Fig 1 - uploaded by Irum Mukhtar
Content may be subject to copyright.
a, Aloe field infected with leaf spot disease caused by Alternaria alternata. b, Leaf spots symptoms on aloe leaves. c, Infected leaves of Aloe vera. d, Conidia of Alternaria alternata at 40×.
Source publication
A leaf spot disease was observed on Aloe vera plants as small, circular to oval dark brown necrotic sunken spots on the leaves. Infected tissues collected from different sites in diseased fields were cultured on malt extract agar medium, and the pathogen was identified as Alternaria alternata on the basis of morphological and cultural characteristi...
Contexts in source publication
Context 1
... leaf spot disease affected a significant number of plants and caused heavy losses (Fig. 1a). Small, circular to oval, necrotic and sunken dark brown spots on the leaf, ranging from less than 1.0 mm to an average diameter of 3.0 mm were typical symptoms of disease (Fig. 1b). Characteristic leaf spots had grey centres with brown margins. In later stages of infection, the affected leaves started yellowing and dried from the tip ...
Context 2
... leaf spot disease affected a significant number of plants and caused heavy losses (Fig. 1a). Small, circular to oval, necrotic and sunken dark brown spots on the leaf, ranging from less than 1.0 mm to an average diameter of 3.0 mm were typical symptoms of disease (Fig. 1b). Characteristic leaf spots had grey centres with brown margins. In later stages of infection, the affected leaves started yellowing and dried from the tip downwards with loss of leaf texture and mucilaginous jelly (Fig. 1c). The same pathogen was isolated from all infected samples and no other pathogenic fungus was isolated from the ...
Context 3
... brown spots on the leaf, ranging from less than 1.0 mm to an average diameter of 3.0 mm were typical symptoms of disease (Fig. 1b). Characteristic leaf spots had grey centres with brown margins. In later stages of infection, the affected leaves started yellowing and dried from the tip downwards with loss of leaf texture and mucilaginous jelly (Fig. 1c). The same pathogen was isolated from all infected samples and no other pathogenic fungus was isolated from the leaf spots. The fungus grew well on 2% MEA, and formed an effuse, olivaceous black colony with dark olive green margins, reverse black and of about 9 cm in diameter at 25 ± 2 °C in six days. The fungus produced abundant ...
Context 4
... singly, simple, straight, golden brown, smooth up to 60 μm long, 3 μm thick with one conidial scar. Conidia formed in long and branched chains, obpyriform, golden brown, smooth with up to eight transverse septa with three to four longitudinal septa, overall length 20-48 μm, 8-10 μm thick in the broadest part with pale short beak up to 3 μm thick (Fig. 1d). The isolated fungus was identified as Alternaria alternata (Fr.) Keissler based on symptoms on aloe and morphological and cultural characteristics (Ellis, 1971;Shakir et al., ...
Citations
... The pathogenicity of this fungus was established on Chinese cabbage and other cruciferous crops by other workers [20,21] also and their findings support the pathogenic nature of the fungus as observed in the present case. (i) The symptoms of the disease under investigation are described on leaves, stems and pods under natural field conditions. ...
Chinese cabbage (Brassica chinensis L.) is an important leafy vegetable crop. It has good nutritional and medicinal value. Among all diseases affecting the plant, Alternaria leaf spot is a serious disease hampering its successful cultivation. Keeping in view this serious implication, an experiment on Alternaria leaf spot of Chinese cabbage caused by Alternaria brassicae, A. brassicicola and A. alternata was carried out at Main Experimental Station, Vegetable of ANDUA&T, Kumarganj Ayodhya for studying a means to effectively manage the disease. The disease was first appeared in the first week of November as small, yellow to brown spots with a light green to yellow halo. As the disease advances, several lesions coalesced, giving a blighted appearance. Stem and pods were also affected by the disease. The pathogen was readily isolated on 2% Potato Dextrose Agar medium and pathogenicity was proved following Koch's postulates. Cultural and morphological characters were observed as colonies of pure black amphigenous, effused, radial growth, conidia light brown to black in colour. The size of the conidia of A. brassicae, A. brassicicola and A. alternata were found 110.16 -162.0 µm, 94.08 – 120.72 µm and 25.44 - 46.32 µm, having septal variation 5-11, 0-8 and 2-6, respectively.
... To confirm Koch's postulates, the pathogenicity of the representative strain C. aenigma BY827 was tested on healthy leaves of A. japonica. Firstly, inoculation was performed in a laminar flow workstation (Haier, Qingdao, China) using sterilized needles to perform pathogen inoculation on healthy A. japonica detached leaves (n = 9; Bajwa et al., 2010). Then, strain C. aenigma BY827 plugs (d = 5 mm) were inoculated onto the leaves, obtained from active growing C. aenigma BY827 colonies that were 7 days old. ...
Aucuba japonica Thunb is an evergreen woody ornamental plant with significant economic and ecological values. It also produces aucubin, showing a variety of biological activities. It is widely planted in the southwest region of China, including karst landscape areas in Guizhou Province. In January 2022, a serious leaf blight disease was observed on the leaves of A. japonica in the outdoor gardens of Guizhou University, Guiyang, Guizhou, China. The causal agent was identified as Colletotrichum aenigma through amplification and sequencing of the internal transcribed spacer (ITS) region, translation of the chitin synthase ( CHS ) and actin ( ACT ) genes, and morphological characterizations. Koch’s postulates were confirmed by its pathogenicity on healthy leaves, including re-isolation and identification. To our knowledge, this is the first report of C. aenigma causing leaf blight on A. japonica worldwide. To identify pathogen characteristics that could be utilized for future disease management, the effects of temperature and light on mycelial growth, conidia production, and conidial germination, and the effects of humidity on conidial germination were studied. Optimal temperatures for mycelial growth of C. aenigma BY827 were 25–30°C, while 15°C and 35°C were favorable for conidia production. Concurrently, alternating 10-h light and 14-h dark, proved to be beneficial for mycelial growth and conidial germination. Additionally, conidial germination was enhanced at 90% humidity. In vitro screenings of ten chemical pesticides to assess their efficacy in suppressing C. aenigma representative strain BY827. Among them, difenoconazole showed the best inhibition rate, with an EC 50 (concentration for 50% of maximal effect) value of 0.0148 μg/ml. Subsequently, field experiment results showed that difenoconazole had the highest control efficiency on A. japonica leaf blight (the decreasing rate of disease incidence and decreasing rate of disease index were 44.60 and 47.75%, respectively). Interestingly, we discovered that C. aenigma BY827 may develop resistance to mancozeb, which is not reported yet among Colletotrichum spp. strains. In conclusion, our study provided new insights into the causal agent of A. japonica leaf blight, and the effective fungicides evaluated provided an important basis and potential resource for the sustainable control of A. japonica leaf blight caused by C. aenigma in the field.
... F. humuli has frequently been isolated only from leaves of different plants as endophytes [26,28], and C. aenigma was reported from Achyranthes aspera plants as endophytes in India [29]. A. alternata is one of the Alternaria species that is widely recognized to be an endophyte and pathogen in various plants [30]. The fungus has been reported as a pathogen in Aloe vera and Pyrus sikiangensis [31,32], indicating its extreme host diversity. In Vitex rotundifolia, A. alternata was reported as an endophyte [27], but we identified it as a pathogen in this study, indicating that A. alternata can be an opportunistic pathogen. ...
The beach vitex (Vitex rotundifolia L.), a member of the Lamiaceae family, is a salt-tolerant, woody perennial common in coastal areas worldwide. Plant–fungal association was monitored in the shoreline forest area of Wando Island in Korea in 2020, and leaf samples showing leaf spot disease were collected. Eight fungal isolates were recovered from the samples on PDA and identified based on the morphological characteristics and multilocus molecular phylogeny. Among the eight isolates, four were identified as Alternaria alternata, two as Fusarium humuli, one as Colletotrichum aenigma, and one as Stagonosporopsis caricae. Pathogenicity tests of the fungal isolates on the detached leaves of beach vitex revealed that S. caricae CMML20–2 and A. alternata (CMML20–7, CMML20–8, CMML20–9, and CMML20–10) caused disease lesions while the other species did not. The fungal species S. caricae, C. aenigma, and F. humuli are the first reported in the host worldwide, and S. caricae and F. humuli are first reported in Korea. In vitro fungicide sensitivity assays were carried out based on a measurement of diametrical mycelial growth on media amended with different doses of the fungicides fludioxonil, metconazole, and fluxapyroxad. Fungicide sensitivity varied significantly among the species, and the A. alternata and S. caricae isolates were more sensitive to fluxapyroxad than the other isolates. Our study contributes to the understanding of fungal diversity in forest mycology and demonstrates that pathogenic fungi including A. alternata and S. caricae might accelerate decline in leaf health.
... Alternaria spp. can cause essential diseases in cereals, ornamental plants, vegetables, and fruits, and more than 95% of the species reported globally can become facultative parasites on different plants [17][18][19][20]. A recent study revealed that six Alternaria species are the causal agents of pear black spot diseases, resulting in massive economic losses in China [20]. 2 of 21 To date, members of the genus Alternaria have been found to harbor several mycoviruses. ...
Alternaria fungus can cause notable diseases in cereals, ornamental plants, vegetables, and fruits around the world. To date, an increasing number of mycoviruses have been accurately and successfully identified in this fungus. In this study, we discovered mycoviruses from 78 strains in 6 species of the genus Alternaria, which were collected from 10 pear production areas using high-throughput sequencing technology. Using the total RNA-seq, we detected the RNA-dependent RNA polymerase of 19 potential viruses and the coat protein of two potential viruses. We successfully confirmed these viruses using reverse transcription polymerase chain reaction with RNA as the template. We identified 12 mycoviruses that were positive-sense single-stranded RNA (+ssRNA) viruses, 5 double-strand RNA (dsRNA) viruses, and 4 negative single-stranded RNA (−ssRNA) viruses. In these viruses, five +ssRNA and four −ssRNA viruses were novel mycoviruses classified into diverse the families Botourmiaviridae, Deltaflexivirus, Mymonaviridea, and Discoviridae. We identified a novel −ssRNA mycovirus isolated from an A. tenuissima strain HB-15 as Alternaria tenuissima negative-stranded RNA virus 2 (AtNSRV2). Additionally, we characterized a novel +ssRNA mycovirus isolated from an A. tenuissima strain SC-8 as Alternaria tenuissima deltaflexivirus 1 (AtDFV1). According to phylogenetic and sequence analyses, we determined that AtNSRV2 was related to the viruses of the genus Sclerotimonavirus in the family Mymonaviridae. We also found that AtDFV1 was related to the virus family Deltaflexivirus. This study is the first to use total RNA sequencing to characterize viruses in Alternaria spp. These results expand the number of Alternaria viruses and demonstrate the diversity of these mycoviruses.
... The fungi of both genera are plant pathogens and are commonly found on the grain surface and in soil and plant tissues [33,34], causing diseases in several plant species and capable of reducing the quality and quantity of plant production worldwide [35][36][37]. Fusarium species have been reported to co-infect with some pathogenic fungi; for instance, F. circinatum and Phytophthora spp. cause pine pitch canker disease on Pinus radiate [38]. ...
Dirty panicle disease in coconuts (Cocos nucifera) was first observed in the KU-BEDO Coconut BioBank, Nakhon Pathom province, Thailand. The occurrence of the disease covers more than 30% of the total coconut plantation area. The symptoms include small brown to dark brown spots and discoloration of male flowers. Herein, three fungal strains were isolated from infected samples. Based on the morphological characteristics the fungal isolates, they were classified into two genera, namely, Alternaria (Al01) and Fusarium (FUO01 and FUP01). DNA sequences of internal transcribed spacer (ITS), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), translation elongation factor 1-α (tef1-α), and RNA polymerase II second largest subunit (rpb2) revealed Al01 as Alternaria burnsii, whereas DNA sequences of ITS, rpb2, and tef1-α identified FUO01 and FUP01 as Fusarium clavum and F. tricinctum, respectively. A pathogenicity test by the agar plug method demonstrated that these pathogens cause dirty panicle disease similar to that observed in natural infections. To the best of our knowledge, this is the first report on the novel dirty panicle disease in coconuts in Thailand or elsewhere, demonstrating that it is associated with the plant pathogenic fungi A. burnsii, F. clavum, and F. tricinctum.
... In Pakistan, different plant species like Mango (Mohsan et al., 2011), Tomato (Akhtar et al., 2004) and Aloe vera (Bajwa et al., 2010) are affected by common disease caused bya black spot of Alternaria. Major plant pathogens are Alternaria species cause 20% losses and most serve the losses reach up to 80%. ...
A survey of diseased fields of total (35) areas located in four different Districts of Khyber Pakhtun Khwa like Buner (4 areas), Swabi (23 areas) Mardan (3 areas) and Haripur (5areas) was carried out for estimation of losses and identification of root disease causing pathogens in 14 different economically important crops like Tobacco (Nicotiana tabacum), Ladyfinger (Abelmoscus esculentus), Chilli (Capsicum anuum), Eggplant (Solanum melongena), Maize (Zea mays), Tomato (Solanum lycopersicum), Wheat (Triticum estivum), Garlic (Allium sativum), Mustard (Brassica compestres), Clover (Trifolium repens), Onion (Allium cepa), Turnip (Brassica rapa), Radish (Raphanus sativus) and Pea (Pisum sativum). The most common root rot pathogens found in all the areas visited were Alternaria alternate, A.solani, Rhizoctonia solani Macrophomina phaseolina and species of Fusarium viz., Fusarium solani and F.oxysporum. Two species of root-knot nematode Meloidogyne javanica and M. incognita were also found causing root-knot disease. The eggplant was found upto 20-76% losses when an infection caused by the combined effect of F. oxysporum, M.phaseolina. R. solani and root-knot nematodes. Similarly, the loss of chiliplants was found 40-65% due to the combined effect of F. solani, M.phaseolina, R. solani, and root-knot nematodes. Zea mays crops were reported 50-77% losses due to Drecslera spp, F.solani, and A. solani Losses recorded by these root-rot and root-knot pathogens were found variable depending upon a combination of pathogens, temperature and soil types.
... Agave americana extract [8]; leaves of Cistus ladanifer extract [9]; Aloe Vera extract [10,11]; Henna [12]; Oxandra asbecki [13]; Musa paradisica peel [14]; Azadirachta indica [15]; Mentha pulegium [16]; Damsissa [17]; Ananas comosus [18]; Lasianthera africana [19]; Carica papaya [20]; Justicia gendarussa [21]; fruit barks [22]; Ferula assa-foetida and Dorema ammoniacum [23]; Ephedra sarcocarpa [24]; Calligonum comosum [25]; Salvia officinalis [26]; Armoracia rusticana [27]; Myristica fragrans [28]; Cuscuta reflexa [29]; and the extract of Sida cordifolia [30]. ...
In the dental office, surgical instruments must be sterilized for each patient, following their contamination by saliva and blood. Repeated sterilization cycles cause corrosion. A worn out and corroded instrument may cause toxicity to the patient. The aim of our study is to improve the corrosion resistance of orthodontic pliers during sterilization using green inhibitors. The behaviour of AISI 410 stainless steel with respect to corrosion was studied in a \(0.5~\hbox {M H}_{{2}}\hbox {SO}_{{4}}\), using cladodes of Opuntia ficus-indica (OFI) as a green inhibitor. Temperature effect on OFI efficacy was studied for different ranges (25, 35 and \(45^{\circ } \hbox {C}\)). The study was carried out using the weight loss method, the stationary electrochemical techniques (polarization curves), the transients (electrochemical impedance spectroscopy), and the scanning electron microscopy associated with X-ray dispersive energy spectroscopy (SEM–EDX) and atomic force microscopy (AFM) observations. OFI behaves as a mixed inhibitor, with a physisorbed adsorption obeying to Langmuir isotherm and, with an efficacy ranging from 95.12 to 15% (v/v) obtained after 12 h immersion at a temperature of \(25^{\circ } \hbox {C}\). The SEM–EDX and AFM observations confirm the obtained results. In conclusion, OFI improves corrosion resistance of AISI 410 stainless steels in \(0.5~\hbox {M H}_{{2}}\hbox {SO}_{{4}}\) at \(25^{\circ } \hbox {C}\).
... Mycotoxins are hazardous to human and animal health, which can cause cancer, hemorrhage, edema and immune deficiency (Makun et al, 2010) [16] .7 Aloe vera is susceptible to various pathogenic microorganisms, which causes quality loss and reduce the production of economic part of the plant. Leaf spot of Aloe caused by the genus Alternaria have been reported in different parts of the world; namely-leaf spot of A. barbadensis by Alternaria alternata in India (Chavan and Korekar, 2011) [8] , in Lousinia, USA (Silva and Singh, 2012) [24] , in Pakistan (Bajwa et al, 2010) [24] . In Bangladesh, Shamsi and Shutrodhar (2013) [23] recorded Alternaria pluriseptata as associated fungal pathogen on Aloe vera leaf. ...
An experiment was conducted to find out fungal pathogen associated with leaf samples of Aloe vera obtained from commercial fields of Northern part of Bangladesh. Leaf spot disease causing fungus-Alternaria alternata was identified through morphological characterization based on mycelium, conidia, colony features as well as molecular characterization using internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) of fungi. Molecular identification revealed that ITS sequences of our studied fungus (MH368103.1) was genetically similar to sequences of Alternaria alternata in NCBI database. Typical leaf spot was reproduced by artificial inoculations of the isolated fungus. The mycelial growth of this fungus was evaluated on different culture media i.e., potato dextrose agar (PDA), carrot agar (CA), potato sucrose agar (PSA), Richard agar (RA), Honey peptone agar (HPA), Honey agar (HA); temperature (15, 20, 25, 30, 35⁰C) and light condition (complete light, complete dark, alternate light-dark). A. alternata showed the maximum mycelial growth on PDA at 25⁰C temperature. Both complete dark and alternate light-dark condition were mostly favored for profuse vegetative growth of the fungus. Fungal antagonist-Trichoderma reesei showed very promising results, which inhibited the mycelial growth under in vitro condition. Systemic fungicide Tilt 250EC (500ppm) showed complete inhibition of the vegetative growth of the studied fungus. To the best of our knowledge, Alternaria alternata causing Aloe vera leaf spot disease in Bangladesh, a new record.
... eupyrena, Polyrostrata indica, Pythium aphanidermatum, Helminthosporium sp., and Phomopsis sp.,were isolated from different parts of A. vera. Previously, Alternaria alternata has also been reported as a main leaf spot pathogen of A. vera which damage 30-40% crop and also altered the properties of plant [30][31][32][33]. Cedeno et al., [34] and Avasthi et al., [35] have isolated Colletotrichum gloeosporioides from A. vera leaves causing anthracnose disease. ...
The survey was conducted to record the disease incidence, severity and frequency of occurrence of fungal pathogens on Aloe vera in sixteen nurseries and two botanical gardens of Gwalior during winter and rainy season of 2013 & 2014. The present survey revealed that disease incidence was found significantly higher in winter season as compared to rainy season. Four different fungal diseases namely leaf spot, leaf rot, collar and root rot were found associated with the A. vera plants. Amongst all, leaf spot was found as dominant fungal disease with maximum 50.99% and 53.35% incidence in winter season and 32.49% and 31.42% in rainy season during the years 2013 & 2014, respectively. Total fifteen fungal species i.e. Alternaria alternata, Colletotrichum gloeosporioides, Cladosporium sphaerospermum, Curvularia ovoidea, C. lunata, Fusarium fusaroides, F. proliferatum, F. solani, Penicillium purpurogenum, Phoma eupyrena, P. betae, Polyrostrata indica, Pythium aphanidermatum, and species of Helminthosporium and Phomopsis were isolated from different parts of A. vera. In winter seasons, Alternaria alternata and Fusarium proliferatum were recorded as a prominent fungal species causing various diseases in plants. While, Colletotrichum gloeosporioides was isolated as a most prevalent fungal species from the leaves of A. vera during the rainy seasons. The association of these fungal species may not only diminish the plant growth but, also have the potential to alter the efficacy of phytochemicals which eventually nullify the quality and quantity of gel.
... Our results were in accordance to Rao (1965) and Nadziakiewicz et al. (2012) but in contradiction to Abbas et al (2017). In Pakistan, leaf spot is one of the major diseases of most economically important crops such as broccoli, ber, potato, tomato, okra, Aloe vera (Bajwa et al., 2010;Arain et al., 2012;Shahid et al., 2017;Mehmood et al., 2018;Javaid et al., 2018). Different control practices; cultural, biological, and chemical have been used previously for the effective management of this disease. ...
Rosa indica L. (family: Rosaceae) is an important and widely grown plant in the floriculture industry. Alternaria leaf spot disease of rose was observed in rose plantation at College of Agriculture, University of Sargodha, Sargodha. The study was carried out to isolate and purify the pathogen, which was identified as Alternaria alternata. Additionally, in vitro efficacy of five fungicides; success, copper oxychloride, metalaxyl+mancozeb, topsin M and kumulus against A. alternata were tested by using food poisoning technique. Three concentrations (100, 200 and 300 ppm) of each fungicide were used. Mycelial growth after 3rd, 5th and 7th day was measured. All the fungicides significantly inhibited the mycelial growth of A. alternata. Among those, metalaxyl+mancozeb was the most effective as compared to others. Maximum inhibition was observed after 3rd (89%), 5th (91.6%) and 7th (93.3) day by metalaxyl+mancozeb followed by success 43.3%, 41.0% and 29.6% respectively. After 3rd and 5th day copper oxychloride was least effective with 19.6% and 9.6% mycelial inhibition respectively while after 7th day the minimum 4.3% mycelial inhibition was observed by topsin M instead of copper oxychloride. Therefore, A. alternata is responsible for alternaria leaf spot disease of rose and metalaxyl+mancozeb was found to be the most effective fungicide against A.alternata in vitro.
