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Ramatsitsi MN, Khosa MC, Mashamaite CV, Ramachela K. In Vitro Assessment of Eight Selected Indigenous Fungal Isolates Tolerance to Various Abiotic Stresses and their Effects on Seed Germination. Curr Microbiol 2023; 80:386. [PMID: 37875629 PMCID: PMC10598106 DOI: 10.1007/s00284-023-03507-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/26/2023] [Indexed: 10/26/2023]
Abstract
Fungal bio-control agents (BCA) can minimize use of agro-chemicals while increasing plant productivity and tolerance to biotic-abiotic stressors. Ideally, BCA should tolerate varying environmental conditions they are introduced into, to successfully dominate and protect plants from stressors. However, BCA are living micro-organisms, their survival and efficacy can be impeded by extreme conditions. The current study aimed at evaluating whether indigenous fungal isolates, viz, Aspergillus flavus, A. terreus, Penicillium sp. AL-38 IRH-2012b, Talaromyces minioluteus, T. purpureogenus, T. sayulitensis, Trichoderma ghanense and T. viride can tolerate different levels of salinity, pH, nutrient and temperature. Certain fungal species are pests with potential of destroying many crops; the pathogenic effects of the aforementioned fungal isolates were further assessed on different crops' seeds. The results showed that, although being indigenous, Aspergillus, T. sayulitensis and T. ghanense failed to thrive in high salinity and pH. While Penicillium sp. AL-38 IRH-2012b failed to thrive under reduced nutrient level and all fungal isolates failed to grow at 10-20 °C. Furthermore, it was noted species within the same genus could affect crops in both favorable and unfavorable ways. The study demonstrated that the selected indigenous fungal isolates can tolerate different abiotic conditions and have potential to improve seed germination and seedling growth.
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Affiliation(s)
- Mukondeleli N Ramatsitsi
- School of Agricultural Sciences, North-West University, Private Bag X2046, Mahikeng, 2745, South Africa.
| | - Mbokota C Khosa
- Agricultural Research Council-Tropical and Subtropical Crops, Private Bag X11208, Mbombela, 1200, South Africa
| | - Chuene V Mashamaite
- Department of Agronomy, University of Fort Hare, Private Bag X 1314, Alice, 5700, South Africa
| | - Khosi Ramachela
- School of Agricultural Sciences, North-West University, Private Bag X2046, Mahikeng, 2745, South Africa
- Food Security and Safety Niche Area, Crop Science Department, North-West University, Private Bag X2046, Mahikeng, 2745, South Africa
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Awan UA, Meng L, Xia S, Raza MF, Zhang Z, Zhang H. Isolation, fermentation, and formulation of entomopathogenic fungi virulent against adults of Diaphorina citri. PEST MANAGEMENT SCIENCE 2021; 77:4040-4053. [PMID: 33896118 DOI: 10.1002/ps.6429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 04/13/2021] [Accepted: 04/25/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Mycopesticides are important for integrated management of the Asian citrus psyllid, Diaphorina citri. However, there are few reports on the fermentation and formulation for mycopesticides with high virulence against D. citri. RESULTS From four different locations in South China, 12 fungal strains were isolated and classified into Beauveria bassiana (two isolates), Fusarium fujikuroi (five isolates), and Cordyceps javanica (five isolates) based on the phylogenetic analysis of ITS1-5.8S rDNA-ITS4 and morphology of colonies and conidia. Based on the highest initial virulence (86.52 ± 2.35%) and best growth characteristics, F-HY002-ACPHali was further optimized for biphasic fermentation (7.85 ± 2.62 × 109 g-1 dry substrate) with soybean meal + cottonseed flour (1:1) as the solid substrate and full light as the light/dark cycle. Furthermore, the oil-based conidial formulation was optimized with sesame oil as an effective carrier, which significantly enhanced conidial shelf life up to 16 weeks at 26 °C and 4 °C, thermo-stress (50 °C) and UV-B stress resistance, and virulence against adults of D. citri with increased mortalities and decreased LT50 in comparison to that of unformulated conidia. CONCLUSION Our results not only provide a valuable native strain with high virulence against adults of D. citri, but also imply the soybean meal + cottonseed flour as valuable solid substrate, full-light exposure as environmental stimuli for solid-state fermentation, and the sesame oil as an effective carrier for the formulation of the C. javanica. These findings will facilitate the development of a potential mycopesticide for the biological control of Asian citrus psyllid.
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Affiliation(s)
- Umar Anwar Awan
- State Key Laboratory of Agricultural Microbiology, Key Laboratory of Horticultural Plant Biology (MOE), College of Plant Science and Technology, Institute of Urban and Horticultural Entomology, Huazhong Agricultural University, Wuhan, China
| | - Lixue Meng
- School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Shuang Xia
- State Key Laboratory of Agricultural Microbiology, Key Laboratory of Horticultural Plant Biology (MOE), College of Plant Science and Technology, Institute of Urban and Horticultural Entomology, Huazhong Agricultural University, Wuhan, China
| | - Muhammad Fahim Raza
- State Key Laboratory of Agricultural Microbiology, Key Laboratory of Horticultural Plant Biology (MOE), College of Plant Science and Technology, Institute of Urban and Horticultural Entomology, Huazhong Agricultural University, Wuhan, China
| | - Zhenyu Zhang
- State Key Laboratory of Agricultural Microbiology, Key Laboratory of Horticultural Plant Biology (MOE), College of Plant Science and Technology, Institute of Urban and Horticultural Entomology, Huazhong Agricultural University, Wuhan, China
| | - Hongyu Zhang
- State Key Laboratory of Agricultural Microbiology, Key Laboratory of Horticultural Plant Biology (MOE), College of Plant Science and Technology, Institute of Urban and Horticultural Entomology, Huazhong Agricultural University, Wuhan, China
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Acheampong MA, Coombes CA, Moore SD, Hill MP. Temperature tolerance and humidity requirements of select entomopathogenic fungal isolates for future use in citrus IPM programmes. J Invertebr Pathol 2020; 174:107436. [PMID: 32619548 DOI: 10.1016/j.jip.2020.107436] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/21/2020] [Accepted: 06/20/2020] [Indexed: 11/26/2022]
Abstract
Several isolates of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitacae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitacae) have been investigated as possible microbial control agents of key citrus pests in South Africa. Although laboratory results have been promising, field trials against foliar pests have shown limited success. These findings highlighted the need to investigate other biological attributes of these fungal isolates besides virulence in order to select candidates that may be better suited for the foliar environment. Thus, this study investigated the influence of temperature on the in vitro growth of seven indigenous local isolates and the humidity requirements necessary to promote successful infection, in comparison with two commercial isolates (B. bassiana PPRI 5339 and M. anisopliae ICIPE 69). All the fungal isolates grew across a range of temperatures (8-34 °C) and optimally between 26 and 28 °C. Similarly, fungal infection of Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) fifth instars occurred across a range of humidity levels (12%, 43%, 75%, 98%) regardless of fungal concentration, although external sporulation was restricted to treatments exposed to 98% relative humidity. It was concluded that neither temperature nor humidity, when considered alone, is likely to significantly influence the efficacy of any of the isolates in the field, given that they are active within temperature and humidity ranges experienced in South African citrus orchards.
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Affiliation(s)
- M A Acheampong
- Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
| | - C A Coombes
- Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
| | - S D Moore
- Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa; Citrus Research International, Walmer, P.O. Box 5095, Port Elizabeth 6065, South Africa.
| | - M P Hill
- Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
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Ibarra-Cortés KH, Guzmán-Franco AW, González-Hernández H, Ortega-Arenas LD, Villanueva-Jiménez JA, Robles-Bermúdez A. Susceptibility of Diaphorina citri (Hemiptera: Liviidae) and Its Parasitoid Tamarixia radiata (Hymenoptera: Eulophidae) to Entomopathogenic Fungi under Laboratory Conditions. NEOTROPICAL ENTOMOLOGY 2018; 47:131-138. [PMID: 28721609 DOI: 10.1007/s13744-017-0539-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 06/29/2017] [Indexed: 06/07/2023]
Abstract
Diaphorina citri (Kuwayama) is a global pest of citrus that transmits the bacteria associated with the disease, Huanglongbing. Entomopathogenic fungi and the parasitoid Tamarixia radiata (Waterston) are important biological control agents of this pest and likely to interact in D. citri populations. As a basis for interaction studies, we determined the susceptibility of nymphs and adults of D. citri and adults of the parasitoid T. radiata to six fungal isolates from the species Beauveria bassiana s.l. (Bals.-Criv.) Vuill. (isolates B1 and B3), Metarhizium anisopliae s.s. (Metsch.) (Ma129 and Ma65) and Isaria fumosorosea Wize (I2 and Pae). We conducted experiments evaluating infection levels in all three insect groups following inoculation with a series of conidial concentrations (1 × 104-1 × 108 conidia mL-1). Results showed that D. citri nymphs and T. radiata were more susceptible to fungal isolates than D. citri adults. Overall, B. bassiana and M. anisopliae isolates caused the greatest infection compared with I. fumosorosea isolates in all three groups of insects. Isolates B1 (B. bassiana) and Ma129 (M. anisopliae) infected a greater proportion of adults and nymphs of D. citri, respectively. Both isolates of B. bassiana caused greater infection in T. radiata compared with isolates of the other fungal species. We propose that isolates B1 and Ma129 are the strongest candidates for control of D. citri. Our results represent the first report of entomopathogenic fungi infecting T. radiata, and the basis for future studies to design a biological control programme that uses both agents more efficiently against D. citri populations.
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Affiliation(s)
- K H Ibarra-Cortés
- Posgrado en Fitosanidad - Entomología y Acarología, Colegio de Postgraduados, Km. 36.5 Carretera México-Texcoco, Montecillo, Mpio., 56230, Texcoco, Edo. de Mexico, Mexico
| | - A W Guzmán-Franco
- Posgrado en Fitosanidad - Entomología y Acarología, Colegio de Postgraduados, Km. 36.5 Carretera México-Texcoco, Montecillo, Mpio., 56230, Texcoco, Edo. de Mexico, Mexico.
| | - H González-Hernández
- Posgrado en Fitosanidad - Entomología y Acarología, Colegio de Postgraduados, Km. 36.5 Carretera México-Texcoco, Montecillo, Mpio., 56230, Texcoco, Edo. de Mexico, Mexico
| | - L D Ortega-Arenas
- Posgrado en Fitosanidad - Entomología y Acarología, Colegio de Postgraduados, Km. 36.5 Carretera México-Texcoco, Montecillo, Mpio., 56230, Texcoco, Edo. de Mexico, Mexico
| | | | - A Robles-Bermúdez
- Facultad de Agronomía, Univ Autónoma de Nayarit, Xalisco, Nayarit, Mexico
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Characterization and virulence of Beauveria bassiana associated with auger beetle ( Sinoxylon anale ) infesting allspice ( Pimenta dioica ). J Invertebr Pathol 2016; 139:67-73. [DOI: 10.1016/j.jip.2016.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/26/2016] [Accepted: 07/28/2016] [Indexed: 11/21/2022]
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