Differential Allocation of Seed-Borne Ergot Alkaloids During Early Ontogeny of Morning Glories (Convolvulaceae)
Differential Allocation of Seed-Borne Ergot Alkaloids During Early Ontogeny of Morning Glories (Convolvulaceae)
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DOI：
10.1007/s10886-013-0314-z
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发表时间：
2013-07-01
影响因子：
2.3
通讯作者：
Clay, Keith
中科院分区：
文献类型：
--
作者：
Beaulieu, Wesley T.;Panaccione, Daniel G.;Clay, Keith
麦角生物碱是一种真菌毒素，可以增加宿主植物对地上和地下食草动物的抵抗力。一些牵牛花（旋花科）被棒形真菌（Periglandula spp.）在种子中产生高浓度的麦角生物碱--比内生菌感染的草高1000倍。在这里，我们评估了种子和幼苗中生物碱的多样性和分布以及种间生物碱分布的差异。我们用杀真菌剂处理了一半的植物，以区分种子携带的生物碱和萌发后从头产生的生物碱，并在子叶和第一叶阶段取样幼苗组织。番薯种子中的生物碱，I.泥生菌属和I. hildebrandtii主要存在于子叶中，而I. Tricolor将麦角酸酰胺分配到根中，而将棒形麦角酸保留在子叶中。在重症hildebrandtii的子叶中发现了几乎所有的festuclavine。这些观察结果表明个别生物碱的差异分配。种内生物碱分布格局没有变化之间的杀菌剂处理和对照苗。每个物种含有四到六种独特的麦角生物碱，两个物种含有麦角肽碱麦角巴兰新碱。生物碱的从头生产并没有立即开始，因为除I.泥生菌。在一个扩展的时程实验中，I。三色，在第一叶期后检测到从头产生。我们的研究结果表明，种子传播麦角生物碱的分配不同的物种和组织，但不改变杀菌剂处理。这种变化可能反映了对天敌防御选择的反应。
Ergot alkaloids are mycotoxins that can increase host plant resistance to above- and below-ground herbivores. Some morning glories (Convolvulaceae) are infected by clavicipitaceous fungi (Periglandula spp.) that produce high concentrations of ergot alkaloids in seeds-up to 1000-fold greater than endophyte-infected grasses. Here, we evaluated the diversity and distribution of alkaloids in seeds and seedlings and variation in alkaloid distribution among species. We treated half the plants with fungicide to differentiate seed-borne alkaloids from alkaloids produced de novo post-germination and sampled seedling tissues at the cotyledon and first-leaf stages. Seed-borne alkaloids in Ipomoea amnicola, I. argillicola, and I. hildebrandtii remained primarily in the cotyledons, whereas I. tricolor allocated lysergic acid amides to the roots while retaining clavines in the cotyledons. In I. hildebrandtii, almost all festuclavine was found in the cotyledons. These observations suggest differential allocation of individual alkaloids. Intraspecific patterns of alkaloid distribution did not vary between fungicide-treated and control seedlings. Each species contained four to six unique ergot alkaloids and two species had the ergopeptine ergobalansine. De novo production of alkaloids did not begin immediately, as total alkaloids in fungicide-treated and control seedlings did not differ through the first-leaf stage, except in I. argillicola. In an extended time-course experiment with I. tricolor, de novo production was detected after the first-leaf stage. Our results demonstrate that allocation of seed-borne ergot alkaloids varies among species and tissues but is not altered by fungicide treatment. This variation may reflect a response to selection for defense against natural enemies.