Anthracnose Development Research Articles

Novel cellular functions of Cys2-His2 zinc finger proteins in anthracnose development and dissemination on pepper fruits by Colletotrichum scovillei.

Colletotrichum species are notorious for causing anthracnose on many fruits, leading to significant economic losses worldwide. As a model, we functionally characterized cys2-his2 (C2H2) zinc finger proteins (CsCZFs) in Colletotrichum scovillei, a major causal agent of pepper fruit anthracnose in many countries. In all, 62 CsCZFs were identified by in silico genomic analysis. Twelve were selected based on their expression profiles to generate targeted deletion mutants for functional investigation. ΔCsczf1 markedly reduced conidiation and constitutive expression of CsCZF1 partially recovered conidiation in an asexual reproduction-defective mutant, ΔCshox2. Deletion of CsCZF12, orthologous to the calcineurin-responsive transcription factor Crz1, impaired autophagy in C. scovillei. ΔCsczf9 was defective in surface recognition, appressorium formation, and suppression of host defenses. CsCZF9 was identified as an essential and novel regulator under the control of the mitogen-activated protein kinase (CsPMK1) in an early step of appressorium development in C. scovillei. This study provides novel insights into CsCZF-mediated regulation of differentiation and pathogenicity in C. scovillei, contributing to understanding the regulatory mechanisms governing fruit anthracnose epidemics.IMPORTANCEThe phytopathogenic fungus Colletotrichum scovillei is known to cause serious anthracnose on chili pepper. However, the molecular mechanism underlying anthracnose caused by this fungus remains largely unknown. Here, we systematically analyzed the functional roles of cys2-his2 zinc finger proteins (CsCZFs) in the dissemination and pathogenic development of this fungus. Our results showed that CsCZF1 plays an important role in conidiation and constitutive expression of CsCZF1 restored conidiation in an asexual reproduction-defective mutant, ΔCshox2. The CsCZF9, a novel target of the mitogen-activated protein kinase (CsPMK1), is essential for surface recognition to allow appressorium formation and suppression of host defenses in C. scovillei. The CsCZF12, orthologous to the calcineurin-responsive transcription factor Crz1, is involved in the autophagy of C. scovillei. Our findings reveal a comprehensive mechanism underlying CsCZF-mediated regulation of differentiation and pathogenicity of C. scovillei, which contributes to the understanding of fruit anthracnose epidemics and the development of novel strategies for disease management.

Caprylic Acid From Vitex mollis Pulp Alters Colletotrichum gloeosporioides Plasma Membrane and Reduces Anthracnose Development on Papaya Fruit

ABSTRACTSynthetic fungicides are used to control anthracnose caused by Colletotrichum gloeosporioides; however, their frequent application increases the risk of pathogen resistance, environmental damage, and health concerns. It has been reported that caprylic acid (CA) inhibits the in vitro development of C. gloeosporioides; however, its antifungal mechanism and in vivo antifungal potential are still unknown. Therefore, the present work aims to analyse the effect of a CA‐enriched sub‐fraction (CAES) extracted from Vitex mollis fruit on the fungal microstructure by confocal fluorescence microscopy and morphometric analysis. Moreover, the effect of CAES on anthracnose development and quality parameters in papaya fruit was evaluated. The confocal microscopy images confirmed that CAES damaged the cell wall of conidia, given their decreased width. The increased fluorescence intensity in the CAES and CA‐treated mycelium suggested they were attached to the plasma membrane. These treatments produced structural alterations of the vacuoles and septa in mycelium, while in the fungicide thiabendazole (TBZ) treatment, apoptotic bodies appeared. CAES at 1.0 g L−1 had the best effect against anthracnose incidence and severity in papaya fruit, whereas TBZ was only effective on anthracnose severity. None of the applied treatments affected the fruit quality parameters. Therefore, CAES may be develop as an effective option to suppress anthracnose on papaya fruit.

Interventions based on alternative and sustainable strategies for postharvest control of anthracnose and maintain quality in tropical fruits.

Colletotrichum spp. is a phytopathogen causing anthracnose in a variety of tropical fruits. Strategies used to control postharvest diseases in tropical fruits typically rely on the use of synthetic fungicides, which have stimulated the emergence of resistant pathogens. Safer alternative strategies to control anthracnose in tropical fruits have been described in the literature. This review presents and discusses the main innovative interventions concerning the application of sustainable alternative strategies in the postharvest control of pathogenic Colletotrichum species in tropical fruits, with a particular emphasis on the studies published in the last 5 years. The available studies have shown the use of various methods, including physical barriers, natural antimicrobials, and biological control with antagonistic microorganisms, to reduce anthracnose lesion severity and incidence in tropical fruits. The available literature showed high inhibitory activity in vitro, reduced anthracnose incidence and lesion diameter, and total disease inhibition in tropical fruits. Most studies focused on the inhibition of Colletotrichum gloeosporioides on avocado, papaya, and mango, as well as of Colletotrichum musae on banana; however, the inhibition of other Colletotrichum species was also demonstrated. The application of emerging sustainable alternative methods, including natural antimicrobial substances, also stimulated the induction of defense systems in tropical fruits, including enzymatic activity, such as polyphenol oxidase, peroxidase, and phenylalanine ammonia-lyase. The retrieved data helped to understand the current state of the research field and reveal new perspectives on developing efficient and sustainable intervention strategies to control pathogenic Colletotrichum species and anthracnose development in tropical fruits.

Potential Antagonists Trichoderma viride as Biofungicide, Plant Spacing, and Agricultural Lime Application to Suppress Anthracnose on Chili

Anthracnose caused by Colletotrichum capsici and C. gloesporium on chili is a disease that can reduce chili yields up to 80%. Control with fungicide has not been able to provide maximum results, because Colletotrichum can spread due to splashing of water, especially in the rainy season. The use of antagonistic fungi against Colletotrichum spp. has been widely published but is still limited to the laboratory and greenhouse scale, while field conditions are unpredictable. This study aims to identify the potency of Trichoderma viride that can be used as a biofungicide to control anthracnose in chili and to determine aspects of agronomic that can reduce the risk of anthracnose in chili. Samples of infected plants of stems, leaves, and fruits were collected from experimental farm of Bogor Agricultural Development Polytechnic. The experiment was conducted using Randomized Complete Design and Randomized Complete Block Design. The percentage of disease intensity of the fungus C capsici and the intensity of anthracnose in chili both under screen house and open fields. While testing the effect of cultivation aspects using different types of fertilizer on plant height, fruit weight, number of fruits, and the percentage of disease intensity of Colletotrichum spp. were analyzed. The results of this study shown that four isolates of fungi have been identified such as Penicillium sp., Aspergillus flavus, T. viride, and C. capsici. In vitro analysis shown the ability of T. viride to suppress the growth of the C. capsici up to 71%. The fungus T. viride with a density of 7×106 CFU/mL can suppress the development of anthracnose by 59 to 87% under screen house conditions. However, under field conditions, the fungus T. viride was not able to suppress the development of anthracnose. Agronomic aspects such as plant height, number of fruits and production, and productivity of chili were not significantly effect on anthracnose.

VEGETABLE BEAN IN POLYCROPPING

Purpose. To scientifically justify the influence of protection systems (biological, chemical) on the growth and development of bean plants in strip cropping. Methods. Field, statistical. Results. To create a polycrop agrogroup, strips that were multiples of the rig width (for example, 2.8 m, 4.2 m, 5.6 m, etc.) were formed. Solid-planted companion crops (spiked cereals [for example, winter triticale – the most optimal forecrop for bean]) were grown in alkalized strips, and bean was grown in non-alkalized strips. Crops were rotated by periodic alternating alkalized and non-alkalized strips. A clear pattern was revealed: the farther bean plants from the companion crops (70 cm, 140 cm, 210 cm) were, the taller they were: when sown with winter triticale, their height increased from 57 cm to 59 cm; when sown with spring triticale, it increased from 54 cm to 58 cm. On average for two years, a clear similar trend was observed for bush width: the farther bean plants from the companion crops (70 cm, 140 cm, 210 cm) were, the wider bean bush became: when sown with winter triticale, the bush width increased from 55 cm up to 59 cm; when sown with spring triticale, it increased from 54 cm to 57 cm. The farther bean rows from the companion crops were, the fewer nodules per plant formed: when the bean was sown with winter triticale, the nodule number decreased from 110/plant to 95/plant; when it was sown with spring triticale, this parameter decreased from 68/plant to 53/plant. In 2022, the bean sown with winter triticale as a predecessor and companion crop in the strip cropping was least affected by Alternaria leaf spot (5–9%); when the bean was sown with spring triticale as a companion crop, the Alternaria leaf spot prevalence ranged from 11 to 13%. In 2023, with winter triticale as a companion crop and predecessor, the bean anthracnose prevalence was 13–20%; in the other variants, it amounted to 35–40%. Conclusions. Strip cropping, in particular with vegetable bean, is a promising trend in organic farming. The farther bean plants from the companion crops (70 cm, 140 cm, 210 cm) were, the taller they were and the wider bean bushes became, but the number of nitrogen-fixing nodules, on the contrary, decreased. The biological regimen of plant protection restrained the Alternaria leaf spot and bean anthracnose development on bean plants where winter triticale was a companion crop and forecrop.

Potensi Cendawan Antagonis Trichoderma Viride Isolat Bogor sebagai Agensi Pengendalian Hayati Penyakit Antraknosa Tanaman Cabai Merah

Anthracnose disease caused by Colletottrichum capsici on chili plants that can damage yields by up to 80%. Control with fungicides has not been able to provide maximum results, because the fungus can move due to water splashes, especially in the rainy season. The use of antagonistic fungi against Colletotrichum capsici. has been widely published but is still limited to laboratory and greenhouse scales. This study aims to analyze the potential of Bogor isolate Trichoderma viride antagonist fungus against the fungus C. capsici through in-vitro study in the laboratory, screen houses, and field conditions. The experiment was structured using Complete Randomized Design (CRD) with parameters that measured respectively the antagonistic ability, and the percentage of attack by C. capsici and the severity of anthracnose disease on chili plants were both tested in screen house condition. Bogor Isolate T. viride has potential as a biological control agent for chili plants. This is proven by the ability to suppress the growth of C. capsici by 71% in vitro. The use of the fungus T. viride with a concentration of 7x106 conidia/ml (full strength) can suppress the development of anthracnose by 59 to 87% under screen house conditions. In other words, the pathogenicity of capsici in red chili plants shows a severity level of 13 to 41%.

Essential Oils for Managing Anthracnose in Mango (Mangifera indica): Laboratory Results Do Not Translate into Field Efficacy.

Essential oil-based products with broad plant disease control claims are commercially available and may be a practical alternative to copper fungicides for crop protection in organic mango orchards. We evaluated the disease control efficacy and crop safety of thyme oil, savory oil, and tree tea oil through replicated in vitro, in vivo (detached leaf and potted trees), and field assays. Three Colletotrichum species associated with mango anthracnose were tested in vitro, whereas only C. siamense was used for in vivo assays. Within the range of concentrations tested in vitro (62.5 to 2,000 μl active ingredient [a.i.]/liter), thyme and savory oil displayed fungicidal activity, whereas no fungistatic or fungicidal activity was observed with tea tree oil. In the in vivo assays, none of the treatments based on a preventive application rate of thyme (1,150 μl a.i./liter), savory (2,000 μl a.i./liter), or tea tree oil (342 μl a.i./liter) were effective in preventing the development of anthracnose on wounded and artificially inoculated leaves. Although field applications of thyme or tea tree oil did not result in phytotoxicity or negative impacts on fruit yield, they were ineffective in reducing the incidence and severity of naturally occurring anthracnose. Applications of copper hydroxide approved for organic agriculture were effective in controlling anthracnose in the field, and no added benefits were found by premixing this compound with thyme oil. Results indicate that essential oil products based on thyme or tea tree oil are inefficient at controlling anthracnose in mangoes.

Cluster Zone Leaf Removal Reduces the Rate of Anthracnose (Elsinöe ampelina) Progress and Facilitates Its Control.

Anthracnose caused by Elsinöe ampelina is an economically important disease that affects certain hardy and semihardy grapevine cultivars. The control of this disease requires repeated application of fungicides, which has financial and environmental consequences. In this study, leaf removal in the cluster area was studied with a view to facilitating integrated anthracnose management. First, the effect of leaf removal timing (BBCH stage 53 or 71) and intensity (one or both sides of rows) on the progression of anthracnose and on the microclimate was studied in plots planted with Vidal blanc (Vitis vinifera) at two sites in both 2020 and 2021. Overall, at both sites and in both years, anthracnose on leaves was more severe in plots without cluster zone leaf removal. Regardless of the timing of leaf removal, anthracnose severity on leaves and incidence of infected berries at harvest were significantly lower in plots where leaves had been removed on both sides of the rows compared with plots where leaves were removed on one side only. Second, anthracnose management programs with leaf removal, with or without disease risk estimation, were evaluated. All anthracnose management programs including leaf removal in the cluster zone reduced anthracnose development compared with the standard program without leaf removal. Overall mean leaf anthracnose severity, severity at harvest, and anthracnose incidence on clusters at harvest were lower in plots with leaf removal than in the standard program, but the differences between the two treatments were not significant (P > 0.05). More fungicide applications were made in plots managed using the standard programs, specifically 13 applications, compared with plots managed based on assessing the weather-related risk of anthracnose, with 9 and 10 applications made at sites 1 and 2 for the risk-based program, respectively, and 5 and 7 applications made at sites 1 and 2, respectively, when microclimate within the cluster zone was considered. The results of this study clearly show the important role that leaf removal can play in managing grape anthracnose.

Determination of Antifungal Activity on Pepper Anthracnose and Plant Growth Promoting Activity of Pleurospermum camtschaticum Root Extract

This study was conducted to confirm the utilization of <i>Pleurospermum camtschaticum</i> root extract as an organic agricultural material. Antioxidant activity of <i>P. camtschaticum</i> root extract, closely related to antibacterial activity, increased in a dose-dependent manner. In mycelial growth inhibitory activity, 100% <i>P. camtschaticum</i> root extract supressed over 70% for <i>Colletotrichum</i> coccodes and over 68% for <i>Colletotrichum dematium</i>. In the pepper fruit anthracnose development test, the size of the lesion decreased in a dose-dependent manner, which showed the same tendency as the previous results in inhibitory activity on mycelial growth. In the pepper seed germination and red pepper growth promotion test of <i>P. camtschaticum</i> root extract, oposite results was confirmed. The lower the concentration, the more the seed germination and growth promotion effects were shown. The phenol content of pepper leaves was also measured after pepper growth promotion test have been completed. The phenol content related to antibacterial activity increased in all treated groups compared to the untreated group. Therefore, the results of this study showed the possibility of development as an organic material.

The Potential of Rhizophagus intraradices, Bacillus thuringiensis Bt BMKP and Silica for Anthracnose Disease Control in Shallot

Anthracnose caused by <em>Colletotrichum gloeosporioides</em> is a prevalent disease that poses a significant threat to shallot production in Indonesia. To mitigate this issue, the use of biological agents presents an alternative for disease control, reducing the inherent risks associated with the use of chemical pesticides. Therefore, this study aimed to determine the potentiality and mechanism of the biological agents (<em>Rhizophagus intraradices</em> and <em>Bacillus thuringiensis</em>) combined with silica. These agents were evaluated both individually and in combination to suppress the development of anthracnose in Tajuk variety shallot. The study was conducted in the laboratory and greenhouse, arranged in a completely randomized design with six treatments and three replications. The ability to suppress pathogenic fungi was determined based on <em>in vitro</em> antagonism tests of <em>B. thuringiensis</em>, disease severity, area under disease progress curve (AUDPC), plant height, number of leaves, number of tillers and the percentage of mycorrhizal fungal infections. Furthermore, the mycorrhizal infection on plant roots was observed using staining methods. The results showed that the <em>Bt</em> BMKP isolate was included in the <em>B. thuringiensis</em> strain RC9 group with the capacity to inhibit <em>C. gloeosporioides</em> <em>in vitro</em> by 18.88%. The combination treatment of <em>R. intraradices</em>, <em>B. thuringiensis</em> and silica reduced infection from anthracnose by 15.52% compared with control. These three treatments also significantly increased the agronomic performance of shallot up to six weeks after planting compared to control and other treatments.

Pentaene macrolides AB023a and takanawaene C produced by Streptomyces xanthocidicus strain S3 for controlling pepper anthracnose

A natural product library consisting of the culture extracts of 814 actinomycete strains was screened for antifungal compounds that disrupt the cell integrity of plant pathogenic fungi using an adenylate kinase (AK) assay system. The culture extract of Streptomyces xanthocidicus strain S3 exhibited high AK activity against various plant pathogens. The active ingredients, AT-1 and AT-2, were isolated from the culture extract using a series of chromatographic procedures. Based on MS, UV, and NMR spectrometric analyses, the structures of AT-1 and AT-2 were determined as the pentaene macrolides, AB023a and takanawaene C. AB023a and takanawaene C displayed broad-spectrum antifungal activity against Aspergillus oryzae, Botrytis cinerea, Colletotrichum coccodes, C. gloeosporioides, C. orbiculare, Cylindrocarpon destructans, and Fusarium oxysporum f. sp. lycopersici, showing minimum inhibitory concentrations of 1–32 μg/mL. Treatment of AB023a and takanawaene C successfully inhibited anthracnose development on pepper plants in a concentration-dependent manner without phytotoxicity. The disease control efficacy of both compounds was comparable to that of the commercial fungicide chlorothalonil. Collectively, these results suggest that the polyene macrolides produced by S. xanthocidicus strain S3 can be used as natural fungicides for plant disease control.

Long-Term Cover Cropping Suppresses Foliar and Fruit Disease in Processing Tomatoes.

While links between soil and plant health are implied, there are few opportunities to empirically evaluate this due to inherent differences among sites. An exception is a long-term experiment established in 2007 (repeated in 2008) in Ridgetown, ON, where improved soil health scores and changes in soil microbial communities were observed in the medium-term with annual cover crops (CC). This led us to hypothesize that CC-induced changes in soil health might affect bacterial spot (Xanthomonas hordorum pv. gardneri) and anthracnose (Colletotrichum coccodes) development in processing tomato. Five CC treatments (no CC control, winter cereal rye, oat, radish, and mix of radish + rye) planted after winter wheat harvest were evaluated in 2019 and 2020 (CC grown nine times over 12 years). Fruit yields and net revenue were similar or greater with CC than without. In 2019, there was greater defoliation (area under the disease progress stairs = 4,370 ± 204), percent red fruit (71.0% ± 5.38), and rots (1.91% ± 0.5) in no CC than with radish (3,410, 39.1%, and 0.62%, respectively, P ≤ 0.0366), indicating earlier fruit maturity in no CC plots. Similarly, no CC had a greater incidence of red fruits with anthracnose (25.8% ± 2.89) compared with all CCs but rye (7.4 to 12.1% ± 2.89; P = 0.0029). Environmental conditions in 2020 were less favourable for disease development. Defoliation was not affected by CC treatment (P = 0.1254), and anthracnose incidence was low (≥90.3 ± 1.22% healthy fruit), which may have limited the ability to detect treatment effects (P = 0.2922). Long-term cover crops have the potential to produce greater or equivalent tomato yield with decreased defoliation and anthracnose fruit rot.

Exogenous application of a Burkholderia sp. and jasmonic acid at the postharvest stage for management of anthracnose in dessert banana (Musa acuminata)

AbstractThe present study was conducted to determine the potential of controlling natural (latent) and wound infections of anthracnose using a biological control agent (Burkholderia sp. [BS]) and jasmonic acid (JA). Exogenous application of BS (1 × 108 cfu/mL) and JA (0.2 mM) reduced both types of anthracnose in banana cultivars Kolikuttu and Seenikesel within a range of 67.6%–100%. Due to BS and JA treatments, three selected defence genes (β‐1,3‐glucanase, PR‐1 and chitinase) were up‐regulated in the fruit peels of the two banana cultivars over a period of 144 h after treatment (HAT), indicating the ability to induce host plant resistance by the two treatments. BS treatment resulted in a 1.5‐ to 2.5‐fold increase of the above gene transcripts under natural infection in both cultivars. The findings revealed that induction of the three selected defence genes varies depending on the type of the treatment and infection. JA‐treated fruits with natural infections showed a 1‐day delay of ripening and resulted in the lowest ripening indices till 6th day after treatment in comparison to the BS‐ and untreated banana. BS and JA concentrations used in the study, significantly reduced mycelial growth and spore production of C. musae. Lowering of the ripening index, reduction of mycelial growth and spore production of the fungal pathogen and increased expression of the three selected defence genes by BS and JA treatments reduced the disease progression and lesion development of anthracnose in the two banana cultivars under natural and wound infections of C. musae.

Effect of combined application of carbonate salts and hot water treatment for the management of postharvest anthracnose (Colletotrichum gloeosporioides) of papaya.

Postharvest anthracnose (Colletotrichum gloeosporioides Penz.Sacc) is the most economically important biological constraint to papaya production and consumption, which causes substantial yield loss worldwide. The effect of combined application of carbonate salts and hot water treatments on the development of postharvest anthracnose and maintenances of postharvest quality of papaya fruit was studied in completely randomized design (CRD) under laboratory condition. The results revealed that combined application of hot water treatment and carbonate salts significantly (p < .05) reduced the incidence and severity of postharvest papaya anthracnose disease. The disease incidence reached 100% 21 days after inoculation in the control treatment; this level was significantly reduced to 26.70% by dipping the fruits in NH4CO3 at 50°C and NH4CO3 at 54°C. Similarly, treatments significantly (p < .05) reduced the disease severity in different degrees from the first day of disease appearance to the date of 100% unmarketability of control fruits. Furthermore, the combined application of carbonate salt and hot water treatments significantly improves fruit marketability by 93.33%. Moreover, the treatments showed significant (p < .05) effect on maintaining pH, TSS, TA, and reducing postharvest weight loss of papaya fruit. In conclusion, postharvest treatment of papaya fruit with NH4CO3 at 54°C, NH4CO3 at 52°C, and NaCO3 at 54°C can significantly reduce anthracnose development and improve marketability of the fruits without pronounced effect on their edible qualities.

Effect of chitosan with different molecular weights on the antifungal activity against Colletotrichum gloeosporioides and activation of the non‐enzymatic antioxidant system on infected papaya

Chitosan (Ch) is a biopolymer with excellent antimicrobial and antioxidant properties, capable of maintaining the organoleptic quality of fruits. These properties have been related to its molecular weight. However, the effect of different molecular weights on the non-enzymatic antioxidant system and postharvest quality of anthracnose-infected papaya is still unknown. Therefore, this study evaluated the effect of different Ch molecular weights (13, 25, and 55kDa) on anthracnose development, antioxidant capacity, and postharvest quality of papaya. The Ch-55, Ch-25, and 13kDa inhibited the development of Colletotrichum gloeosporioides. In comparison with thiabendazole, Ch with different molecular weights showed fungicidal effects. Ch-55kDa reduced anthracnose incidence and severity and maintained postharvest quality parameters of papaya. In addition, Ch-55 and Ch-13kDa favored synthesis of ascorbic acid, total phenolics, and antioxidant capacity. Therefore, Ch-55kDa is an alternative to the protection against C. gloeosporioides and a stimulant of the non-enzymatic antioxidant system in papaya fruits during its postharvest storage. PRACTICAL APPLICATION: Ch with different molecular weights have different effects over anthracnose control and postharvest quality in papaya. In addition, they have different stimulation levels on the non-enzymatic antioxidant system of papaya fruits, in a higher level than the chemical fungicide TBZ, by regulating the growth of the fungus and the degradative processes that are generated in fungal infection. In this sense, we believe that our findings could be of interest for producers and farmers to take advantage of this biopolymer to control anthracnose, preserve the postharvest quality, and stimulate the non-enzymatic antioxidant system of papaya fruit.

Preventive and curative effect of difenoconazole + azoxytrobin and thiophanate-methyl against lucky bamboo anthracnose disease caused by Colletotrichumdracaenophilum

In Egypt, Dracaena sanderiana (lucky bamboo) is an ornamental plant imported from several countries. Two weeks after they arrived at the nurseries, anthracnose indications were detected on the shoots of imported D. sanderiana samples. Four Colletotrichum spp. isolates were obtained from the symptomatic lucky bamboo plants. The obtained isolates belonged to the species of C. gloeosporioides or C. dracaenophilum based on their morphological characteristics and molecular biology analyses. Pathogenicity tests reveal that C. dracaenophilum isolate 4 was found to be more pathogenic than the other isolates. The in vitro investigation was conducted with the objectives of evaluating six systemic fungicides for their inhibitory effect against C. dracaenophilum. Data reveal that, thiophanate-methyl and difenoconazole + azoxytrobin at ≥15 ppm completely inhibited the pathogen growth. Tebuconazole and flusllazole inhibited growth completely at ≥20 ppm, whereas iprodione and cyprodinil + fludioxonil had a lower effect (56.6 and 54.4% reduction, respectively) at this dose. The in vivo investigation was conducted with the objectives of evaluating the preventive and curative effects of the most effective fungicides against anthracnose disease. Lucky bamboo plants were treated with fungicide and either inoculated or not with C. dracaenophilum before being left for 25 or 60 days. On both insidiously infected and vaccinated lucky bamboo plants, the combination of difenoconazole, azoxytrobin, and thiophanate-methyl at 20 ppm greatly reduced the development of anthracnose. Tebuconazole and flusllazole were found to be phytotoxic.

Arbuscular mycorrhizal fungus alleviates anthracnose disease in tea seedlings.

Tea has been gaining increasing popularity all over the world in recent years, and its yield and quality depend on the growth and development of tea plants [Camellia sinensis (L.) Kuntze] in various environments. Nowadays, biotic stress and extreme weather, such as high temperature, drought, waterlogging, pests, and diseases, bring about much pressure on the production of tea with high quality. Wherein anthracnose, which is the most common and serious disease of tea plants, has earned more and more attention, as its control mainly relies on chemical pesticides. Arbuscular mycorrhizal fungi (AMF), forming symbiosis with most terrestrial plants, participate in plant resistance against the anthracnose disease, which was found by previous studies in a few herbaceous plants. However, there are a few studies about arbuscular mycorrhizal (AM) fungal regulation of the resistance to the anthracnose pathogen in woody plants so far. In this paper, we investigated the effect of AMF on the development of anthracnose caused by Colletotrichum camelliae and tried to decipher the pertinent mechanism through transcriptome analysis. Results showed that inoculating AMF significantly reduced the damage of anthracnose on tea seedlings by reducing the lesion area by 35.29% compared to that of the control. The content of superoxide anion and activities of catalase and peroxidase significantly increased (P < 0.05) in mycorrhizal treatment in response to the pathogen with 1.23, 2.00, and 1.39 times higher, respectively, than those in the control. Pathways of plant hormone signal transduction, mitogen-activated protein kinase (MAPK) signaling, and phenylpropanoid biosynthesis might play roles in this regulation according to the transcriptomic results. Further redundancy analysis (RDA) and partial least squares structural equation modeling (PLS-SEM) analysis found that plant hormones, such as auxin and ethylene, and the antioxidant system (especially peroxidase) were of great importance in the AM fungal alleviation of anthracnose. Our results preliminarily indicated the mechanisms of enhanced resistance in mycorrhizal tea seedlings to the anthracnose pathogen and provided a theoretical foundation for the application of AMF as one of the biological control methods in tea plantations.

The impact of meteorological variables on the development of blackgram anthracnose caused by Colletotrichum lindemuthianum

The impact of meteorological variables on the development of blackgram anthracnose caused by Colletotrichum lindemuthianum

The G protein subunit α1, CaGα1, mediates ethylene sensing of mango anthracnose pathogen Colletotrichum asianum to regulate fungal development and virulence and mediates surface sensing for spore germination.

Mango is an important tropic fruit, but its production is highly restricted by anthracnose diseases. Mango anthracnose development is related to the fruit-ripening hormone ethylene, but how the pathogen senses ethylene and affects the infection remains largely unknown. In this study, mango pathogen Colletotrichum asianum strain TYC-2 was shown to sense ethylene to enhance spore germination, appressorium formation and virulence. Upon further analysis of ethylene sensing signaling, three histidine kinase genes (CaHKs) and a G-protein gene (CaGα1) were functionally characterized. Ethylene upregulated the expression of the three CaHKs but had no influence on CaGα1 expression. No function in ethylene sensing was identified for the three CaHKs. Ethylene enhanced spore germination and multiple appressorium formation of the wild-type TYC-2 but not CaGα1 mutants. TYC-2 has extremely low germination in water, where self-inhibition may play a role in ethylene sensing via CaGα1 signaling. Self-inhibitors extracted from TYC-2 inhibited spore germination of TYC-2 and CaGα1 mutants, but ethylene could not rescue the inhibition, indicating that the self-inhibition was not mediated by CaGα1 and had no interactions with ethylene. Interestingly, spore germination of CaGα1 mutants was significantly enhanced in water on hydrophobic but not hydrophilic surfaces, suggesting that CaGα1 is involved in surface sensing. In the pathogenicity assay, CaGα1 mutants showed less virulence with delayed germination and little appressorium formation at early infection on mango leaves and fruit. Transcriptome and qRT-PCR analyses identified several pathogenicity-related genes regulated by ethylene, indicating that ethylene may regulate TYC-2 virulence partially by regulating the expression of these genes.

The Autophagy Protein CsATG8 is Involved in Asexual Development and Virulence in the Pepper Anthracnose Fungus Colletotrichum scovillei

Autophagy serves as a survival mechanism and plays important role in nutrient recycling under conditions of starvation, nutrient storage, ad differentiation of plant pathogenic fungi. However, autophagy-related genes have not been investigated in Colletotrichum scovillei, a causal agent of pepper fruit anthracnose disease. ATG8 is involved in autophagosome formation and is considered a marker of autophagy. Therefore, we generated an ATG8 deletion mutant, ΔCsatg8, via homologous recombination to determine the functional roles of CsATG8 in the development and virulence of C. scovillei. Compared with the wild-type, the deletion mutant ΔCsatg8 exhibited a severe reduction in conidiation. Conidia produced by ΔCsatg8 were defective in survival, conidial germination, and appressorium formation. Moreover, conidia of ΔCsatg8 showed reduced lipid amount and PTS1 selectivity. A virulence assay showed that anthracnose development on pepper fruits was reduced in ΔCsatg8. Taken together, our results suggest that CsATG8 plays various roles in conidium production and associated development, and virulence in C. scovillei.