mutant strains was significantly inhibited by the increase in the concentration of H2O2, inhibition was complete at 40mmol/l. However, in the quantitative analysis by HPLC, the concentration of AFB1 increased with the increased H2O2 until 10mmol/l. Following an analysis based on the information provided by the NCBI BLAST analysis, it was assumed that Afap1, a basic leucine zipper (bZIP) transcription factor, was associated with the oxidative stress in this fungus. Treatment with 5mmol/l H2O2 completely inhibited the growth of the mutant strains in afap 1 but did not affect the growth of the CA14PTs strain (non-mutant strain). In addition, the concentration of AFB1 in the mutant strains was approximately » of that observed in the CA14PTs strain. These results suggested that Afap1 plays a key role in the regulation of oxidative stress and aflatoxin production in A. flavus.

Pseudomonas qingdaonensis sp. nov., an aflatoxin-degrading bacterium, isolated from peanut rhizospheric soil.

A Gram-stain-negative, aerobic, mobile, and rod-shaped bacterium, designated JJ3T, was isolated from peanut rhizospheric soil in Qingdao, Shandong Province, China, and was characterized using a polyphasic approach. Strain JJ3T grew at 4-40 °C, at pH 5.0-9.0 and 0-4% NaCl. The strain was positive for both catalase and oxidase tests, and was able to degrade aflatoxin B1. According to the 16S rRNA gene sequence comparisons, the strain JJ3T was identified as a member of the genus Pseudomonas and was most closely related to Pseudomonas japonica JCM 21532T and Pseudomonas alkylphenolica JCM 16553T with sequence similarity of 99.0% and 98.9%, respectively. A multilocus sequence analysis (MLSA) of concatenating 16S rRNA, gyrB and rpoD gene sequences showed that strain JJ3T belonged to the Pseudomonas putida subcluster. Genomic comparison of strain JJ3T with its closest phylogenetic type strain using average nucleotide index (ANI) and digital DNA-DNA relatedness revealed 76.7-82.9% and 20.2-37.1%, respectively. All values were distinctly lower than the thresholds established for species differentiation. The predominant cellular fatty acids of strain JJ3T were C17:0 cyclo (24.0%), C16:0 (21.4%), summed features 3 (C16:1ω7c and/or C16:1ω6c) (11.5%) and summed features 8 (C18:1ω7c and/or C18:1ω6c) (10.5%). The major polar lipids of strain JJ3T were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The physiological, biochemical, and genetic characteristics support the assignment of JJ3T to the genus Pseudomonas, but are different to those of phylogenetically neighboring species to represent a novel species. The name Pseudomonas qingdaonensis sp. nov. is proposed, with JJ3T (= JCM 32579T = KCTC 62384T = CGMCC 1.16493T) as the type strain.

A Survey of Aflatoxin-Producing Aspergillus sp. from Peanut Field Soils in Four Agroecological Zones of China.

Peanut pods are easily infected by aflatoxin-producing Aspergillus sp.ecies from field soil. To assess the aflatoxin-producing Aspergillus sp. in different peanut field soils, 344 aflatoxin-producing Aspergillus strains were isolated from 600 soil samples of four agroecological zones in China (the Southeast coastal zone (SEC), the Yangtze River zone (YZR), the Yellow River zone (YR) and the Northeast zone (NE)). Nearly 94.2% (324/344) of strains were A. flavus and 5.8% (20/344) of strains were A. parasiticus. YZR had the highest population density of Aspergillus sp. and positive rate of aflatoxin production in isolated strains (1039.3 cfu·g-1, 80.7%), the second was SEC (191.5 cfu·g-1, 48.7%), the third was YR (26.5 cfu·g-1, 22.7%), and the last was NE (2.4 cfu·g-1, 6.6%). The highest risk of AFB1 contamination on peanut was in YZR which had the largest number of AFB1 producing isolates in 1g soil, followed by SEC and YR, and the lowest was NE. The potential risk of AFB1 contamination in peanuts can increase with increasing population density and a positive rate of aflatoxin-producing Aspergillus sp. in field soils, suggesting that reducing aflatoxigenic Aspergillus sp. in field soils could prevent AFB1 contamination in peanuts.

Draft genome of the peanut A-genome progenitor (Arachis duranensis) provides insights into geocarpy, oil biosynthesis, and allergens.

Peanut or groundnut (Arachis hypogaea L.), a legume of South American origin, has high seed oil content (45-56%) and is a staple crop in semiarid tropical and subtropical regions, partially because of drought tolerance conferred by its geocarpic reproductive strategy. We present a draft genome of the peanut A-genome progenitor, Arachis duranensis, and 50,324 protein-coding gene models. Patterns of gene duplication suggest the peanut lineage has been affected by at least three polyploidizations since the origin of eudicots. Resequencing of synthetic Arachis tetraploids reveals extensive gene conversion in only three seed-to-seed generations since their formation by human hands, indicating that this process begins virtually immediately following polyploid formation. Expansion of some specific gene families suggests roles in the unusual subterranean fructification of Arachis For example, the S1Fa-like transcription factor family has 126 Arachis members, in contrast to no more than five members in other examined plant species, and is more highly expressed in roots and etiolated seedlings than green leaves. The A. duranensis genome provides a major source of candidate genes for fructification, oil biosynthesis, and allergens, expanding knowledge of understudied areas of plant biology and human health impacts of plants, informing peanut genetic improvement and aiding deeper sequencing of Arachis diversity.

Preparation, characterisation and physicochemical properties of the phosphate modified peanut protein obtained from Arachin Conarachin L.

The objective of this work is to obtain a new phosphate modified peanut protein (PMPP) with good physicochemical properties by using a simple and reliable method. For this purpose, response surface methodology (RSM), based on a Box-Behnken design, was used to optimise conditions for the microwave-assisted formation of phosphate modified peanut protein isolate (PPI) with sodium tripolyphosphate (STP) as the substrate. The results indicate that emulsification activity index (EAI) was optimised at 65.04 m(2)/g under the following conditions: substrate mass fraction of 10%, initial pH of 9.90, STP mass fraction of 7.70%, microwave power of 800 W, reaction temperature of 43.0 °C, and incubation time of 3.15 min. The emulsification activity of PPI improved after phosphate modification. Phosphatisation of both the Ser and Thr hydroxyl groups and the Lys amino groups was confirmed for the reaction between STP and PPI according to analysis of FTIR, XRD, TG/DTA, NMR-(31)P and SEM of the product. Physicochemical properties of PMPP were better than those of PPI.

Nutritional composition and protein quality of the edible beetle Holotrichia parallela.

The adult edible beetle Holotrichia parallela Motschulsky (Coleoptera: Scarabaeoidea) represents a traditional food source in China. Based on nutritional analyses, adult H. parallela is high in protein (70%) and minerals and low in fat. H. parallela contained approximately 10% chitin; the corrected protein content was 66%. Oleic acid and linoleic acid were the most abundant fatty acids. Of the total amino acids in H. parallela, 47.4% were essential amino acids. The amino acid scores were 87 and 100, based on the corrected crude and net protein contents, respectively; threonine was the limiting amino acid. In vitro protein digestibility was 78%, and the protein digestibility-corrected amino acid score was 89 based on the net protein content. Adult H. parallela may be a potential source of proteins and minerals for humans and animals.

Molecular characterization of atoxigenic Aspergillus flavus isolates collected in China.

Aspergillus flavus strains were isolated from peanut fields of Liaoning, Shandong, Hubei and Guangdong Provinces in China, and identified through phenotypic and molecular approaches. Of the 323 A. flavus strains isolated, 76 strains did not produce aflatoxins detectable by UPLC. The incidence of atoxigenic A. flavus strains decreased with increase in temperature and increased with increase in latitude in different geographical locations. Amplification of all the aflatoxin genes in the aflatoxin gene cluster in the atoxigenic isolates showed that there were 25 deletion patterns (A-Y), with 22 deletion patterns identified for the first time. Most of the atoxigenic A. flavus isolates with gene deletions (97%) had deletions in at least one of the four genes (aflT, nor-1, aflR, and hypB), indicating that these four genes could be targeted for rapid identification of atoxigenic strains. The atoxigenic isolates with gene deletions, especially the isolates with large deletions, are potential candidates for aflatoxin control.

Ultrasonic-assisted enzymolysis to improve the antioxidant activities of peanut (Arachin conarachin L.) antioxidant hydrolysate.

The objective of this work is to provide a theoretical basis for preparing peanut antioxidant hydrolysate in order to improve its antioxidant activities. Therefore, response surface methodology (RSM) based on the Box-Behnken design was used to optimize ultrasonic-assisted enzymolysis for the purpose of preparing peanut antioxidant hydrolysate. Results indicated that the DPPH free radical scavenging activity of peanut hydrolysate could reach 90.06% under the following optimum conditions: ultrasonic power of 150.0 w, reaction temperature of 62.0 °C, incubation time of 25.0 min, and initial pH value of 8.5. The DPPH free radical scavenging rate of peanut hydrolysate from ultrasonic-assisted enzymolysis improved comparing with that of peanut hydrolysate from protease hydrolysis alone. The peanut antioxidant hydrolysate was found to display eight improved kinds of antioxidant activities. In conclusion, the optimal ultrasonic-assisted enzymolysis technology conditions described in this paper, appear to be beneficial for preparing peanut antioxidant hydrolysate.

Optimization of a microwave-coupled enzymatic digestion process to prepare peanut peptides.

The best enzyme to prepare peanut peptides, papain, coupled with microwave irradiation was selected from five common proteases according to the results of the yield of peanut peptides [nitrogen solution index (NSI) in trichloroacetic acid (TCA), TCA-NSI] and the degree of hydrolysis (DH). The main factors that influenced the microwave-coupled enzymatic digestion method were optimized by response surface analysis. The optimal conditions obtained were as follows: microwave extraction time, 9.5 min; power, 600 W; substrate concentration, 4%; enzymatic reaction temperature, 50 °C; enzyme quantity, 6,500 U/g; pH, 7.1 (phosphate buffer, 0.05 mol/L). Under these conditions, TCA-NSI was 62.00% and DH was 25.89%, which is higher than that obtained with either protease hydrolysis or microwave hydrolysis alone.

Extraction and characterization of chitin from the beetle Holotrichia parallela Motschulsky.

Insect chitin was isolated from adult Holotrichia parallela by treatment with 1 M HCl and 1 M NaOH, following by 1% potassium permanganate solution for decolorization. The yield of chitin from this species is 15%. This insect chitin was compared with the commercial a-chitin from shrimp, by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and elemental analysis. Both chitins exhibited similar chemical structures and physicochemical properties. Adult H. parallela is thus a promising alternative source of chitin.

Chemical composition and antioxidant activities of Broussonetia papyrifera fruits.

Fruits of Broussonetia papyrifera from South China were analyzed for their total chemical composition, and antioxidant activities in ethanol and aqueous extracts. In the fruit of this plant, the crude protein, crude fat and carbohydrates was 7.08%, 3.72% and 64.73% of dry weight, respectively. The crude protein, crude fat and carbohydrates were 15.71%, 20.51% and 36.09% of dry weight, respectively. Fatty acid and amino acid composition of the fruit were analyzed. Unsaturated fatty acid concentration was 70.6% of the total fatty acids. The percentage of the essential amino acids (EAAs) was 40.60% of the total amino acids. Furthermore, B. papyrifera fruit are rich in many mineral elements and vitamins. Total phenolic content was assessed using the Folin-Ciocalteau assay, whereas antioxidant activities were assessed by measuring the ability of the two extracts to scavenge DPPH radicals, inhibit peroxidation, and chelate ferric ions. Their reducing power was also assessed. Results indicated that the aqueous extract of B. papyrifera was a more potent reducing agent and radical-scavenger than the ethanol extract. GC-MS analysis of the ethanol extract showed the presence of some acid-containing compounds. The changes in total phenolic content and antioxidant capacity in B. papyrifera from four different regions grown under normal conditions were assessed. The antioxidant activity of different extracts was positively associated with their total phenolic content. These results suggest that the fruit of B. papyrifera could be used in dietary supplement preparations, or as a food additive, for nutritional gain, or to prevent oxidation in food products.

Antioxidant activity and phenolic compounds of Holotrichia parallela Motschulsky extracts.

Insects have been relatively unexplored as potential sources of natural antioxidants. We report the antioxidant activity of extracts of the adult large black chafer beetle Holotrichia parallela Motschulsky, a common crop pest in China. The antioxidant activity of the ethanolic extract (EE) and the water extract (WE) of adult H. parallela were evaluated by four different in vitro assays. EE showed potent metal-chelating activity and inhibition of lipid peroxidation. WE proved to be an excellent antioxidant in the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and metal-chelating activity. Catechin was identified in the ethanolic extract and proteins were the main components in the water extracts. Both compounds could contribute to the antioxidant activity of the species. These results suggest that adult H. parallela might be used as a nutraceutical to alleviate oxidate-induced diseases and as a natural antioxidant additive in the food industry.