Changes in the phytoalexin content in unripe fruit of banana, Musa acuminata, were analyzed after various treatments. The results show that level of hydroxyanigorufone started to increase 1-2 day after either wounding or inoculation with conidia of Colletotrichum musae. Inoculation followed by wounding induced the formation of many other phenylphenalenones. The accumulation of hydroxyanigorufone decreased, after its transient maximum, on ripening by exposure of the wounded fruit to ethylene. The level of production of hydroxyanigorufone in ripe fruit treated by wounding and/or by inoculation was much lower than that in unripe fruit. 2-Aminooxyacetic acid, an inhibitor of phenylalanine ammonia-lyase (PAL), inhibited the accumulation of hydroxyanigorufone in wounded fruit, and the PAL activity increased after wounding and ethylene treatment, respectively. Feeding experiments with [1-13C] and [2-13C]cinnamic acids, and [2-13C]malonate show that two molecules of cinnamic acid and one of malonate were incorporated into each molecule of hydroxyanigorufone. The phytoalexins isolated from fruit to which deuterated hydroxyanigorufone and irenolone had been administered revealed that 2-(4′-hydroxyphenyl)-1,8-naphthalic anhydride was biosynthesized from hydroxyanigorufone rather than from irenolone.
分析了香蕉(Musa acuminata)未熟果实中植物毒素含量在经过各种处理后的变化。结果表明,在造成伤口或接种 Colletotrichum musae 的分生孢子后 1-2 天,羟基
茴香酮的含量开始增加。接种后再造成伤口,会诱导形成许多其他苯
丙烯酮。羟基
苯并呋喃酮的积累量在短暂达到最大值后,在果实成熟时,通过将受伤果实暴露于
乙烯中而减少。在经过伤口和/或接种处理的成熟果实中,羟基安哥
氟酮的产生
水平远远低于未熟果实。苯丙
氨酸
氨解酶(PAL)
抑制剂 2-Aminooxyacetic acid 可抑制伤果中羟基安哥
氟酮的积累,伤果和
乙烯处理后 PAL 活性分别升高。用[1-13C]和[2-13C]
肉桂酸以及[2-13C]
丙二酸盐进行的喂养实验表明,每个羟基安鲁酮分子中含有两个
肉桂酸分子和一个
丙二酸分子。从施用了
氘代羟基安哥
氟酮和壬内酯的果实中分离出的植物毒素表明,2-(4′-羟基苯基)-1,8-
萘酸酐是由羟基安哥
氟酮而不是壬内酯
生物合成的。