Agent Of Rot Diseases Research Articles

First report of fruit rot disease agent, Colletotrichum fioriniae, on Olea europea cv. Gemlik in Turkey

First report of fruit rot disease agent, Colletotrichum fioriniae, on Olea europea cv. Gemlik in Turkey

Determination of chemical compositions of rosemary and sweet marjoram essential oils and their blends and their antifungal potential against potato rubbery rot disease agent Geotrichum candidum

AbstractIn this study, the chemical compositions of rosemary (Rosmarinus officinalis Spenn.) and sweet marjoram (Origanum majorana L.) essential oils, both individually and in various blend ratios, were investigated by using Gas Chromatography-Mass Spectrometry. Their antifungal activities were also determined against the potato rubbery rot disease agent, Geotrichum candidum, under in vitro and in vivo conditions. Camphor (20.69%) and terpinen-4-ol (35.13%) were determined as primary constituents in rosemary and sweet marjoram essential oils, respectively. Sweet marjoram and rosemary essential oils completely inhibited mycelial growth of G. candidum at 55.0 and 65.0 µL/Petri concentrations, respectively. Essential oils at these concentrations were found as fungicidal. Notably, a synergistic fungicidal antifungal effects were also observed in essential oil blends. Blend of sweet marjoram and rosemary essential oil in a 3:1 ratio (O75R25) significantly enhanced antifungal activity at the relatively lower concentration (45.0 µL/Petri). Microscopic observations revealed structural deformations in exposed hyphae, including cytoplasmic coagulation and vacuolization. Essential oil blend (O75R25), sweet marjoram and rosemary essential oils completely inhibited the disease lesion caused by G. candidum on potato tubers at concentrations of 100.0, 125.0, and 150.0 µL/L air, respectively. These findings emphasized that essential oil blends of rosemary and sweet marjoram have synergistic antifungal potential and can be used as effective biofungicides against plant fungal diseases.

Determination of the Antifungal Effect of Boron, Sodium and Potassium Salts against Pomegranate Fruit and Crown Rot Disease Agent Coniella granati

Determination of the Antifungal Effect of Boron, Sodium and Potassium Salts against Pomegranate Fruit and Crown Rot Disease Agent Coniella granati

Isolation of endophytic bacterial isolates from healthy banana trees and determination of their in vitro antagonistic activities against crown rot disease agent Fusarium verticillioides

Aims: Fungal diseases are one of the most important biotic factors causing serious losses in banana cultivation in field or greenhouses during cultivation, harvest, storage and transportation periods. Crown rot, caused by Fusarium verticillioides, is considered one of the most important postharvest fungal disease of banana fruits. In this study, endophytic bacterial isolates were obtained from fruits, branches and leaves of healthy banana trees and their antagonistic potentials were investigated against F. verticillioides as a biological control agent (BCA) in vitro conditions.Methods and Results: A total of 23 putative endophytic bacterial isolates were obtained from fruits, stems and leaves of healthy banana trees. All bacterial isolates were identified by MALDI-TOF MS (Matrix Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometry) analysis. In vitro antagonistic efficiencies of 12 different bacterial isolates, from eight different species (Bacillus subtilis ssp. spizizenii (3), Bacillus amyloliquefaciens (2), Bacillus subtilis ssp. subtilis (2), Bacillus mojavensis, Enterococcus faecium, Enterobacter cloacae, Enterobacter ludwigii and Pseudomonas stutzeri), were tested on inhibiting mycelial growth by using dual culture tests. Among bacterial isolates, the highest antagonistic activity was displayed by Bacillus mojavensis BEn3 isolate which significantly inhibited the mycelial growth by 50.83%. Enterobacter cloacae BEn1, Enterobacter ludwigii BEn2, Enterobacter faecium BEn7, however, failed to inhibit the mycelial growth of fungi.Conclusions: Significant suppression in the mycelial growth caused by endophytic bacterial isolates indicates that Bacillus mojavensis BEn3 isolate could be considered as possible BCA against crown rot disease agent.Significance and Impact of the Study: Our findings suggest that B. mojavensis Ben3, as the most successful endophyte bacterial isolate that suppresses the growth of F. verticillioides, can be used as a promising biological control agent as an alternative to chemical control against crown rot disease.

Pathogenic Interactions between Macrophomina phaseolina and Magnaporthiopsis maydis in Mutually Infected Cotton Sprouts

The soil fungus Macrophomina phaseolina, the charcoal rot disease agent, poses a major threat to cotton fields. In Israel, highly infected areas are also inhabited by the maize pathogen Magnaporthiopsis maydis. This study reveals the relationships between the two pathogens and their impact on cotton sprouts. Infecting the soil 14 days before sowing (DBS) with each pathogen or with M. phaseolina before M. maydis caused a strong inhibition (up to 50–65%) of the sprouts’ development and survival, accompanied by each pathogen’s high DNA levels in the plants. However, combined or sequence infection with M. maydis first led to two distinct scenarios. This pathogen acted as a beneficial protective endophyte in one experiment, leading to significantly high emergence and growth indices of the plants and a ca. 10-fold reduction in M. phaseolina DNA in the sprouts’ roots. In contrast, M. maydis showed strong virulence potential (with 43–69% growth and survival suppression) in the other experiment, proving its true nature as an opportunist. Interestingly, soil inoculation with M. phaseolina first, 14 DBS (but not at sowing), shielded the plants from M. maydis’ devastating impact. The results suggest that the two pathogens restrict each other, and this equilibrium may lead to a moderate disease burst.

First report of soft rot of cabbage caused by Pectobacterium wasabiae in Japan.

Cabbage (Brassica oleracea var. capitata) is one of the important vegetables in Japan. In the summer of 2019, some cabbages with soft rot were found in commercial fields in Hokkaido, the northern island in Japan. All diseased plants showed grey to brown discoloration and expanding water-soaked lesions on leaves. We obtained two independent strains (NACAB191 and NACAB192) from diseased leaves. DNA from these strains yielded an expected single size amplicon with the primer set of PhF/PhR for P. wasabiae (De Boer et al. 2012) by PCR, but did not yield the expected amplicon with the primer set of BR1f/L1r for P. carotovorum subsp. brasiliense (Duarte et al. 2004) and Eca1f/Eca2r for P. atrosepticum (De Boer et al., 1995) by PCR. These two strains grew at 37°C, and their ability to utilize raffinose and lactose. These bacterial strains were gram-negative and rod-shaped. The bacterium was positive for O-nitrophenyl-beta-D-galactopyranoside, N-acetylglucosaminyl transferase, gelatin liquefaction, and acid production from D-galactose, lactose, melibiose, raffinose, citrate, and trehalose. The bacterium was negative for indole production and acid production from maltose, α-methyl-D-glucoside, sorbitol, D-arabitol, inositol, inulin, and melezitose. All strains exhibited pectolytic activity on potato slices. The sequence analysis of 16S rDNA (LC597897 and LC597898) showed more than 98% identities to P. wasabiae strain (e.g. HAFL01 in Switzerland) by BLAST analysis. In addition, Multi-locus sequence analysis (Ma et al. 2007) was performed by MEGA10 (Kumer et al. 2018) using concatenated DNA sequences of seven housekeeping genes (aconitate hydratase(acnA, LC597923 and LC597924), glyceraldehyde-3-phosphate dehydrogenase A(gapA, LC597970 and LC597971), isocitrate dehydrogenase (icdA, LC597996 and LC597997), malate dehydrogenase(mdh, LC598022 and LC598023), mannitol-1-phosphate dehydrogenase (mtlD, LC598048 and LC598049), glucose-6-phosphate isomerase (pgi, LC598074 and LC598075) and gamma-glutamyl phospate reductase (proA, LC598079 and LC598080)), and all clustered NACAB191 and NACAB192 into a clade containing other confirmed strains of P. wasabiae. As a result, these two strains shared high identity with each other (>98%, E-Values showed 0). The clade containing these two strains was consistently placed in a larger clade with the other P. wasabiae and 100% bootstrap support for its separation from other Pectobacterium species available in GenBank when the consensus tree constructed using Maximum Likelihood method. Pathogenicity of these strains against cabbage (cv. 'Rakuen') was confirmed by the field experiments with five weeks growth plants sprayed with bacterial suspension (1×107cfu/ml). Thirty cabbages per strain were used in this study, 12 plants treated the suspension of NACAB191 and 16 plants treated the suspension of NACAB192 which died with the same soft rot symptoms about four weeks after inoculation. Whereas water-inoculated plants remained symptomless. Strains re-isolated from the artificially diseased stems were confirmed as P. wasabiae using the methods as biochemical characterization and multiple genetic analyses. Based on the disease symptoms, the cultural, molecular, and pathological features of the strains, we conclude that the soft rot symptoms of cabbage in Hokkaido in 2019 were caused by P. wasabiae. To our knowledge, this is the first report of P. wasabiae as the soft rot disease agent of cabbage in Japan.

First report of soft rot of onion caused by Pectobacterium wasabiae in Japan.

Onion (Allium cepa L.) is one of the important vegetables in Japan. In the summer of 2019, onions with soft rot were found in commercial fields in Hokkaido, the northern island in Japan. Diseased onion showed chlorosis, maceration of leaves, and rotted bulbs. We sampled some diseased onions and isolated three independent isolations (NAONI191, NAONI192 and NAONI193) from infected bulbs on LB medium. These strains were identified as Pectobacterium wasabiae based on their inability to grow at 37°C, and their ability to utilize raffinose and lactose. These bacterial strains were gram-negative, rod-shaped, N-acetylglucosaminyl transferase, gelatin liquefaction. The bacterium was positive for O-nitrophenyl-beta-D-galactopyranoside, N-acetylglucosaminyl transferase, gelatin liquefaction, and acid production from D-galactose, lactose, melibiose, raffinose, citrate, and trehalose. The bacterium was negative for indole production and acid production from maltose, α-methyl-D-glucoside, sorbitol, D-arabitol, inositol, inulin, and melezitose. All the strains exhibited pectolytic activity on potato slices. DNA from these strains yielded a single size amplicon with the primer set of PhF/PhR for P. wasabiae (De Boer et al. 2012) by PCR. However, DNA from these strains did not yield the expected amplicon with the primer set of BR1f/L1r for P. carotovorum subsp. brasiliense (Duarte et al. 2004) and Eca1f/Eca2r for P. atrosepticum (De Boer et al., 1995) by PCR. The sequence analysis of 16S rDNA (LC597917- LC597919) showed more than 98% identities to P. wasabiae strains (e.g. HAFL01 in Switzerland) by BLAST analysis. In addition, Multi-locus sequence analysis (Ma et al. 2007) was performed by MEGA6.06 using concatenated DNA sequences of seven housekeeping genes (aconitate hydratase(acnA, LC597925- LC597927), glyceraldehyde-3-phosphate dehydrogenase A(gapA, LC597972-LC597974), isocitrate dehydrogenase (icdA, LC597998- LC597998LC598000), malate dehydrogenase(mdh, LC598024- LC598026), mannitol-1-phosphate dehydrogenase (mtlD, LC598050- LC598052), glucose-6-phosphate isomerase (pgi, LC598076- LC598078) and gamma-glutamyl phospate reductase (proA, LC598099- LC598101)), and all clustered into a clade containing other confirmed strains of P. wasabiae. As a result, these three strains shared high identity with each other (>98%, E-Values showed 0). The clade containing these three strains was consistently placed in a larger clade with the other P. wasabiae and 100% bootstrap support for its separation from other Pectobacterium species available in GenBank when the consensus tree constructed using Maximum Likelihood method. Pathogenicity of these strains against onion (cv. 'Hayate') was confirmed by the field experiments with 5 weeks growth plants sprayed with bacterial suspension (1×107cfu/ml) resulting in soft rot on the plants about four weeks after inoculation, whereas water-inoculated plants remained symptomless. Strains re-isolated from the artificially diseased stems were confirmed as P. wasabiae using the methods as biochemical characterization and multiple genetic analyses. Based on the disease symptoms, the cultural, molecular, and pathological features of the strains, we conclude that the soft rot symptoms of onion in Hokkaido in 2019 were caused by P. wasabiae. To our knowledge, this is the first report of P. wasabiae as the soft rot disease agent of onion in Japan.

Antimicrobial Activity of Natural Plant Compound Carvacrol Against Soft Rot Disease Agent Dickeya zeae.

Dickeya zeae is a globally important bacterial pathogen that has been reported to cause severe soft rot diseases in several essential food crops, including bananas, rice, maize, and potatoes. Carvacrol, a hydrophobic terpene component, is found in aromatic plants of the Labiatae family and various essential oils. However, little work has been done on its antimicrobial potential against D. zeae. This study aimed to evaluate the antimicrobial activity and the functional mechanism of carvacrol against D. zeae. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of carvacrol against D. zeae were 0.1mg/mL and 0.2mg/mL, respectively. Carvacrol affected the cell membrane of D. zeae, as revealed by decreased intracellular ATP concentration, nucleic acid leakage, and decreased membrane potential. Scanning electron microscopy (SEM) micrographs confirmed that D. zeae cell membranes were damaged by carvacrol. Furthermore, a significant inhibition of D. zeae swimming motility and biofilm formation was observed following treatments with carvacrol at sub-inhibitory concentrations, indicating a significantly negative effect on these virulence factors. Accordingly, the tissue infection test revealed that carvacrol significantly reduced the pathogenicity of D. zeae. In a pot experiment, inoculated banana seedlings displayed remarkably lesser disease symptoms following treatment with carvacrol, and the control efficiency for banana soft rot was 32.0% at 14days post-inoculation. To summarize, carvacrol exhibits strong antimicrobial activity against D. zeae and great potential applications in the control of D. zeae-associated crop diseases.

Efficiency of bio-evaporation of Arugula leaves to control root rot disease on cucumber caused by Pythium intermedium in Greenhouse

The efficiency of the Arugula (Eruca vesicaria) leaves extracts against the fungus Pythium intermedium, the root rot disease agent, was evaluated with three concentrations of 2.5, 5, 10 g / kg soil as biofumigation. The fungi around infected root of cucumber plants were isolated and diagnosed from different locations in Baghdad such as Rashidiya, Madaen, Yousifiya and Mahmudiya. The extract of arugula plants significantly reduced the incidence and severity of root rot disease on cucumber plant after 45 days of cultivation compared with control. The highest reduction in incidence and severity of the disease was about 4% and 5% respectively with arugula extract 10 g / kg soil. The study was the first record to evaluate the incidence of P. intermedium on root of cucumber plants in Iraq. Further, all concentrations of arugula extract showed increase on the growth parameters compared with control. In arugula extract 10 g/kg soil the growth parameter such as plant length, leaf length, leaf width, wet weight and dry weight were 35 cm, 5.5 cm, 6 cm, 4 g and 0.28 g respectively. Furthermore, Significant differences in the value of the biological index of arugula plant extract treatments ranging from 2627 to 3433 compared to the treatment of P. intermedium, which was about 1910, while did not differ significantly from the treatment of control with a vital index of 3830.

Determination of antagonistic traits of bacterial isolates obtained from apricot against green fruit rot disease agent Sclerotinia sclerotiorum

Determination of antagonistic traits of bacterial isolates obtained from apricot against green fruit rot disease agent <i>Sclerotinia sclerotiorum</i>

In vitro antifungal activities of endophytic bacterial isolates against postharvest heart rot disease agentAlternaria alternatain pomegranate fruits

In vitro antifungal activities of endophytic bacterial isolates against postharvest heart rot disease agent<i>Alternaria alternata</i>in pomegranate fruits

Assessment of glucosinolate‐derived isothiocyanates as potential natural antifungal compounds against citrus sour rot disease agent Geotrichum citri‐aurantii

AbstractIn this study, the antifungal effects of six different isothiocyanate (ITCs) compounds (methyl, allyl, butyl, ethyl, benzyl and 2‐phenylethyl ITCs) were investigated to be use against the citrus sour rot disease caused by Geotrichum citri‐aurantii in vitro and semi‐commercial (in vivo) conditions. Antifungal activities of the vapour phases of different ITC compounds were examined on the arthroconidia germination and mycelial growth of G. citri‐aurantii. Mycelial growth of G. citri‐aurantii was inhibited in a concentration‐dependent way. The minimum inhibitory concentrations of benzyl, methyl, allyl and ethyl ITCs on mycelial growth were 0.06, 0.08, 0.10 and 0.10 µl/L, respectively. Arthroconidia germination of G. citri‐aurantii was completely inhibited by benzyl, methyl, allyl and ethyl ITCs at concentrations of 0.05, 0.07, 0.07 and 0.07 µl/L, respectively. Light microscopy observations revealed that the ITC compounds, at completely inhibiting concentrations, caused considerable morphological changes in the fungal hyphae. Under in vivo conditions, the average rotting area caused by G. citri‐arantii was inhibited 100% by ethyl, methyl and allyl ITC compounds at concentrations of 8.0, 12.0 and 12.0 µl/L, respectively. Results suggest that ITC’s may be useful and effective natural antifungal compounds to control the citrus sour rot disease agent.

Effect of photosensitisers on growth and morphology of Phytophthora citrophthora coupled with leaf bioassays in pear seedlings

The phytopathogenic oomycetes of the genus Phytophthora cause devastating economic losses worldwide.&lt;br /&gt;Naphthodianthrone compounds, present in plant extracts of buckwheat and Saint John’s wort act as photosensitiser&lt;br /&gt;agents and exhibit antimicrobial activity against a number of pathogens. In this study, we investigated the potential&lt;br /&gt;inhibitory effects of fagopyrin and hypericin on Phytophthora citrophthora (R.E. Sm. &amp;amp; E.H. Sm.) Leonian 1906, the&lt;br /&gt;main causal agent of rot diseases in deciduous trees. Fagopyrin had the highest inhibitory effect in the colony growth&lt;br /&gt;at a concentration of 2% of a stock solution (3 mg/mL), inducing clubbed hyphae with round tips. Notably, hypericin&lt;br /&gt;also inhibited the radial colony growth and increased the hyphal branching at the subapical region, while also promoting&lt;br /&gt;the formation of enlarged cells with irregular shapes growing collectively as biofilm-like structures. In terms of the&lt;br /&gt;mycelial dry weight, although both photosensitisers had considerable inhibitory effects, the fagopyrin treatment was&lt;br /&gt;most effective. Leaf bioassays showed that under dark conditions the photosensitiser pre-treated zoospores formed a&lt;br /&gt;dense, but aberrant, mycelial growth with penetration defects. In contrast, when the zoospore production was performed&lt;br /&gt;under light conditions, the zoospores failed to cause necrotic lesions and penetration events implying that their&lt;br /&gt;virulence was impaired. These findings shed light on the biological effects of fagopyrin and hypericin in the regulation&lt;br /&gt;of the mycelial growth, morphology and pathogenicity of P. citrophthora.

Biocontrol studies on rizpspheric microorganisms against black rot disease of tea caused by Corticium theae Bernard

Assessment of plant growth promoter and biocontrol properties of plant growth promoting rhizomicroorganisms (PGPR) from tea soil against black rot disease agent of tea caused by Corticium theae Bernard in Bangladesh was done. The antagonistic microorganisms were isolated from rhizosphere soils of tea fields and cultured on different nutrient media. The isolates were screened for their antagonism against Corticium theae by dual culture technique. The microbial strains were inoculated with tea nursery soils by mixing with 50 g of decomposed cowdung. In tea plantations, the microbial strains were sprayed on diseased plants two times at 15 days intervals. Four different species of PGPR strains such as Bacillus, Pseudomonas, Streptomyces, Trichoderma were isolated from rhizospheric soil of tea. These PGPR strains enhanced plant growth in nursery and had a positive effect on the rate of increased in number of leaves, height of plants and girth of plants by 33, 43 and 3%, respectively. Lowest severity of black rot was found in plants treated with Trichoderma followed by Bacillus, Pseudomonas and Streptomyces strains. Trichoderma and Bacillus caused 16 and 14% reduction of disease severity while both Pseudomonas and Streptomyces strains reduced disease severity by 10%. All the PGPR’s have a great influence in reducing disease severity by 19% with optimistic relations. Radial mycelial growth of C. theae was also inhibited in similar trends. The biofertilizer showed comparatively lower response in reducing disease severity (8%) in comparison to PGPR’s. It can be concluded that Bacillus, Pseudomonas, Streptomyces and Trichoderma isolated from tea soil have their growth enhance capacity as well as decrease the disease severity of black rot in tea.

Antibacterial Effect of Potassium Tetraborate Tetrahydrate against Soft Rot Disease Agent Pectobacterium carotovorum in Tomato.

Soft rot caused by Pectobacterium carotovorum is one of most common bacterial diseases occurring in fruits and vegetables worldwide, yet consumer-acceptable options for post-harvest disease management are still insufficient. We evaluated the effect of potassium tetraborate tetrahydrate (B4K2O7.4H2O) (PTB) on the growth of P. carotovorum using strain BA17 as a representative of high virulence. Complete inhibition of bacterial growth was achieved by treatment with PTB at 100 mM both at pH 9.2 and after adjustment to pH 7.0. Bactericidal activity was quantified and validated by counting fluorescently labeled live and dead bacterial cells using flow cytometry, and reconfirmed using qPCR with high-affinity photoreactive DNA binding dye propidium monoazide (PMA). The results of flow cytometry, qPCR, and culturing confirmed that bacterial cells were killed following exposure to PTB at 100 mM. Bacterial cell membranes were damaged following a 5-min treatment and extrusion of cytoplasmic material from bacterial cells was observed using electronic transmission microscopy. Soft rot incidence on inoculated tomato fruit was significantly reduced by dipping infected fruits in PTB at 100 mM for 5 min and no lesions developed following a 10-min treatment. PTB does not pose a hazard to human health and is an effective alternative to other bactericides and antibiotics for controlling soft rot disease of tomato caused by P. carotovorum.

Molecular diagnosis of the brown root rot disease agent Phellinus noxius on trees and in soil by rDNA ITS analysis

Phellinus noxius (P. noxius) is an important pathogen that causes brown root rot of trees in tropical and sub-tropical areas and has led to severe damage to trees. A quick and accurate diagnostic technique is essential to the timely confirmation of the pathogen and possible treatment. In this study, a fast, sensitive and accurate approach of molecular technique was used to diagnose the brown root rot pathogen on trees and in soils of subtropical Hong Kong. Two pairs of specific PCR primers were used to amplify the target rDNA internal transcribed spacer (ITS) region through polymerase chain reaction (PCR) for both tree tissues and soil samples. The amplified ITS fragments were then sequenced and analyzed phylogenetically for the diagnostic identification of the pathogen P. noxius. The results showed that 13 of 38 suspected trees in Hong Kong were infected with P. noxius through molecular detection. The pathogen showed no specific preference to any particular tree species. Quantitative PCR was applied to soils grown with trees identified both positive and negative for P. noxius, but the soils with healthy trees were also found positive for P. noxius. For the first time, P. noxius was reported to infect a wide range of tree species in Hong Kong and widely presented in soils, probably serving as a reservoir for the pathogen. Through this study, it is proposed that P. noxius is a soil-borne pathogen, which increases its infectivity when trees start to grow in the soil as a means in addition to the previously proposed root-to-root contact.

Molecular diagnosis of the brown root rot disease agent Phellinus noxius on trees and in soil by rDNA ITS analysis

Molecular diagnosis of the brown root rot disease agent Phellinus noxius on trees and in soil by rDNA ITS analysis

Analysis of Differential Transcript Expression Reveals Time-Dependent Leaf Responses to Sclerotinia sclerotiorum in Wild and Cultivated Sunflower

The necrotrophic pathogen Sclerotinia sclerotiorum is a causal agent of rot diseases in sunflower and is described as one of the most damaging pathogens of cultivated sunflower. Resistance to this pathogen is found in some genotypes of wild sunflower in particular characterised by significantly reduced lesion lengths in capitulum, stems and leaves. This study was conducted to characterise transcriptomic alterations during interaction of host and pathogen in lesion-surrounding areas of the leaf using differential display RT-PCR and to compare molecular responses between a resistant and a susceptible genotype. Leaves were examined during the first stages of pathogenesis (dpi 2, 3 and 4) after inoculation with S. sclerotiorum. By means of computational analysis of fluorescently labelled expression data, expression patterns were evaluated and significant differentially expressed transcripts were selected. The expression profile revealed that a response measured by the number of significant differentially expressed transcripts differed between the resistant and susceptible genotype in timing. Nine differentially expressed transcripts were successfully sequenced of which two transcripts originated from the mRNA population of the pathogen, two transcripts were derived from the susceptible cultivar of Helianthus annuus and five transcripts were isolated from the resistant genotype of Helianthus maximiliani. Semi-quantitative real-time PCR was accomplished to verify the significant differential expression of the potentially resistance-associated transcripts coumarate-CoA-ligase and cysteine protease transcript in the resistant H. maximiliani accession and differential expression of a chlorophyll-a/b-binding-protein and an S-adenosyl-methionine-synthetase transcript originating from the susceptible H. annuus cultivar.

Isolation and Partial Characterization of Antifungal Metabolites Produced by Bacillus sp. IBA 33

Antifungal proteins produced by Bacillus sp. IBA 33 were purified by ammonium sulfate precipitation and DEAE-Sephacel column chromatography. The two purified proteins inhibited the growth of Geotrichum candidum, the sour rot disease agent in lemon. The proteins were stable at 20 (3 months), 40, 60 and 100 degrees C (30 min) and remained active after sterilization at 121 degrees C for 15 min. Their hydrophobic nature was proved and when were developed with ninhydrin they did not show any free amino groups. The infrared spectrum showed vibrational modes corresponding to peptide, ester or ketone links and saturated CH links corresponding to long chain fatty acids. UV scan spectroscopy showed tyrosine and or tryptophan amino acids in their composition. The remarkable thermo-resistance of proteins may be a good feature to be used in the development of a new biocontrol method of Geotrichum candidum.