http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
이동률,Chaw Ei Htwe Maung,Ajuna Henry,김길용 한국토양비료학회 2019 한국토양비료학회지 Vol.52 No.2
The melanose disease causing Diaporthe citri is important pathogen in citrus plants worldwide. Currently, there are few researches related to biological control of melanose disease. In this study, we investigated control of Diaporthe citri by Bacillus amyloliquefaciens Y1 isolated from the soil. Low-cost fertilizer based PB medium and large-scale fermenter have been developed for field application of biological control. We prove that Y1 can be successfully grown in large-scale fermenters using PB medium without contamination. In addition, Y1 bacterial culture filtrates (BCF) of large-scale cultivation in PB medium (LP-Y1), present better growth inhibition of D. citri than small-scale cultivation in TSB medium (ST-Y1). Microscopic observations also showed that pathogen mycelial morphology was significantly affected by BCF, presumably due to metabolites produced by Y1. Finally, in pot experiment, pre-treatment with fungicide and Y1 to leaves significantly reduced disease incidence compared to the control group. This study showed that Y1 incubated with fertilizer based medium inhibited the occurrence of D. citri and could be grown in large scale field conditions without contamination as well as cost optimization.
Dong Ryul Lee,Chaw Ei Htwe Maung,Tae Gyu Choi,Kil Yong Kim 한국토양비료학회 2021 한국토양비료학회지 Vol.54 No.3
Diaporthe citri is an important fungal pathogen which causes melanose in various citrus growing regions of the world. In our study, control of D. citri was performed by using effective biocontrol agent, Bacillus velezensis CE 100. Mycelial growth of D. citri was highly restricted by strain CE 100 in dual culture plates. Our study demonstrates large-scale inoculation of strain CE 100 in non-sterilized PB medium. In addition, bacterial culture filtrate (BCF) of strain CE 100 from the large-scale culture showed better growth inhibition of D. citri than those from small-scale culture in the laboratory. Moreover, microscopic observation revealed that hyphal morphology of the pathogen was significantly affected by BCF, probably because of various cell-wall degrading enzymes and metabolites produced by strain CE 100. In addition, 50% BCF of strain CE 100 inhibited D. citri conidial germination by over 80%. Treatments, applied by foliar spray with fungicide and strain CE 100 culture, significantly lowered melanose disease incidence more than did control. The results of this study indicate that large-scale culture of strain CE 100 was effective for control of D. citri by means of adequate active metabolites and cells. Therefore, we demonstrate biocontrol applicability of B. velezensis CE 100 on control of citrus melanose by developing a low-cost PB medium using affordable large-scale fermenter.
Growth Enhancement of Tomato by a Plant Growth Promoting Bacterium, Bacillus subtilis PE
한성은,김길용,김길성,Chaw Ei Htwe Maung 한국토양비료학회 2023 한국토양비료학회지 Vol.56 No.4
Bacillus species are well recognized as effective bio-stimulants to enhance crop quality and productivity. Our study demonstrates the effect of a plant growth promoting bacterium, Bacillus subtilis PE7 on tomato growth. In vitro screening assay for plant growth promoting traits indicated that the indole-3-acetic acid (IAA) production of B. subtilis PE7 in terms of increasing intensity of pink color with the increasing concentration of ⳑ-tryptophan supplemented in tryptone soy broth (TSB) medium. The supplementation of ⳑ-tryptophan (1 g L-1) in the TSB medium resulted in the maximum IAA production of strain PE7 with 25.59 µg mL-1 at 6 days after incubation. Moreover, the highest ammonia production of strain PE7 with 21.22 µg mL-1 was observed at an incubation period of 72 h. The results of our pot experiment revealed that treatment with the strain PE7 culture (inoculated in fertilizer-based medium) induced a significant growth promotion of tomato plants resulting in higher values of leaf number, length, fresh and dry weights of shoot as compared to the control and fertilizer treatment. Therefore, B. subtilis PE7 could be considered as an effective candidate for the development of eco-friendly commercial fertilizer in crop production
Aphicidal activity of Bacillus thuringiensis strain AH‐2 against cotton aphid (Aphis gossypii)
Ajuna Henry B.,Kim Iksoo,Han Yeon Soo,Maung Chaw Ei Htwe,Kim Kil Yong 한국곤충학회 2021 Entomological Research Vol.51 No.4
Bacillus thuringiensis (Bt) is the most commercialized entomopathogenic species. However, the low efficacy against notorious sap‐sucking Hemipteran pests and the high costs of production, reduce the applicability of Bt biopesticides. In this context, B. thuringiensis AH‐2 (Bt‐2) isolated from soil was found to release parasporal inclusions and aphicidal activity. Bt‐2 showed optimal growth at pH 8 and 30°C in tryptic soy broth (TSB) and maintained normal growth when cultured in cost‐effective test media, pink brown (PB), supplemented with either glucose (PBG) or sucrose (PBS). To study aphicidal activity against cotton aphid (Aphis gossypii), Bt‐2 and a commercial B. thuringiensis subspecies kurstaki (Btk) were used. Using third nymph (3 N) instars, treatment with Bt‐2 caused 70.2, 78.1 and 88.4% mortality at 10, 25 and 50% culture concentrations, respectively. Similarly, Btk resulted in 79.9, 80.4 and 92.9% mortality at 10, 25 and 50%, respectively. When cultured in TSB, PBG and PBS media, Bt‐2 culture (50%) resulted in 85.9, 82.9 and 82.2% 3 N mortality, respectively. Equally, Btk caused a mortality of 79.9, 78.9 and 78.9% in TSB, PBG and PBS, respectively. Bt‐2 exerted a notably higher aphicidal efficacy at 24 h after treatment compared to Btk, especially at low concentration. Moreover, both Bt strains significantly suppressed adult fecundity compared to control. At 50% culture concentration, Bt‐2 and Btk suppressed adult fecundity by 98.3 and 91.1%, respectively. Our result demonstrates a strong aphicidal efficacy of Bt‐2, and its potential production using cost‐effective PB medium.