24 アブシシン酸生産糸状菌におけるカロテノイドの存在

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The C_15 pathway via the direct cyclization of farnesyi diphosphate has been proposed for the abscisic acid (ABA) biosynthetic pathway in fungi. However, feeding experiments with ^<18>O_2 have suggested that a fungus biosynthesizes ABA via oxidative cleavage of carotenoids as well as higher plants, although 9Z-carotenoids that would be substrates for the oxidative cleavage have not been found. We examined whether two ABA-producing fungi, Cercospora cruenta and Botrytis cinerea, produce carotenoids including 9Z-isomers. C.cruenta was cultured on a liquid medium with cotton cap or silicon cap. ABA in the medium, and carotenoids in the mycelia were analyzed by HPLC equipped with a photodiode array detector. The maximum level of ABA was 3.6 mg/L. in the culture with cotton cap, and 0.17 mg/L in the culture with silicon cap. all-E-β-Carotene (4.0 mg) was detected in the mycelia cultured with cotton cap, while 15Z-phytoene (0.7 mg) and unidentified carotenoid (0.2 mg) were found in addition to all-E-β-carotene (0.6 mg) in the mycelia cultured with silicon cap,. The cultural condition of silicon cap is more anaerobic than that of cotton cap. Suppression of oxidation under the anaerobic condition may cause accumulation of metabolic intermediates of carotenoids and result in decrease in ABA production. B. cinerea also produced a small amount of a carotenoid-like compound
植物化学調節学会の論文
2001-10-09