EAGER: An Unexplored Avenue of Striga Resistance in Maize

Striga是一种寄生植物，通过玉米，高粱，高地，小米和豇豆的根部为食，破坏这些作物以及撒哈拉以南非洲和其他发展中国家地区依赖它们的人的生活。 联合国粮食及农业组织（粮农组织）指出，虽然玉米在非洲所有大田作物中面积最大，但平均产量（1.6吨/公顷）不到世界其他地方单位面积产量的三分之一。这种情况进一步恶化，因为与玉米粒和玉米穗混合的独脚金种子被广泛散布到市场上。 这个EAGER项目将测试一种潜在的新策略，使用新鉴定的转座子诱导的（非转基因）玉米突变体来处理Striga侵扰。 这种植物在编码类胡萝卜素裂解双加氧酶8（ccd 8）的基因中携带突变，并且已被证明几乎不产生独脚金内酯（SL）的前体，独脚金内酯是一种玉米激素，由独脚金寄生虫感知，并且是宿主定位和自身种子萌发所需的化学信号。这种新的玉米突变体的非转基因性质也增加了其被不同文化的人民接受和使用的前景。该项目将测试玉米和独脚金之间的实际相互作用受到独脚金内酯在植物生物学中部分理解的作用的影响程度。具体目标是：1）确定由ccd 8突变提供的对独脚金种子萌发和宿主吸引的抗性程度，和2）测试以下概念：通过基于杂种优势和天然存在的遗传修饰剂的育种策略，可以在不丧失独脚金抗性的情况下抵消ccd 8玉米中相对适度的产量损失。 如果成功，EAGER项目将提供一种新的策略，可以对抗Striga的产量损失，从15%到100%，从而使玉米生产在Striga出没的地区可持续发展。

Striga is a parasitic plant that feasts through the roots of corn, sorghum, upland rice, millet, and cowpea, devastating these crops and the lives of people who depend on them in sub-Saharan Africa and other areas in the developing world. The Food and Agriculture Organization of the United Nations (FAO) notes that, while maize has the largest acreage of all field crops in Africa, the average yield (1.6 t/hectare) is less than 1/3 of that achieved per unit area elsewhere in the world. The situation is further exacerbated by widespread dispersal of Striga seeds that intermix with maize kernels and ears going to market. This EAGER project will test a potentially novel strategy for dealing with Striga infestation using a newly identified transposon-induced (non-transgenic) mutant of maize. This plant carries a mutation in a gene that encodes a carotenoid cleavage dioxygenase 8 (ccd8) and has been shown to produce little to no precursors for strigolactone (SL), a maize hormone that is sensed by the Striga parasite and is required as a chemo-signal for host location and germination of its own seeds. The non-transgenic nature of this new maize mutant also enhances prospects for its acceptance and use by peoples with diverse cultures. This project will test the extent to which actual interactions between maize and Striga are affected by the partially-understood roles of strigolactone in plant biology. The specific objectives are to: 1) determine the degree of resistance to Striga seed germination and host attraction offered by the ccd8 mutation, and 2) test the concept that a relatively modest yield penalty in ccd8 maize can be countered without losing Striga resistance, by breeding strategies based on hybrid vigor and naturally-occurring genetic modifiers. If successful, this EAGER project will provide for a new strategy that could counter Striga-based yield losses that extend from 15% to 100%, thereby making maize production sustainable in Striga infested regions.