Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK.
Africa Rice Center, East and Southern Africa Rice Program, PO Box 33581, Tanzania.
New Phytol. 2011 Dec;192(4):952-963. doi: 10.1111/j.1469-8137.2011.03846.x. Epub 2011 Aug 29.
Striga hermonthica and S. asiatica are root parasitic weeds that infect the major cereal crops of sub-Saharan Africa causing severe losses in yield. The interspecific upland NEw RICe for Africa (NERICA) cultivars are popular amongst subsistence farmers, but little is known about their post-attachment resistance against Striga. Here, we evaluate the post-attachment resistance levels of the NERICA cultivars and their parents against ecotypes of S. hermonthica and S.asiatica, characterize the phenotype of the resistance mechanisms and determine the effect of Striga on host biomass. Some NERICA cultivars showed good broad-spectrum resistance against several Striga ecotypes, whereas others showed intermediate resistance or were very susceptible. The phenotype of a resistant interaction was often characterized by an inability of the parasite to penetrate the endodermis. Moreover, some parasites formed only a few connections to the host xylem, grew slowly and remained small. The most resistant NERICA cultivars were least damaged by Striga, although even a small number of parasites caused a reduction in above-ground host biomass. The elucidation of the molecular genetic basis of the resistance mechanisms and tolerance would allow the development of cultivars with multiple, durable resistance for use in farmers' fields.
独脚金和亚洲独脚金是寄生在撒哈拉以南非洲主要粮食作物根部的杂草，会导致严重的减产。非州新型旱地稻（NERICA）品种在自给农民中很受欢迎，但对其与独脚金的种间附生后抗性知之甚少。在这里，我们评估了 NERICA 品种及其亲本对独脚金和亚洲独脚金生态型的附生后抗性水平，描述了抗性机制的表型，并确定了独脚金对宿主生物量的影响。一些 NERICA 品种对几种独脚金生态型表现出良好的广谱抗性，而其他品种则表现出中等抗性或非常易感。抗性互作的表型通常表现为寄生虫无法穿透内皮层。此外，一些寄生虫只与宿主木质部形成少数几个连接，生长缓慢且体积较小。抗性最强的 NERICA 品种受独脚金的损害最小，尽管只有少数寄生虫也会导致地上宿主生物量减少。阐明抗性机制和耐受性的分子遗传基础将允许开发具有多种持久抗性的品种，用于农民的田间。
