Decolorization and biodegradation of acid orange 7 by white-rot fungi / 生物工程学报

Azo dyes are widely used in textile, paper and packing industries, and have become one of the research hot spots in dye wastewater treatment because of their carcinogenicity, teratogenic mutagenicity, stable structure and degradation difficulty. In this study, the biodecolorization of acid orange 7 (AO7), an azo dye, by different white rot fungi was investigated, and the effect of different conditions on the decolorization rate of the dye was analyzed. At the same time, the degradation liquor was analyzed and the phytotoxicity experiment was performed to deduce the possible degradation pathway of AO7 and assess the toxicity of its degradation products. The results showed that the decolorization rate reached 93.46% in 24 h at pH 4.5, 28 ℃ by Pleurotus eryngii and Trametes versicolor when AO7 concentration was 100 mg/L. The biodegradation pathway of AO7 was initiated by the cleavage of the azo bond of AO7, generating p-aminobenzenesulfonic acid and 1-amino-2-naphthol. Subsequently, the sulfonic acid group of p-aminobenzene sulfonic acid was removed to generate hydroquinone. Moreover, the 1-amino-2-naphthol was de-ringed to generate phthalic acid and p-hydroxybenzaldehyde, and then further degraded into benzoic acid. Finally, hydroquinone and benzoic acid may be further oxidized into other small molecules, carbon dioxide and water. Phytotoxicity experiment showed that the toxicity of AO7 could be reduced by P. eryngii and T. versicolor.

Analysis of Fusarium oxysporum infection on changes of Astragalus metabolism by metabolomic approach / 药学学报

italic>Astragalus is a commonly used Chinese medicinal material in traditional Chinese medicine (TCM), and with the increase of planting area in recent years, the damage of Astragalus root rot has worsened year by year, which seriously affecting its quality and yield. Fusarium oxysporum is one of the main pathogens causing root rot in astragalus. In this study, UPLC-Q-TOF-MS based metabolomic approach combined with multivariate statistical analysis were used to analyze the metabolite changes of Astragalus in response to F. oxysporum infection. The results showed that 62 metabolites in the Astragalus had significant changes after inoculation of F. oxysporum. Polar metabolites included 40 flavonoids, 8 saponins, 2 nucleosides, 1 vitamin, 1 organic acid, 1 amino acid; while lipid metabolites included 3 fatty acids, 1 diradylglycerols, 2 lysophosphatidylcholine, 1 lysophosphatidylglycerol, 1 phosphatidylinositol, 1 sterol lipid. Among these differential metabolites, the relative content of flavonoids, vitamin B2, tryptophan and salicylic acid were increased, while the relative content of saponins were decreased. Correlation analysis showed that the flavonoids were positively correlated with each other, and positively correlated with most lipids, but negatively correlated with most saponins. In addition, studies have shown that F. oxysporum infection is not an influencing factor for the generation of malonyl substitution of flavonoid. This study elucidates the effect of F. oxysporum infection on Astragalus from the perspective of plant metabolism, which provides a basis for exploring the interaction mechanism between the Astragalus and F. oxysporum and further promoting molecular breeding.

Ligninolytic enzymes profiling in association with the aggressiveness of Ganoderma boninense isolates

Aims@#This study was designed to examine the enzyme activity of selected virulent isolates of Ganoderma boninense against oil palm. In a separate in vitro assessment, the effect of macronutrients on the mycelial growth of four selected Ganoderma spp. was also tested.@*Methodology and results@#The study involved a comparison of ligninolytic enzymes; lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Lac) profiling of eight isolates of G. boninense, categorized into three levels of aggressiveness, with two control isolates (G. boninense PER71 and G. tornatum NPG1) using solid-state fermentation (SSF). The Principal Component Analysis (PCA) revealed that the isolates had a significant production of ligninolytic enzymes on day 80. The most aggressive isolate, ET61 had the highest Lac production. As for the macronutrient test, mycelial growth for all the Ganoderma spp. was highly affected by potassium (K).@*Conclusion, significance and impact of study@#The findings of this study elucidated the characteristics of G. boninense in relation to enzyme production for the degradation of oil palm lignin and the identification of essential nutrients involved in the survival and growth of Ganoderma spp. The study provides vital information on the pathogenic characteristics of G. boninense isolates involved in biomass degradation along with the role of nutrient on the growth of Ganoderma spp. that may influence basal stem rot (BSR) management in the field.

Advances in research and application of Trichoderma for inducing resistance against root rot diseases in root and rhizome of Chinese medicinal materials / 中国中药杂志

Root rot is a microbial disease that is difficult to control and can result in serious losses in the planting of most Chinese medicinal materials. As high as 87.6% of roots or rhizomes of Chinese medicinal materials are susceptible to root rot, which seriously affects the cultivation development of Chinese medicinal materials. Trichoderma fungi, possessing biological control functions, can induce plants to improve their resistance to microbial diseases, promote plant growth, and effectively reduce the losses caused by various microbial diseases on cultivation. At present, Trichoderma is rarely used in the cultivation of Chinese medicinal materials, so it has great application potential for the prevention and control of root rot diseases in farmed Chinese medicinal materials. Based on the above situation, after comparison and discussion, it is believed that compared with chemical control and physical control, biological control of root rot diseases of Chinese medicinal materials is more efficient and meets the development needs of Chinese medicinal materials ecological planting in China. This paper reviewed the progress in the research and application of Trichoderma in the control of root rot diseases in the root and rhizome of farmed Chinese medicinal materials in the past 10 years and found that most of the current research on the biological control of root rot diseases in Chinese medicinal materials was mostly limited to the verification of the inhibitory effect of Trichoderma strains on the growth of the pathogenic microbes. Studies on the induction effect of Trichoderma on Chinese medicinal materials are not in depth. Studies on the responding mechanisms of most Chinese medicinal materials to Trichoderma are highly absent. Moreover, there are few reports on field experiments, which indicates that there is a long way to go before Trichoderma is widely applied in the farming practice of Chinese medicinal materials. To sum up, this paper aimed to link the present and the future and advocated further relevant research and more experiments on the application of Trichoderma in the farming of Chinese medicinal materials.

Inhibitory effect of three strains of biocontrol microbes on pathogens causing rhizome rot of Polygonatum cyrtonema / 中国中药杂志

Rhizome rot is one of the main disease in the cultivation of Polygonatum cyrtonema, and it is also a global disease which seriously occurs on the perennial medicinal plants such as Panax notoginseng and P. ginseng. There is no effective control method at present. To identify the effects of three biocontrol microbes(Penicillium oxalicum QZ8, Trichoderma asperellum QZ2, and Brevibacillus amyloliquefaciens WK1) on the pathogens causing rhizome rot of P. cyrtonema, this study verified six suspected pathogens for their pathogenicity on P. cyrtonema. The result showed that Fusarium sp. HJ4, Colletotrichum sp. HJ4-1, and Phomopsis sp. HJ15 were the pathogens of rhizome rot of P. cyrtonema, and it was found for the first time that Phomopsis sp. could cause rhizome rot P. cyrtonema. Furthermore, the inhibitory effects of biocontrol microbes and their secondary metabolites on three pathogens were determined by confrontation culture. The results showed that the three tested biocontrol microbes significantly inhibited the growth of three pathogens. Moreover, the secondary metabolites of T. asperellum QZ2 and B. amyloliquefaciens WK1 showed significant inhibition against the three pathogens(P<0.05), and the effect of B. amyloliquefaciens WK1 sterile filtrate was significantly higher than that of high tempe-rature sterilized filtrate(P<0.05). B. amyloliquefaciens WK1 produced antibacterial metabolites to inhibit the growth of pathogens, and the growth inhibition rate of its sterile filtrate against three pathogens ranged from 87.84% to 93.14%. T. asperellum QZ2 inhibited the growth of pathogens through competition and antagonism, and P. oxalicum QZ8 exerted the inhibitory effect through competition. The research provides new ideas for the prevention and treatment of rhizome rot of P. cyrtonema and provides a basis for the di-sease control in other crops.

Identification and biological characteristics of violet root rot pathogen of Pseudostellaria heterophylla in Fujian province / 中国中药杂志

Violet root rot is one of the main root diseases in the production process of Pseudostellaria heterophylla. To clarify the pathogenic species that cause the violet root rot of P. heterophylla in Fujian province, the roots and the sclerotia with violet root rot symptoms were collected from the main producing areas of P. heterophylla(Fujian province) from 2017 to 2021, and the pathogens were isolated by tissue separation method and identified by morphology and multi-gene phylogenetic analysis. Additionally, the biological characteristics of the pathogens were studied and the fungicides were determined. The results showed that 78 strains of violet root rot were isolated from the collected root samples, which belonged to one type after preliminary morphological identification. Two represen-tative strains were selected from the pathogens for multi-gene phylogenetic analysis, and they were clustered with Helicobasidium mompa together. The suitable culture conditions for the mycelium were OA medium, 25 ℃, pH 6, and ammonium oxalate as the nitrogen source. The lethal temperature of the mycelium was 50 ℃ for 10 minutes. Moreover, 99.1% propiconazole and 98.7% azoxystrobin had the optimal bacteriostatic effect, and the concentrations with the 50% bacteriostatic rate were 16.85 and 12.24 μg·mL~(-1), respectively. On the basis of the above results, the pathogen causing violet root rot of P. heterophylla in Fujian province was H. mompa. The medium type, growth temperature, pH value, nitrogen source, etc. had significant effect on the growth of mycelium.

Isolation, identification, and pathogenicity research of brown rot pathogens from Gastrodia elata / 中国中药杂志

Brown rot is a common disease in the cultivation and production of Gastrodia elata, but its pathogens have not been fully revealed. In this study, the pathogenic fungi were isolated and purified from tubers of 77 G. elata samples with brown rot. Pathogens were identified by the pathogenicity test and morphological and molecular identification. The pathogenicity of each pathogen and its inhibitory effects on Armillaria gallica were compared. The results showed that 119 strains of fungi were isolated from tubers of G. elata infected with brown rot. Among them, the frequency of separation of Ilyonectria fungi was as high as 42.01%. The pathogenicity test showed that the pathogenicity characteristics of six strains of fungi were consistent with the natural symptoms of brown rot in G. elata. The morphological and molecular identification results showed that the six strains belonged to I. cyclaminicola and I. robusta in the Nectriaceae family of Sordariomycetes class, respectively. Both types of fungi could produce pigments, conidia, and chlamycospore, and the growth rate of I. cyclaminicola was significantly higher than that of I. robusta. The comparison of pathogenicity showed that the spots formed by I. cyclaminicola inoculation were significantly larger than those of I. robusta inoculation, suggesting I. cyclaminicola was superior to I. robusta in pathogenicity. The results of confrontation culture showed that I. cyclaminicola and I. robusta could signi-ficantly inhibit the germination and cordage growth of A. gallica. A. gallica also inhibited the growth of pathogens, and I. cyclaminicola was less inhibited as compared with I. robusta. The results of this study revealed for the first time that I. cyclaminicola and I. robusta were the pathogens responsible for G. elata brown rot.

Resistance of different ecotypes of Gastrodia elata to tuber rot / 中国中药杂志

Tuber rot has become a serious problem in the large-scale cultivation of Gastrodia elata. In this study, we compared the resistance of different ecotypes of G. elata to tuber rot by field experiments on the basis of the investigation of G. elata diseases. The histological observation and transcriptome analysis were conducted to reveal the resistance differences and the underlying mechanisms among different ecotypes. In the field, G. elata f. glauca had the highest incidence of tuber rot, followed by G. elata f. viridis, and G. elata f. elata and G. elata f. glauca×G. elata f. elata showed the lowest incidence. Tuber rot showcased obvious plant source specificity and mainly occurred in the buds and bottom of G. elata plants. After infection, the pathogen spread hyphae in host cortex cells, which can change the endophytic fungal community structure in the cortex and parenchyma of G. elata. G. elata f. glauca had thinner lytic layer and more sugar lumps in the parenchyma than G. elata f. elata. The transcription of genes involved in immune defense, enzyme synthesis, polysaccharide synthesis, carbohydrate transport and metabolism, hydroxylase activity, and aromatic compound synthesis had significant differences between G. elata f. glauca and G. elata f. elata. These findings suggested that the differences in resis-tance to tuber rot among different ecotypes of G. elata may be related to the varied gene expression patterns and secondary metabolites. This study provides basic data for the prevention and control of tuber rot and the improvement of planting technology for G. elata.

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.

Identification, biological characteristics, and control of pathogen causing Pinellia ternata soft rot in Hubei province / 中国中药杂志

This study was designed to identify the pathogen causing soft rot of Pinellia ternata in Qianjiang of Hubei province and screen out the effective bactericides, so as to provide a theoretical basis for the control of soft rot of P. ternata. In this study, the pathogen was identified based on molecular biology and physiological biochemistry, followed by the detection of pathogenicity and pathogenicity spectrum via plant tissue inoculation in vitro and the indoor toxicity determination using the inhibition zone method to screen out bactericide with good antibacterial effects. The control effect of the bactericide against P. ternata soft rot was verified by the leave and tuber inoculation in vitro. The phylogenetic tree was constructed based on the 16 S rDNA, dnaX gene, and recA gene sequences, respectively, and the result showed that the pathogen belonged to the same branch as the type strain Dickeya fangzhongdai JS5. The physiological and biochemical tests showed that the pathogen was identical to D. fangzhongdai, which proved that the pathogen was D. fangzhongdai. The pathogenicity test indicated that the pathogen could obviously infect leaves at 24 h and tubers in 3 d. As revealed by the indoor toxicity test, 0.3% tetramycin, 5% allicin, and 80% ethylicin had good antibacterial activities, with EC_(50) values all less than 50 mg·L~(-1). Tests in tissues in vitro showed that 5% allicin exhibited the best control effect, followed by 0.3% tetramycin and 10% zhongshengmycin oligosaccharide, and their preventive effects were better than curative effects. Therefore, 5% allicin can be used as the preferred agent for the control of P. ternata soft rot, and 0.3% tetramycin and 10% zhongshengmycin oligosaccharide as the alternatives. This study has provided a certain theoretical basis for the control of P. ternata soft rot.

Development and Evaluation of Biocontrol Agents Against Panax ginseng Root Rot / 中国实验方剂学杂志

ObjectiveTo develop safe and effective microbial agents against Panax ginseng root rot. MethodP. notoginseng endophytes were screened in plate confrontation tests， followed by morphological and molecular biological identification of antagonistic strains， optimization of strain fermentation conditions in a single factor test， and determination of optimal carriers and auxiliary agents of the microbial agent and their ratio using response surface methodology for formulating the production process. The prevention and control effects of the microbial agent were verified in the confrontation and pot culture experiments. ResultThe plate confrontation test yielded a strain named Fusarium pseudoanthophilum with significant resistance to root rot， and its antibacterial rate was 53.33%. According to the single factor test， the fermentation conditions of F. pseudoanthophilum were determined to be fermentation time 60 h， fermentation temperature 26 ℃， speed 120 r·min-1， and pH 6.5. The response surface optimization results showed that the number of viable bacteria reached the maximum （5.23×109 cfu·g-1） when the peat was 60.00 g， sodium carboxymethylcellulose 3.50 g， and sodium alginate 4.76 g. The influences of carriers and auxiliary agents on the number of viable bacteria were sorted by degree in a descending order as follows： peat>sodium carboxymethylcellulose >sodium alginate. The confrontation test results showed that when the microbial agent concentration was greater than 1.00 g·L-1， it had a significant inhibitory effect on the root rot pathogen F. oxysporum and the inhibitory rate was more than 42.3%. As demonstrated by the pot culture experiment， the inoculation of biocontrol agent for 28 d significantly reduced the incidence （66.99%） of root rot in P. ginseng seedlings and disease index （61.69%） and increased their leaf length （33.04%） and fresh weight （34.48%）. ConclusionF. pseudoanthophilum inoculant is efficient in preventing and controlling the root rot， making it worthy of further development and utilization.

Evaluación de la resistencia de genotipos de Passifloras a Fusarium solani f.sp. passiflorae en granadilla / Evaluation of the resistance of Passifloras genotypes to Fusarium solani f.sp. passiflorae in granadilla / Avaliação da resistência de genótipos de Passifloras a Fusarium solani f.sp. passiflorae em granadilla

RESUMEN En Colombia la enfermedad más limitante en el cultivo de la granadilla es la pudrición del cuello causada por Fusarium solani f.sp. passiflorae. Este patógeno afecta a las plantas en todos los estados de desarrollo en la base de los tallos y causa la muerte en un corto tiempo. El objetivo de esta investigación fue evaluar la resistencia en dieciocho especies de la familia Passifloraceae a la pudrición del cuello. Para este experimento se utilizó un aislamiento altamente virulento según los resultados de las pruebas de patogenicidad con plantas de granadilla. Según los resultados después de la inoculación con el patógeno once especies de Passifloras fueron susceptibles, en contraste cinco genotipos de maracuyás (PE10, PE11, PE13, PE15 y PE17) y dos cholupas (PM02 y PM04), fueron resistentes no manifestaron síntomas. Se recomienda utilizar las especies resistentes para el mejoramiento genético de esta especie o emplearlos como porta injertos.

ABSTRACT In Colombia the most limiting disease in the cultivation of granadilla is neck rot caused by Fusarium solani f.sp, passiflorae. This pathogen affects plants in all stages of development at the base of the stems and causes death in a short time. The objective of this research was to evaluate the resistance in eighteen species of the Passifloraceae family to neck rot. For this experiment, a highly virulent isolate was used according to the results of pathogenicity tests with passion fruit plants. According to the results after inoculation with the pathogen, eleven Passifloras species were susceptible, in contrast, five passion fruit genotypes (PE10, PE11, PE13, PE15 and PE17) and two cholupas (PM02 and PM04), were resistant and did not show symptoms. It is recommended to use resistant species for the genetic improvement of this species or to use them as rootstock.

RESUMO Na Colômbia, a doença mais limitante no cultivo do granadilla é a podridão do pescoço causada pelo Fusarium solani f.sp, passiflorae. Este patógeno afeta as plantas em todos os estágios de desenvolvimento na base dos caules e causa a morte em um curto espaço de tempo. O objetivo desta pesquisa era avaliar a resistência de dezoito espécies da família Passifloraceae à podridão do colar Para esta experiência, foi utilizado um isolado altamente virulento de acordo com os resultados dos testes de patogenicidade em plantas de maracujá. De acordo com os resultados após a inoculação com o patógeno onze espécies de Passifloraceae eram suscetíveis, em contraste, cinco genótipos de maracujá (PE10, PE11, PE13, PE15 e PE17) e dois cholupas (PM02 e PM04) eram resistentes e não apresentavam sintomas. Recomenda-se usar as espécies resistentes para o melhoramento genético desta espécie ou usá-las como porta-enxertos.

Investigation and Suggestions on Factors Affecting Quality of Angelicae Dahuricae Radix (Baizhi) in Some Post-harvest Processes / 中国实验方剂学杂志

Objective:To investigate the factors affecting the quality of post-harvest Angelicae Dahuricae Radix （Baizhi） and to provide the corresponding suggestions according to these factors. Method:A series of factors affecting the quality of Baizhi were analyzed comprehensively by visiting several origins， medicinal material markets， pharmacies， supermarkets and storehouses combined with plenty of literature reports. Result:The rot of Baizhi was the most common phenomenon after harvest， and mildew， discoloration and moth could occur during the processes of processing， storage and packaging. So the quality of Baizhi should be controlled strictly through the whole process. The roots of Baizhi should be harvested on sunny days to avoid mining damage and dried as soon as possible to prevent rotting. The drying methods included both traditional lime burial and modern ways such as sulfur fumigation， saline dehydration， sun drying method， and oven drying method. However， the water content should be strictly controlled. Furthermore， the storehouses should be disinfected firstly. The temperature and humidity of the storehouses should be controlled strictly. Some suitable ways could be adopted to prevent moth and discoloration during storage， which included airtight fumigation of aluminum phosphide， cold storage， air conditioning maintenance， antagonism storage with other Chinese medicinal materials， dry ice storage at room temperature， etc. Large quantities of Baizhi were generally packaged in woven bags. Otherwise， kraft paper bags， polyvinyl chloride plastic bags， glass bottles， aluminum foil composite film bags， and other packaging materials had been adopted for the retail. However， the packaging specification should be selected according to the situation. Conclusion:The quality of Baizhi can be directly affected by harvesting， drying， processing， storage and packaging. Scientific and reasonable methods should be adopted to ensure the quality of Baizhi.

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.

Isolation and identification of a new phytopathogen causing root rot of Rehmannia glutinosa / 中国中药杂志

Root rot was occurred widely in the production area of Rehmannia glutinosa, and which result in serious influence on the yield and quality of R. glutinosa. In the present work, a new phytopathogen was isolated from roots with root rot symptom in the production area of R. glutinosa. The colony of the pathogen growing on PDA medium was gray-black, the structure of hyphae was compact, the aerial hyphae was less developed, and the back of the colony was black. The hyphae of the pathogen were uneven in size, about 2 to 3 μm in diameter and twined with each other, the conidia of the pathogen were small, nearly round and about 1 μm in diameter. The healthy roots of R. glutinosa were inoculated with the pathogen in vitro, black-brown rot was observed at the inoculate sites after a few days' incubation. The rhizosphere soil of healthy R. glutinosa seedlings were inoculated in vivo, the leaves were wilted and the roots were black-brown rotted after several days' normal culture, the symptoms were consistent with those observed in the field. The genomic DNA of the pathogen was amplified by fungus rDNA-ITS universal primer ITS1/ITS4 and homologous analyzed, the pathogen was in a branch with Heterophoma sp., Phoma sp., P. novae-verbascicola and P. herbarum with the nuclear acid homology of 99.21% to 99.43%. The pathogen shown 97.00% to 98.02% nuclear acid homology with H. verbascicola, H. novae-verbascicola, H. poolensis, P. herbarum, H. sylvatica, H. verbascicola and H. verbasci-densiflori when amplified by the tub2 gene special primer Btub2 fd/Btub4 rd, and H. novae-verbascicola was the highest. The pathogen was in a branch with H. novae-verbascicola when amplified by the lsu gene special primer LR0 R/LR7. Based on the morphological characteristics, nucleotide sequence analysis and Koch's test results, the isolated pathogen causing root rot of R. glutinosa was identified as H. novae-verbascicola. This study is of great significance for the further theoretical research on root rot of R. glutinosa and root rot control in field.

Effectiveness of indigenous fluorescent pseudomonads in suppressing Rhizoctonia solani root rot disease and promoting plant growth in chilli seedlings

Aims@#This study aimed to isolate and evaluate the indigenous fluorescent Pseudomonas spp. with bio-control potential against Rhizoctonia solani and promoting growth in chilli seedlings. @*Methodology@#A total of 120 fluorescent bacterial were isolated from the healthy chilli rhizosphere soil from the seven major chilli cultivation localities in Terengganu, Malaysia. Only 115 Gram negative fluorescent isolates were further invitro screened for antagonistic activities against R. solani and plant growth-promoting properties. The 50 most effective fluorescent Pseudomonads antagonist against R. solani with minimum percentage inhibition of radial growth (PIRG) of 65% were selected. Hierarchical cluster analysis was further conducted with two dendrograms derived from SPSS Statistic 20 to facilitate the comparison between these 50 isolates for antagonistic and growth-promoting properties. A total of 40 fluorescent isolates within the most potential cluster were further selected and identified using 16S rRNA sequencing. Thirty four fluorescent isolates were identified as Pseudomonas spp. and six isolates as Burkholderia spp. The top 13 ranked fluorescent Pseudomonas spp. from the scoring index were evaluated for seed germination and vigor index in chilli seedlings. There was no significant difference in germination rate between fluorescent Pseudomonas inoculated with control. However, vigor index of chilli seeds pre-inoculated with fluorescent P. putida (B5C1), P. aeruginosa (B3C56) and P. putida (B5C7) were significantly increased with 4684.9, 4657.3 and 4401.0 over control (P ≤ 0.05).@*Conclusion, significance and impact of study@#These selected fluorescent isolates: P. putida (B5C1), P. aeruginosa (B3C56) and P. putida (B5C7) have the potential to be developed as biofungicide against R. solani and as growthpromoter in chilli production system.

Evaluation on the effectiveness of combination of biocontrol agents in managing Ganoderma boninense of oil palm

Aims@#The development of an effective biocontrol formulation for inhibition of Ganoderma boninense, a well-known destructive pathogen in oil palm plantation is important to prolong the palm’s lifespan and reduce the losses due to this disease. In this paper, we present some new bioformulations with combination of different types of biocontrol agents in managing basal stem rot (BSR) disease. @*Methodology@#The effectiveness of the treatments designed as T1 (Trichoderma harzianum + Lecanicillium spp. + Streptomyces sundarbansensis + Pseudomonas aeruginosa), T2 (Penicillium simplicissimum + Lecanicillium sp. + S. sundarbansensis + P. aeruginosa), T3 (P. simplicissimum + P. aeruginosa) and T4 (LEStani®) was evaluated through treatment on the oil palm seedlings artificial infected by G. boninense and the results were expressed in disease severity index (DSI), bole severity index (BSI) and ergosterol content.@*Conclusion, significance and impact of study@#All tested treatments (T1-T4) managed to control the severity of the Ganoderma infection from continuously increasing when the treatments were applied either one month before or after artificial inoculation. The disease severity of infected seedlings without treatments had increased for almost 2-fold at the end of the trial. Moreover, T1 had the greatest inhibition of G. boninense with the lowest ergosterol content (a bioindicator of Ganoderma colonization) detected (676.67 g/mL), which is about 1.9-fold lower than control (1273.33 ug/mL) without treatments and a BSI score of 1. Based on the effectiveness among the four tested biocontrol formulations, T1 is the most promising formulation to be further evaluated in the field for control of BSR disease. However, more research is needed in the future to estimate the effective amount for application in open environment.

Genetic characterization of maize doubled haploid lines for Fusarium stalk rot caused by Fusarium verticillioides

Fusarium stalk rot disease (FSR) of maize caused by Fusarium verticillioides (Sacc.) Nirenberg is becoming an important biotic production constraint in many of the major maize growing areas causing substantial yield losses. Inbreds are preferred as parents in hybrid development owing to homozygous nature and high heterotic ability. Double haploid (DH) technology has emerged as a significant milestone. A total of 339 DH lines were generated from two inbred lines, VL1043 (susceptible) and CM212 (resistant), through in vivo haploid induction method. The 339 DH lines along with parents were phenotyped for their response to the FSR at the College of Agriculture, V. C. Farm, Mandya, India during summer, kharif and rabi seasons of the 2019–2020. Best linear unbiased predictors (BLUPs) were estimated for the FSR disease scores over three seasons. A wide range of BLUP scores of three to nine indicated the presence of higher variation for response of DH lines to FSR disease. The higher estimates of standardized range (1.31) and phenotypic coefficient of variation (19.80) also displayed higher variability. Nine lines were moderately resistant and 188 exhibited moderately susceptible reaction. The distribution of DH lines was positively skewed (1.34) and platykurtic (2.31) which suggested complementary epistasis and involvement of large number of genes in the disease expression.

A critical-point yield model to appraise the damage caused to soybean by white-mold / Modelo de ponto crítico para estimar os danos causados pelo mofo-branco ​​em soja

A model to estimate the damage caused by white mold to soybean yield from experimental field data gathered during the summer season of 2009-10 was generated. Six soybean cultivars were grown on six sites of the Savana (Cerrados) region, resulting in a total of nine separate experiments. The gradient of disease intensity (plant stem incidence) and yield was generated through the application of different fungicides and rates three times over the course of the season. The disease incidence in plant stems was evaluated at the R1, R5.2 and R5.5 growing stages. Manual harvest at the physiological ripening stage was followed by grain drying, threshing, and cleaning. Finally, grain yield was estimated in kg/ha, and regression analysis was performed. Nine linear equations representing the damage function were generated. The mean damage function was y = - 6.7 x + 1,000, where y represents grain yield normalized to 1,000 kg/haand x represents WM incidence in plants. To appraise the damage caused by various disease intensities, these models should first be validated. Damage coefficients may be used to determine the level of economic damage.

Desenvolveu-se um modelo para estimar os danos causados pelo mofo-branco (MB) (Sclerotinia sclerotiorum) na cultura da soja, com dados gerados em experimentos de campo conduzidos na safra de soja de 2009/10. Seis cultivares de soja foram cultivados em seis locais perfazendo um total de nove experimentos em distintas regiões edafoclimáticas na região do Cerrado. O gradiente da intensidade da doença, avaliada em função de incidência de sintomas/sinais em hastes, foi gerado pela aplicação de diferentes fungicidas em momentos e doses distintas. A intensidade da doença foi avaliada, nos estádios fenológicos de R1, R5.2 e R5.5. A colheita foi realizada na maturação fisiológica e o rendimento de grãos expresso em kg/ha. As análises de regressão entre o rendimento de grãos e a incidência da doença foram realizadas para todas as combinações obtidas e geraram nove equações lineares da função de dano. Função de dano média de nove experimentos foi R = 1.000 - 6,7 I (onde R = rendimento de grãos normalizado para 1.000 kg/ha e I incidênciaa do MB em plantas). Para estimar o dano causado por intensidades diferentes da doença, esses modelos devem ser previamente validado. Os coeficientes de dano podem ser usados para determinar o limiar de dano econômico