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The optimum germination conditions for foxtail millet sprouts enriched with γ-aminobutyric acid (GABA) and antioxidant polyphenols were investigated. From single-factor experimental results, both the GABA level and total phenolic content (TPC) were more significantly affected by soaking temperature and time, and concentration of sucrose culture solution. Response surface methodology (RSE) was used to optimize the germination conditions of foxtail millet sprouts, where the interaction between soaking temperature and sucrose concentration exhibited a significant (p < 0.05) effect on TPC, and the interaction between soaking time and sucrose concentration displayed a significant (p < 0.05) effect on GABA content. The optimal germination conditions for TPC and GABA enrichment of foxtail millet sprouts were soaking at 31 °C for 4.5 h and germinating at 35 °C with 4.5 g/L sucrose solution for 5 days. Under the optimized conditions, the TPC and GABA content of foxtail millet sprouts were 926.53 milligrams of ferulic acid equivalents per 100 g dry weight (mg FAE/100 g DW) and 259.13 mg/kg, separately, with less difference from the predicted values of 929.44 mg FAE/100 g DW and 263.60 mg/kg, respectively. Collectively, all the individual phenolic compounds increased significantly (p < 0.05) by optimization, except for cis-p-coumaric acid and cis-ferulic acid in bound. The results provide a practical technology for suitable germination conditions to improve the health components of foxtail millet sprouts and increase their added value. [ABSTRACT FROM AUTHOR]

This review covers, for the first time, all methods based on the use of Aspergillus strains as biocontrol agents for the management of plant diseases caused by fungi and oomycetes. Atoxigenic Aspergillus strains have been screened in a variety of hosts, such as peanuts, maize kernels, and legumes, during the preharvest and postharvest stages. These strains have been screened against a wide range of pathogens, such as Fusarium, Phytophthora, and Pythium species, suggesting a broad applicability spectrum. The highest efficacies were generally observed when using non-toxigenic Aspergillus strains for the management of mycotoxin-producing Aspergillus strains. The modes of action included the synthesis of antifungal metabolites, such as kojic acid and volatile organic compounds (VOCs), secretion of hydrolytic enzymes, competition for space and nutrients, and induction of disease resistance. Aspergillus strains degraded Sclerotinia sclerotiorum sclerotia, showing high control efficacy against this pathogen. Collectively, although two Aspergillus strains have been commercialized for aflatoxin degradation, a new application of Aspergillus strains is emerging and needs to be optimized. [ABSTRACT FROM AUTHOR]

Sclerotinia sclerotiorum is an economically damaging fungal pathogen that causes Sclerotinia stem rot in leguines, producing enormous yield losses. This pathogen is difficult to control due to its wide host spectrum and ability to produce sclerotia. which are resistant bodies that can remain active for long periods under harsh environmental conditions. Here, the biocontrol methods for the management of S. sclerotiorum in legumes are reviewed. Baciltus strains, which synthesized lipopeptides and volatile organic compounds, showed high efficacies in soybean plants, whereas the highest efficacies for the control of the pathogen in alfalfa and common bean were observed when using Coniothyrium minitans and Streptomyces spp., respectively. The biocontrol efficacies in fields were under 65%, highlighting the lack of strategies to achieve a complete control. Overall, although most studies involved extensive sci·eenings using different biocontrol agent concentrations and application conditions, there is a lack of knowledge regarding the specific anti fungal mechanisms, which limits the optimization of the reported methods. [ABSTRACT FROM AUTHOR]

Thiram is a toxic fungicide extensively used for the management of pathogens in fruits. Although it is known that thiram degrades in plant tissues, the key enzymes involved in this process remain unexplored. In this study, we report that a tau class glutathione S-transferase (GST) from Carica papaya can degrade thiram. This enzyme was easily obtained by heterologous expression in Escherichia coli, showed low promiscuity toward other thiuram disulfides, and catalyzed thiram degradation under physiological reaction conditions. Site-directed mutagenesis indicated that G-site residue S67 shows a key in- fluence for the enzymatic activity toward thiram, while mutation of residue S13, which reduced the GSH oxidase activity, did not significantly affect the thiram-degrading activity. The formation of dimethyl dithiocarbamate, which was subsequently converted into carbon disulfide, and dimethyl dithiocarbamoylsulfenic acid as the thiram degradation products suggested that thiram undergoes an alkaline hydrolysis that involves the rupture of the disulfide bond. Application of the GST selective inhibitor 4- chloro-7-nitro-2,1,3-benzoxadiazole reduced papaya peel thiram-degrading activity by 95%, indicating that this is the main degradation route of thiram in papaya. GST from Carica papaya also catalyzed the degradation of the fungicides chlorothalonil and thiabendazole, with residue S67 showing again a key influence for the enzymatic activity. These results fill an important knowledge gap in understanding the catalytic promiscuity of plant GSTs and reveal new insights into the fate and degradation products of thiram in fruits. [ABSTRACT FROM AUTHOR]

Background: Ceratocystis fimbriata is a fungal pathogen that infects sweet potato roots, producing enormous economic losses. Cyclic polyhydroxy compound quinic acid is a common metabolite synthesized in plant tissues, including sweet potato tubers, showing weak antifungal properties. Although several O-acylated quinic acid derivatives have been synthesized and found in nature and their antifungal properties have been explored, derivatives based on modification of the carboxylic acid have never been evaluated., Results: In this study, amide derivatives were synthesized via linkage of amines with the carboxylic acid moiety of quinic acid. Derivatives with high dipolar moments and a low number of rotatable bonds showed greater antifungal activities toward C. fimbriata in vitro than quinic and chlorogenic acids. Derivative 5b, which was synthesized by coupling p-aminobenzoic acid (pABA) with quinic acid, had the greatest antifungal activity. 5b showed iron(II)-chelating properties and reduced ergosterol content in C. fimbriata cells, causing irregularities in the fungal cell wall and inhibiting conidia agglutination. Application of 3 mm 5b reduced black rot symptoms in sweet potatoes by 70.1%., Conclusions: Collectively, derivatization of the carboxylic acid from quinic acid was demonstrated to be a suitable strategy to improve the antifungal properties of this compound. This study reveals a new efficient strategy for management of the sweet potato pathogen C. fimbriata. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

This review covers, for the first time, all methods based on the use of Aspergillus strains as biocontrol agents for the management of plant diseases caused by fungi and oomycetes. Atoxigenic Aspergillus strains have been screened in a variety of hosts, such as peanuts, maize kernels, and legumes, during the preharvest and postharvest stages. These strains have been screened against a wide range of pathogens, such as Fusarium , Phytophthora , and Pythium species, suggesting a broad applicability spectrum. The highest efficacies were generally observed when using non-toxigenic Aspergillus strains for the management of mycotoxin-producing Aspergillus strains. The modes of action included the synthesis of antifungal metabolites, such as kojic acid and volatile organic compounds (VOCs), secretion of hydrolytic enzymes, competition for space and nutrients, and induction of disease resistance. Aspergillus strains degraded Sclerotinia sclerotiorum sclerotia, showing high control efficacy against this pathogen. Collectively, although two Aspergillus strains have been commercialized for aflatoxin degradation, a new application of Aspergillus strains is emerging and needs to be optimized., Competing Interests: The authors declare no conflict of interest.

Epicoccum sorghinum is a notorious fungal pathogen that causes leaf spot symptoms on a wide range of plants, leading to devastating losses in crop production and quality. Here, all reports regarding the occurrence and management of E. sorghinum are covered for the first time. E. sorghinum has been detected in tropical and subtropical climate areas during the rainy season, mainly from March to August, since 2016. Although E. sorghinum shows broad host spectrum, the disease incidence is especially notorious in cereal crops and ornamental plants, suggesting that these plants are especially susceptible. Control methods based on synthetic fungicides, plant extracts, and microbial biocontrol agents have been reported. However, most agents were applied using only in vitro conditions, restricting the information about their actual applicability in field conditions. Additionally, E. sorghinum can colonize cereal grains and synthesize the carcinogenic mycotoxin tenuazonic acid, posing an enormous hazard for human health. Furthermore, although E. sorghinum is an emerging pathogen that is currently causing yield penalties in important crops, there is lack of information about its pathogenic mechanisms and virulence factors, and there is currently no commercial antifungal agent to manage E. sorghinum. Collectively, it is imperative to conduct in vivo studies to determine the efficacy of antifungal agents and the most effective methods of application in order to develop suitable management strategies against E. sorghinum.

In September 2022, leaf blight symptoms (Fig. 1) were detected on six-year-old kiwi trees (Actinidia chinensis cv. 'Hongyang') in Xuzhou municipality (117.29º E, 34.23º N), Jiangsu Province. Early-stage disease symptoms included light brown necrotic lesions of irregular shape ranging in length from 0.2 to 2.4 cm, which turned into leaf blight after approximately 2 weeks. Those symptoms were similar to those previously reported during a Pestalotiopsis sp. infection on kiwi trees in Turkey (Karakaya 2001). Approximately 20% of the leaves from 300 trees examined in one kiwi orchard, 3000 m2 in size, showed the disease symptoms. Ten leading edges of symptomatic leaves were sterilized with 2% sodium hypochlorite for 1 min, rinsed twice with sterile ddH2O and cultured at 26ºC for 3 days on PDA medium containing 50 µg/ml chloramphenicol. The fungal colonies were collected, and the single spore isolation method was used to obtain four isolates. The obtained isolates showed white aerial mycelia that turned greyish after 2 days of cultivation on PDA medium at 26ºC. ITS (OR054113, OR054153-OR054155), TUB2 (OR060951-OR060953, OR249978), and CMD (OR255947-OR255950) genes were amplified using the ITS1/ITS4, BT2a/BT2b and CMD5/CMD6 primers, respectively (Visagie et al. 2014a). The obtained ITS, TUB2, and CMD sequences shared 99.81%-100%, 96.72%-96.96%, and 90.17%-92.58% homology compared to the ex-type strain P. oxalicum CBS 219.30 (MH855125, KF296462, and KF296367), while the obtained ITS and TUB2 sequences showed 99.62%-99.81%, and 96.46%-96.72% identity compared to the representative strain P. oxalicum DTO 179B9 (KJ775647 and KJ775140) (Visagie et al. 2014b). The sequences obtained also showed high homology compared to P. oxalicum HP7-1 (ITS: 99.81%-100% homology; TUB2: 98.98%-99.38% homology; CMD: 94.71%-95.10% homology) (Li et al. 2022). A molecular phylogenetic tree was constructed using MEGA X with representative Penicillium strains retrieved from GenBank (Fig. 2). Microscope observations revealed the presence of curved septate hyphae. Conidia were colorless, unicellular, and ellipsoidal (5-8 μm in length; > 2000 observations), whereas conidiophores were mainly monoverticillate (approximately 20% of the conidiophores were biverticillate) (50-70 μm in length; 43 observations) and contained cylindrical phialides (13-15 μm in length). These findings are consistent with P. oxalicum morphology (Wu et al. 2022; Zheng et al. 2023). The pathogenicity of the four isolates was screened using healthy non-detached 'Hongyang' kiwi leaves. Fifteen leaves from five different two-month-old trees were used for each isolate, with three repetitions. For inoculation, a 10 mL solution containing 1 × 106 spores/mL was sprayed on the leaves. Sterilized water was used in the control experiment, which was carried out using fifteen leaves from five different two-month-old trees, with three repetitions. Inoculated trees were stored at 26ºC and 60% relative humidity for 2 days. All the infected leaves had necrotic lesions and leaf blight symptoms comparable to those found in the field, but the control leaves had no lesions. The pathogen was recovered, and its identity was confirmed by ITS sequencing and morphology analysis, fulfilling Koch's postulates. P. oxalicum is a common cause of blue mould in postharvest fruits (Tang et al. 2020). P. oxalicum has been recently reported as the causal agent of leaf spot in pineapple (Wu et al. 2022; Zheng et al. 2023), and leaf blight on maize (Han et al. 2023). Although Alternaria sp., Glomerella cingulate, Pestalotiopsis sp., Phomopsis sp., and Phoma sp. were previously isolated from kiwi leaves with blight symptoms (Kim et al. 2017), this is the first report of P. oxalicum causing leaf blight on kiwi trees worldwide. P. oxalicum is a well-known source of mycotoxins, such as secalonic acid (Otero et al. 2020), indicating that its presence in kiwifruit orchards may pose a significant risk to human health. The discovery of this hazardous pathogen in kiwi trees must drive the development of management strategies. Kiwifruit is an important dietary source of vitamins, fiber, folate, and potassium, and China is the major producer of kiwifruit, with more than 1.2 million metric tons harvested in 2021. This report will help to generate a better understanding of the pathogens affecting kiwifruit orchards in China.