Anthon G E, Emerich D W
Department of Biochemistry, University of Missouri-Columbia, Columbia, Missouri 65211.
Plant Physiol. 1990 Feb;92(2):346-51. doi: 10.1104/pp.92.2.346.
Soybean (Glycine max) nodules formed by inoculation with either an effective strain or an ineffective (noninvasive, nodule-forming) strain of Bradyrhizobium japonicum were assayed for changes in developmental patterns of carbon metabolic enzymes of the plant nodule cells. Of the enzyme activities measured, only sucrose synthase, glutamine synthetase, and alcohol dehydrogenase were altered in the ineffective nodules relative to the effective nodules. Sucrose synthase and glutamine synthetase activities were greatly reduced, whereas alcohol dehydrogenase activity was elevated. Dark-induced senescence severely affected sucrose synthase but had little, if any, effect on the other enzymes measured. The developmental patterns of the anaerobically induced enzymes, aldolase and alcohol dehydrogenase, were different from those expected, implying that their development is not regulated solely by oxygen deprivation. However, anaerobic treatment of nodules resulted in responses similar to those enzymes in maize. The developmental profiles of the carbon metabolic enzymes suggest that carbohydrates are metabolized via the sucrose synthase and pentose phosphate pathways. This route of carbon metabolism, compared to glycolysis, would reduce the requirement of ATP for carbohydrate catabolism, generate NADPH for biosynthetic reactions, and provide intermediates for plant secondary metabolism.
通过接种有效的大豆慢生根瘤菌菌株或无效的（非侵入性、形成根瘤的）大豆慢生根瘤菌菌株形成的大豆（Glycine max）根瘤，被检测其根瘤细胞碳代谢酶发育模式的变化。在所测量的酶活性中，相对于有效根瘤，无效根瘤中只有蔗糖合酶、谷氨酰胺合成酶和乙醇脱氢酶发生了改变。蔗糖合酶和谷氨酰胺合成酶活性大幅降低，而乙醇脱氢酶活性升高。黑暗诱导的衰老严重影响蔗糖合酶，但对所测量的其他酶几乎没有影响（如果有影响的话也很小）。厌氧诱导的酶醛缩酶和乙醇脱氢酶的发育模式与预期不同，这意味着它们的发育并非仅由缺氧调节。然而，对根瘤进行厌氧处理会产生与玉米中这些酶类似的反应。碳代谢酶的发育概况表明，碳水化合物通过蔗糖合酶和磷酸戊糖途径进行代谢。与糖酵解相比，这种碳代谢途径将减少碳水化合物分解代谢对ATP的需求，为生物合成反应生成NADPH，并为植物次生代谢提供中间体。
