Increased conidiation associated with progression along the sterigmatocystin biosynthetic pathway
Increased conidiation associated with progression along the sterigmatocystin biosynthetic pathway
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DOI：
10.2307/3762134
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发表时间：
2004-11-01
期刊：
影响因子：
2.8
通讯作者：
Keller, NP
中科院分区：
文献类型：
--
作者：
Wilkinson, HH;Ramaswamy, A;Keller, NP
构巢曲霉杂色曲霉素（ST）基因簇包含ST生产所需的调节基因（aflR）和生物合成基因（stc基因）。该簇中共有26个基因，其中13个在生物合成途径中具有已知功能。这种复杂的次级途径代表了真菌的生理成本。我们用一系列的A.在另一个实施方案中，本发明的菌株是nidulans，不同之处仅在于aflR中的突变（导致不含ST中间体的菌株）或三个stc基因中的突变，所述三个stc基因不产生ST中间体（DeltastcJ）、产生早期ST中间体去甲异喹啉酸（DeltastcE）或产生晚期ST中间体versicolorin A（DeltastcU）。在两个独立的重复实验中，我们比较了由这些突变株和野生型ST生产者在中性（生长培养基）和宿主（玉米种子）环境中产生的分生孢子的数量。随着ST途径中的每一个渐进步骤，观察到无性孢子产生的逐步增加。因此，数据表明，这些次级代谢物途径基因的募集或丢失除了代谢物的生理活性外，还具有选择性优势。
The Aspergillus nidulans sterigmatocystin (ST) gene cluster contains both regulatory (aflR) and biosynthetic genes (stc genes) required for ST production. A total of 26 genes are in the cluster, 13 of which have been assigned a known function in the biosynthetic pathway. This complex secondary pathway represents a physiological cost to the fungus. We tested the amount of asexual spore production using a series of isogenic lines of A. nidulans, differing only in a mutation in aflR (resulting in a strain containing no ST intermediates) or a mutation in three stc genes that produced either no ST intermediates (DeltastcJ), an early ST intermediate, norsoloroinic acid (DeltastcE) or a late ST intermediate, versicolorin A (DeltastcU). In two independently replicated experiments we compared the numbers of conidia produced by each of these mutant strains and a wild type ST producer in a neutral (growth media) and a host (corn seed) environment. A stepwise increase in asexual spore production was observed with each progressive step in the ST pathway. Thus, the data suggest that recruitment or loss of these secondary metabolite pathway genes has a selective advantage apart from the physiological activity of the metabolite.