Peanut Plants Research Articles

Bioefficacy of Trichoderma harzianum and Chitosan Oligo-saccharin as Seed Coating to Control Fusarium oxysporum Disease in Peanut

Formulations of biological fungicides to replace synthetic fungicides, which are potent and effective in controlling wilt and root rot in Peanut plants have not been found, so the results of the study can be the latest information. The research aims to find the most effective formulation when cultivating Peanut plants with Seed Coating. Seed-coating treatment of T. harzianum and chitosan compounds is expected to be more effective in preventing or controlling the attack of Fusarium wilt disease on Peanut plants. The study was designed according to Randomized Group Design (RAK) with the treatment of Seed Coating T. harzianum and Chitosan nanoparticles (Chitosan olligosaccharin), with a Control Treatment Design without Seed Coating, Seed Coating T. harzianum, Seed Coating Kitosan, Seed Coating Kitosan + T. harzianum, Inorganic Seed Coating with 64% Metalaxil. The lowest intensity of wilting was still shown by the control treatment of 64% Metalaxil chemical pesticide, with an average wilting intensity of 23.5%, but the Seed Coating Kitosan + T. harzianum treatment was the closest with an average wilting rate of 31.5%, significantly different from the control wilting intensity which reached 92.5%. While the best control effectiveness after Metalaxil is also Chitosan + T. harzianum. Seed Coating Chitosan and T. harzianum also provide better dry weight of stalks than other Seed Coating treatments with an average of 5.1 Kg/Ha

Enhanced dosage delivery of pesticide under unmanned aerial vehicle condition for peanut plant protection: tank-mix adjuvants and formulation improvement.

Suspension concentrate (SC) is one of the most widely used formulations for agricultural plant protection. With the rapid development of unmanned aerial vehicle (UAV) plant protection, the problems of spray drift, droplet rebound and poor wettability in the application of SC from UAVs have attracted wide attention. Although some tank-mix adjuvants have been used to enhance dosage delivery for UAV, their effects and mechanisms are not fully clear, and few formulations are specifically designed for UAV. The type and concentration of tank-mix adjuvant affect the dosage delivery of SC. MO501 can significantly reduce DV<100μm , and inhibit droplet rebound on peanut leaves at concentrations ≥0.5%. Silwet 408 can achieve complete wetting and superspreading after adding ≥0.2% concentrations, but only ≥0.5% can inhibit rebound. XL-70 shows excellent regulation ability even at low concentration, and 0.2% concentration can simultaneously suppress impact and promote spreading. Besides, the formulation oil dispersion (OD) can significantly reduce the driftable fine fraction and inhibit rebound at dilution ratios of ≤250-fold, thus enhancing dosage delivery. SC is prone to rebound on hydrophobic leaf surfaces and shows poor wetting and spreading properties. Appropriate types and concentrations of tank-mix adjuvants and formulation improvement are two effective strategies for improving the dosage delivery of pesticides, whereas the addition of inappropriate adjuvants may cause potential risks instead. These findings provide guidance for the rational selection of tank-mix adjuvants and potential applications of OD for UAV plant protection. © 2023 Society of Chemical Industry.

Stereoselective, Diastereoselective Dissipation and Risk Assessment of Chiral Metconazole in Soybean, Peanut, Cabbage, Celery, Tomato, and Soil.

The stereoselective behaviors and dietary risks of metconazole (MZE) in soil and five vegetables were investigated. The results showed that there was species-specific stereoselective and diastereoselective dissipation, and the half-lives ranged from 0.69 to 8.17 days. cis-(+)-1S,5R-MZE was preferentially dissipated in soybean pods, cabbages, celeries, and tomatoes, which was contrary to soybean plants and soil. trans-(+)-1R,5R-MZE was preferentially dissipated in peanut plants, peanut shells, celeries, and tomatoes, while trans-(-)-1S,5S-MZE was preferentially dissipated in soybean plants. cis-MZE was preferentially dissipated in the test vegetables and soil, except celery. The stereoisomeric excess changes were higher than 10%, indicating that the stereoselectivity and diastereoselectivity should be considered in the risk assessment of MZE in soybean plants, pods, and peanut plants. The acute and chronic dietary intake risks of rac-MZE for different groups of people were acceptable. The preferentially dissipated and high activity cis-(+)-1S,5R-MZE with lower toxicity might be suitable for application as monocase.

Genome-wide identification of peanut IGT family genes and their potential roles in the development of plant architecture

IGT family genes play essential roles in shaping plant architecture. However, limited amount of information is available about IGT family genes in peanuts (Arachis hypogaea). In the current study, 13 AhIGT genes were identified and classified into three groups based on their phylogenetic relationship. Gene structure, conserved domain analyses indicated all AhIGTs were observed to share a similar exon–intron distribution pattern. AhIGTs within the same subfamily maintained a consistent motif composition. Chromosomal localization and synteny analyses showed that AhIGTs were unevenly localized on 9 chromosomes and that segmental duplication and purifying selection may have played important roles in the evolution of AhIGT genes. The analysis of conserved motifs, GO annotation, and transcript profile suggested that AhLAZY1-3 may play roles in gravity sensing and shaping peanut plant architecture. Transcript profile analysis suggested that AhTAC1 could potentially be involved gynophore (‘peg’) penetration into the soil. The cis-element analysis revealed that the light-responsive elements accounted for most of all cis-acting elements. Furthermore, qRT-PCR analysis showed that the expression of several AhIGT genes, like AhTAC1-2/4, was light-dependent, indicating that these genes may regulate plant architecture in response to light signals. This study may facilitate functional studies of the IGT genes in peanut.

Comparative proteomic analysis of the moderately resistant and susceptible peanut cultivars during infestation by Cylindrocladium parasiticum

Cylindrocladium parasiticum Crous, Wingfield & Alfenas, the causal agent of Cylindrocladium black rot of peanut, has led to economic losses in China. However, the response of peanut plant to C. parasiticum is poorly understood. Here, two contrasting peanut cultivars, T09 (C. parasiticum-moderately resistant) and P562 (C. parasiticum-susceptible) were used for comparative analysis of protein profiles in root segment of plant tissues in responses to C. parasiticum infection. Proteomic profiling identified 1647 and 391 differentially accumulated proteins (DAPs) in P562 and T09 relative to uninoculated control, respectively. A total of 350 and 1095 DAPs were identified between P562 and T09 after 9 day(s) post infection (dpi), respectively. Functional categorization showed that C. parasiticum-responsive proteins were mainly involved in catalytic activity and binding functions. KEGG pathway analysis indicated both moderately resistant and susceptible peanut cultivars can regulate gene expression in the phenylpropanoid pathway, terpenoid backbone biosynthesis, SA, and JA pathways to induce defensive genes and protein expression which enhances plant defence or susceptibility capacity. However, MAPK signal pathway was more pronounced in moderately resistant peanut cultivar T09. We also observed an increase of CYP73A100 involved in phenylpropanoid and flavonoid biosynthesis pathways in susceptible peanut ecotype P562, while decrease in moderately resistant interaction. Additionally, there was a marked activation of brassinosteroid biosynthesis in T09, which indicated a possible involvement of activation of plant immune response in moderately resistant responses of peanut to C. parasiticum. This study provides some insights into molecular networks involved in cellular and physiological responses to C. parasiticum in peanut.

Characteristics and Mechanisms of Soil Co-Contamination Affecting the Transfer of Cadmium and Arsenic in Peanut (Arachis hypogaea L.)

Soil co-contamination with cadmium (Cd) and arsenic (As) occurs frequently and has caused increasing concern. This study aimed to explore the transfer characteristics and the chemical forms, subcellular distribution of Cd and As, as well as the synthesis of phytochelatins (PCs) and other chelates in peanut (Arachis hypogaea L.) plants grown in a Cd and As co-contaminated soil, shedding light on the mechanisms involved. Compared with the single Cd contamination, Cd–As co-contamination led to a higher accumulation of Cd in peanut plants. Conversely, compared to the single As contamination, the As content increased in peanut shoots but decreased in roots and grains under Cd–As co-contamination. Furthermore, the Cd–As interaction resulted in notable changes in peanut plants’ physiological and biochemical responses. In the roots and shoots, there was an 81.8% and 60.0% increase in water-soluble Cd. In the roots, metallothioneins (MTs) content increased by 50%, while PCs increased by 6.4% in the shoots. These changes promoted the translocation of Cd from roots to grains. The Cd–As interaction also influenced the synthesis of MTs in the roots, showing a 41.2% increase, and facilitated the transfer of As to the shoots. In peanut shoots, Cd increased the cell wall fraction of As by 34.5%, decreased the proportion of water-soluble As by 31.8%, and increased PCs content by 6.9%. These changes inhibited the migration of As from shoots to grains. Overall, Cd–As co-contamination increased Cd in peanut grains by increasing water-soluble forms and MTs in roots, while Cd–As co-contamination decreased As in peanut grains by increasing cell wall fractions and PCs in shoots. These findings provide a theoretical basis for understanding Cd–As interactions in soil–peanut systems.

Study of The Chemical Properties of The Post-Harvest Peanut (Arachis hypogaea L.) Pertilized by The Mushroom Baglog Waste Compost

Availability in the soil varies greatly, influenced by the interaction between the chemical properties of the soil and some other soil traits such as the physical and biological properties of the soil. An analysis of the chemical properties of the soil is vital to recognizing availability of nutrients for future crop cultivation. The purpose of this study is to know the chemical conditions of the ground after the harvest of the peanut plant after given the mushroom compost post fertilizer. The design of the experiment used in this study is a complete random design (ral) with a dose of mushroom post baglog fertilizer 6 and a degree of fertilizer recommendation 1 (as control). As for the treating cedar that is used is p1 = 100% recommendation fertilizer, p2 = 2 ton ha-1 fertilizer compost of the mushroom baglog, p4 = 4 tons of ha-1 fertilizer compost of the mushroom baglog, p5 = 6 tons of ha-1 Studies show a different dosage of fertilizer has a real impact on all the parameters observed.

Response of peanut to foliar application of molybdenum and seed inoculation with Bradyrhizobium spp. in Cerrado region, Brazil

The adoption of sustainable technologies that optimize biological nitrogen fixation (BNF) by peanut crops is essential to improve plant growth and ensure high grain yield potential. A study was conducted to investigate the efficiency of inoculation with Bradyrhizobium spp. and foliar application of molybdenum (Mo) in improving the productive response of peanut crop (Arachis hypogaea L., cv. IAC Tatu ST) in moderately acidic sandy soil (pH 5.0) of the Cerrado region, Brazil during two growing seasons (2016/2017 and 2017/2018). Treatments consisted of uninoculated seeds (control) and inoculated with Bradyrhizobium spp. and foliar application of Mo at five rates (0, 25, 50, 100, and 150 g Mo ha−1). These treatments were arranged in a randomized block design in split plots with four replicates. Nodulation, shoot dry matter, leaf N concentration, and peanut grain yield were significantly high in plants inoculated with Bradyrhizobium spp. in both growing seasons. The grain yield increased by 13% and 12% with the inoculation of Bradyrhizobium spp. compared with non-inoculated plants in the 2016/2017 and 2017/2018 seasons, respectively. Plants fertilized with Mo showed higher root nodulation, leaf N concentration, and shoot dry matter production than control plants in both growing seasons. However, the crop grain yield was significantly high (24%) only in the 2016/2017 season in plants fertilized with Mo. The optimal rate of foliar Mo application in peanut plants cultivated in sandy soils varies from 80 to 100 g of Mo ha−1. Due to improved root nodulation, N uptake, plant growth, and higher crop grain yield, rhizobium inoculation and foliar application of Mo are sustainable agricultural practices that should be recommended for peanut growers.

In Vitro Peanut Culture: From Seed to Seed

AbstractIn vitro plants are widely used in biotechnology studies. In general, tissue culture requires special skills in order to obtain healthy and fertile axenic plants. Peanuts are considered recalcitrant, meaning they are difficult to regenerate under in vitro conditions. Thus, in vitro completion of the peanut plant cycle is the limiting factor in projects that require plant and seed recovery when applying molecular tools such as CRISPR. The protocols presented here allow for obtaining multiple shoots by micropropagation and inducing these shoots to produce flowers that successfully result in fertile pegs and pods, completing the life cycle under in vitro conditions. This is a significant step to perform studies that require axenic conditions in their entirety. These protocols outline the steps required to micropropagate Georgia 06G peanut plants under aseptic conditions, prepare culture medium, maintain shoot multiplication cultures, induce flowering and pegging, and maintain culture conditions to allow the development of pods. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.Basic Protocol 1: Seed sterilization and germinationBasic Protocol 2: Shoot multiplicationBasic Protocol 3: Flower inductionBasic Protocol 4: Peg formation

The genus Arachis: an excellent resource for studies on differential gene expression for stress tolerance.

Peanut Arachis hypogaea is a segmental allotetraploid in the section Arachis of the genus Arachis along with the Section Rhizomataceae. Section Arachis has several diploid species along with Arachis hypogaea and A. monticola. The section Rhizomataceae comprises polyploid species. Several species in the genus are highly tolerant to biotic and abiotic stresses and provide excellent sets of genotypes for studies on differential gene expression. Though there were several studies in this direction, more studies are needed to identify more and more gene combinations. Next generation RNA-seq based differential gene expression study is a powerful tool to identify the genes and regulatory pathways involved in stress tolerance. Transcriptomic and proteomic study of peanut plants under biotic stresses reveals a number of differentially expressed genes such as R genes (NBS-LRR, LRR-RLK, protein kinases, MAP kinases), pathogenesis related proteins (PR1, PR2, PR5, PR10) and defense related genes (defensin, F-box, glutathione S-transferase) that are the most consistently expressed genes throughout the studies reported so far. In most of the studies on biotic stress induction, the differentially expressed genes involved in the process with enriched pathways showed plant-pathogen interactions, phenylpropanoid biosynthesis, defense and signal transduction. Differential gene expression studies in response to abiotic stresses, reported the most commonly expressed genes are transcription factors (MYB, WRKY, NAC, bZIP, bHLH, AP2/ERF), LEA proteins, chitinase, aquaporins, F-box, cytochrome p450 and ROS scavenging enzymes. These differentially expressed genes are in enriched pathways of transcription regulation, starch and sucrose metabolism, signal transduction and biosynthesis of unsaturated fatty acids. These identified differentially expressed genes provide a better understanding of the resistance/tolerance mechanism, and the genes for manipulating biotic and abiotic stress tolerance in peanut and other crop plants. There are a number of differentially expressed genes during biotic and abiotic stresses were successfully characterized in peanut or model plants (tobacco or Arabidopsis) by genetic manipulation to develop stress tolerance plants, which have been detailed out in this review and more concerted studies are needed to identify more and more gene/gene combinations.

Pengaruh Ekstra Lidah Buaya ( Aloe vera) Sebagai ZPT Alami untuk Pertumbuhan Tanaman Kacang Tanah (Arachis hypogaea)

Aloe Vera plants (Aloe vera) contain minerals including selenium, calcium, magnesium, potassium and several enzymes of sugar, fatty acids, and also growth hormones, namely auxin and gibberellin. This study was conducted to determine the extra effect of Aloe vera on the growth of peanut plants. The study was conducted by providing treatment in the form of watering peanut plants with Aloe vera solution exta at several different concentrations and controls as a reference. The treatment was carried out for 14 days and observation of the growth of green bean plants was carried out every 3 days. The data obtained were tested using One-Way ANOVA, Then analyzed descriptively. The results showed that peanut plants had significantly different growth in the 10% gel concentration treatment which resulted in the highest plant height, while the number of leaves, leaf area, and stem diameter did not have a significant effect. Keywords: aloe vera, growth, ZPT

Development of a Rapid Phenotyping Method to Screen for Didymella arachidicola Resistance in Peanuts

Net or web blotch (NB), caused by Didymella arachidicola, is an emerging threat causing a significant reduction in yield of peanuts in cooler production regions globally, including Australia, China, and Southern Africa. Host resistance against NB is poorly understood, with field screenings reliant on favorable climatic conditions. A rapid and effective phenotyping method is essential to differentiate between resistant and susceptible breeding lines and improve selection accuracy. In this study, a greenhouse screening method using mycelium as the inoculum to determine host response to D. arachidicola was developed. A liquid-culture mycelia suspension of the pathogen was sprayed onto 9-week-old peanut plants, and one disease assessment was made between 14 and 17 days after inoculation. Lesion growth in the greenhouse was found to correlate with disease response assessed under field conditions ( r = 89%). The phenotyping method developed in this study can facilitate the identification of NB resistance lines and assist in identifying regions of genetic resistance within the peanut host. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Metabolic profiles of peanut (Arachis hypogaea L.) in response to Puccinia arachidis fungal infection

Background Puccinia arachidis fungus causes rust disease in the peanut plants (Arachis hypogaea L.), which leads to high yield loss. Metabolomic profiling of Arachis hypogaea was performed to identify the pathogen-induced production of metabolites involved in the defense mechanism of peanut plants. In this study, two peanut genotypes, one susceptible (JL-24) and one resistant (GPBD-4) were inoculated with Puccinia arachidis fungal pathogen. The metabolic response was assessed at the control stage (0 day without inoculation), 2 DAI (Day after inoculation), 4 DAI and 6 DAI by Gas Chromatography-Mass Spectrometry (GC-MS). Results About 61 metabolites were identified by NIST library, comprising sugars, phenols, fatty acids, carboxylic acids and sugar alcohols. Sugars and fatty acids were predominant in leaf extracts compared to other metabolites. Concentration of different metabolites such as salicylic acid, mannitol, flavonoid, 9,12-octadecadienoic acid, linolenic acid and glucopyranoside were higher in resistant genotype than in susceptible genotype during infection. Systemic acquired resistance (SAR) and hypersensitive reaction (HR) components such as oxalic acid was elevated in resistant genotype during pathogen infection. Partial least square-discriminant analysis (PLS-DA) was applied to GC-MS data for revealing metabolites profile between resistant and susceptible genotype during infection. Conclusion The phenol content and oxidative enzyme activity i.e. catalase, peroxidase and polyphenol oxidase were found to be very high at 4 DAI in resistant genotype (p-value < 0.01). This metabolic approach provides information about bioactive plant metabolites and their application in crop protection and marker-assisted plant breeding.

Excessive manure application stimulates nitrogen cycling but only weakly promotes crop yields in an acidic Ultisol: Results from a 20-year field experiment

Population growth and growing demand for livestock products produce large amounts of manure, which can be harnessed to maintain soil sustainability and crop productivity. However, the impacts of excessive manure application on crop yields, nitrogen (N)-cycling processes and microorganisms remain unknown. Here, we explored the effects of 20-year of excessive rates (18 and 27 Mg ha–1 yr–1) of pig manure application on peanut crop yields, soil nutrient contents, N-cycling processes and the abundance of N-cycling microorganisms in an acidic Ultisol in summer and winter, compared with none and a regular rate (9 Mg ha–1 yr–1) of pig manure application. Long-term excessive pig manure application, especially at the high-rate, significantly increased soil nutrient contents, the abundance of N-cycling functional genes, potential nitrification and denitrification activity, while it had a weaker effect on peanut yield and plant biomass. Compared with manure application, seasonality had a much weaker effect on N-cycling gene abundance. Random forest analysis showed that available phosphorus (AP) content was the primary predictor for N-cycling gene abundance, with significant and positive associations with all tested N-cycling genes. Our study clearly illustrated that excessive manure application would increase N-cycling gene abundance and potential N loss with relatively weak promotion of crop yields, providing significant implications for sustainable agriculture in the acidic Ultisols.

Respon Pertumbuhan dan Produksi Kacang Tanah (Arachis hypogea L.) Terhadap Pemberian Pupuk Organik Asam Humat

Peanuts are a crop with a large demand in Indonesia after soybeans and will increase every year in the projected development of peanuts even until 2025. In Indonesia, especially in the East Java region as a center for Indonesian peanuts, production fluctuates due to inadequate land availability. . This study aims to assess the response of growth and production of peanut plants to doses of humic acid in Antirogo Village, Sumbersari District, Jember Regency. It was carried out from October 25 2022 to January 2023. This study was designed using a non-factorial randomized block design with a single factor, namely humic acid dose. The treatment consisted of 6 levels namely Control, 5kg/ha, 10kg/ha, 15kg/ha, 20kg/ha, 25kg/ha. These results were analyzed using ANOVA if they showed significantly different results then further tested using the BNJ level of 5%. The results showed that the application of humic acid at a dose of 25 kg/ha had a significant effect on the number of branches, fresh pod weight, and the SPAD value. The application of humic acid at a dose of 10 kg/ha had a significantly different effect on the parameter number of rich pods with an average of 36.38 rich pods.

Effect of phosphate-solubilizing bacteria on growth and yield of Arachis hypogaea L. in varied soil types

Peanut (Arachis hypogaea L.) is widely cultivated both in monoculture and polyculture (usually with corn) on dry land in Madura. Generally, the soil types of Madura are grumusol, regosol, and mediterranean. These three types of soil each have different physical and chemical properties. The effect of the addition of phosphate-solubilizing bacteria on the three soil types is unknown. The study aimed to determine the response of peanut plant growth due to the addition of phosphate solubilizing bacteria, Pseudomonas fluorescens, in three different soil types. The research was conducted in the experimental garden of Agroecotechnology, Faculty of Agriculture, Universitas Trunojoyo Madura. The research design used a non-factorial completely randomized design (CRD) with six treatments and four replications. The treatment consisted of three types of soil, namely regosol, grumosol, and mediteran as well as with and without the addition of P. fluorescens. The results showed that the treatment had a significant effect on the parameters of plant height, number of leaves, number of pods, pod dry weight, seed weight, above-ground biomass, root dry weight, and plant P content. The treatment did not show a significant effect on the root-canopy ratio and P. fluorescens population parameters.

Fungal endophyte promotes plant growth and disease resistance of Arachis hypogaea L. by reshaping the core root microbiome under monocropping conditions

Fungal endophytes play critical roles in helping plants adapt to adverse environmental conditions. The root endophyte Phomopsis liquidambaris can promote the growth and disease control of peanut plants grown under monocropping systems; however, how such beneficial traits are produced is largely unknown. Since the plant endophytic microbiome is directly linked to plant growth and health, and the composition of which has been found to be potentially influenced by microbial inoculants, this study aims to clarify the roles of root endophytic bacterial communities in P. liquidambaris-mediated plant fitness enhancement under monocropping conditions. Here, we found that P. liquidambaris inoculation induced significant changes in the root bacterial community: enriching some beneficial bacteria such as Bradyrhizobium sp. and Streptomyces sp. in the roots, and improving the core microbial-based interaction network. Next, we assembled and simplified a synthetic community (SynII) based on P. liquidambaris-derived key taxa, including Bacillus sp. HB1, Bacillus sp. HB9, Burkholderia sp. MB7, Pseudomonas sp. MB2, Streptomyces sp. MB6, and Bradyrhizobium sp. MB15. Furthermore, the application of the simplified synthetic community suppressed root rot caused by Fusarium oxysporum, promoted plant growth, and increased peanut yields under continuous monocropping conditions. The resistance of synII to F. oxysporum is related to the increased activity of defense enzymes. In addition, synII application significantly increased shoot and root biomass, and yield by 35.56%, 81.19%, and 34.31%, respectively. Collectively, our results suggest that the reshaping of root core microbiota plays an important role in the probiotic-mediated adaptability of plants under adverse environments.

General and specialized metabolites in peanut roots regulate arbuscular mycorrhizal symbiosis

Arbuscular mycorrhizae (AM) fungi form symbiotic associations with plant roots, providing nutritional benefits and promoting plant growth and defenses against various stresses. Metabolic changes in the roots during AM fungal colonization are key to understanding the development and maintenance of these symbioses. Here, we investigated metabolic changes in the roots of peanut (Arachis hypogaea L.) plants during the colonization and development of AM symbiosis, and compared them to uncolonized roots. The primary changes during the initial stage of AM colonization were in the contents and compositions of phenylpropanoid and flavonoid compounds. These compounds function in signaling pathways that regulate recognition, interactions, and pre-colonization between roots and AM fungi. Flavonoid compounds decreased by 25% when the symbiosis was fully established compared to the initial colonization stage. After AM symbiosis was established, general metabolism strongly shifted toward the formation of lipids, amino acids, carboxylic acids, and carbohydrates. Lipid compounds increased by 8.5% from the pre-symbiotic stage to well-established symbiosis. Lyso-phosphatidylcholines, which are signaling compounds, were only present in AM roots, and decreased in content after the symbiosis was established. In the initial stage of AM establishment, the content of salicylic acid increased two-fold, whereas jasmonic acid and abscisic acid decreased compared to uncolonized roots. The jasmonic acid content decreased in roots after the symbiosis was well established. AM symbiosis was associated with high levels of calcium, magnesium, and D-(+)-mannose, which stimulated seedling growth. Overall, specific metabolites that favor the establishment of AM symbiosis were common in the roots, primarily during early colonization, whereas general metabolism was strongly altered when AM symbiosis was well-established. In conclusion, specialized metabolites function as signaling compounds to establish AM symbiosis. These compounds are no longer produced after the symbiosis between the roots and AM becomes fully established.

First report of Colletotrichum fructicola causing anthracnose on peanut (Arachis hypogaea L.) in China.

Peanut (Arachis hypogaea L.) is an important cash crop and oil crop around the world. In August 2021, symptoms of leaf spot were found on nearly 50% of peanut plants in the peanut planting base of Xuzhou Academy of Agriculture Sciences, Jiangsu, China. Symptoms began as small, round or oval, dark brown spots on the leaf. As the spot expanded, the center of the spot became gray to light brown and the spot was covered with small black dots. Fifteen leaves with typical symptoms were randomly collected from fifteen plants in three fields about a kilometer apart from each other. Leaf pieces (5 × 5 mm) were cut from the junction part of diseased and healthy leaf tissue, sterilized with 75% ethanol for 30 s and 5% NaClO for 30 s, washed 3 times with sterile water, placed on full strength potato dextrose agar (PDA) and incubated at 28°C in darkness. Five days after incubation, 12 isolates were obtained. Fungal colonies were white to gray on the upper surface and orange to gray on the reverse side. Conidia were single-celled, cylindrical and colorless after maturation, and were 12 - 16.5 × 4.5 - 5.5 μm (n = 50) in size. Ascospores were one-celled, hyaline, with tapering ends and one or two large guttulates at the center, and measured 9.4 - 21.5 × 4.3 - 6.4 μm (n = 50). Based on morphological characteristics, the fungi were preliminarily identified as Colletotrichum fructicola (Prihastuti et al. 2009; Rojas et al. 2010). Single spore isolates were cultured on PDA medium and two representative strains (Y18-3 and Y23-4) were selected for DNA extraction. The internal transcribed spacer (ITS) rDNA region, partial actin gene (ACT), partial calmodulin gene (CAL), partial chitin synthase gene (CHS), partial glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH), and partial beta-tubulin 2 gene (TUB2) were amplified. The nucleotide sequences were submitted to Genbank (accession numbers of strain Y18-3: ITS: ON619598; ACT: ON638735; CAL: ON773430; CHS: ON773432; GAPDH: ON773436; TUB2: ON773434; accession numbers of strain Y23-4: ITS: ON620093; ACT: ON773438; CAL: ON773431; CHS: ON773433; GAPDH: ON773437; TUB2: ON773435). The phylogenetic tree was constructed using MEGA 7 based on the tandem of six genes (ITS-ACT-CAL-CHS-GAPDH-TUB2). The result showed that isolates Y18-3 and Y23-4 reside in the clade of C. fructicola species. To determine pathogenicity, conidial suspensions (107/mL) of isolate Y18-3 and Y23-4 were sprayed on ten 30-day-old healthy peanut seedlings per isolate. Five control plants were sprayed with sterile water. All plants were kept moist at 28°C in the dark (> 85% RH) for 48 h and then transferred to a moist chamber at 25°C with a 14-h photoperiod. After two weeks, typical anthracnose symptoms similar to those observed in the field appeared on leaves of inoculated plants, whereas controls remained asymptomatic. C. fructicola was re-isolated from symptomatic leaves but not from controls. Koch's postulates verified that C. fructicola was the pathogen of peanut anthracnose. C. fructicola is a well-known fungus causing anthracnose on many plant species worldwide. In recent years, new plant species infected by C. fructicola have been reported, like cherry, water hyacinth and Phoebe sheareri (Tang et al. 2021; Huang et al. 2021; Huang et al. 2022). To our knowledge, this is the first report of C. fructicola causing peanut anthracnose in China. Thus, it is recommended to pay close attention and take necessary prevention and control measures against potential spread of peanut anthracnose in China. .

Droplet size and hydraulic spray nozzles in peanut plant spray deposition

Droplet size and hydraulic spray nozzles in peanut plant spray deposition