Examples of two tRNAs that aligned with sRNAs.

<p>The numbers following the sRNA sequence are the abundance values in the two sRNA libraries. The first number represents the reads in the control library, and the second number represents the reads in the heat stress library. (A) tRNA-Thr-UGU. (B) tRNA-Val-CAC. (C) The cleavage probability of a given site on the TΨC-arm of tRNA-Thr-UGU in the two libraries.</p

Characterization of Small RNAs Derived from tRNAs, rRNAs and snoRNAs and Their Response to Heat Stress in Wheat Seedlings

<div><p>Small RNAs (sRNAs) derived from non-coding RNAs (ncRNAs), such as tRNAs, rRNAs and snoRNAs, have been identified in various organisms. Several observations have indicated that cleavage of tRNAs and rRNAs is induced by various stresses. To clarify whether sRNAs in wheat derived from tRNAs (stRNAs), rRNAs (srRNAs) and snoRNAs (sdRNAs) are produced specifically in association with heat stress responses, we carried out a bioinformatic analysis of sRNA libraries from wheat seedlings and performed comparisons between control and high-temperature-treated samples to measure the differential abundance of stRNAs, srRNAs and sdRNAs. We found that the production of sRNAs from tRNAs, 5.8S rRNAs, and 28S rRNAs was more specific than that from 5S rRNAs and 18S rRNAs, and more than 95% of the stRNAs were processed asymmetrically from the 3’ or 5’ ends of mature tRNAs. We identified 333 stRNAs and 8,822 srRNAs that were responsive to heat stress. Moreover, the expression of stRNAs derived from tRNA-Val-CAC, tRNA-Thr-UGU, tRNA-Tyr-GUA and tRNA-Ser-UGA was not only up-regulated under heat stress but also induced by osmotic stress, suggesting that the increased cleavage of tRNAs might be a mechanism that developed in wheat seedlings to help them cope with adverse environmental conditions.</p></div

The number and abundance of differentially expressed sRNAs derived from tRNAs, rRNAs and snoRNAs.

<p>The number and abundance of differentially expressed sRNAs derived from tRNAs, rRNAs and snoRNAs.</p

Nucleotide composition around cleavage sites.

<p>The numbers on the X-axis represent the relative position from the terminal nucleotides of the sRNAs, which was assigned as ‘0’. -1 and -2 are the first and second nucleotides upstream of the cleavage site, while +1 and +2 are the first and second nucleotides downstream of cleavage site. (A) Nucleotide composition around the 5’-tRFs and 3’-tRFs cleavage sites. (B) Nucleotide composition around the cleavage sites at both ends of the non-tRFs.</p

Classification of stRNAs, srRNAs and sdRNAs.

<p>(A) stRNAs were divided into non-tRFs and tRFs according to their positions in the tRNAs. (B) srRNAs were classified according to the rRNA species, including 5S rRNA, 5.8s rRNA, 18S rRNA and 28S rRNA. (C) sdRNAs were divided into two types on the basis of their snoRNA classifications.</p

tRFs detection via real-time RT-PCR.

<p>The levels four tRFs were estimated through real-time RT-PCR in the seedlings. The expression levels were normalized to the control samples. The asterisks mean that the values were statistically different from the controls, as determined by Student’s <i>t</i>-test (**, P < 0.01; *, P < 0.05).</p

Fold change of the significantly differentially expressed stRNAs.

<p>The stRNAs were sorted based on their combined abundance in the two libraries, from high to low.</p

Summary of read mapping statistics.

<p>Summary of read mapping statistics.</p

The size distribution of sRNAs derived from tRNAs, rRNAs and snoRNAs.

<p>(A) Size distribution of 5’-tRFs, 3’-tRFs and non-tRFs; (B) size ditribution of 5S-srRNAs, 5.8S-srRNAs, 18S-srRNAs and 28S-srRNAs; (C) size distribution of sdRNAs.</p

A proposed model for GA biosynthesis and response pathway in regulation of heterosis in plant height

<p><b>Copyright information:</b></p><p>Taken from "Gibberellins and heterosis of plant height in wheat (L.)"</p><p>http://www.biomedcentral.com/1471-2156/8/40</p><p>BMC Genetics 2007;8():40-40.</p><p>Published online 29 Jun 2007</p><p>PMCID:PMC1929121.</p><p></p> Differential expressions of genes in GA metabolism and response pathways are listed in the box, with the bar heights representing the expression levels of female (left bar), hybrid (middle bar) and male (right bar) parent