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MiRNAs are known as regulatory genes in eukaryotic genomes, regulating their target genes expression. Here, we have investigated five pathogen responsive miRNAs; tae-miR156, tae-miR159, tae-miR167, tae-miR171 and tae-miR393 expression pattern in wheat Taichung 29 cultivar between day 10 to 20th of the seedling life. Since plant seedlings are mostly used for plant-pathogene interaction analysis, this research was committed to analyze the expression pattern of these miRNAs independent of pathogenesis and in 10 to 20 days old seedlings. Plants were grown in soil in greenhouse condition, and 10, 11, 13, 17 and 20 days old seedlings were harvested for RNA extraction and cDNA synthesis. QRT-PCR analysis of candidate miRNAs expression indicated that, tae-miR156 and tae-miR159 expression level has been sharply increased between day 13th to 17th and then after, decreased to the minimum level before day 20th. On the other hand, tae-miR167, tae-miR171 and tae-miR393 expression level has been gradually increased since day 13th of the growth. These data suggest that day 13th to 17th of the wheat seedling life, is crucial period of life in terms of drastic physiological changes which are affected by miRNAs expression. Since majority of the target genes of these candidate miRNAs are not known yet, their expression alterations is only suggested to be consistent with the expression of some known target genes, belong to the signaling pathway like auxin signaling. Considering sequence conservation pattern of miRNA precursors, here we suggested functional miR*s for tae-miR156, tae-miR159, and tae-miR393.

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Bacteria of the genus Azospirillum are well known as plant growth promoting rhizobacteria. The ability to synthesize phytohormones is considered one of the most important mechanisms to promote plant growth and is widely distributed among plant-associated rhizobacteria.The most important phytohormone produced by Azospirillum is the auxin indole-3-acetic acid, with the L-tryptophan as the precursor. In the present study, we evaluate the capacity of eight Azospirillum strains isolated from rice and wheat, to produce in vitro auxins using plant exudates. Our results show that isolates produced auxins in tryptophan free media, but, generally, the amount produced increased when the tryptophan concentration increased. Some plants root exudates had a similar effect to tryptophan for the auxin production. In this sense, bean, rice and canola root extracts produced, respectively, 93.3%, 96.2%, and 88.31% more auxin than L-tryptophan. Azospirillum sp. isolate A3 had the maximal capacity to produce auxin. Therefore, the effect of cell free supernatant was studied on rice root development. Statistical analysis did not show any significant difference between root number and dry weight of the treated and control seedlings. However, significant differences were observed in root length and wet weight at α=0.01 and α=0.05, respectively.