Effects of Jasmonyl-Isoleucine (JA-Ile) and Glutathion (GSH) on MYC7 transcript accumulation after mechanical wounding.

<p>JA-Ile (A) and GSH (B) were added to wounding sites as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034855#s4" target="_blank">Material and Methods</a> and transcript accumulation of MYC7 was measured at different time points as indicated. Data was normalized. All experiments have been performed with at least three biological replicates. A Student t test was used for proof of significance (*, P≤0.05) compared with the respective control (A). For (B) different letters (a–c) represent significant differences for MYC7 transcript accumulation (All ANOVA P values<0.01 with Tukey test corrections for multiple comparisons; P<0.05).</p

Effects of glutathione (GSH) on jasmonic acid accumulation (A) and volatile release (B).

<p>A, GSH was added to the wounding site and Jasmonic acid accumulation (<i>cis</i> and <i>trans</i>) measured after 45 and 90 min. A Student t test was used for proof of significance between MW and GSH-MW treated plants (*, P≤0.05). B, GSH was added to a wounding site and volatiles release measured after 5 h. All experiments have been performed with at least three biological replicates. Different letters (a–c) represent significant differences for trans JA, cis JA, and total JA, respectively (A) and VOC (B) (All ANOVA P values<0.01 with Tukey test corrections for multiple comparisons; P<0.05). DMNT, 3<i>E</i>-4,8-dimethyl-l,3,7-nonatriene.</p

Mechanical wounding (MW) and insect elicitor (IE) induced within-leaf expression of MYC7.

<p>Transcript accumulation was measured after MW and IE treatment in distal (leaf upward), local (damage site), and basal segments of the second leaf at different time points. Upper panel shows the response to MW. Lower panel shows results for IE. Gene expression is shown as PCR/GapC product. Data was normalized. All experiments have been performed with at least three biological replicates. A schematic maize leaf has been added to demonstrate the experimental setup. Designation of treatments is as follows: C, control, D, distal; L, local; B, basal; MW, mechanical wounding; IE, insect elicitor (here: <i>N</i>-linolenoyl-gluatamine); 20, 60, 180, time after treatment in minutes. A Student t test was used for proof of significance (*, P≤0.05) compared with the respective control.</p

Evolutionary Expansion of WRKY Gene Family in Banana and Its Expression Profile during the Infection of Root Lesion Nematode, <i>Pratylenchus coffeae</i>

<div><p>The WRKY family of transcription factors orchestrate the reprogrammed expression of the complex network of defense genes at various biotic and abiotic stresses. Within the last 96 million years, three rounds of <i>Musa</i> polyploidization events had occurred from selective pressure causing duplication of <i>MusaWRKYs</i> with new activities. Here, we identified a total of 153 WRKY transcription factors available from the DH Pahang genome. Based on their phylogenetic relationship, the MusaWRKYs available with complete gene sequence were classified into the seven common WRKY sub-groups. Synteny analyses data revealed paralogous relationships, with 17 <i>MusaWRKY</i> gene pairs originating from the duplication events that had occurred within the <i>Musa</i> lineage. We also found 15 other <i>MusaWRKY</i> gene pairs originating from much older duplication events that had occurred along Arecales and Poales lineage of commelinids. Based on the synonymous and nonsynonymous substitution rates, the fate of duplicated <i>MusaWRKY</i> genes was predicted to have undergone sub-functionalization in which the duplicated gene copies retain a subset of the ancestral gene function. Also, to understand the regulatory roles of <i>MusaWRKY</i> during a biotic stress, Illumina sequencing was performed on resistant and susceptible cultivars during the infection of root lesion nematode, <i>Pratylenchus coffeae</i>. The differential <i>WRKY</i> gene expression analysis in nematode resistant and susceptible cultivars during challenged and unchallenged conditions had distinguished: 1) <i>MusaWRKY</i>s participating in general banana defense mechanism against <i>P</i>.<i>coffeae</i> common to both susceptible and resistant cultivars, 2) <i>MusaWRKY</i>s that may aid in the pathogen survival as suppressors of plant triggered immunity, 3) <i>MusaWRKY</i>s that may aid in the host defense as activators of plant triggered immunity and 4) cultivar specific <i>MusaWRKY</i> regulation. Mainly, <i>MusaWRKY</i>52, -69 and -92 are found to be <i>P</i>.<i>coffeae</i> specific and can act as activators or repressors in a defense pathway. Overall, this preliminary study in <i>Musa</i> provides the basis for understanding the evolution and regulatory mechanism of <i>MusaWRKY</i> during nematode stress.</p></div

Conserved motifs of 81 Musa WRKY proteins.

<p>MEME was used to predict motifs and these motifs represented with boxes.</p

Unrooted phylogenetic tree representing relationships among WRKY domains of <i>Musa</i> and <i>Arabidopsis</i>.

<p>Amino acid sequences of WRKY genes were aligned with clustal W and 1000 bootstrap values in neighbor-joining method in MEGA 5.2.Branch name of sub trees are colored indicating different WRKY groups and subgroups. Triangle symbols indicated that significant expression in susceptible or resistant cultivars. Ο symbol shows that no genes were expressed, and arcs symbol showed that up-regulated in resistant and down-regulated in susceptible cultivar during nematode infection.</p

Chromosomal distribution of WRKY genes in Musa.

<p>Eleven synteny blocks of <i>Musa</i> chromosomes are represented as in the banana genome hub.The paralogous chromosome segments are represented in the same colors. The 17 paralogs are linked by the same colored lines. Number and size of the each chromosome are given at the top.</p

Differential regulation of <i>MusaWRKY</i>s in resistant and susceptible cultivars during <i>P</i>.<i>coffeae</i> infestation.

<p>Differential regulation of <i>MusaWRKY</i>s in resistant and susceptible cultivars during <i>P</i>.<i>coffeae</i> infestation.</p

WRKY TF's identified in Musa with complete CD's.

<p>WRKY TF's identified in Musa with complete CD's.</p