5 research outputs found
Isolation and molecular identification of endophytic diazotrophs from seeds and stems of three cereal crops.
Ten strains of endophytic diazotroph were isolated and identified from the plants collected from three different agricultural crop species, wheat, rice and maize, using the nitrogen-free selective isolation conditions. The nitrogen-fixing ability of endophytic diazotroph was verified by the nifH-PCR assay that showed positive nitrogen fixation ability. These identified strains were classified by 879F-RAPD and 16S rRNA sequence analysis. RAPD analyses revealed that the 10 strains were clustered into seven 879F-RAPD groups, suggesting a clonal origin. 16S rRNA sequencing analyses allowed the assignment of the 10 strains to known groups of nitrogen-fixing bacteria, including organisms from the genera Paenibacillus, Enterobacter, Klebsiella and Pantoea. These representative genus are not endophytic diazotrophs in the conventional sense. They may have obtained nitrogen fixation ability through lateral gene transfer, however, the evolutionary forces of lateral gene transfer are not well known. Molecular identification results from 16S rRNA analyses were also confirmed by morphological and biochemical data. The test strains SH6A and MZB showed positive effect on the growth of plants
Comparative analysis of 16S rRNA sequence from the RAPD strains SH6A, KHSA, GYA, B73A, KHB, GYB, MZA and representative strains from the GenBank.
<p>The significance of each branch is indicated by a bootstrap value calculated for 1000 subsets. Scalebar, 2 nt substitution per 100 nt.</p
Characteristics of the isolates used in this study.
<p>Characteristics of the isolates used in this study.</p
(a) <i>nif</i>H gene fragments amplification (b) 879F-RAPD patterns, (c) 16S rRNA <i>Hin</i>fI-RFLP fingerprinting, (d) 16S rRNA <i>Msp</i>I-RFLP fingerprinting.
<p>DL2000 DNA marker (M), SH6A (lane 1), KHSA (lane 2), GYA (lane 3), ZY1A (lane 4), B73A (lane 5), KHB (lane 6), SH6B (lane 7), MZB (lane 8) and GYB (lane 9) and MZA (lane 10).</p