Characterization of <i>MORE AXILLARY GROWTH</i> Genes in <i>Populus</i>

<div><p>Background</p><p>Strigolactones are a new class of plant hormones that play a key role in regulating shoot branching. Studies of branching mutants in Arabidopsis, pea, rice and petunia have identified several key genes involved in strigolactone biosynthesis or signaling pathway. In the model plant Arabidopsis, <i>MORE AXILLARY GROWTH1</i> (<i>MAX1</i>), <i>MAX2</i>, <i>MAX3</i> and <i>MAX4</i> are four founding members of strigolactone pathway genes. However, little is known about the strigolactone pathway genes in the woody perennial plants.</p><p>Methodology/Principal Finding</p><p>Here we report the identification of MAX homologues in the woody model plant <i>Populus trichocarpa</i>. We identified the sequence homologues for each MAX protein in <i>P. trichocarpa</i>. Gene expression analysis revealed that <i>Populus MAX</i> paralogous genes are differentially expressed across various tissues and organs. Furthermore, we showed that <i>Populus MAX</i> genes could complement or partially complement the shoot branching phenotypes of the corresponding Arabidopsis <i>max</i> mutants.</p><p>Conclusion/Significance</p><p>This study provides genetic evidence that strigolactone pathway genes are likely conserved in the woody perennial plants and lays a foundation for further characterization of strigolactone pathway and its functions in the woody perennial plants.</p></div

MOESM1 of Simultaneous knockdown of six non-family genes using a single synthetic RNAi fragment in Arabidopsis thaliana

Additional file 1: Figure S1. Alignment of cDNAs of AtHY2, AtTRY, AtLNG1, AtNPQ1, AtSEX1, AtMAX3 and AtGUN4

居民組織

2003-2004 > Academic research: refereed > Chapter in an edited book (author

Expression of <i>Populus MAX</i> homologous genes across various tissues and organs.

<p>(<b>A</b>) Illustration of tissues and organs used for expression analysis. (<b>B</b>) Quantitative RT-PCR data. Shown are means ± S.E. of three biological replicates.</p

Genetic complementation of <i>Arabidopsis max4</i> mutants with <i>Populus MAX4</i> genes.

<p>(<b>A</b>) RT-PCR analysis of <i>35S:PtrMAX4a</i> transgenic lines. (<b>B</b>) RT-PCR analysis of <i>35S:PtrMAX4b</i> transgenic lines. (<b>C</b>) Number of primary rosette-leaf branches. Shown are average numbers of primary rosette-leaf branches from at least 10 individual plants ± S.E. *, significant difference from <i>max4-1</i>, p<0.05.</p

Genetic complementation of <i>Arabidopsis max1</i> mutants with <i>Populus MAX1</i> genes.

<p>(<b>A</b>) RT-PCR analysis of <i>35S:PtrMAX1a</i> transgenic lines. (<b>B</b>) RT-PCR analysis of <i>35S:PtrMAX1b</i> transgenic lines. (<b>C</b>) Number of primary rosette-leaf branches. Shown are average numbers of primary rosette-leaf branches from at least 10 individual plants ± S.E. *, significant difference from <i>max1-4</i>, p<0.05.</p

Genetic complementation of <i>Arabidopsis max2</i> mutants with <i>Populus MAX2</i> genes.

<p>(<b>A</b>) RT-PCR analysis of <i>35S:PtrMAX2a</i> transgenic lines. (<b>B</b>) RT-PCR analysis of <i>35S:PtrMAX2b</i> transgenic lines. (<b>C</b>) Number of primary rosette-leaf branches. Shown are average numbers of primary rosette-leaf branches from at least 10 individual plants ± S.E. *, significant difference from <i>max2-4</i>, p<0.05.</p

Subcellular localization of various organelle markers in <i>Populus</i> protoplasts.

<p>(<b>A</b>) Plasma membrane; (<b>B</b>) Golgi apparatus; (<b>C</b>) Nucleus; (<b>G</b>) Peroxisome; (<b>H</b>) endoplasmic reticulum (ER); (<b>I</b>) An ubiquitously-localized protein (RACK1, Receptor for Activated C-protein Kinase 1). Shown in (<b>D</b>), (<b>E</b>), (<b>F</b>), (<b>J</b>), (<b>K</b>) and (<b>L</b>) are bright field images for fluorescent images of (<b>A</b>), (<b>B</b>), (<b>C</b>), (<b>G</b>), (<b>H</b>) and (<b>I</b>), respectively. The organelle markers were fused with mCherry fluorescent protein, and RACK1 was fused with YFP fluorescent protein. The mCherry signal was separated from chloroplast autofluorescence using spectral imaging and linear unmixing. The mCherry and YFP signals are false-colored green and the chloroplast autofluorescence is shown in red. Scale bar, 1 µm.</p

Highly Efficient Isolation of <em>Populus</em> Mesophyll Protoplasts and Its Application in Transient Expression Assays

<div><h3>Background</h3><p><em>Populus</em> is a model woody plant and a promising feedstock for lignocellulosic biofuel production. However, its lengthy life cycle impedes rapid characterization of gene function.</p> <h3>Methodology/Principal Findings</h3><p>We optimized a <em>Populus</em> leaf mesophyll protoplast isolation protocol and established a <em>Populus</em> protoplast transient expression system. We demonstrated that <em>Populus</em> protoplasts are able to respond to hormonal stimuli and that a series of organelle markers are correctly localized in the <em>Populus</em> protoplasts. Furthermore, we showed that the <em>Populus</em> protoplast transient expression system is suitable for studying protein-protein interaction, gene activation, and cellular signaling events.</p> <h3>Conclusions/Significance</h3><p>This study established a method for efficient isolation of protoplasts from <em>Populus</em> leaf and demonstrated the efficacy of using <em>Populus</em> protoplast transient expression assays as an <em>in vivo</em> system to characterize genes and pathways.</p> </div

<i>Populus</i> leaf mesophyll protoplasts.

<p>(<b>A</b>) Optimal yield and quality of protoplasts can be isolated from one month-old <i>Populus</i> plants grown on MS medium in a magenta box. (<b>B</b>) High transfection efficiency is indicated with GFP signal.</p