Isoflavonoid biosynthesis and accumulation in developing soybean seeds
Isoflavonoid biosynthesis and accumulation in developing soybean seeds
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DOI：
10.1023/b:plan.0000023666.30358.ae
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发表时间：
2003-12-01
影响因子：
5.1
通讯作者：
Gijzen, M
中科院分区：
文献类型：
--
作者：
Dhaubhadel, S;McGarvey, BD;Gijzen, M
异黄酮是具有生物活性的天然产物，在发育过程中积累在大豆种子中。大豆种子中存在的叶绿素的量是可变的，取决于尚未完全了解的遗传和环境因素。进行实验以确定是否在发育过程中在种子组织内合成，或在其他植物器官中合成并运输到种子中积累。通过HPLC分析大豆植株的所有器官中的黄酮类化合物，但黄酮类化合物的存在量取决于组织和发育阶段。成熟种子和叶片中的浓度最高。研究了2-羟基异黄烷酮合酶基因IFS 1和IFS 2，以确定其在不同组织和发育阶段的表达模式。IFS 1在根和种皮中的表达水平最高，而IFS 2在胚和豆荚中以及激发子处理或病原体攻击的组织中表达最高。当用[C-14]苯丙氨酸喂养发育中的胚胎和其他植物器官时，观察到放射性标记掺入到胚胎中。从发育中的大豆种子上切下的胚也从合成培养基中积累了大量的蛋白质。在不同的大豆品种间的正反交中，发现了母体对种子叶绿素含量的影响。从这些结果中，我们提出，发展中的大豆胚有能力合成从头开始，但从母体组织的运输可能部分有助于这些天然产物在种子中的积累。
Isoflavonoids are biologically active natural products that accumulate in soybean seeds during development. The amount of isoflavonoids present in soybean seed is variable, depending on genetic and environmental factors that are not fully understood. Experiments were conducted to determine whether isoflavonoids are synthesized within seed tissues during development, or made in other plant organs and transported to the seeds where they accumulate. An analysis of isoflavonoids by HPLC detected the compounds in all organs of soybean plant, but the amount of isoflavonoids present varied depending on the tissue and developmental stage. The greatest concentrations were found in mature seeds and leaves. The 2-hydroxyisoflavanone synthase genes IFS1 and IFS2 were studied to determine their pattern of expression in different tissues and developmental stages. The highest level of expression of IFS1 was observed in the root and seed coat, while IFS2 was most highly expressed in embryos and pods, and in elicitor-treated or pathogen-challenged tissues. Incorporation of radiolabel into isoflavonoids was observed when developing embryos and other plant organs were fed with [C-14] phenylalanine. Embryos excised from developing soybean seeds also accumulated isoflavonoids from a synthetic medium. A maternal effect on seed isoflavonoid content was noted in reciprocal crosses between soybean cultivars that differ in seed isoflavonoids. From these results, we propose that developing soybean embryos have an ability to synthesize isoflavonoids de novo, but that transport from maternal tissues may in part contribute to the accumulation of these natural products in the seed.