IAA biosynthetic pathways in a basidiomycetous yeast, Rhodosporidiobolus fluvialis DMKU-CP293, were investigated. The yeast strain showed tryptophan (Trp)-dependent IAA biosynthesis when grown in tryptophan supplemented mineral salt medium. Gas chromatography–mass spectrometry was used to further identify the pathway intermediates of Trp-dependent IAA biosynthesis. The results indicated that the main intermediates produced by R. fluvialis DMKU-CP293 were tryptamine (TAM), indole-3-acetic acid (IAA), and tryptophol (TOL), whereas indole-3-pyruvic acid (IPA) was not found. However, supplementation of IPA to the culture medium resulted in IAA peak detection by high-performance liquid chromatography analysis of the culture supernatant. Key enzymes of three IAA biosynthetic routes, i.e., IPA, IAM and TAM were investigated to clarify the IAA biosynthetic pathways of R. fluvialis DMKU-CP293. Results indicated that the activities of tryptophan aminotransferase, tryptophan 2-monooxygenase, and tryptophan decarboxylase were observed in cell crude extract. Overall results suggested that IAA biosynthetic in this yeast strain mainly occurred via the IPA route. Nevertheless, IAM and TAM pathway might be involved in R. fluvialis DMKU-CP293.

研究了担子菌酵母，Rhodosporidiobolus fluvialis DMKU-CP293中的IAA生物合成途径。当在补充色氨酸的无机盐培养基中生长时，酵母菌株显示出色氨酸（Trp）依赖性的IAA生物合成。气相色谱-质谱法用于进一步鉴定依赖Trp的IAA生物合成的途径中间体。结果表明，河豚草产生的主要中间体DMKU-CP293为色胺（TAM），吲哚-3-乙酸（IAA）和色胺醇（TOL），而未发现吲哚-3-丙酮酸（IPA）。但是，向培养基中补充IPA会通过高效液相色谱分析培养上清液而导致IAA峰检测。3种IAA生物合成途径，即关键酶，IPA，IAM和TAM进行了研究，以澄清的IAA生物合成途径R.河流弧菌DMKU-CP293。结果表明，在细胞粗提物中观察到了色氨酸氨基转移酶，色氨酸2-单加氧酶和色氨酸脱羧酶的活性。总体结果表明，该酵母菌株中IAA的生物合成主要通过IPA途径进行。尽管如此，IAM和TAM途径可能参与了R. fluvialis DMKU-CP293。