Plant Genetic Control of Nodule Number in Medicago truncatula

9808197库克根瘤菌-豆科植物共生是生物圈中氮减少的主要来源之一。 这种关系在植物根部发育的一个专门器官（称为“根瘤”）内的共生固氮中达到高潮。 几条证据表明，植物通过调节植物根部形成的根瘤数量来控制共生活动。 最近，PI的实验室已经确定了适当控制根瘤数量所需的两种植物基因。 这些基因的突变导致植物根部的根瘤数量增加约10倍。 遗传分析表明，这些突变体，命名为“多余”（太阳）和“镰刀”（skl），代表独立的，不连锁的基因，可能独立地控制根瘤数量。 根据这项资助的研究将进一步研究这些突变体的性质，目的是了解宿主植物如何调节共生发展。 本研究的具体目标包括：（1）建立sun、skl和其他促生长突变体促生长的遗传途径框架;（2）研究sun和skl在植物激素感知中的可能作用;（3）定位和克隆sun和skl基因。

9808197 Cook The Rhizobium-legume symbiosis constitutes one of the major sources of reduced nitrogen in the biosphere. This relationship culminates in symbiotic nitrogen fixation within a specialized organ, termed a "nodule", that develops on the plant root. Several lines of evidence indicate that the plant controls symbiotic activity by regulating the number of nodules that form on the plant root. Recently, the PI's laboratory has identified two plant genes that are required for appropriate control of nodule number. Mutations in these genes result in an approximately 10-fold increase in the number of nodules on the plant root. Genetic analyses indicate that these mutants, named "supernumerary" (sun) and "sickle" (skl), represent separate, unlinked genes that may act independently to control nodule number. Research under this grant will further examine the nature of these mutants with the goal of understanding how the host plant regulates symbiotic development. The specific objectives of this research include (1) developing a frame work genetic pathway for nodulation involving sun, skl and other nodulation mutants, (2) examining the probable role of sun and skl in plant hormone perception, and (3) to map and clone the sun and skl genes.