Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR
The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing areas in California. Several isolates can produce aflatoxins that occasionally contaminate nut kernels conditioning their sale. The strain AF36 of A. flavus, which does not produce aflatoxins, is registe...
| Main Authors: | , , , , , |
|---|---|
| Format: | Journal Article |
| Language: | Inglés |
| Published: |
Scientific Societies
2021
|
| Subjects: | |
| Online Access: | https://hdl.handle.net/10568/110905 |
| _version_ | 1855527060197343232 |
|---|---|
| author | Garcia-Lopez, M.T. Luo, Y. Ortega Beltran, A. Jaime, R. Moral, J. Michailides, T. |
| author_browse | Garcia-Lopez, M.T. Jaime, R. Luo, Y. Michailides, T. Moral, J. Ortega Beltran, A. |
| author_facet | Garcia-Lopez, M.T. Luo, Y. Ortega Beltran, A. Jaime, R. Moral, J. Michailides, T. |
| author_sort | Garcia-Lopez, M.T. |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing areas in California. Several isolates can produce aflatoxins that occasionally contaminate nut kernels conditioning their sale. The strain AF36 of A. flavus, which does not produce aflatoxins, is registered as a biocontrol agent for use in almond, pistachio, and fig crops in California. After application in the orchards, AF36 displaces aflatoxin-producing Aspergillus spp. and thus reduces aflatoxin contamination. Vegetative compatibility assays (VCA) have traditionally been used to track AF36 in soils and crops where it has been applied. However, VCA is labor-intensive and time-consuming. Here, we developed a quantitative real-time PCR (qPCR) protocol to quantify proportions of AF36 accurately and efficiently in different substrates. Specific primers to target AF36 and toxigenic strains of A. flavus and A. parasiticus were designed based on sequence of aflC, a gene essential for aflatoxin biosynthesis. Standard curves were generated to calculate proportions of AF36 based on threshold values (Cq). Verification assays using pure DNA and conidial suspension mixtures demonstrated a significant relationship by regression analysis between known and qPCR-measured AF36 proportions in DNA (R2 = 0.974; P < 0.001) and conidia mixtures (R2 = 0.950; P < 0.001). The tests conducted by qPCR in pistachio leaves, nuts, and soil samples demonstrated the usefulness of the qPCR method to precisely quantify proportions of AF36 in diverse substrates, ensuring important time and cost savings. The outputs of the current study will serve to design better aflatoxin management strategies for pistachio and other crops. |
| format | Journal Article |
| id | CGSpace110905 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Scientific Societies |
| publisherStr | Scientific Societies |
| record_format | dspace |
| spelling | CGSpace1109052025-01-28T07:08:05Z Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR Garcia-Lopez, M.T. Luo, Y. Ortega Beltran, A. Jaime, R. Moral, J. Michailides, T. aflatoxins aspergillus flavus aspergillus parasiticus biological control The species Aspergillus flavus and A. parasiticus are commonly found in the soils of nut-growing areas in California. Several isolates can produce aflatoxins that occasionally contaminate nut kernels conditioning their sale. The strain AF36 of A. flavus, which does not produce aflatoxins, is registered as a biocontrol agent for use in almond, pistachio, and fig crops in California. After application in the orchards, AF36 displaces aflatoxin-producing Aspergillus spp. and thus reduces aflatoxin contamination. Vegetative compatibility assays (VCA) have traditionally been used to track AF36 in soils and crops where it has been applied. However, VCA is labor-intensive and time-consuming. Here, we developed a quantitative real-time PCR (qPCR) protocol to quantify proportions of AF36 accurately and efficiently in different substrates. Specific primers to target AF36 and toxigenic strains of A. flavus and A. parasiticus were designed based on sequence of aflC, a gene essential for aflatoxin biosynthesis. Standard curves were generated to calculate proportions of AF36 based on threshold values (Cq). Verification assays using pure DNA and conidial suspension mixtures demonstrated a significant relationship by regression analysis between known and qPCR-measured AF36 proportions in DNA (R2 = 0.974; P < 0.001) and conidia mixtures (R2 = 0.950; P < 0.001). The tests conducted by qPCR in pistachio leaves, nuts, and soil samples demonstrated the usefulness of the qPCR method to precisely quantify proportions of AF36 in diverse substrates, ensuring important time and cost savings. The outputs of the current study will serve to design better aflatoxin management strategies for pistachio and other crops. 2021-06 2021-01-19T11:24:45Z 2021-01-19T11:24:45Z Journal Article https://hdl.handle.net/10568/110905 en Open Access Scientific Societies Garcia-Lopez, M.T., Luo, Y., Ortega-Beltran, A., Jaime, R., Moral, J. & Michailides, T. (2021). Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR. Plant Disease, 1-43. |
| spellingShingle | aflatoxins aspergillus flavus aspergillus parasiticus biological control Garcia-Lopez, M.T. Luo, Y. Ortega Beltran, A. Jaime, R. Moral, J. Michailides, T. Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR |
| title | Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR |
| title_full | Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR |
| title_fullStr | Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR |
| title_full_unstemmed | Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR |
| title_short | Quantification of the aflatoxin biocontrol strain Aspergillus flavus AF36 in soil, and nuts and leaves of pistachio by real-time PCR |
| title_sort | quantification of the aflatoxin biocontrol strain aspergillus flavus af36 in soil and nuts and leaves of pistachio by real time pcr |
| topic | aflatoxins aspergillus flavus aspergillus parasiticus biological control |
| url | https://hdl.handle.net/10568/110905 |
| work_keys_str_mv | AT garcialopezmt quantificationoftheaflatoxinbiocontrolstrainaspergillusflavusaf36insoilandnutsandleavesofpistachiobyrealtimepcr AT luoy quantificationoftheaflatoxinbiocontrolstrainaspergillusflavusaf36insoilandnutsandleavesofpistachiobyrealtimepcr AT ortegabeltrana quantificationoftheaflatoxinbiocontrolstrainaspergillusflavusaf36insoilandnutsandleavesofpistachiobyrealtimepcr AT jaimer quantificationoftheaflatoxinbiocontrolstrainaspergillusflavusaf36insoilandnutsandleavesofpistachiobyrealtimepcr AT moralj quantificationoftheaflatoxinbiocontrolstrainaspergillusflavusaf36insoilandnutsandleavesofpistachiobyrealtimepcr AT michailidest quantificationoftheaflatoxinbiocontrolstrainaspergillusflavusaf36insoilandnutsandleavesofpistachiobyrealtimepcr |