Penrose Donna M., Glick Bernard R.
Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Physiol Plant. 2003 May;118(1):10-15. doi: 10.1034/j.1399-3054.2003.00086.x.
One of the major mechanisms utilized by plant growth-promoting rhizobacteria (PGPR) to facilitate plant growth and development is the lowering of ethylene levels by deamination of 1-aminocyclopropane-1-carboxylic acid (ACC) the immediate precursor of ethylene in plants. The enzyme catalysing this reaction, ACC deaminase, hydrolyses ACC to alpha-ketobutyrate and ammonia. Several bacterial strains that can utilize ACC as a sole source of nitrogen have been isolated from rhizosphere soil samples. All of these strains are considered to be PGPR based on the ability to promote canola seedling root elongation under gnotobiotic conditions. The treatment of plant seeds or roots with these bacteria reduces the amount of ACC in plants, thereby lowering the concentration of ethylene. Here, a rapid procedure for the isolation of ACC deaminase-containing bacteria, a root elongation assay for evaluating the effects of selected bacteria on root growth, and a method of assessing bacterial ACC deaminase activity are described in detail. This should allow researchers to readily isolate new PGPR strains adapted to specific environments.
植物促生根际细菌（PGPR）促进植物生长发育的主要机制之一，是通过对1-氨基环丙烷-1-羧酸（ACC，植物中乙烯的直接前体）进行脱氨作用来降低乙烯水平。催化此反应的酶，即ACC脱氨酶，将ACC水解为α-酮丁酸和氨。从根际土壤样本中分离出了几种能够将ACC作为唯一氮源利用的细菌菌株。基于在无菌条件下促进油菜幼苗根伸长的能力，所有这些菌株都被视为PGPR。用这些细菌处理植物种子或根会减少植物中ACC的量，从而降低乙烯浓度。在此，详细描述了一种快速分离含ACC脱氨酶细菌的方法、一种用于评估所选细菌对根生长影响的根伸长测定法以及一种评估细菌ACC脱氨酶活性的方法。这应使研究人员能够轻松分离出适应特定环境的新PGPR菌株。
