A potential mating-type biomarker to detect pathogenic Ganoderma species

Aims@#The basal stem rot disease in oil palm is caused by the pathogenic Ganoderma boninense, which is infectious after mating and forming dikaryotic hyphae. This study was aimed to generate a mating-type biomarker for the detection of pathogenic Ganoderma species.@*Methodology and results@#Mating-type region of Ganoderma was amplified using polymerase chain reaction (PCR) and primers flanking the mating-type region of other basidiomycetes. Amplified fragments were sequenced and were identified as the Ganoderma pheromone receptor gene of matB locus called the gprb2 gene. Using this biomarker, the pheromone receptor gene was detected in a total of 107 pathogenic Ganoderma spp. while the gene was not detected in the non-pathogenic Ganoderma lucidum. Phylogenetic tree analyses of the gene fragment encoding the partial amino acid sequence of gprb2 showed clades of close evolutionary relationship among the 107 pathogenic Ganoderma spp. Phylogenetic analyses using deduced amino acid sequences of the Ganoderma pheromone receptor b2 gene, gprb2 with homologous pheromone receptors of other basidiomycetous fungi revealed high conservation of this pheromone receptor within their respective taxonomy.@*Conclusion, significance and impact of study@#A potential mating-type biomarker was successfully identified that could detect pathogenic Ganoderma spp. The research findings will be helpful in oil palm screening to detect pathogenic Ganoderma spp. and gain further insight into the role of the mating-type loci of Ganoderma towards its pathogenesis in causing the basal stem rot disease of oil palm.

A novel pathogenic Colletotrichum species for rhizome rot disease of Polygonatum kingianum / 中国中药杂志

Rhizome rot disease is one of the main disease of planted Polygonatum kingianum. In this study, six strains of pathogenic fungus was isolated from P. kingianum samples with rhizome rot disease collected from six counties in Yunnan province. Its pathogenicity was confirmed by inoculation to healthy P. kingianum rhizome according to Koch's postulates. The colonies of the isolated fungi on potato dextrose agar(PDA) were orange with abundant crescentic conidia which were eseptate with a mean size of 19. 3-24. 9 μm×5. 2-5. 9 μm and a L/W ratio of 3. 4-4. 5. There was an oil ball in the center of the conidium. It's easy to see setae on PDA colony.The phylogenetic tree based on ITS, GAPDH, CHS-1, HIS3, ACT, and TUB2 sequences by maximum likelihood(ML) method indicated that the pathogenic fungus for P. kingianum rhizome rot disease was clustered into the clade of Colletotrichum spaethianum species complex, and was close to C. spaethianum. However, there were some differences in morphological and genetic characteristics between the pathogenic fungus and C. spaethianum. Therefore, the pathogenic fungus for rhizome rot disease of P. kingianum was identified as a new Colletotrichum species named C. kingianum. The disease spreads primarily due to the plantation of infected seedlings of P. kingianum. It is necessary to choose healthy seedlings and take rigorous disinfection measures for the disease prevention.

Biocontrol capability of bacteriophages against soft rot disease caused by Dickeya chrysanthemi

Aims@#This study aims to evaluate the effectiveness of bacteriophages isolated from Klang and Penang, Malaysia against Dickeya chrysanthemi that causes soft rot disease.@*Methodology and results@#Basic characterization such as dextrose test, citrate test, lactose fermentation test and ornithine test were carried out on D. chrysanthemi. Activity of bacteriophages against D. chrysanthemi was evaluated using spot test. Double agar overlay assay was performed to purify and enumerate the quantify of bacteriophages.Bacteriophages were also checked for its effectiveness in controlling soft rot on post-harvested vegetables: potato (Solanum tuberosum), cucumber (Cucumis sativus) and apple (Malus domestica). Results showed that D. chrysanthemiable to utilize citrate and dextrose as the source of energy, which indicated that D. chrysanthemi inclined to choose fruits and vegetables containing citrate and dextrose as the target of attack. Clear zone observed on the bacterial lawn (spot test) indicated the ability of the bacteriophages to infect and lyse D. chrysanthemi. All the bacteriophages studied herein reached the highest concentration on day 3 and were monovalent.@*Conclusion, significance and impact of study@#All the isolated bacteriophages were able to restrain the spreading of soft rot caused by D. chrysanthemi either work alone or as cocktail. This study provides information for the formulation development of bacteriophage against soft rot disease cause by D. chrysanthemi. Furthermore, this study reveals the potential of locally isolated bacteriophages against the D. chrysanthemi and paving the application of phage treatment on agriculture products that are not limited to potatoes, cucumber and apple.

Investigation, analysis and identification of disease of Gastrodia elata f. glauca / 中国中药杂志

Fungal disease is an important factor restricting the healthy development of Gastrodia elata industry. The control of fungal disease in G. elata is an important issue in production. This paper makes a detailed investigation on the current situation of G. elata disease in China through statistics on the failure rate, rotten pit rate and occurrence rate of G. elata disease in the main producing areas of China. It was found that G. elata disease was mainly infected from the top bud and junction, causing the occurrence rate of disease was 6%-17%, and the yield decreased by 10%-30%. The 23 dominant fungi were isolated from 18 typical G. elata disease samples. Through identification of colony morphology, mycelium morphology, spore morphology and genetic characteristics, they were finally identified as 13 species, belonging to 7 families and 7 genera. Trichoderma harzianum, Ilyonectria sp. and Ilyonectria destructans are the most frequently separated. Their isolation frequency were 22.22%,16.67%,16.67% respectively. Ilyonectria sp. and I. destructans were the first time isolated from G. elata disease samples. They may be the main pathogens causing soil-borne diseases of G. elata. T. harzianum has certain potential as Gastrodia biocontrol bacteria. This study can provide a theoretical basis for the research and development of control technology of Gastrodia fungi disease.

Diversity of culturable fungi isolated from Coptis chinensis rot root in Shizhu city of Chongqing / 中国中药杂志

Root rot disease restricts the Coptis chinensis industry in Shizhu of Sichuan province. To disclose fungi composition and pathogen in rot root,so as to prevent and treat the root rot disease,the C. chinensis rot root of 5 years from 4 areas in Shizhu were collected in 3 seasons respectively. The fungi were isolated and molecularly and morphological identified,followed with population statistics. 437 fungi were isolated,belonging to 5 subphylum,11 classes,16 orders,22 families and 28 genus respectively. There are great difference among the fungi compositions of different area,year and sampling season,while there was no obvious variation rule. Ilyonectria sp.,Pythium sp.,Phoma sp,Trichoderma sp.are dominant genus,while Pythium sp.,Ilyonectria sp.,Phoma sp.,Fusarium sp. may contain root rot pathogen. Antagonistic bacteria may be screened from the strains of Trichoderma sp. isolated.

Antagonistic activity of Streptomyces thermocarboxydus to Fusarium oxysporum: The cause of leaf rot disease on Aloe Vera (Aloe barbadensis Mill.) in Bali, Indonesia

@#Aims: Aloe vera (Aloe barbadensis Miller) has been cultured in Bali, Indonesia since 2006. Its cultivation area is 170 haincluding 5 regencies i.e. Buleleng, Karangasem, Bangli, Badung and Gianyar. This study was conducted to isolate andidentify the Streptomyces sp. that potentially can be used to inhibit the growth of F. oxysporum and control the leaf rotdisease on aloe vera with and to study the structural responses of F. oxysporum to the treatment of Streptomycesculture filtrate.Methodology and results: Samples were collected from Serokadan, Kerobokan, and Saba, Bali, Indonesia. The isolateof Streptomyces sp. that resulted in the highest antifungal activity was further observed on its morphological andultrastructure characteristics using SEM and TEM. Identification was done by using 16S rRNA sequencing techniques. Agreenhouse experiment was conducted to evaluate the effectiveness of the filtrate of Streptomyces sp. to control the leafrot disease on aloe vera. The Streptomyces GYRRK was identified to be S. thermocarboxydus and the filtrate inhibitedthe growth of F. oxysporum by damaging cell wall and plasma membrane of macro conidia cell, micro conidia, andhypha. Treatment with the filtrate of S. thermocarboxydus with four sprays (one spray equal to 0.5 mL) over inoculatedleaves of aloe vera reduced the leaf rot disease by 68%.Conclusion, significance and impact of study: This result suggests that filtrate of S. thermocarboxydus potentiallycan be used as an alternative control agent against leaf rot disease on aloe vera in Bali.

Identification and Characterization of New Record of Grape Ripe Rot Disease Caused by Colletotrichum viniferum in Korea

In 2016, grape fruits showing ripe rot symptom were found in fields of Korea. The fungus was isolated and identified as Colletotrichum viniferum based on morphological characteristics and nucleotide sequence data of the internal transcribed spacer, glyceraldehyde-3-phosphate dehydrogenase and β-tubulin. To our knowledge, this is the first report of C. viniferum causing grape ripe rot disease of grape fruits in Korea.

Molecular cloning, bacterial expression analysis and functional characterization of pathogenesis-related PR10-2 gene in Panax notoginseng / 中国中药杂志

Base on the transcriptome analysis and RT-PCR techniques,a pathogenesis-related protein 10 gene was isolated from Panax notoginseng root and named as PnPR10-2. Bioinformatics and phylogenetic trees analysis revealed that open reading frame (ORF) of PnPR10-2 was 465 bp in length,encoding 154 amino acids,containing one typical conserved domain of pathogenesis related protein Bet v I family, and showed high similarity with that from P. ginseng. The recombinant expressed plasmid pET32a(+)-PnPR10-2 was expressed in Escherichia coli BL21. The expression conditions were optimized and it could be expressed well in soluble and inclusion body protein. Purified PnPR10-2 recombinant protein from the supernatant of cells was used to analysis the pathogen resistance activity by paper method. The purified recombinant protein could inhibit typical root rot disease pathogen (Fusarium solani and Cylindrocarpon destructans）growth evidently, we conjecture that PnPR10-2 may participated in defense response of P. notoginseng resistance to root rot disease pathogen.

Control of Root Rot and Wilt Diseases of Roselle under Field Conditions

Roselle (Hibiscus sabdariffa L.) is one of the most important medicinal crops in many parts of the world. In this study, the effects of microelements, antioxidants, and bioagents on Fusarium oxysporum, F. solani, and Macrophomina phaseolina, the causal pathogens of root rot and wilt diseases in roselle, were examined under field conditions. Preliminary studies were carried out in vitro in order to select the most effective members to be used in field control trials. Our results showed that microelements (copper and manganese), antioxidants (salicylic acid, ascorbic acid, and EDTA), a fungicide (Dithane M45) and biological control agents (Trichoderma harzianum and Bacillus subtilis) were significantly reduced the linear growth of the causal pathogens. Additionally, application of the previous microelements, antioxidants, a fungicide and biological control agents significantly reduced disease incidence of root rot and wilt diseases under field conditions. Copper, salicylic acid, and T. harzianum showed the best results in this respect. In conclusion, microelements, antioxidants, and biocontrol agents could be used as alternative strategies to fungicides for controlling root rot and wilt diseases in roselle.

Effect of Shading on Incidence of Black Rot Disease and Yield Quality of Broccoli in Humid Tropical Regions of Thailand.

The study was carried out in the experimental location of Department of Plant Science, Faculty of Natural Resources, Prince of Songkla University, Thailand, from April to June, 2012. Split-plot in randomized complete block design was used in this experiment with four replications. The broccoli plants under the shading had the lowest incidence of black rot disease (14.48%) which was significantly lower than the full sunlight (76.91%). There was a positive impact of the shading on yield quality of the broccoli. The Yok Kheo had the highest head length and diameter (39.13 cm and 12.11 cm, respectively) when planting under the shading. These results consistent with broccoli total yield, the highest total yield was obtained from the Yok Kheo under the both shading and full sunlight (10.92 t.ha-1 and 8.29 t.ha-1, respectively), followed by the Green Queen under the shading (6.21 t.ha-1). Therefore, the appropriate variety for planting during dry season in humid tropical regions of Thailand was the Yok Kheo and Green Queen because its total yield per hectare was higher than of the Top Green and they also had higher quality of head.

Stem Rot of Garlic (Allium sativum) Caused by Sclerotium rolfsii

Stem rot disease was found in garlic (Allium sativum L.) cultivated from 2008 to 2010 in the vegetable gardens of some farmers in Geumsan-myon, Jinju City, Gyeongnam province in Korea. The initial symptoms of the disease were typical water-soaked spots, which progressed to rotting, wilting, blighting, and eventually death. White mycelial mats had spread over the lesions near the soil line, and sclerotia had formed over the mycelial mats on the stem. The sclerotia were globoid in shape, 1~3 mm in size, and tan to brown in color. The optimum temperature for growth and sclerotia formation on potato dextrose agar (PDA) medium was 30degrees C. The diameter of the hyphae ranged from approximately 4 to 8 microm. Typical clamp connection structures were observed in the hyphae of the fungus, which was grown on PDA medium for 4 days. On the basis of the mycological characteristics and pathogenicity of the fungus on the host plants, the causal agent was identified as Sclerotium rolfsii Saccardo. This is the first report of stem rot disease in garlic caused by S. rolfsii in Korea.

Evaluation of Antagonism of Penicillium TS67 Against Soy-bean Root Rot Disease and Corn Southern Leaf Blight / 微生物学通报

Through pot experiments, the disease index and control efficiency of TS67 cell, the fermentation liquid of TS67 and the supernatant of TS67 separately act on Fusarium oxysporum and Bipolaris maydis was detected. Experiment results analysis with SPSS statistical analysis software indicated all treatments of TS67 could inhibit both of soybean root rot disease and corn southern leaf blight (P