Isolation and identification of Desmodium root exudates from drought tolerant species used as intercrops against Striga hermonthica.
Isolation and identification of Desmodium root exudates from drought tolerant species used as intercrops against Striga hermonthica.
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DOI：
10.1016/j.phytochem.2015.06.026
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发表时间：
2015-09
期刊：
影响因子：
3.8
通讯作者：
Khan ZR
中科院分区：
文献类型：
--
作者：
Hooper AM;Caulfield JC;Hao B;Pickett JA;Midega CAO;Khan ZR
耐旱的山蚂蝗属物种，当成熟时，产生抑制独脚金寄生的根分泌物，其包含一系列二-C-糖基黄酮。耐旱山蚂蝗根系分泌物的研究。通过HPLC和LCMS分析。使用标准品将化合物鉴定为二-C-糖基黄酮。4个月后，耐旱物种的分泌物彼此相似。在所有情况下，渗出物在盆栽实验中具有独脚金抑制特性。山蚂蝗属在半干旱的田间条件下，山蚂蝗属植物，特别是山蚂蝗D.在撒哈拉以南的小农户农场中，将Striga hermonthica和Striga asiatica用作间作作物，以通过化感作用机制抑制Striga hermonthica和Striga asiatica对谷类作物的寄生。寻找适应更干旱条件的山蚂蝗属物种，并表现出对干旱胁迫的适应性，以前确定的D。intortum，D. incanum和D.具有潜在的耐旱性。在资源贫乏的雨养谷物生产地区，干旱条件可能通过正常的气象活动持续存在，或干旱可能通过气候变化产生越来越大的影响，评估了它们作为间作作物的潜力。根分泌物的化学成分进行了表征和整个分泌物的生物活性被证明是活跃的盆栽试验抑制Striga寄生在玉米上。此外，雨养小区试验表明，耐旱的山蚂蝗间作是有效的抑制独脚金。这项工作证明了新的耐旱间作的化感作用的性质，通过根分泌物的活性和分泌物中看到的主要化合物的特点是C-糖基类黄酮。在幼小的植物中，渗出物显示出很大的质的差异，但随着植物成熟，在赋予生物活性的活性山蚂蝗间作中，C-糖基类黄酮渗出物化学特征高度趋同。这定义了用于检查独脚金抑制机制的材料。
Drought tolerant Desmodium species, when mature, produce root exudates that inhibit Striga parasitism and which comprise a range of di-C-glycosylflavones. Root exudates from drought tolerant Desmodium spp. were analysed by HPLC and LCMS. Compounds were identified as di-C-glycosylflavones using standards. After 4 months, exudates from drought tolerant species were similar to each other. Exudates possessed Striga inhibitory properties in pot experiments in all cases. Desmodium spp. identified are active against Striga in semi-arid field conditions. Plants from the genus Desmodium, in particular D. uncinatum, are used on sub-Saharan small-holder farms as intercrops to inhibit parasitism of cereal crops by Striga hermonthica and Striga asiatica via an allelopathic mechanism. The search for Desmodium species which are adapted to more arid conditions, and which show resilience to increased drought stress, previously identified D. intortum, D. incanum and D. ramosissimum as potential drought tolerant intercrops. Their potential as intercrops was assessed for resource poor areas of rain-fed cereal production where drought conditions can persist through normal meteorological activity, or where drought may have increasing impact through climate change. The chemical composition of the root exudates were characterised and the whole exudate biological activity was shown to be active in pot experiments for inhibition of Striga parasitism on maize. Furthermore, rain fed plot experiments showed the drought tolerant Desmodium intercrops to be effective for Striga inhibition. This work demonstrates the allelopathic nature of the new drought tolerant intercrops through activity of root exudates and the major compounds seen in the exudates are characterised as being C-glycosylflavonoid. In young plants, the exudates show large qualitative differences but as the plants mature, there is a high degree of convergence of the C-glycosylflavonoid exudate chemical profile amongst active Desmodium intercrops that confers biological activity. This defines the material for examining the mechanism for Striga inhibition.