Transcriptomic characterization of gall tissue of Japanese elm tree (<i>Ulmus davidiana</i> var. japonica) induced by the aphid <i>Tetraneura nigriabdominalis</i>

<p>Insect galls are abnormal plant tissues induced by parasitic insect(s) for use as their habitat. In previous work, we suggested that gall tissues induced by the aphid <i>Tetraneura nigriabdominalis</i> on Japanese elm trees are less responsive than leaf tissues to jasmonic acid (JA), which is involved in the production of volatile organic compounds as a typical defensive reaction of plants against attack by insect pests. A comprehensive analysis of gene expression by RNA sequencing indicated that the number of JA responsive genes was markedly lower in gall tissues than in leaf tissues. This suggests that gall tissues are mostly defective in JA signaling, although JA signaling is not entirely compromised in gall tissue. Gene ontology analysis sheds light on some stress-related unigenes with higher expression levels in gall tissues, suggesting that host plants sense aphids as a biotic stress but are defective in the JA-mediated defense response in gall tissues.</p> <p>The aphid-induced gall tissues on Japanese elm trees are less responsive than leaf tissues to jasmonic acid, which may provide the aphid with beneficial environments.</p

Nitrate analogs as attractants for soybean cyst nematode

<p>Soybean cyst nematode (SCN) <i>Heterodera glycines</i> Ichinohe, a plant parasite, is one of the most serious pests of soybean. In this paper, we report that SCN is attracted to nitrate and its analogs. We performed attraction assays to screen for novel attractants for SCN and found that nitrates were attractants for SCN and SCN recognized nitrate gradients. However, attraction of SCN to nitrates was not observed on agar containing nitrate. To further elucidate the attraction mechanism in SCN, we performed attraction assays using nitrate analogs (, , ). SCN was attracted to all nitrate analogs; however, attraction of SCN to nitrate analogs was not observed on agar containing nitrate. In contrast, SCN was attracted to azuki root, irrespective of presence or absence of nitrate in agar media. Our results suggest that the attraction mechanisms differ between plant-derived attractant and nitrate.</p> <p>Nitrate and its analogs regulate the attraction of soybean cyst nematode.</p

Effect of chemicals on 2-week-old rice seedlings.

<p>(A) <i>epi</i>-5DS levels in root exudates of 1 µM chemical-treated rice seedlings determined by LC-MS/MS. The data are means ± SD of three samples. (B) The length of 2nd leaf sheath in 10 µM chemical-treated rice. The data are means ± SD of six samples.</p

A comparison of the effects caused by TIS13 and TIS108 treatment.

<p>(A) Chemical structures of strigolactone biosynthesis inhibitors. (B) <i>epi</i>-5DS levels in root exudates of chemical-treated rice seedlings determined by LC-MS/MS. The data are means ± SD of three samples. (C) The length of 2nd leaf sheath in 10 µM chemical-treated rice. The data are means ± SD of six samples.</p

Effects of TIS108 on 2-week-old rice seedlings.

<p>(A) <i>epi</i>-5DS levels in roots and root exudates of TIS108-treated rice seedlings determined by LC-MS/MS. (B) Germination stimulant levels in culture media of 1 µM TIS108-treated rice seedlings using <i>Striga</i> seeds. DW, distilled water; GR24, 1 µM GR24; control, non-treated rice culture media; TIS108, culture media of 1 µM TIS108-treated rice; TIS108+GR24, culture media coincubated with 1 µM GR24 and 1 µM TIS108. The data are means ± SD of three samples.</p

Kinetic parameters of Pl-<i>scyllo</i>-IDH mutants with <i>sycllo</i>-inositol and L-glucose.

<p>Kinetic parameters of Pl-<i>scyllo</i>-IDH mutants with <i>sycllo</i>-inositol and L-glucose.</p

Binding mode of NADH.

<p>(A) L-glucono-1,5-lactone (yellow) and NADH (green) bound in Pl-<i>scyllo</i>-IDH are shown as stick models. β-L-glucose, colored in cyan, is superposed on the lactone molecule, and the H1 hydrogen in the axial conformation is colored white. The distance between NC4 and C1 is 3.4 Å, and the distance between H1 and NC4 is 2.0 Å shown as a red dotted line. From this structure, Pl-<i>scyllo</i>-IDH is concluded to be an A-type enzyme. (B) Structures of each of chain B in Pl-<i>scyllo</i>-IDH complexed with L-glucono-1,5-lactone colored in green and pale green, and <i>myo</i>-IDH from <i>B</i>. <i>subtilis</i> complexed with <i>scyllo</i>-inosose (PDB code: 3NT5) colored in orange and pale orange were superposed using the program Chimera [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0198010#pone.0198010.ref025" target="_blank">25</a>]. The superposed active sites are shown with substrates, NADH, and the catalytic triad, K-D-H in stick models. The difference is observed in the orientations of the nicotinamide rings between Pl-s<i>cyllo</i>-IDH and <i>myo</i>-IDH, which represent the A-type and B-type enzymes, respectively.</p

Superposition of flexible loop regions in each complex.

<p>The Pl-<i>scyllo</i>-IDH structures complexed with L-glucono-1,5-lactone, <i>myo</i>-inositol, <i>scyllo</i>-inosose, and acetate are shown superimposed, and the flexible loop regions are shown. Arg178 in the loop is also shown as a stick model. The regions colored in cyan and magenta indicate <i>myo</i>-inositol and <i>scyllo</i>-inosose, and L-glucono-1,5-lactone and acetate, respectively.</p

Phylogenetic tree of GOFR/IDH/MocA family members present in PDB.

<p>The amino acid sequences of GFO/IDH/MocA family enzymes in PDB were aligned and then subjected to a phylogenetic analysis using the program MEGA7. The number after PDB code indicates the oligomeric state of enzyme. A red line shows structures harboring the swap loop region as observed in Pl-<i>scyllo</i>-IDH.</p

Kinetic parameters of Pl-<i>scyllo</i>-IDH with L-2-<i>epi</i>-inosose and substrates.

<p>Kinetic parameters of Pl-<i>scyllo</i>-IDH with L-2-<i>epi</i>-inosose and substrates.</p