Morkunas Iwona, Marczak Łukasz, Stachowiak Jerzy, Stobiecki Maciej
Department of Plant Physiology, August Cieszkowski Agricultural University, Wołyńska 35, 60-637 Poznań, Poland.
Plant Physiol Biochem. 2005 Apr;43(4):363-73. doi: 10.1016/j.plaphy.2005.02.011. Epub 2005 Mar 17.
Defense responses to inoculation with Fusarium oxysporum SCHLECHT f. sp. lupini were studied in embryo axes of Lupinus luteus L. cv. Polo cultured on a medium with sucrose (60 mM) or without it. Exogenous sucrose caused a marked endogenous increase in concentrations of sucrose, glucose and fructose in embryo axes. In axes cultured with sucrose, high performance liquid chromatography (HPLC) revealed generally higher levels of isoflavone glycosides (particularly until 48 h of culture) and free aglycones (genistein, wighteone, luteone). Inoculation resulted in a considerable decline in soluble carbohydrates between 24 and 72 h of culture. Simultaneously, the infection stimulated an increase in the level of free isoflavone aglycones in inoculated embryo axes, as compared to non-inoculated ones. Concentrations of free aglycones (i.e. genistein, wighteone and luteone) after infection were particularly high in inoculated embryo axes fed with sucrose. Genistein was a better inhibitor to F. oxysporum growth than genistein 7-O-glucoside tested. Exogenous sucrose also stimulated the activity of phenylalanine ammonialyase (PAL, EC 4.3.1.5)--an important enzyme initiating phenylpropanoid metabolism. After infection of tissues, a strong increase was observed in the activity of PAL and beta-glucosidase (EC 3.2.1.21)--an enzyme hydrolyzing isoflavone glycosides. Furthermore, the growth of inoculated embryo axes cultured with sucrose was less inhibited as a result of infection than inoculated axes cultured under carbohydrate deficiency conditions. Additionally, it had been reported previously that disease symptoms of embryo axes growing in the presence of sucrose were less intensive [30]. These results suggest that soluble sugars are involved in the mechanism of resistance, as they can stimulate phenylpropanoid metabolism and contribute to the increase in concentration of isoflavonoids, which are important elements of the defense system of legumes.
在添加蔗糖（60 mM）或不添加蔗糖的培养基上培养的白羽扇豆（Lupinus luteus L. cv. Polo）胚轴中，研究了对尖孢镰刀菌（Fusarium oxysporum SCHLECHT f. sp. lupini）接种的防御反应。外源蔗糖导致胚轴中蔗糖、葡萄糖和果糖的内源浓度显著增加。在用蔗糖培养的胚轴中，高效液相色谱（HPLC）显示异黄酮苷（特别是在培养48小时之前）和游离苷元（染料木黄酮、鹰嘴豆芽素A、黄羽扇豆酮）的水平普遍较高。接种导致培养24至72小时之间可溶性碳水化合物大幅下降。同时，与未接种的胚轴相比，感染刺激了接种胚轴中游离异黄酮苷元水平的增加。在添加蔗糖的接种胚轴中，感染后游离苷元（即染料木黄酮、鹰嘴豆芽素A和黄羽扇豆酮）的浓度特别高。与测试的染料木黄酮7-O-葡萄糖苷相比，染料木黄酮对尖孢镰刀菌生长的抑制作用更好。外源蔗糖还刺激了苯丙氨酸解氨酶（PAL，EC 4.3.1.5）的活性，PAL是启动苯丙烷代谢的一种重要酶。组织感染后，观察到PAL和β-葡萄糖苷酶（EC 3.2.1.21，一种水解异黄酮苷的酶）的活性大幅增加。此外，与在碳水化合物缺乏条件下培养的接种胚轴相比，用蔗糖培养的接种胚轴生长受感染的抑制较小。此外，先前已有报道称，在蔗糖存在下生长的胚轴的病害症状较轻[30]。这些结果表明，可溶性糖参与了抗性机制，因为它们可以刺激苯丙烷代谢并有助于增加异黄酮的浓度，而异黄酮是豆类防御系统的重要组成部分。
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