Characterization and abolishment of the cyclopiazonic acids produced by Aspergillus oryzae HMP-F28 |
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| Authors: | Ting Cao Junhong Ling Yi Liu Xiaoqi Chen Xiaoyue Tian Dali Meng |
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| Institution: | 1. Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China;2. College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China;3. School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, China;4. School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, China |
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| Abstract: | Extracellular alkalinization and H2O2 production are important early events during induced resistance establishment in plants. In a screen for metabolites as plant resistance activators from 98 fungal isolates associated with marine sponge Hymeniacidon perleve, the cyclopiazonic acids (CPAs) produced by Aspergillus oryzae HMP-F28 induced significant extracellular alkalinization coupled with augmented H2O2 production in tobacco cell suspensions. Bioassay-guided fractionation led to the isolation and structural elucidation of a new CPA congener (4, 3-hydroxysperadine A) and three known ones (1–3). To construct a mutasynthetic strain to generate unnatural CPA analogues, a hybrid pks-nrps gene (cpaS) was disrupted to abolish the production of the critical precursor of cyclo-acetoacetyl-L-tryptophan (cAATrp) and all the downstream CPA products. Elimination of cAATrp will allow cAATrp mimics being processed by the CPA biosynthetic machinery to produce CPA derivatives with designed structural features. |
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| Keywords: | Cyclopiazonic acid Aspergillus oryzae oxidative burst hybrid pks-nrps plant immune |
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