Screening of rhizobacteria containing plant growth promoting (PGPR) traits in rhizosphere soils and their role in enhancing growth of pigeon pea
Screening of rhizobacteria containing plant growth promoting (PGPR) traits in rhizosphere soils and their role in enhancing growth of pigeon pea
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根际土壤中具有植物促生长（PGPR）性状的根际细菌的筛选及其促进木豆生长的作用
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发表时间：
2012
期刊：
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通讯作者：
G. Reddy
中科院分区：
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作者：
M. U. Rani;A. Arundhathi;G. Reddy
植物生长促进根际细菌(PGPR)是一种能在植物根部定植并通过多种机制促进植物生长的有益细菌。PGPR在农业中的使用量正在稳步增加，为替代化肥、农药和补充剂提供了一条诱人的途径。在此，我们从木豆根际土壤中分离、列举和鉴定了促进木豆生长的PGPR。从Samalkot、Pithapuram、Peddapuram和Kakinada不同地区采集了根际土壤。对65个菌株进行了形态、培养、染色和生化特性的鉴定，其中35个菌株用于PGPR菌株的筛选。对16株菌株进行了产吲哚乙酸、溶磷、产尿素酶、几丁质酶、淀粉酶、纤维素酶、蛋白酶和β-1，3葡聚糖酶等生理生化特性的测定，并用铁载体测定法、1-氨基环丙烷-1-羧酸脱氨酶特性、双平板培养法和产HCN技术评价了这些菌株对真菌和细菌的拮抗作用，从中筛选出一株最佳菌株。进一步研究表明，PGPR在木豆出苗、地上部长度、根长、地上部干物质生产、根瘤数和根瘤质量等方面表现出明显的性状。此外，PGPR分离物显著提高了木豆种子的发芽率。在16个菌株中，有7个菌株的IAA产量较高。其中6株是高效的磷酸盐增溶剂，5株对病原真菌有较好的拮抗作用，8株具有较好的产酶能力，可提高土壤矿化效率。三个菌株在IAA生产、磷酸盐溶解、对真菌的拮抗作用和矿化能力方面表现出很好的前景。因此，本研究建议将这些菌株用作接种剂生物肥料，这可能对木豆种植更有利，因为它们提高了生长和其他生长参数。关键词：吲哚乙酸(IAA)、促进植物生长的根际细菌(PGPR)、溶磷、产酶、种子萌发
Plant growth promoting rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and enhance plant growth with a wide variety of mechanisms. The use of PGPR is steadily increasing in agriculture and offers an attractive way to replace chemical fertilizers, pesticides and supplements. Here, we have isolated, enumerated and characterized the PGPR from the rhizosphere soil of pigeon pea for the enhancement of growth of pigeon pea. Rhizosphere soils were collected from different areas of Samalkot, Pithapuram, Peddapuram and Kakinada. Sixty five (65) isolates were identified and characterized for their morphological, cultural, staining and biochemical characteristics, of which 35 was selected for the screening of PGPR isolates. Sixteen isolates were successfully characterized for the PGPR traits like indole acetic acid (IAA) production, phosphorus solubilization, and production of enzymes like urease, chitinase, amylase, cellulase, protease and β-1,3 glucanase and were assayed. The antagonistic nature of these strains towards fungi and bacteria were estimated by siderophore estimation, 1-amino-cyclopropane-1-carboxylate (ACC) deaminase characterization, dual plate culture method and HCN production technique, and the best one was selected. These were further investigated to show the PGPR traits in pigeon pea seedling emergence, increase of shoot length, root length, dry matter production of shoot, nodule number and nodule mass. Furthermore, PGPR isolates remarkably increased seed germination of pigeon pea. Among the sixteen isolates, seven were found to be high IAA producing. Six were found to be efficient phosphate solubilizers, five isolates were found to be good antagonistic towards pathogen soil fungi and eight isolates were found to be better in enzyme productions, and thus, may enhance the mineralization efficiency of soils. Three isolates were shown to be promising in IAA production, phosphate solubilization, antagonism towards fungi, and mineralizing capacity. Thus, this study suggests the use of these isolates as inoculant biofertilizers which might be beneficial for pigeon pea cultivation as they enhanced the growth and other growth parameters. Keywords: Indole acetic acid (IAA), plant growth promoting rhizobacteria (PGPR), phosphorus solubilization, enzyme productions, seed germination