Department of Microbiology, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, India.
J Basic Microbiol. 2012 Jun;52(3):285-95. doi: 10.1002/jobm.201100113. Epub 2011 Sep 23.
Decreased levels of ACC (1-aminocyclopropane-1-carboxylic acid) result in lower levels of endogenous ethylene, which eliminate the potentially inhibitory effects of stress-induced higher ethylene concentrations. It is worth noting the substantial ability of the bacterial species to colonize different environments, including taxonomically distinct plants cultivated in distantly separated geographical regions. For example, Enterobacter cloacae, designated as MSA1 and Enterobacter cancerogenus, designated as MSA2 were recovered from the rhizosphere of Jatropha in the present work. This study first time confirms the ACC deaminase activity in the Enterobacter cancerogenus on the preliminary basis. Several bacterial plant growth-promoting mechanisms were analyzed and detected like phosphate solubilization, siderophore production, IAA production, GA(3) (gibberellic acid) production and ACC deaminase activity in the isolated cultures. Isolates were grown until exponential growth phase to evaluate their ACC deaminase activity and the effect of pH, temperature, salt, metals and substrate concentration after the partial purification of enzyme by ion exchange chromatography. The FOURIER TRANSFORM INFRARED (FT-IR) spectra were recorded for the confirmation of α-ketobutyrate production. By using lineweaver Burk plot K(m) and V(max) value for ACC deaminase of both the organism was calculated in the different fractions. In this work, we discuss the possible implications of these bacterial mechanisms on the plant growth promotion or homeostasis regulation in natural conditions.
ACC（1-氨基环丙烷-1-羧酸）水平降低会导致内源乙烯水平降低，从而消除应激诱导的较高乙烯浓度的潜在抑制作用。值得注意的是，这些细菌物种具有在不同环境中定殖的巨大能力，包括在地理上相距遥远的不同地区种植的分类上不同的植物。例如，本工作从麻疯树的根际中回收了肠杆菌 cloacae（命名为 MSA1）和 Enterobacter cancerogenus（命名为 MSA2）。这项研究首次在初步基础上确认了 Enterobacter cancerogenus 中的 ACC 脱氨酶活性。分析和检测了几种细菌的植物生长促进机制，如磷酸盐溶解、铁载体生产、IAA 生产、GA(3)（赤霉素）生产和分离培养物中的 ACC 脱氨酶活性。将分离物培养至指数生长期，以评估其 ACC 脱氨酶活性，并在离子交换色谱法对酶进行部分纯化后，评估 pH 值、温度、盐、金属和底物浓度对其的影响。记录 FOURIER 变换红外（FT-IR）光谱以确认α-酮丁酸的产生。通过使用 Lineweaver Burk 图，计算了两种生物在不同分数中的 ACC 脱氨酶的 K(m)和 V(max)值。在这项工作中，我们讨论了这些细菌机制对自然条件下植物生长促进或内稳态调节的可能影响。
