Laboratory of Molecular Biology, Agricultural University, De Dreijen 11, 6703 BC Wageningen, The Netherlands.
EMBO J. 1983;2(6):961-6. doi: 10.1002/j.1460-2075.1983.tb01528.x.
Nodule-specific root proteins - so called nodulins - were identified in root nodules of pea plants by an immunological assay. Nodulin patterns were examined at different stages of nodule development. About 30 nodulins were detectable during development. Some were preferentially synthesized before nitrogen fixation started, whereas the majority were synthesized concomitantly with leghaemoglobin. Some of the nodulins were located within the peribacteroid membrane. Ineffective Rhizobium strains (a natural nodfix and a pop fix) appeared to be useful in studying the expression of nodulin genes. Synthesis of some nodulins was repressed in ineffective root nodules, indicating that nodulins are essential for the establishment of nitrogen fixation. In both types of ineffective root nodules, leghaemoglobin synthesis was not completely repressed. Low amounts of leghaemoglobin were always detected in young ineffective root nodules whereas in old nodules no leghaemoglobin was present.
根瘤特异性根蛋白 - 即所谓的根瘤蛋白 - 通过免疫学检测在豌豆植物的根瘤中被鉴定出来。在根瘤发育的不同阶段检查根瘤蛋白模式。在发育过程中可检测到约 30 种根瘤蛋白。有些在固氮开始之前优先合成,而大多数与豆血红蛋白同时合成。一些根瘤蛋白位于类细菌膜内。无效的根瘤菌(一种天然固氮菌和一种流行固氮菌)似乎可用于研究根瘤蛋白基因的表达。在无效的根瘤中,一些根瘤蛋白的合成受到抑制,这表明根瘤蛋白对于固氮的建立是必不可少的。在这两种类型的无效根瘤中,豆血红蛋白的合成并没有完全被抑制。在年轻的无效根瘤中始终检测到少量的豆血红蛋白,而在老的根瘤中则不存在豆血红蛋白。