Gloeosporioides Sensu Stricto Research Articles

Colletotrichum Species Causing Cyclocarya paliurus Anthracnose in Southern China

Cyclocarya paliurus, native to China, is a medicinal and edible plant with important health benefits. Anthracnose is an emerging disease in southern China that causes severe economic losses and poses a great threat to the C. paliurus tea industry. However, to date, the species diversity of pathogens causing C. paliurus anthracnose has remained limited. From 2018 to 2022, a total of 331 Colletotrichum isolates were recovered from symptomatic leaves in eight major C. paliurus planting provinces of southern China. Phylogenetic analyses based on nine loci (ITS, GAPDH, ACT, CHS-1, TUB, CAL, HIS3, GS and ApMat) coupled with phenotypic characteristics revealed that 43 representative isolates belonged to seven known Colletotrichum species, including C. brevisporum, C. fructicola, C. gloeosporioides sensu stricto, C. godetiae, C. nymphaeae, C. plurivorum and C. sojae. Pathogenicity tests demonstrated that all species described above were pathogenic to wounding detached leaves of C. paliurus, with C. fructicola being the most aggressive species. However, C. brevisporum, C. plurivorum and C. sojae were not pathogenic to the intact plant of C. paliurus. These findings reveal the remarkable species diversity involved in C. paliurus anthracnose and will facilitate further studies on implementing effective control of C. paliurus anthracnose in China.

Identification and pathogenicity of Colletotrichum species associated with twig dieback of citrus in Western Australia

AbstractUp to 32 Colletotrichum species have been reported to be associated with pre‐ or postharvest diseases of citrus globally, while in Australia, six species have been reported to cause citrus leaf and fruit disease. Twig or shoot dieback has recently been observed as an emerging disease in citrus orchards in Western Australia. Colletotrichum species were isolated from diseased twigs showing dieback (withertip) or lesions, with or without gummosis, collected from 12 varieties of orange, mandarin and lemon. Colletotrichum gloeosporioides sensu stricto, Colletotrichum karstii and Colletotrichum novae‐zelandiae were identified using a polyphasic approach that included multigene phylogenetic analysis using sequences of internal transcribed spacer and intervening 5.8S nrDNA (ITS), glyceraldehyde‐3‐phosphate dehydrogenase (gapdh), β‐tubulin (tub2), actin (act) and histone (his3) for isolates in the boninense species complex, and Apn2–Mat1–2 intergenic spacer and partial mating type (Mat1–2) (ApMat) and glutamine synthetase (gs) for isolates in the gloeosporioides species complex, as well as morphological characteristics. C. gloeosporioides was the most prevalent species associated with twig dieback in Western Australia, while C. novae‐zelandiae was reported for the first time in Australia. Pathogenicity tests on shoot twigs from lemon and orange trees confirmed C. gloeosporioides, C. karstii and C. novae‐zelandiae as the cause of twig dieback, with C. gloeosporioides being the most aggressive species. Knowledge of the species causing twig dieback and their lifestyle will assist the development of integrated control methods.

Diversity of Colletotrichum species causing anthracnose on three oak species (Quercus acutissima, Q. mongolica and Q. variabilis) in China

AbstractAnthracnose of oak (Quercus) caused by Colletotrichum spp. is one of the most common diseases in oak forests. To investigate the species diversity of Colletotrichum associated with oak anthracnose, symptomatic leaf samples of three oak species (Q. acutissima, Q. mongolica and Q. variabilis) were collected from Anhui, Hainan, Henan, Shaanxi and Shandong Provinces, Inner Mongolia Autonomous Region, and Beijing City in China from 2019 to 2022. A total of 219 Colletotrichum isolates were obtained and identified by morphological and phylogenetic analyses of the rDNA internal transcribed spacer (ITS), glyceraldehyde‐3‐phosphate dehydrogenase (gapdh), chitin synthase 1 (chs‐1), actin (act) and β‐tubulin (tub2) sequences. Nine species were identified: C. fioriniae (two isolates, 0.9%), C. camellia‐japonicae (two isolates, 0.9%), C. karstii (three isolates, 1.4%), C. quercicola (two isolates, 0.9%), C. aenigma (three isolates, 1.4%), C. endophyticum (two isolates, 0.9%), C. fructicola (68 isolates, 31.1%), C. gloeosporioides sensu stricto (74 isolates, 33.8%) and C. siamense (63 isolates, 28.8%). Pathogenicity was confirmed using Koch's postulates, which showed that five species (C. camellia‐japonicae, C. endophyticum, C. fructicola, C. gloeosporioides s. s. and C. siamense) caused Q. acutissima anthracnose, four species (C. karstii, C. fructicola, C. gloeosporioides s. s. and C. siamense) caused Q. mongolica anthracnose and six species (C. fioriniae, C. quercicola, C. aenigma, C. fructicola, C. gloeosporioides s. s. and C. siamense) caused Q. variabilis anthracnose. This study demonstrates the pathogenic species diversity of Colletotrichum on Q. acutissima, Q. mongolica and Q. variabilis.

Leaf Spots of Salix babylonica Caused by Colletotrichum gloeosporioides s.s. and C. siamense Newly Reported in China.

Salix babylonica L. shows a great potential for restoration of contaminated water or soils and has a high ornamental value (Li et al. 2015). In mid-October 2021, a leaf spot disease, with an incidence of approximately 61%, occurred on leaves of 25-year-old S. babylonica on the campus of Nanjing Forestry University. On average, 65% of the leaves per tree were infected. Symptoms began as dark brown, irregular spots, and the centers were grayish white. The spots gradually enlarged with time. Fresh specimens were collected from 3 trees (10 leaves/tree). Small tissue pieces cut from lesion margins were surface-sterilized (Mao et al. 2021), plated on potato dextrose agar (PDA), and incubated at 25°C. Three representative isolates (NL1-7, NL1-10, and NL1-13) were obtained and deposited in The China Forestry Culture Collection Center. The colonies of 3 isolates were white, grayish white at the center. The conidia of 3 isolates were one-celled, straight, subcylindrical, hyaline, smooth, 14.6-18.6 × 4.3-6.7 µm, 13.8-16.7 × 4.7-6.0 µm and 12.1-16.9 × 5.4-7.5 µm (n = 50) for NL1-7, NL1-10, and NL1-13, respectively. The conidiophores of NL1-7 were hyaline to pale brown, septate, and branched, 18.9-48.0 µm (n = 50). Appressoria were one-celled, ellipsoidal, brown or dark brown, thick-walled. The conidiophores and appressoria of the other two isolates were almost identical to NL1-7. Based on morphological characteristics, the 3 isolates matched the Colletotrichum gloeosporioides species complex (Weir et al. 2012). DNA of the 3 isolates was extracted. The internal transcribed spacer region (ITS), actin (ACT), calmodulin (CAL), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and β-tubulin 2 (TUB2) loci were amplified using the primer pairs ITS1/ITS4, ACT-512F/ACT-783R, CL1C/CL2C, CHS-79F/CHS-354R, GDF1/GDR1, and T1/Bt2b, respectively (Weir et al. 2012). The sequences were deposited in GenBank [Accession Nos. ON870951 and ON858477 to ON858481 for NL1-7; ON908707 and ON858482 to ON858486 for NL1-10; ON870949 and ON858487 to ON858491 for NL1-13]. BLAST result showed that ITS, ACT, CAL, CHS-1, GAPDH, and TUB2 sequences of NL1-7 were identical to C. gloeosporioides at a high level (>99%). The sequences of NL1-10 and NL1-13 were consistent with C. siamense at a high level (>99%). A maximum likelihood and Bayesian Inference analyses using IQtree v. 1.6.8 and MrBayes v. 3.2.6 with the concatenated sequences (ITS, ACT, CAL, CHS-1, GAPDH, and TUB2) placed NL1-7 in the clade of C. gloeosporioides sensu stricto and NL1-10 and NL1-13 in the clade of C. siamense. To confirm their pathogenicity, 9 healthy 3-yr-old seedlings, and 10 leaves/seedling were wounded with a sterile needle and inoculated with 10 µL of conidial suspension (106 conidia/mL) of the 3 isolates, respectively. Three control plants were treated with sterile water. Seedlings were covered with plastic bags after inoculation and kept in a greenhouse at 25 ± 2°C and RH 80%. Within 7 days, all inoculated leaves showed lesions similar to those in the field, and controls were asymptomatic. C. gloeosporioides s.s. and C. siamense were reisolated from the infected tissues. It was reported that Colletotrichum species can cause many plant diseases, for example, C. acutatum causes twig canker (Swain et al. 2012), and C. salicis causes willow anthracnose (Okorski et al. 2018), etc. However, some Colletotrichum species are endophytic (Martin et al. 2021) and may only become pathogenic under the right conditions. This is the first report of C. gloeosporioides s.s. and C. siamense causing leaf spots on S. babylonica in the world. These data will help select appropriate strategies for managing this disease and further studies on the pathogen and the host.

Molecular Characterization and Fungicide Sensitivity of Jujube Pathogens Colletotrichum gloeosporioides Sensu Stricto and Colletotrichum nymphaeae in South Korea.

Jujube (Ziziphus jujuba) is cultivated across South Korea because of its medicinal and economic value. It is used as a sweetener in jam, tea, and snacks and a garnish in many cuisines. Anthracnose caused by Colletotrichum spp. accounts for huge economic losses for jujube growers. In 2019 and 2020, severe anthracnose was observed in the jujube-growing areas of South Korea. The infected fruit displayed small, water-soaked, sunken, circular spots. Infected fruit were collected from different commercial orchards of Boeungun and Gyeongsan regions of South Korea, and putative causal agents were isolated on potato dextrose agar. Based on the morphological and molecular characteristics, the fungal isolates were identified as Colletotrichum gloeosporioides sensu stricto and C. nymphaeae. The pathogenicity of these isolates was confirmed by inoculating a conidial suspension (1 × 106 conidia ml-1) on healthy fruit. The in vitro sensitivity of the fungal isolates to tebuconazole, carbendazim, and azoxystrobin was also tested. All isolates showed high sensitivity to azoxystrobin in terms of mycelial growth inhibition (half maximal effective concentration value of 0.01 to 0.6 µg/ml). To the best of our knowledge, this is also the first report of jujube anthracnose caused by C. nymphaeae in South Korea.

Diversity of Colletotrichum Species Causing Apple Bitter Rot and Glomerella Leaf Spot in China.

Bitter rot and Glomerella leaf spot (GLS) of apples, caused by Colletotrichum species, are major diseases of apples around the world. A total of 98 isolates were obtained from apple fruits with bitter rot, and 53 isolates were obtained from leaves with leaf spot in the primary apple production regions in China. These isolates were characterized morphologically, and five gene regions (ITS, ACT, GAPDH, CHS-1 and TUB2) were sequenced for each isolate. A phylogenetic analysis, combined with a comparison of the morphological, cultural and pathogenic characters, sorted bitter rot isolates into six species: C. alienum, C. fructicola, C. gloeosporioides sensu stricto, C. nymphaeae, C. siamense and one new species, C. orientalis Dandan Fu & G.Y. Sun. Among these, C. siamense was the predominant pathogen associated with bitter rot. Isolates from leaf spot were identified as two species, C. aenigma and C. fructicola. This is the first report of C. orientalis as an apple bitter rot pathogen worldwide, and the results provide important insights into the diversity of Colletotrichum species in China.

Identification of Colletotrichum Species Associated with Anthracnose Disease of Strawberry in Sichuan Province, China.

Strawberry anthracnose, caused by Colletotrichum species, is a major fungal disease threatening the strawberry industry in Sichuan Province of southwestern China. However, research on identification of Colletotrichum species associated with strawberry anthracnose in Sichuan remains scarce. In this study, 73 representative Colletotrichum strains were isolated from diseased leaves, stolons, petioles, and crowns of 11 major strawberry-planting localities in Sichuan Province. Based on morphological characteristics and multiloci phylogenetic analysis, the Colletotrichum strains were identified as three distinct species: Colletotrichum fructicola (53 strains, 72.60%), Colletotrichum siamense (17 strains, 23.29%), and Colletotrichum gloeosporioides sensu stricto (3 strains, 4.11%). Among them, C. fructicola was the most ubiquitous and dominant species, whereas C. gloeosporioides sensu stricto was restricted to Chongzhou. Importantly, our pathogenicity tests showed that C. fructicola and C. siamense can infect both leaves and stolons, whereas C. gloeosporioides sensu stricto was only pathogenic to leaves. Interestingly, although the sexual stage of C. siamense was not observed in this study, it still exhibited the strongest virulence to strawberry compared with C. gloeosporioides sensu stricto and C. fructicola. This is the first study to characterize Colletotrichum species causing strawberry anthracnose and evaluate their pathogenicity in Sichuan Province of southwestern China, which will provide a better strategy for accurate diagnosis and management of anthracnose disease in strawberry.

Bitter Rot of Apple in the Mid-Atlantic United States: Causal Species and Evaluation of the Impacts of Regional Weather Patterns and Cultivar Susceptibility.

Apple growers in the Mid-Atlantic region of the United States have been reporting an increase in losses to bitter rot of apple and are requesting up-to-date management recommendations. Management is complicated by variations in apple cultivar susceptibility, temperature, rainfall, and biology of the Colletotrichum spp. that cause bitter rot. Over 500 apple fruit with bitter rot were obtained from 38 orchards across the Mid-Atlantic and the causal species were identified as Colletotrichum fioriniae and C. nymphaeae of the C. acutatum species complex and C. chrysophilum, C. noveboracense, C. siamense, C. fructicola, C. henanense, and C. gloeosporioides sensu stricto of the C. gloeosporioides species complex, the latter two being first reports. Species with faster in vitro growth rates at higher temperatures were more abundant in warmer regions of the Mid-Atlantic, while those with slower growth rates at higher temperatures were more abundant in cooler regions. Regional bloom dates are earlier and weather data show a gradual warming trend that likely influenced but was not necessarily the main cause of the recent increase in bitter rot in the region. A grower survey of apple cultivar susceptibility showed high variation, with the increase in acres planted to the highly susceptible cultivar Honeycrisp broadly corresponding to the increase in reports of bitter rot. These results form a basis for future studies on the biology and ecology of the Colletotrichum spp. responsible, and suggest that integrated bitter rot management must begin with selection of less-susceptible apple cultivars.

Etiology of Cyclocarya paliurus Anthracnose in Jiangsu Province, China.

Cyclocarya paliurus is an extremely valuable and multifunctional tree species whose leaves have traditionally been used in used in medicine or as a medicinal tea in China. In recent years, anthracnose has been frequently observed on young leaves of C. paliurus in several nurseries located in Jiangsu Province, resulting in great yield and quality losses. To date, no information is available about the prevalence of C. paliurus anthracnose in China. The main purpose of the present study was to characterize the etiology of C. paliurus anthracnose. Phylogenetic analysis of the eight-loci concatenated dataset revealed that all 44 single-spore Colletotrichum isolates belonged to three species in the Colletotrichum gloeosporioides species complex, namely, Colletotrichum aenigma, Colletotrichum fructicola, and C. gloeosporioides sensu stricto. Phenotypic features, including the colony appearance and the morphology of conidia, appressoria, and ascospores, were consistent with the phylogenetic grouping. Virulence tests validated that the three Colletotrichum species could cause typical symptoms of anthracnose on C. paliurus leaves, similar to those observed in the field. The optimum mycelial growth temperature ranged from 25 to 30°C for all representative isolates, while C. gloeosporioides s. s. isolates exhibited greater tolerance to high temperature (40°C). Fungicide sensitivity assays indicated that all three Colletotrichum species were sensitive to tetramycin, which may be a potential alternative for the management of C. paliurus anthracnose. To our knowledge, this study provides the first report of C. aenigma, C. fructicola, and C. gloeosporioides s. s. causing C. paliurus anthracnose in China as well as in the world.

Identification and characterization of Colletotrichum gloeosporioides sensu stricto, the agent of anthracnose disease of Sorbaria sorbifolia in China

The pathogen causing Sorbaria sorbifolia anthracnose in Shandong Province, China was identified as Colletotrichum gloeosporioides sensu stricto using morphological and molecular approaches. The daily growth rate was 13.7 mm/d (25 °C); the optimum for growth and conidial germination was 25–30 °C, pH 5.0–9.0.

First Report of Colletotrichum siamense and C. gloeosporioides Causing Anthracnose of Citrus spp. in Mexico.

Citrus anthracnose, caused by Colletotrichum spp., is a major disease in many citrus-growing regions of the world. During the spring of 2019, symptoms of petal necrosis and necrotic lesions on fruits were detected on Mexican lime (Citrus aurantifolia), sweet orange (Citrus sinensis), and grapefruit (Citrus paradisi) trees in three commercial orchards distributed in northern Sinaloa (El Fuerte and Ahome municipalities), Mexico. Colletotrichum-like colonies were consistently isolated on potato dextrose agar (PDA) medium from symptomatic petals and fruits, and 30 monoconidial isolates (10 per orchard) were obtained. Five isolates were selected as representative for morphological characterization, multilocus phylogenetic analysis, and pathogenicity tests. The isolates were designated as FAVF355-FAVF359 and were deposited in the Culture Collection of Phytopathogenic Fungi of the Faculty of Agronomy of El Fuerte Valley at the Autonomous University of Sinaloa (Mexico). Colonies grown on PDA at 25ºC were cottony, dense, with grayish white aerial mycelium and with pink conidial masses. Conidia (n= 100) were cylindrical, hyaline, aseptate, 13.7 to 18.8 × 4.3 to 5.8 μm, with both ends rounded. Based on morphological features, the five isolates were tentatively identified in the Colletotrichum gloeosporioides species complex (Weir et al. 2012). For molecular identification, total DNA was extracted, and the internal transcribed spacer (ITS) region (White et al. 1990), and partial sequences of actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and β-tubulin (TUB2) genes were amplified by PCR (Weir et al. 2012), and sequenced. A phylogenetic tree based on Bayesian inference for species belonging to the C. gloeosporioides species complex was constructed. The multilocus phylogenetic analysis distinguished the isolates FAVF355-FAVF357 as C. gloeosporioides sensu stricto and the isolates FAVF358-FAVF359 as C. siamense. The sequences were deposited in GenBank (accession numbers ITS: MT850050-MT850054; ACT: MT834528-MT834532; GAPDH: MT855979-MT855982; TUB2: MT834533-MT834536). Pathogenicity of the five isolates was verified on healthy fruits of their original host species. Five fruits per isolate were inoculated using the colonized agar plug method. Fruits were wounded with a sterile toothpick and mycelial plugs (5 mm in diameter) removed from the margin of a 6-days-old culture were placed onto three wound sites in each fruit. Non-colonized agar plugs were placed on the wounds of 10 fruits used as the control. The fruits were kept in a moist chamber at 25°C for 8 days. The experiment was repeated twice. All inoculated fruits developed circular and necrotic lesions 6 days after inoculation, whereas the control fruits remained symptomless. The fungi were consistently re-isolated from the diseased fruits and were morphologically identical to that originally inoculated, fulfilling Koch´s postulates. To date, only C. gloeosporioides sensu lato and C. acutatum sensu lato has been associated with sweet orange and Mexican lime in Mexico (Farr and Rossman 2020), whereas C. gloeosporioides sensu stricto has been recently recorded in a different area (Iguala, Guerrero) of Mexico (Cruz-Lagunas et al. 2020). To our knowledge, this is the first report of C. gloeosporioides sensu stricto causing anthracnose on sweet orange, and of C. siamense on Mexican lime in Mexico, as well as C. gloeosporioides s. s. causing disease on grapefruit in Sinaloa, Mexico.

Characterization of the Colletotrichum gloeosporioides species complex causing grape ripe rot in Nagano Prefecture, Japan

Isolates of the Colletotrichum gloeosporioides species complex from grape ripe rot in Nagano Prefecture, Japan in 2016–2017 were identified and their morphology, virulence, and fungicide sensitivity clarified. Based on phylogenetic analysis of the ApMat locus, 80 isolates were identified as belonging to four species, C. perseae (17.5%), C. viniferum (8.8%), C. fructicola (7.5%), and C. gloeosporioides sensu stricto (2.5%) and another species designated Clade V (63.8%). Clade V was the most important pathogen in Nagano Prefecture because of its predominance and high virulence. Colletotrichum perseae and C. fructicola both had a sexual stage and were often found to be resistance to QoI fungicides; they were dominant in the northern region of Nagano Prefecture in 2016. These four species and Clade V can be distinguished by the growth rate of their colonies and morphology of their conidia and ascospores. The results of this study suggest that identification of dominant species in each field is necessary to determine the most suitable fungicide application for disease control.

First Report of Species of Colletotrichum Causing Leaf Spot of Liriodendron chinense × tulipifera in China

First Report of Species of <i>Colletotrichum</i> Causing Leaf Spot of <i>Liriodendron chinense</i> × <i>tulipifera</i> in China

A High-Quality Draft Genome Sequence of Colletotrichum gloeosporioides sensu stricto SMCG1#C, a Causal Agent of Anthracnose on Cunninghamia lanceolata in China.

Colletotrichum has a broad host range and causes major yield losses of crops. The fungus Colletotrichum gloeosporioides is associated with anthracnose on Chinese fir. In this study, we present a high-quality draft genome sequence of C. gloeosporioides sensu stricto SMCG1#C, providing a reference genomic data for further research on anthracnose of Chinese fir and other hosts.

Characterization and Fungicide Sensitivity of Colletotrichum spp. from Different Hosts in Shandong, China.

Anthracnose, caused by Colletotrichum species, can severely infect the fruits and leaves of more than 30 plants and thus results in great yield and quality losses. To identify the major Colletotrichum species infecting walnut fruits, strawberry leaves, grape fruits, and tea leaves in Shandong Province, China, 101 strains were collected and isolated. The morphological characteristics of all isolates were observed, and multilocus phylogenetic analyses (ITS, GAPDH, ACT, TUB2, CAL, CHS-1, and HIS3) were conducted on the representative isolates. The strains were identified as five Colletotrichum species, namely, C. gloeosporioides sensu stricto, C. fructicola, C. camelliae, C. acutatum sensu stricto, and C. viniferum. Among them, C. viniferum was reported for the first time from walnut fruits and strawberry leaves in Shandong Province, China. Corresponding leaves or fruits were used as a model to clarify the pathogenicity of these isolates. The results showed that C. fructicola obtained from strawberry leaves was more aggressive than C. viniferum. All of the isolates obtained from various hosts were highly sensitive to pyraclostrobin, difenoconazole, fludioxonil, tebuconazole, pyrisoxazole, and tetramycin in terms of mycelial growth inhibition (EC50 values of 0.07 to 1.63 mg/liter). The fastest mycelial growth was observed in the temperature range of 25-28°C for all isolates. In addition, anthracnose symptoms occur frequently under these conditions. Overall, this study can improve the understanding of Colletotrichum species causing anthracnose in walnut fruits, strawberry leaves, grape fruits, and tea leaves and can provide a solid foundation for the effective control of this disease in different hosts.

Differentiation of phylogenetic lineages within the ‘Colletotrichum gloeosporioides species complex’ associated with cassava anthracnose disease by PCR-RFLP

Different species were found associated with cassava anthracnose, considered a major disease of this crop. The correct identification of the causal agent is a first step for defining appropriate control strategies, such as resistant varieties. In silico analyses used sequences of six genomic regions of ex-type specimens from the ‘Colletotrichum gloeosporioides species complex’ (C.g.SC) and 21 restriction enzymes to identify phylogenetic lineages. The three best combinations of region/enzymes were validated in 18 Colletotrichum spp. isolates from cassava. Dendrograms for in silico PCR-RFLP for CAL, ITS and TUB2 showed considerable agreement with the phylogenetic analysis of each genomic region; however, the CAL gene presented greater discriminatory power. Since the band patterns from in gel analysis were almost the same as expected for the in silico analysis for the CAL region, a new approach was proposed based on the combined data from these two methodologies, allowing the differentiation of five phylogenetic lineages within the C.g.SC (C. tropicale; C. fructicola; C. siamense; C. gloeosporioides sensu stricto and C. theobromicola), and one outside of this complex (C. cliviae). This evaluation showed to be a reliable technique for preliminary identification of species prior to sequencing.

Why species delimitation matters for fungal ecology: Colletotrichum diversity on wild and cultivated cashew in Brazil

Anthracnose is one of the most important plant diseases globally, occurring on a wide range of cultivated and wild host species. This study aimed to identify the Colletotrichum species associated with cashew anthracnose in Brazil, determine their phylogenetic relationships and geographical distribution, and provide some insight into the factors that may be influencing community composition. Colletotrichum isolates collected from symptomatic leaves, stems, inflorescences, and fruit of cultivated and wild cashew, across four Brazilian biomes, were identified as Colletotrichum chrysophilum, Colletotrichum fragariae, Colletotrichum fructicola, Colletotrichum gloeosporioides sensu stricto, Colletotrichum queenslandicum, Colletotrichum siamense and Colletotrichum tropicale. Colletotrichum siamense was the most dominant species. The greatest species richness was associated with cultivated cashew; leaves harbored more species than the other organs; the Atlantic Forest encompassed more species than the other biomes; and Pernambuco was the most species-rich location. However, accounting for the relative abundance of Colletotrichum species and differences in sample size across strata, the interpretation of which community is most diverse depends on how species are delimited. The present study provides valuable information about the Colletotrichum/cashew pathosystem, sheds light on the causal agents identification,and highlights the impact that species delimitation can have on ecological studies of fungi.

Epidemiology, pathology and identification of Colletotrichum including a novel species associated with avocado (Persea americana) anthracnose in Israel

Anthracnose disease caused by Colletotrichum species is a major constraint for the shelf-life and marketability of avocado fruits. To date, only C. gloeosporioides sensu lato and C. aenigma have been reported as pathogens affecting avocado in Israel. This study was conducted to identify and characterize Colletotrichum species associated with avocado anthracnose and to determine their survival on different host-structures in Israel. The pathogen survived and over-wintered mainly on fresh and dry leaves, as well as fresh twigs in the orchard. A collection of 538 Colletotrichum isolates used in this study was initially characterized based on morphology and banding patterns generated according to arbitrarily primed PCR to assess the genetic diversity of the fungal populations. Thereafter, based on multi-locus phylogenetic analyses involving combinations of ITS, act, ApMat, cal, chs1, gapdh, gs, his3, tub2 gene/markers; eight previously described species (C. aenigma, C. alienum, C. fructicola, C. gloeosporioides sensu stricto, C. karstii, C. nupharicola, C. siamense, C. theobromicola) and a novel species (C. perseae) were identified, as avocado anthracnose pathogens in Israel; and reconfirmed after pathogenicity assays. Colletotrichum perseae sp. nov. and teleomorph of C. aenigma are described along with comprehensive morphological descriptions and illustrations, for the first time in this study.

Colletotrichum gloeosporioides sensu stricto: an endophytic species or citrus pathogen in Brazil?

Postbloom fruit drop (PFD) was first associated with Colletotrichum gloeosporioides until 1990s. Thereafter, the causal agent was reclassified as a species belonging to C. acutatum complex. Recent findings suggested that among the species, within the C. acutatum complex, C. abscissum is the PFD causal agent. Moreover, previous study reported C. abscissum as the most frequent species among isolates of Colletotrichum from blooms showing PFD symptoms. Despite the recent increase in knowledge concern PFD epidemiology, strategies of pathogen survival in citrus leaves remain unclear. Therefore, the aim of this study was to identify the Colletotrichum endophytic species obtained from leaves of sweet orange and weeds from orchards located in Sao Paulo state, Brazil, and to evaluate the ability of these isolates to cause typical PFC symptoms on flowers. Species-specific PCR was used to identify 188 isolates belonging to the C. gloeosporioides complex, which were characterized as C. gloeosporioides sensu stricto based on multilocus sequence analysis. The pathogenicity test indicated that one isolate of C. gloeosporioides sensu stricto, obtained from citrus leaf, was associated with PFD symptoms on inoculated flowers. Lastly, the species associated with PFD may survive on leaf surface, but only C. gloeosporioides sensu stricto is able to colonize endophytically the sweet orange leaves in Brazil.

Identification of Colletotrichum species associated with postbloom fruit drop in Brazil through GAPDH sequencing analysis and multiplex PCR

The genus Colletotrichum comprises a group of important fungal pathogens that can infect a wide variety of host plants worldwide. Postbloom fruit drop (PFD) of citrus plants is responsible for extensive crop losses annually, and is particularly detrimental to Brazilian citrus production. The disease was first associated with Colletotrichum gloeosporioides and subsequently linked to Colletotrichum acutatum. However, a new species, C. abscissum, was described in 2015 as the causative agent of PFD in Brazil. The species description used a small number of strains and the distribution of the pathogen remains unclear. The proportion of PFD caused by this species is also unclear, because both C. abscissum and C. gloeosporioides are associated with the disease as well. By analyzing sequences of the GAPDH intron region, we identified 227 isolates of Colletotrichum associated with PFD in orchards of Sao Paulo state, 172 isolates were identified as C. abscissum and 55 as C. gloeosporioides. Morphological characters and multilocus sequencing confirmed species C. abscissum was the only species in the C. acutatum complex associated with PFD disease in Brazil. Although described as sensitive to benzimidazole-based fungicides, 20% of C. gloeosporioides isolates were found in regions with high use of this class of fungicide. Evaluated strains exhibited resistance to this fungicide in vitro. Because previously described primers differentiate between C. acutatum and C. gloeosporioides complexes, but not the particular species associated with PFD, we proposed and validated primers for a single multiplex PCR that specifically distinguished the C. abscissum and C. gloeosporioides sensu stricto.