Metabolites, Biotransformation, and Plant-Growth Dual Regulatory Activity from Aspergillus nishimurae Uncovered by the Fermentation Interaction with a Host

One new azaphilone derivative (1) from Aspergillus nishimurae in ordinary medium, one new phthalide derivative (8), a microbial transformation product of Angelica sinensis ingredients by A. nishimurae, a pair of new austdiol enantiomers (+)-9 and (−)-9, one new epsilon-caprolactone derivative (10), and one new ophiobolin-type sesterterpenoid (13) from the A. nishimurae in host medium were reported. The structures were determined by spectroscopic analysis and single-crystal X-ray diffraction. Compounds 1–3 could completely inhibit the germination of rice seeds at 50 μg/mL, which is higher than that of the positive control. The mixture of compounds 8+2 represented an approximately 84% increase in root length at 20 μg/mL compared with that of phytotoxic compound 2. Compounds 8 and 16 led to approximately 39 and 7% increases in root length at 5 μg/mL compared with those of untreated rice seeds. Fermentation interactions between endophytes and host constituents induced cryptic metabolite, plant growth inhibiting, and plant growth promoting activities.