Colletotrichum Dematium Research Articles

EFFECT OF EPIPHYTES EXTRACT ON THE PEROXIDASE ACTIVITY IN THE CROP SEEDLINGS CHALLENGED WITH FUNGAL PATHOGENS

Objectives: The objective of the present study to test the angiospermic epiphytes such as Bulbophyllum propinquum and Dendrophthoe falcata for their effect against some pathogenic fungi of sorghum, paddy and chilli, through seed treatment and foliar spray in challenging with the infectivity of the pathogens.
 Methods: The plant extracts were carried out by the Soxhlet extraction method and culture of pathogenic fungi were cultured and maintained in vitro for further use. The peroxidase (POX) enzyme activity in the seedlings was measured spectrophotometrically at 300 nm and expressed as Δ optical density 300 nm/min/mg protein.
 Results: The results of this study indicated 92 and 98% seed germination in the control samples, respectively. In the chilli and paddy which were reduced to 64 and 58% in seedlings inoculated with Colletotrichum dematium, Drechslera oryzae, correspondingly. Similar observation was made in sorghum samples on treatment with Fusarium solani and Fusarium oxysporum, whose germination was drastically reduced to 74 and 69% compared to control (92%). In all the cases, seed treated with epiphytes extracts indicated the stimulated germination over pathogen inoculated samples. In parallel to this, the peroxidase assay also indicated its diminished/reduced activity in pathogen treated seedlings of the selected crop species. Seedlings of epiphytes extract treatment challenged with respective pathogens showed an increased activity over only pathogen treated samples.
 Conclusion: The results clearly indicated the influence of POX in early growing stages of the seedlings corresponds to 12–72 h of incubation in spite of pathogenic activity. Thus, it proved the loss of enzyme activity seedlings on pathogen infection. Contrastingly, POX activity in the seedlings irrespective of the crop species remained high during the early growth stages of the seedlings.

MOLECULAR DETECTION AND CONTROLLING OF SEED-BORNE Colletotrichum spp. IN COMMON BEAN AND SOYBEAN

Seed-borne fungi cause several diseases of common bean (Phaseolus vulgaris L.) and soybean (Glycine max L.). The survey of seed-borne fungi of common bean and soybean was carried out on three Egyptian Governorates (Behera, Dakahlia, and Ismailia) in Egypt. Nineteen fungal species comprising therteen genera were isolated from the collected common bean and soybean seed samples, using standard blotter i,e. Alternaria alternata, Alternaria spp., Aspergillus niger, Aspergillus ochraceous, Aspergillus flavus, Botryodiplodia sp., Cladosporium sp., Colletotrichum lindemuthianum, Colletotrichum dematium, Fusarium solani, Fusarium moniliforme, Fusarum oxysporum, Macrophomina phaseolina, Myrothecium sp., Penicillium spp, Rhizoctonia solani, Stemphylium spp., Trichoderma spp. and Trichothecium sp. Pathogenicity tests proved that C. lindemuthianum and C. dematium were pathogenic to common bean and soybean. Polymerase chain reaction (PCR) has many beneficial characteristics that make it highly applicable for detecting Colletotrichum spp. of seeds. PCR diagnosis method and DNA extraction considered one of the most important steps and purity of DNA template for successful PCR assay. For the PCR amplification of C. lindemuthianum and C. dematium, two primers ClF4 and ClF5, stander blotter, agar plate, and deep freezing method were used as seed healthy testing methods. Stander blotter was proved the past and quickly method to detect seed-born of C. lindemuthianum and C. dematium. Trichoderma harzianum reduced linear growth for C. lindemuthianum and C. dematium followed by Trichoderma viride and Bacillus subtilis recording (3.3 cm and 3.9 cm, respectively) followed by Pseudomonas floursence that display a high linear growth (7.4 cm). On the other hand, fungicide Aetro 30% (Iprodione + Tebuconazole) recorded the least linear growth (0.9 cm) for C. lindemuthianum and C. dematium compared with negative control recorded (9.0 cm in diameter). Thymus plant extract caused the lowest liner growth (3.7 cm). Plant extract concentrations caused a significant reduction in the growth of C. lindemuthianum and C. dematium. The highest concentration (1.5 %) gave less fungal growth while the lowest one (0.5%) showed the highest fungal growth compared with negative control.

Unveiling fungal detoxification pathways of the cruciferous phytoalexin rapalexin A: Sequential L-cysteine conjugation, acetylation and oxidative cyclization mediated by Colletotrichum spp.

The metabolism of the phytoalexin rapalexin A, a unique indole isothiocyanate (ITC) produced by crucifers (family Brassicaceae), was investigated. Three phytopathogenic fungal species were examined: Colletotrichum dematium (Pers.:Fr.) Grove, a broad host range pathogen, C. higginsianum Sacc., a host-selective pathogen of crucifers and C. lentis Damm, a host-selective pathogen of lentils (Lens culinaris Medik.). The metabolism of rapalexin A by C. dematium and C. higginsianum was similar, taking place via one common intermediate and two divergent pathways, but C. lentis was unable to transform rapalexin A. Both C. higginsianum and C. dematium transformed rapalexin A to two previously undescribed metabolites, the structures of which were confirmed by chemical synthesis: N-acetyl-S-(8-methoxy-4H-thiazolo[5,4-b]indol-2-yl)-L-cysteine and 4-hydroxy-3-(4-methoxy-1H-indol-3-yl)-2-thioxothiazolidine-4-carboxylic acid. That is, both fungal pathogens metabolized and detoxified rapalexin A by addition of the thiol group of L-Cys residue to the isothiocyanate carbon of rapalexin A, a transformation usually catalyzed by glutathione transferases. Coincidentally, this metabolic pathway is employed by mammals and insects to detoxify isothiocyanates and other xenobiotics. Hence, C. higginsianum could be a useful model fungus to uncover genes involved in the detoxification pathways of ITCs and related xenobiotics. Our overall results suggest that increasing rapalexin A production in specific crucifers could increase crop resistance to certain fungal pathogens.

Effect of the Storage Period and Fungicide Treatment on the Physiological and Sanitary Quality of Soybean Seeds

This study evaluated the effect of storage period on the physiological and health quality of soybean seeds. The experiment was arranged in a factorial scheme (4 x 2 x 2) with four periods of storage (0, 2, 4 and 6 months), two soybean cultivars (‘BRS Pintado’ and ‘MSOY 8866’) and treated and untreated seeds with the formulated mixture of active ingredients pyraclostrobine (25 g i.a L-1) + Methyl-Thiophanate (225 g i.a L-1) + fipronil (250 g i.a L-1) in a 0,1 L.ha-1 dosage of the commercial product. Concerning health, there was a reduction of Aspergillus spp., Cercospora kikuchii, Colletotrichum dematium var. truncata and Fusarium spp fungus when periods of storage were increased independently if storage interactions occurred due to cultivar, treatment and/or all analyzed factors. cv. ‘BRS Pintado’ stood out by presenting lower results on the occurrence of fungi. The isolated cultivar factor presented a significant result concerning the physiological quality and c.v. ‘BRS Pintado’ showed better results in the variables: germination of seeds from the speed aging test, germination, shoot lenght from the speed emergence test, and both shoot dry matter and root dry matter of germination. There was an interaction for the speed emergence index variable between storage versus cultivar, in which cv. ‘BRS Pintado’ achieved better average results in all periods of storage. The storage factor alone was significant for shoot length of plants from the speed emergence index, the shoot plant dry matter from the emergency speed index, root dry matter of seedling germination and germination of seeds subjected to accelerated aging. The isolated treatment factor was significant in the germination variable and the untreated seeds showed better results in relation to the treated ones. However, the difference of these values would not be significant at the field. Treated seeds showed better results compared to untreated ones in most of the analyzed variables and their association with seeds storage did not affect the physiological quality evaluation during six months of evaluation, enabling the maintenance of the health quality of seeds.

Prevalence of Seed Borne Fungi Associated with Chickpea Seeds and Biological and Chemical Control of Fusarium oxysporum Causing Wilt Disease

A total of 20 chickpea seed samples were collected from BARI, Gazipurand different locations of Savar, Dhaka district. Blotter method was used for detection of the associated fungi of chickpea seeds. Altogether 14 fungi comprising 12 genera namely Aspergillus flavus, Aspergillus niger, Aspergillus sp, Botryodiplodia theobromae, Botryti cinerea, Curvularia lunata, Chaetomium globosum, Cladosporium sp., Colletotrichum dematium, Fusarium oxysporum, Macrophomina phasaelina, Rhizoctonia solani, Rhizopus stolonifer and Stemphylium sarciniforme were isolated from chickpea seed samples. Among the fungi isolated fungi, F. oxysporumwas most prevalent with an average incidence of 18.95% and found in all the seed samples. The germination of seed samples varied from 55-90 % on blotter. The pathogenic fungi and other storage fungi like Aspergillus caused lower the germination of the seeds.A pathogenicity test was conducted with 20 isolates of F. oxysporum against their origin of chickpea seed samples in pot culture. The pathogenecity ranged from weak to highly pathogenic. The isolates FO 19, FO 17, FO 11 and FO 18 were highly virulent. The isolates FO 9, FO10 and FO 15 were virulent and rest of the isolates were moderately virulent. The isolates FO 2 and FO 3 were weak pathogen.J. Environ. Sci. & Natural Resources, 10(2): 45-54 2017

Phenazine and 1-Undecene Producing Pseudomonas chlororaphis subsp. aurantiaca Strain KNU17Pc1 for Growth Promotion and Disease Suppression in Korean Maize Cultivars

In this study, strain KNU17Pc1 was tested for its antifungal activity against Rhizoctonia solani AG-1(IA), which causes banded leaf and sheath blight (BLSB) of maize. KNU17Pc1 was tested further for its broad-spectrum antifungal activity and in vitro plant growth promoting (PGP) traits. In addition, the in vivo effects of KNU17Pc1 on reduction of BLSB severity and seedling growth promotion of two maize cultivars under greenhouse conditions were investigated. On the basis of multilocus sequence analysis (MLSA), KNU17Pc1 was confirmed as P. chlororaphis subsp. aurantiaca. The study revealed that KNU17Pc1 had strong in vitro antifungal activity and was effective toward all in vitro PGP traits except phosphate solubilization. In this study, for the first time, a strain of P. chlororaphis against Colletotrichum dematium, Colletotrichum gloeosporioides, Fusarium oxysporum f.sp. melonis, Fusarium subglutinans and Stemphylium lycopersici has been reported. Further biochemical studies showed that KNU17Pc1 was able to produce both types of phenazine derivatives, PCA and 2-OH-PCA. In addition, solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis identified 13 volatile organic compounds (VOCs) in the TSB culture of KNU17Pc1, 1-undecene being the most abundant volatile. Moreover, for the first time, Octamethylcyclotetrasiloxan (D4), dimethyl disulfide, 2-methyl-1,3-butadiene and 1-undecene were detected in P. chlororaphis. Furthermore, this study reported for the first time the effectiveness of P. chlororaphis to control BLSB of maize. Hence, further studies are necessary to test the effectiveness of KNU17Pc1 under different environmental conditions so that it can be exploited further for biocontrol and plant growth promotion.

Évaluation de l’activité antifongique et de la phytotoxicité de Isoberlinia doka craib & staff

This study has been designed to contribute to search alternative solutions based on plant extracts against phytopatogenic fungi. It aims to test the efficacy of ethanolic extract (70%) of Isoberlinia doka trunk bark on the mycelial growth of eight phytopagenic fungi species and on maize and cowpea seedlings germination and growth. The results showed that the ethanolic extract inhibits mycelial growth. This extract has showed an interesting efficiency on three fungi such as Colletotrichum dematium, Curvularia lunata and Fusarium verticilloides. Among these fungi, Curvularia lunata was the most sensitive with a rate of inhibition of mycelial growth of 52.35% after four days incubation at 10 mg / ml. After seven days incubation, the extract was more effective in reducing Fusarium verticilloides mycelial growth with 50,70% inhibition rate at the same concentration. After the phytotoxicity tests, it was found that this extract had no phytotoxic effect on the germination and growth of maize seedlings while it reduced significantly seed germination and cowpea seedling growth. The ethanolic extract of I. doka bark has antifungal properties and did not inhibited maize growth parameters. It could be used in maize seed treatment. Investigations could also be made into the herbicidal properties of some invasive legumes close to cowpea.

Mycoflora associated with post-harvest disease of papaya (Carica papaya L.) and their pathogenic potentiality

Nineteen species of fungi namely, Alternaria alternata (Fr.) Keissler, Aspergillus flavus Link, A. fumigatus Fresineus, A. niger Van. Tieghhm, Colletotrichum dematium (Pers.) ex. Fr., C. gloeosporioides (Penz.) Sacc., Corynespora citricola M.B. Ellis, Curvularia lunata Wakker, Fusarium flocciferum Corda, F. nivale (Fr.) Ces., Fusarium Link, Lasiodiplodia theobromae (Pat.) Griff & Moubl, Monilia Pers., Mucor Fresen, Penicillium Link, Pestalotiopsis guepinii (Desm.) Stay., Rhizoctonia solani J.G. Kuhn, Rhizopus stolonifer Bull. and Syncephalastrum Schroet were found to be associated with the diseased fruits of Carica papaya L. Among the isolated fungi C. gloeosporioides, F. nivale and Fusarium sp. were found to be pathogenic for both red and yellow cultivar Shahi papaya. Association of C. lunata, F. nivale, P. guepinii and Syncephalastrum sp. with papaya is a new record. The present report is the first record of Corynespora citricola and Fusarium flocciferum from Bangladesh.

Colletotrichum kakivorum sp. nov., a new leaf spot pathogen of persimmon in Korea

In this study, a new species within the genus Colletotrichum was isolated from diseased persimmon leaves collected from Sangju and Cheongdo in the Gyeongbuk province of Korea. The disease was characterized by leaf spots with a brown to gray center surrounded by a black ring with a green halo. Black acervuli with setae and numerous curved conidia were observed on the leaf spots. Phylogenetic analysis based on a combination of multiple loci, including sequences of the internal transcribed spacers, actin, beta-tubulin, chitin synthase-1, and glyceraldehyde-3-phosphate dehydrogenase genes, revealed that the isolates were clearly distinct from other species of the Colletotrichum dematium complex, with the closest species being C. anthrisci. Cultural and morphological characteristics and pathogenicity on persimmon leaves were examined. The isolates differed from C. anthrisci in their cultural and morphological characteristics, such as the conidia and appressoria. Based on molecular phylogenetic, morphological, and cultural characteristics and pathogenicity, this fungus was demonstrated to be a new species, Colletotrichum kakivorum, and the causal agent of a leaf spot disease on persimmon in Korea.

Effectiveness of multi-trait Burkholderia contaminans KNU17BI1 in growth promotion and management of banded leaf and sheath blight in maize seedling

Plant growth promoting (PGP) bacteria enhance plant growth and are a green alternative to chemical fertilizers. In our study, an effective plant growth promoting rhizobacteria (PGPR) strain, KNU17BI1, was isolated from rhizospheric soil of maize, South Korea. The strain was tested in vitro for specific PGP and antifungal traits, such as phosphate solubilization, zinc solubilization, indole acetic acid (IAA) production, ammonia production, nitrogen fixation, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, siderophore hydrogen cyanide production (HCN) and hydrolytic enzyme activity. Furthermore, in viro antifungal activity was done in a laboratory and in vivo effect of KNU17BI1 on banded leaf and sheath blight intensity as well as plant growth promotion on maize seedling were conducted under greenhouse conditions. The strain was found to be highly effective toward all the parameters except HCN production. The strain KNU17BI1 was identified on the basis of 16S RNA and multilocus sequence analysis (MLSA) and confirmed as Burkholderia contaminans. This study for the first time demonstrated potent in vitro antifungal activity of B. contaminans against Rhizoctonia solani AG-1(IA), Pythium graminicola, Fusarium moniliforme, Alternaria alternata, Alternaria solani, Fusarium graminearum, Stemphylium botryosum Wallr, Colletotrichum dematium, Stemphylium lycopersici and Fusarium oxysporum f.sp. melonis. Furthermore, in this study, for the first time, the potential of B. contaminans stain KNU17BI1 in controlling banded leaf and sheath blight of maize caused by R. solani AG-1(IA) was reported. Therefore, further studies are warranted on the structural identification of actual compounds behind such activities that would be exploited further for biocontrol as well as plant growth promotion.

Anti-fungicidal activity of medicinal plants leaf extract to control seed mycoflora of urdbean (Vigna mungo L.)

Urdbean seeds had natural incidence of Aspergillus niger, A. fumigatus, A. flavus, Alternaria alternata, A. longissima, Botrytis cinerea and Colletotrichum dematium. All the medicinal plant leaf extracts reduced the incidence of the seed mycoflora and increased seed germination percentage. Inhibition of seed mycoflora incidence was highest in Allium sativum extracts and the lowest in extracts from Azadirachta indica.

Multi-stress tolerant plant growth promoting Pseudomonas spp. MCC 3145 producing cytostatic and fungicidal pigment

Abstract The plant growth promoting bacterial strain 213B was isolated from rice rhizosphere and identified with phenetic, fatty acid profiling, 16 S ribotyping (NCBI accession no. KF291253) and phylogenetic tree as Pseudomonas spp. The strain demonstrated multiple plant growth promoting traits including phosphate solubilization production of indole-3-acetic acid (IAA), hydrogen cyanide (HCN), ammonia and secreted different bioactive metabolites including phenazine, biosurfactant and siderophore. Mung bean (Vigna radiata) seed coated with the strain had shown enhanced seed germination and plant root length. Besides, the strain exhibited significant tolerance against common agricultural contaminants like salt, metals, herbicide and pesticides. Of the bioactives, strain was able to produce yellow colored phenazine derivatives in Pigment Production Medium D (PPMD) after 96 h at 28 ℃ and 120 rpm. The yellow compound was extracted and purified to obtain needle crystals and further characterized by HPLC, FTIR, LCMS, 1H and 13C NMR, EDAX and XRD analysis as phenazine-1-carboxylic acid (PCA). The purified PCA showed profound fungicidal activity against major phytopathogens including Colletotrichum circinans, Colletotrichum dematium, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia sclerotiorum, while, substantial cytostatic activity (

Identification and Characterization of two new Fungal Pathogens of Polygonatum odoratum (Angular Solomon's seal) in Italy

AbstractPolygonatum odoratum (Mill.) Druce (Angular Solomon's seal) is a well‐known ornamental plant and herbal drug, which is used in traditional medicine. Severe leaf spots were observed in wild Angular Solomon's seal plants in a public park in Trento, Italy. A combination of morphological and molecular characteristics, including sequence data of ITS‐rDNA, large subunit (LSU), beta tubulin (TUB) and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) led to identification of two species, namely Phoma odoratissimi and Colletotrichum dematium s. str., isolated from these leaf spots. Pathogenicity of the isolates was confirmed on wounded leaves of Po. odoratum; indeed, both species induced leaf spot symptoms on inoculated leaves within 10 days of inoculation. This is the first report of leaf spot disease caused by Ph. odoratissimi and C. dematium s. str. on Po. odoratum, which can be considered a new host for both the species examined in this study. In addition, isolation of Ph. odoratissimi represents a new record for the mycobiota of Italy.

Systematic Analysis of the Anticancer Agent Taxol-Producing Capacity in Colletotrichum Species and Use of the Species for Taxol Production

Paclitaxel (taxol) has long been used as a potent anticancer agent for the treatment of many cancers. Ever since the fungal species Taxomyces andreanae was first shown to produce taxol in 1993, many endophytic fungal species have been recognized as taxol accumulators. In this study, we analyzed the taxol-producing capacity of different Colletotrichum spp. to determine the distribution of a taxol biosynthetic gene within this genus. Distribution of the taxadiene synthase (TS) gene, which cyclizes geranylgeranyl diphosphate to produce taxadiene, was analyzed in 12 Colletotrichum spp., of which 8 were found to contain the unique skeletal core structure of paclitaxel. However, distribution of the gene was not limited to closely related species. The production of taxol by Colletotrichum dematium, which causes pepper anthracnose, depended on the method in which the fungus was stored, with the highest production being in samples stored under mineral oil. Based on its distribution among Colletotrichum spp., the TS gene was either integrated into or deleted from the bacterial genome in a species-specific manner. In addition to their taxol-producing capacity, the simple genome structure and easy gene manipulation of these endophytic fungal species make them valuable resources for identifying genes in the taxol biosynthetic pathway.

Germination and seedling emergence responses of common bean and cowpea to plant extract seed treatments

SUMMARYThe present study was initiated to investigate the effect of crude plant extracts as seed treatments onPhaseolus vulgaris(common bean) andVigna unguiculata(cowpea) seed germination and emergence in the presence ofColletotrichum lindemuthianumandColletotrichum dematium,respectively. Common bean and cowpea seeds were treated with crude water and acetone extracts ofAgapanthus caulescensSpreng.,Allium sativumL.,Carica papayaL. andSyzygium cordatumHochst.ex Krauss at 5 and 15 mg/ml concentrations. Seeds treated with the synthetic fungicide fludioxonil+mefenoxam (the commercial product Celest®XL) represented the positive control, whereas dimethyl sulphoxide and water-soaked seeds represented negative controls. The rolled paper towel method of the International Seed Testing Association was used to investigate the effect of the treatments on seed germination. Mean emergence time (MET) was determined using seed inoculated with the respective pathogens. The changes in the ultrastructure of embryonic roots and the connecting tissues of embryo-cotyledon of common bean and cowpea treated withSyzygiumacetone extracts andAgapanthuswater extracts were investigated using transmission electron microscopy (TEM). High germination percentages of >90% were observed in bean seeds from two production seasons treated with low concentrations of water extracts ofAllium, SyzygiumandAgapanthusand acetone extracts ofAllium, AgapanthusandCarica. These treatments also recorded high emergence percentages with low MET values, which were similar to the water control. Cowpea seeds treated withCaricawater extract had the highest germination and emergence.Syzygiumacetone was the only extract that gave higher germination and emergence in both IT93K5132 and PAN 311 varieties. Therefore,Caricawater andSyzygiumacetone extracts can be considered as potential bean and cowpea seed treatments. Generally, there were inconsistencies in terms of correlations of germination with emergence percentages in both cowpea and bean seed treated with plant extracts used in the study, which could be due to differences in vigour. The TEM study of embryo-cotyledon tissue of both species revealed thatSyzygiumandAgapanthusextract seed treatment may accelerate metabolic processes as evidenced by the presence of vacuoles, many cristae and few lipid bodies.

Management of seed borne fungal pathogens of okra collected from seed companies

Effect of mehogoni, mehedi and allamanda extracts were tested to control seed borne fungi of okra seeds collected from 6 companies of notunbazar in Mymensingh district. Prevalence of seed borne fungi was studied by blotter method in the Seed Pathology Center (SPC) and MS Laboratory, Department of Plant Pathology, Bangladesh Agricultural University (BAU), Mymensingh. The highest germination percentage was recorded from ACI seeds (88%), while lowest (70%) in BADC seeds. Six predominant fungal genera were identified. These species were Fusarium oxysporum (5.08%), Aspergillus flavus (4.50%), Aspergillus niger (6.50%), Colletotrichum dematium (4.67%), Rhizopus stolonifer (3.33%) and Penicillium spp. (3.00%). Germination percentage and fungal association varied from company to company. The germination was ranged from 70-95% and infections were recorded 0.80-6.1% in all the treated seeds. Mehogoni extracts at the rate of 1:1 showed best performance in increasing seed germination (96.00%) next to allamanda (70%). Vigour index of okra seeds were increased 19.14% over untreated seeds by the treatment of mehogoni seed extracts at the rate of 1:1. Mehogoniseed extract at the rate of 1:1 seemed to be adoptable at the farmer?s level as an organic management practice.Asian J. Med. Biol. Res. December 2015, 1(3): 628-640

Disease severity and mycoflora associated with anthracnose on leaves of five angiosperms

Severe anthracnose symptom was recorded on the leaves of five angiosperms during September to November, 2010. In total nine species of fungi belonging to four genera of the class deuteromycetes and a sterile fungus were found to be associated with the infected leaves of Abelmoschus esculentus (L.) Moench, Cucurbita maxima Duchesne, Datura metel L., Gossypium hirsutum L. and Vigna sinensis L. The associated fungi were Aspergillus flvaus Link, A. fumigatus Fresenius, A. nidulans (Eidam) G. Winter, A. niger van Tiegh, Cercospora sp., Colletotrichum capsici (Syd.) Butler & Bisby, Colletotrichum dematium (Pers.) Grove, Colletotricum gloeosporioides (Penz.) Penz. and Sacc., Curvularia clavata Jain, and a sterile fungus.Bangladesh J. Sci. Res. 28(2): 103-111, Dec-2015

Isolation, identification and inhibition activity of endophytes in Fengdan

Endophytes were isolated and purified from the roots of medicinal plant Fengdan also known as Paeonia suffruticosa from Tongling region, Anhui province, China. Morphology and molecular biology methods were applied to indentify the endophyte strains. And methods of growth rate and filtering paper were also used for studying antibacterial/antifungal effects of the strains. As a result, 129 endophyte strains were isolated. Fifty-eight endophytic fungi strains were identified as 6 species in 4 genera and the dominant genus was Fusarium. Seventy-one endophytic bacteria strains were identified as 9 species in 3 genera and the dominant genus was Bacillus. Inhibitory diameter with endophytic fermenting liquid of Pseudomonas chlororaphis, F. nematophilum and B. megaterium from P. suffruticosa against Staphyloccocus aureus, Escherichia coli and B. subtilis reached 25.0,20.2,24.0 mm respectively. The inhibition rate of endophytic fermenting liquid from F. nematophilum against Penicillium sp. and Colletotrichum dematium reached 90.6% and 83.3%, respectively. The inhibition effect of P. chlororaphis against F. oxysporum f. sp. niveum and Mucor sp. was good and the antifungal rate reached 80.0% and 84.9%, respectively. P. suffruticosa in Tongling region contains abundant endophytes. P. chlororaphis and F. nematophilum are valuable species as starting strain about microbicide.

Silicon Rich Rice Hull Amended Soil Enhances Anthracnose Resistance in Tomato

Silicon (Si) has proven to be effective in controlling diseases in many crops and can be used as a substitute of fungicides. It has been shown that rice hull could be applied to the soil as a non-hazardous silicon rich source in crop production. This study was conducted to investigate the effect of half burnt rice hull (HBRH) as a silicon source in suppression of anthracnose in tomato and understanding underlying mechanisms of disease resistance. HBRH was made by burning raw rice hull at 250°C for 15minutes. Six different levels of HBRH: 0, 5, 10, 15, 20 and 25g per 1kg of soil were incorporated into soil along with Department of Agriculture (DOA) recommended levels of NPK fertilizers. The resistance against anthracnose disease was evaluated by measuring the lesion area of tomato fruits followed by the challenged inoculation with Colletotrichum dematium for 10 days after inoculation. The mechanism behind Si induced resistance was studied by measuring the fruit firmness and cuticle thickness (CT). A significant reduction (at P ≤ 0.05) of anthracnose disease (87 and 77%) was observed in inoculated fruits of 25 and 20g HBRH per 1kg of soil treatments. Onset of the disease was delayed by 4 and 3 days after inoculation in fruits obtained from 25 and 20g HBRH treated plants compared to the control. The increase of fruit firmness and CT were significant in 25 and 20g HBRH per 1kg of soil provided fruits. Consequently, these results suggest that HBRH is a Si rich source and 20g HBRH per 1kg soil would be sufficient in suppressing tomato anthracnose caused by C. dematium and the resistance might have triggered with silicon induced thicken cuticle and increased fruit firmness.

Mycoflora of Cotton Plant (Gossypium hirsutum L.) - with three New Records of Deuteromycetes from Bangladesh

Fungal diseases of cotton plant (Gossypium hirsutum L.) were studied during July, 2011 to June, 2012. Eleven cotton varieties were selected for the experiment. Alternaria alternata (Fr.) Keissler, Aspergillus niger van Tiegh, Colletotrichum gossypii Sowthworth, Colletotrichum dematium (Pers.) Grove, Curvularia clavata Jain, Fusarium sp., Gleotrichum sp., Hyalopycnis sp., Pestalotiopsis guepinii (Desm.) Stay, and a sterile fungus were isolated from infected leaves of cotton varieties CB6 and CB11. Colletotrichum gossypii was isolated from both the varieties and C. dematium was exclusively isolated from CB6. Varieties CB6 and CB11 were more susceptible than other varieties. Cotton varieties CB1, CB2, and CB3 showed negligible infection on leaves and bolls. Colletotrichum gossypii and Hyalopycnis sp. are new record for Bangladesh. Moreover, association of C. dematium, Gleotrichum sp., P. guepinii and Hyalopycnis sp. with cotton is being reported first time. The three fungi Colletotrichum. gossypii, C. dematium and Hyalopycnis sp. are described and illustrated in this account as new Deuteromycetous records for Bangladesh.Journal of Bangladesh Academy of Sciences, Vol. 39, No. 2, 213-221, 2015