Cytokinin production by plant growth promoting rhizobacteria and selected mutants.
Cytokinin production by plant growth promoting rhizobacteria and selected mutants.
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DOI：
10.1139/w01-029
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发表时间：
2001-05
影响因子：
2.8
通讯作者：
Inés E. García de Salamone;R. Hynes;L. Nelson
中科院分区：
文献类型：
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作者：
Inés E. García de Salamone;R. Hynes;L. Nelson
提出的根瘤菌促进植物生长的机制之一是通过生产植物生长调节剂。5株促进植物生长的根瘤菌（PGPR）在纯培养中产生细胞分裂素二氢玉米素核苷（DHZR）。荧光假单胞菌G20-18（一种利福平耐药突变体（RIF））和两种tnphoa衍生突变体（CNT1, CNT2）合成细胞分裂素的能力降低，在纯培养中使用免疫测定和薄层色谱进一步表征细胞分裂素的产生。G20-18在固定期产生的三种细胞分裂素、异戊烯腺苷（IPA）、反式玉米蛋白核糖（ZR）和DHZR的量高于三个突变体。IPA是产生的主要代谢物，但CNT1和CNT2积累的ZR和DHZR的比例随着时间的增加而增加。菌株G20-18与突变体的吲哚乙酸合成量没有差异，上清液中也没有检测到赤霉素。在菌株G20-18培养96 h和168 h时，添加10(-5)M腺嘌呤可使细胞分裂素产量增加约67%。G20-18和突变体CNT1和CNT2可能有助于确定细胞分裂素产生在PGPR促进植物生长中的作用。
One of the proposed mechanisms by which rhizobacteria enhance plant growth is through the production of plant growth regulators. Five plant growth promoting rhizobacterial (PGPR) strains produced the cytokinin dihydrozeatin riboside (DHZR) in pure culture. Cytokinin production by Pseudomonas fluorescens G20-18, a rifampicin-resistant mutant (RIF), and two TnphoA-derived mutants (CNT1, CNT2), with reduced capacity to synthesize cytokinins, was further characterized in pure culture using immunoassay and thin layer chromatography. G20-18 produced higher amounts of three cytokinins, isopentenyl adenosine (IPA), trans-zeatin ribose (ZR), and DHZR than the three mutants during stationary phase. IPA was the major metabolite produced, but the proportion of ZR and DHZR accumulated by CNT1 and CNT2 increased with time. No differences were observed between strain G20-18 and the mutants in the amounts of indole acetic acid synthesized, nor were gibberellins detected in supernatants of any of the strains. Addition of 10(-5) M adenine increased cytokinin production in 96- and 168-h cultures of strain G20-18 by approximately 67%. G20-18 and the mutants CNT1 and CNT2 may be useful for determination of the role of cytokinin production in plant growth promotion by PGPR.