Screening plant growth-promoting rhizobacteria for improving growth and yield of wheat
Screening plant growth-promoting rhizobacteria for improving growth and yield of wheat
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DOI：
10.1046/j.1365-2672.2003.02161.x
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发表时间：
2004-01-01
影响因子：
4
通讯作者：
Zahir, ZA
中科院分区：
文献类型：
--
作者：
Khalid, A;Arshad, M;Zahir, ZA
目的：植物根际促生菌（PGPR）是一种常用的促进农作物生长和提高产量的菌剂，但筛选有效的PGPR菌株至关重要。本研究的重点是筛选有效的PGPR菌株的基础上，他们的潜力，在体外生长素的生产和植物生长促进活性下gnotobiotic conditions.Methods和结果：大量的细菌被分离出从根际土壤中的小麦植株生长在不同地点。选择了30株在琼脂培养基上生长旺盛的菌株，并评价了它们在体外产生生长素的潜力。比色分析表明，根际细菌在体外产生的生长素的量可变（从1.1到12.1毫克l（-1））和L-色氨酸（L-TRP）的培养基的修正案，进一步刺激生长素的生物合成（从1.8到24.8毫克l（-1））。HPLC分析证实了吲哚乙酸（IAA）和吲哚乙酰胺（IAM）作为这些根际细菌的培养物中的主要生长素的存在。对两个品种进行了一系列室内试验。结果表明，在无菌条件下，小麦幼苗的根伸长、根干重、地上部伸长和地上部干重分别增加了17.3%、13.5%、37.7%和36.3%。根据生长素的生物合成和促生活性，筛选出4株根际促生菌（plantgrowth-promoting rhizobacteria，PGPR），并将其命名为根际促生菌（plantgrowth-promoting rhizobacteria，PGPR）。生长素的生物合成灭菌与非灭菌土壤接种选定的PGPR也进行了监测，显示优越的选择PGPR土著微生物。泥炭为基础的种子接种选定的PGPR菌株表现出刺激作用的小麦品种籽粒产量。在盆栽（比对照增加14.7%）和田间试验（比对照增加27.5%）中;然而，响应随CV而变化。结论：它的结论是，菌株，产生的生长素在非灭菌土壤中的最高量，也造成了最大的增长和产量的小麦品种。意义和影响的研究：这项研究表明，潜在的生长素生物合成的根际细菌可以用作有效的PGPR菌株的筛选工具。
Aims: Plant growth promoting rhizobacteria (PGPR) are commonly used as inoculants for improving the growth and yield of agricultural crops, however screening for the selection of effective PGPR strains is very critical. This study focuses on the screening of effective PGPR strains on the basis of their potential for in vitro auxin production and plant growth promoting activity under gnotobiotic conditions.Methods and Results: A large number of bacteria were isolated from the rhizosphere soil of wheat plants grown at different sites. Thirty isolates showing prolific growth on agar medium were selected and evaluated for their potential to produce auxins in vitro. Colorimetric analysis showed variable amount of auxins (ranging from 1.1 to 12.1 mg l(-1)) produced by the rhizobacteria in vitro and amendment of the culture media with L-tryptophan (L-TRP), further stimulated auxin biosynthesis (ranging from 1.8 to 24.8 mg l(-1)). HPLC analysis confirmed the presence of indole acetic acid (IAA) and indole acetamide (IAM) as the major auxins in the culture filtrates of these rhizobacteria. A series of laboratory experiments conducted on two cv. of wheat under gnotobiotic (axenic) conditions demonstrated increases in root elongation (up to 17.3%), root dry weight (up to 13.5%), shoot elongation (up to 37.7%) and shoot dry weight (up to 36.3%) of inoculated wheat seedlings. Linear positive correlation (r = 0.99) between in vitro auxin production and increase in growth parameters of inoculated seeds was found. Based upon auxin biosynthesis and growth-promoting activity, four isolates were selected and designated as plant growth-promoting rhizobacteria (PGPR). Auxin biosynthesis in sterilized vs nonsterilized soil inoculated with selected PGPR was also monitored that revealed superiority of the selected PGPR over indigenous microflora. Peat-based seed inoculation with selected PGPR isolates exhibited stimulatory effects on grain yields of tested wheat cv. in pot (up to 14.7% increase over control) and field experiments (up to 27.5% increase over control); however, the response varied with cv. and PGPR strains.Conclusions: It was concluded that the strain, which produced the highest amount of auxins in nonsterilized soil, also caused maximum increase in growth and yield of both the wheat cv.Significance and Impact of Study: This study suggested that potential for auxin biosynthesis by rhizobacteria could be used as a tool for the screening of effective PGPR strains.