Cao Ting, Ling Junhong, Liu Yi, Chen Xiaoqi, Tian Xiaoyue, Meng Dali, Pan Huaqi, Hu Jiangchun, Wang Nan
a Institute of Applied Ecology , Chinese Academy of Sciences , Shenyang , China.
b College of Life Sciences , University of Chinese Academy of Sciences , Beijing , China.
Biosci Biotechnol Biochem. 2018 Oct;82(10):1832-1839. doi: 10.1080/09168451.2018.1490170. Epub 2018 Jul 9.
Extracellular alkalinization and HO 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 HO 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.
细胞外碱化和过氧化氢（HO）生成是植物诱导抗性建立过程中的重要早期事件。在从与海鞘状海绵 Hymeniacidon perleve 相关的 98 种真菌分离物中筛选作为植物抗性激活剂的代谢物时，米曲霉 HMP-F28 产生的环匹阿尼酸（CPAs）在烟草细胞悬浮液中诱导了显著的细胞外碱化，并伴随着 HO 生成增加。生物测定导向的分级分离导致分离并阐明了一种新的 CPA 同系物（4, 3-羟基麦角硫因 A）和三种已知同系物（1-3）。为构建一个产生非天然 CPA 类似物的突变合成菌株，一个杂合的聚酮合酶-非核糖体肽合成酶基因（cpaS）被破坏，以消除环乙酰乙酰-L-色氨酸（cAATrp）关键前体及所有下游 CPA 产物的产生。消除 cAATrp 将使 cAATrp 类似物能够被 CPA 生物合成机制加工，以产生具有设计结构特征的 CPA 衍生物。
