scholarly journals Screening of biocontrol bacteria against soft rot disease of Colocasia esculenta (L.) schott and its field application

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254070
Author(s):  
Xiaofei Dong ◽  
Lu Fang ◽  
Zuyun Ye ◽  
Guangqiang Zhu ◽  
Qianyu Lai ◽  
...  

Soft rot disease is a major pathogenic bacteria of Fuding areca taro and has caused serious losses. This study aims to screen biocontrol bacterial against soft rot disease. A total of 53 bacterial strains were isolated from the rhizosphere soil, nine of which exhibited good biocontrol effect against the pathogenic bacteria of soft rot disease as seen in antagonistic screening of biocontrol bacteria from corm in vitro. Strains were selected by physical and chemical experiments, biocontrol effect tests in vivo, molecular sequencing, morphological observation and field tests. Four strains including CAB-L005, CAB-L012, CAB-L014, and CAB-L022 exhibited strong antagonistic effects. On the basis of the sequence homology of 16S rRNA genes, the similarity between strain CAB-L005 and Bacillus tropicus was 100%, that between strain CAB-L012 and Bacillus subtilis was 99%, and that between strain CAB-L014 and Bacillus tequilensis was 100%, and similarity between strain CAB-L022 and Bacillus cereus was 100%. The isolated bacteria demonstrated good biocontrol effects in field experiments. In this study, four strains with good biocontrol application value were isolated and identified, providing a foundation for biocontrol against soft rot disease in areca taro.

2020 ◽  
Vol 8 (5) ◽  
pp. 697 ◽  
Author(s):  
Jieling Li ◽  
Ming Hu ◽  
Yang Xue ◽  
Xia Chen ◽  
Guangtao Lu ◽  
...  

Dickeya zeae is the causal agent of bacterial soft rot disease, with a wide range of hosts all over the world. At present, chemical agents, especially agricultural antibiotics, are commonly used in the prevention and control of bacterial soft rot, causing the emergence of resistant pathogens and therefore increasing the difficulty of disease prevention and control. This study aims to provide a safer and more effective biocontrol method for soft rot disease caused by D. zeae. The spot-on-lawn assay was used to screen antagonistic bacteria, and three strains including SC3, SC11 and 3-10 revealed strong antagonistic effects and were identified as Pseudomonas fluorescens, P. parafulva and Bacillus velezensis, respectively, using multi-locus sequence analysis (MLSA) based on the sequences of 16S rRNA and other housekeeping genes. In vitro antimicrobial activity showed that two Pseudomonas strains SC3 and SC11 were only antagonistic to some pathogenic bacteria, while strain 3-10 had broad-spectrum antimicrobial activity on both pathogenic bacteria and fungi. Evaluation of control efficacy in greenhouse trials showed that they all restrained the occurrence and development of soft rot disease caused by D. zeae MS2 or EC1. Among them, strain SC3 had the most impressive biocontrol efficacy on alleviating the soft rot symptoms on both monocotyledonous and dicotyledonous hosts, and strain 3-10 additionally reduced the occurrence of banana wilt disease caused by Fusarium oxysporum f. sp. cubensis. This is the first report of P. fluorescens, P. parafulva and B. velezensis as potential bio-reagents on controlling soft rot disease caused by D. zeae.


Plant Disease ◽  
2019 ◽  
Vol 103 (12) ◽  
pp. 3050-3056
Author(s):  
Washington L. da Silva ◽  
Kuei-Ting Yang ◽  
Gregg S. Pettis ◽  
Natasha R. Soares ◽  
Rebecca Giorno ◽  
...  

Flooding of sweetpotatoes in the field leads to development of soft rot on the storage roots while they remain submerged or on subsequent harvest and storage. Incidences of flooding after periods of intense rainy weather are on the rise in the southeastern United States, which is home to the majority of sweetpotato production in the nation. In an effort to characterize the causative agent(s) of this devastating disease, here we describe two distinct bacterial strains isolated from soft-rotted sweetpotato storage roots retrieved from an intentionally flooded field. Both of these anaerobic spore-forming isolates were identified as members of the genus Clostridium based on sequence similarity of multiple housekeeping genes, and both were confirmed to cause soft rot disease on sweetpotato and other vegetable crops. Despite these common features, the isolates were distinguishable by several phenotypic and biochemical properties, and phylogenetic analysis placed them in separate well-supported clades within the genus. Overall, our results demonstrate that multiple plant-pathogenic Clostridium species can cause soft rot disease on sweetpotato and suggest that a variety of other plant hosts may also be susceptible.


Plant Disease ◽  
2013 ◽  
Vol 97 (5) ◽  
pp. 685-685 ◽  
Author(s):  
E. Golkhandan ◽  
S. Kamaruzaman ◽  
M. Sariah ◽  
M. A. Zainal Abidin ◽  
E. Nazerian ◽  
...  

In August 2011, sweet potato (Ipomoea batatas), tomato (Solanum lycopersicum), and eggplant (S. melongena) crops from major growing areas of the Cameron highlands and Johor state in Malaysia were affected by a soft rot disease. Disease incidence exceeded 80, 75, and 65% in severely infected fields and greenhouses of sweet potato, tomato, and eggplant, respectively. The disease was characterized by dark and small water-soaked lesions or soft rot symptoms on sweet potato tubers, tomato stems, and eggplant fruits. In addition, extensive discoloration of vascular tissues, stem hollowness, and water-soaked, soft, dark green lesions that turned brown with age were observed on the stem of tomato and eggplant. A survey was performed in these growing areas and 22 isolates of the pathogen were obtained from sweet potato (12 isolates), tomato (6 isolates), and eggplant (4 isolates) on nutrient agar (NA) and eosin methylene blue (EMB) (4). The cultures were incubated at 27°C for 2 days and colonies that were emerald green on EMB or white to gray on NA were selected for further studies. All bacterial cultures isolated from the survey exhibited pectolytic ability on potato slices. These bacterial isolates were gram negative; rod shaped; N-acetylglucosaminyl transferase, gelatin liquefaction, and OPNG positive; and were also positive for acid production from D-galactose, lactosemelibiose, raffinose, citrate, and trehalose. They were negative for indol production, phosphatase activity, reducing substances from sucrose, and negative for acid production from maltose, sorbitol, inositol, inolin, melezitose, α-mathyl-D-glocoside, and D-arabitol. The bacteria did not grow on NA at 37°C. Based on these biochemical and morphological assays, the pathogen was identified as Pectobacterium wasabiae (2). In addition, DNA was extracted and PCR assay with two primers (16SF1 and 16SR1) was performed (4). Partial sequences of 16S rRNA (GenBank Accession Nos. JQ665714, JX494234, and JX513960) of sweet potato, tomato, and eggplant, respectively, exhibited a 99% identity with P. wasabiae strain SR91 (NR_026047 and NR_026047.1). A pathogenicity assay was carried out on sweet potato tubers (cv. Oren), tomato stems (cv. 152177-A), and eggplant fruits (cv. 125066x) with 4 randomly representative isolates obtained from each crop. Sweet potato tubers, tomato stems, and eggplant fruits (4 replications) were sanitized in 70% ethyl alcohol for 30 s, washed and rinsed in sterile distilled water, and needle punctured with a bacterial suspension at a concentration of 108 CFU/ml. Inoculated tubers, stems, and fruits were incubated in a moist chamber at 90 to 100% RH for 72 h at 25°C when lesions were measured. All inoculated tubers, stems, and fruits exhibited soft rot symptoms after 72 h similar to those observed in the fields and greenhouses and the same bacteria were consistently reisolated. Symptoms were not observed on controls. The pathogenicty test was repeated with similar results. P. wasabiae have been previously reported to cause soft rot on Japanese horseradish (3), and aerial stem rot on potato in New Zealand (4), the U.S. (2), and Iran (1). To our knowledge, this is the first report of sweet potato, tomato, and eggplant soft rot caused by P. wasabiae in Malaysia. References: (1) S. Baghaee-Ravari et al. Eur. J. Plant Pathol. 129:413, 2011. (2) S. De Boer and A. Kelman. Page 56 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria, 3rd ed. N. Schaad et al., eds. APS Press, St. Paul, 2001. (3) M. Goto et al. Int. J. Syst. Bacteriol. 37:130, 1987. (4) A. R. Pitman et al. Eur. J. Plant Pathol. 126:423, 2010.


2007 ◽  
Vol 57 (12) ◽  
pp. 2908-2911 ◽  
Author(s):  
Hang-Yeon Weon ◽  
Seon-Young Lee ◽  
Byung-Yong Kim ◽  
Hyung-Jun Noh ◽  
Peter Schumann ◽  
...  

Two Gram-negative, rod-shaped, thermophilic bacterial strains, HC145T and HC148T, were isolated from a compost sample from a compost facility in Ichon, Korea. Sequencing of the 16S rRNA genes of HC145T and HC148T and comparative analyses of the resulting sequences clearly showed that these strains had a phylogenetic affiliation to the genus Ureibacillus. The level of 16S rRNA similarity between the two novel strains was 98.4 % and the levels of sequence similarity between them and existing Ureibacillus species were 97.8–98.1 (HC145T) and 97.4–98.7 % (HC148T). The DNA–DNA reassociation values between the two strains and the type strains of Ureibacillus species ranged from 38 to 51 %. The polar lipid profiles for both isolates consisted of phosphatidylglycerol, diphosphatidylglycerol, phospholipids and glycolipids of unknown composition. The major quinones were MK-8, MK-9 and MK-7, the peptidoglycan type was l-Lys←d-Asp and the main cellular fatty acid was iso-C16 : 0. The DNA G+C contents of strains HC145T and HC148T were 42.4 and 38.5 mol%, respectively. On the basis of the data from this polyphasic study, strains HC145T and HC148T represent members of the genus Ureibacillus, for which the names Ureibacillus composti sp. nov. and Ureibacillus thermophilus sp. nov., respectively, are proposed. The type strain of U. composti is HC145T (=KACC 11361T =DSM 17951T) and the type strain of U. thermophilus is HC148T (=KACC 11362T =DSM 17952T).


Agrikultura ◽  
2016 ◽  
Vol 27 (3) ◽  
Author(s):  
Noor Istifadah ◽  
Muhamad Salman Umar ◽  
Sudarjat Sudarjat ◽  
Luciana Djaya

ABSTRACTThe abilities of endophytic bacteria from potato roots and tubers to suppress soft rot disease (Erwinia carotovora pv. carotovora) in potato tuberSoft rot disease caused by Erwinia carotovora pv. carotovora is one of limiting factors in cultivation and post harvest of potato. The eco-friendly control measure that can be developed for controlling the diseases is biological control. Microbes that are potential as biological control agents include endophytic bacteria. This paper discussed the results of study examining the potential of endophytic bacteria isolated from roots and tubers of potato to inhibit the growth of E. carotovora pv. carotovora in vitro and suppress soft rot disease in potato tuber. The results showed that among 24 isolates examined, four isolates of endophytic bacteria (one isolate from potato tuber and three isolates from potato roots) inhibited the growth of E. carotovora pv. carotovora in vitro with inhibition zone 3.5-6.8 mm. In the in vivo test, the isolates inhibited the soft rot disease in potato tuber by 71.5-86.4%. The isolate that tended to show relatively better inhibition in vitro and in vivo was isolate from potato tuber which is CK U3 (Lysinibacillus sp.)Keywords: Biological control, Endophytic bacteria, Post-harvest, Potato, Soft rot diseaseABSTRAKPenyakit busuk lunak yang disebabkan bakteri Erwinia carotovora pv. carotovora, merupakan salah satu kendala dalam budidaya dan pascapanen kentang. Cara pengendalian ramah lingkungan yang dapat dikembangkan untuk menekan penyakit tersebut adalah pengendalian biologi. Kelompok mikroba yang berpotensi sebagi agens pengendali biologi adalah bakteri endofit. Artikel ini mendiskusikan potensi isolat bakteri endofit yang berasal dari ubi dan akar kentang untuk menghambat pertumbuhan bakteri E. carotovora pv. carotovora secara in vitro dan menekan perkembangan penyakit busuk lunak pada ubi kentang. Hasil percobaan menunjukkan bahwa diantara 24 isolat bakteri yang diuji, terdapat empat isolat bakteri endofit (satu isolat dari ubi kentang dan tiga isolat dari akar kentang) yang dapat menghambat pertumbuhan bakteri E. carotovora pv. carotovora secara in vitro dengan zona penghambatan sebesar 3,5-6,8 mm. Pada pengujian secara in vivo, isolat-isolat tersebut dapat menekan perkembangan penyakit busuk lunak pada ubi kentang sebesar 71,5-86,4%. Isolat yang cenderung menunjukkan penghambatan relatif lebih baik secara in vitro dan in vivo adalah isolat bakteri endofit asal ubi kentang yaitu isolat CK U3 (Lysinibacillus sp.).Kata Kunci: Pengendalian biologi, Bakteri endofit, Pascapanen, Kentang, Penyakit busuk basah


2021 ◽  
Vol 4 (2) ◽  
pp. 1077-1086
Author(s):  
Nguyen Thanh Trung ◽  
Nguyen Thi Van Anh ◽  
Tran Thi Dao ◽  
Nguyen Thanh Huyen ◽  
Pham Le Anh Minh ◽  
...  

Erwinia is a genus of Enterobacteriacea containing mostly pathogens, which cause soft rot disease in many ornamental plants and crops, including Asparagus officinalis. Chemical treatments to control Erwinia have lost their attractiveness because of the development of resistant strains and the negative impacts on the environment and human health. Therefore, the study of biological controls of soft rot disease has gained great importance. There are several types of microorganisms that show activity against Erwinia spp. such as Pseudomonas fluorescence, Bacillus subtilis, and Streptomyces spp. Among them, Streptomyces spp. are found to be the most effective control agents. In this study, 64 isolates of Streptomyces were screened for their antibacterial activity against Erwinia spp. The results indicated that 18 isolates showed an antagonistic reaction against Erwinia spp. Among them, isolate D5.1 showed the highest inhibition activity. In addition, the morphological and antibacterial activities of isolate D5.1 grown in different conditions were also characterized. 


2022 ◽  
Author(s):  
Yunpeng Wang ◽  
Xiaoli Wang ◽  
Jingfeng Zhu ◽  
Huan Wei ◽  
Zhipeng Ding ◽  
...  

2019 ◽  
Vol 8 (7) ◽  
Author(s):  
Xing Ma ◽  
Nicole T. Perna ◽  
Jeremy D. Glasner ◽  
Jianjun Hao ◽  
Steven Johnson ◽  
...  

In 2014, an outbreak of potato blackleg and soft rot disease emerged in North America and continues to impact potato production. Here, we report the annotated genome sequence of Dickeya dianthicola ME23, a strain hypothesized to be representative of the bacterial population responsible for this disease outbreak.


2001 ◽  
Vol 47 (10) ◽  
pp. 916-924 ◽  
Author(s):  
Tika B Adhikari ◽  
C M Joseph ◽  
Guoping Yang ◽  
Donald A Phillips ◽  
Louise M Nelson

Of 102 rhizoplane and endophytic bacteria isolated from rice roots and stems in California, 37% significantly (P [Formula: see text] 0.05) inhibited the growth in vitro of two pathogens, Achlya klebsiana and Pythium spinosum, causing seedling disease of rice. Four endophytic strains were highly effective against seedling disease in growth pouch assays, and these were identified as Pseudomonas fluorescens (S3), Pseudomonas tolaasii (S20), Pseudomonas veronii (S21), and Sphingomonas trueperi (S12) by sequencing of amplified 16S rRNA genes. Strains S12, S20, and S21 contained the nitrogen fixation gene, nifD, but only S12 was able to reduce acetylene in pure culture. The four strains significantly enhanced plant growth in the absence of pathogens, as evidenced by increases in plant height and dry weight of inoculated rice seedlings relative to noninoculated rice. Three bacterial strains (S3, S20, and S21) were evaluated in pot bioassays and reduced disease incidence by 50%–73%. Strain S3 was as effective at suppressing disease at the lowest inoculum density (106 CFU/mL) as at higher density (108 CFU/mL or undiluted suspension). This study indicates that selected endophytic bacterial strains have potential for control of seedling disease of rice and for plant growth promotion.Key words: biological control, plant growth promotion, endophytes, rice, seedling disease.


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