Mouhamadou Bello, Sage Lucile, Périgon Sophie, Séguin Virginie, Bouchart Valérie, Legendre Patrick, Caillat Mathilde, Yamouni Hayet, Garon David
Laboratoire d'Ecologie Alpine, UMR 5553 CNRS/USMB Université Grenoble Alpes, 38058 Grenoble Cedex 9, France.
Laboratoire d'Ecologie Alpine, UMR 5553 CNRS/USMB Université Grenoble Alpes, 38058 Grenoble Cedex 9, France.
Fungal Biol. 2017 Feb;121(2):103-111. doi: 10.1016/j.funbio.2016.10.001. Epub 2016 Oct 28.
Mycophenolic acid (MPA) is the fungal secondary metabolite displaying several biological properties. Up to now, screening of fungal strains producing MPA has mainly been the result of the search of this molecule in their culture medium by chemical methods. Here we developed a molecular approach by targeting the expression level of the MpaC gene encoding the polyketide synthase, one of the key enzymes involved in the MPA synthesis. Thirty xerophilic Aspergillus strains were identified using the RNA polymerase II subunit and the β-tubulin genes. Seven Aspergillus species were evidenced. The expression level of the MpaC gene was quantified and compared to the MPA production rate. Only Aspergillus pseudoglaucus and all the eight strains of this species produced MPA. While the MpaC gene was not expressed or weakly expressed in the MPA non-producing strains, all the A. pseudoglaucus strains presented a high level of expression of this gene. The highest expression level of the MpaC gene among the MPA non-producing strains was significantly lower than the lowest expression level of this gene in the MPA producing strains. To our knowledge, this is the first study that demonstrates the effectiveness of molecular approach for the screening of MPA-producing species.
霉酚酸（MPA）是一种具有多种生物学特性的真菌次生代谢产物。到目前为止，筛选产MPA的真菌菌株主要是通过化学方法在其培养基中寻找这种分子的结果。在此，我们通过靶向编码聚酮合酶的MpaC基因的表达水平开发了一种分子方法，聚酮合酶是参与MPA合成的关键酶之一。使用RNA聚合酶II亚基和β-微管蛋白基因鉴定了30株嗜干性曲霉菌株。确定了7个曲霉菌种。对MpaC基因的表达水平进行了定量，并与MPA产生率进行了比较。只有伪青霉曲霉及其该物种的所有8个菌株产生MPA。在不产MPA的菌株中，MpaC基因未表达或表达较弱，而所有伪青霉曲霉菌株该基因均呈现高水平表达。在不产MPA的菌株中，MpaC基因的最高表达水平显著低于产MPA菌株中该基因的最低表达水平。据我们所知，这是第一项证明分子方法筛选产MPA物种有效性的研究。
