Additional file 1 of Physiological responses to drought stress of three pine species and comparative transcriptome analysis of Pinus yunnanensis var. pygmaea

Supplementary Material 1

Additional file 1 of Transcriptome analysis reveals regulatory mechanisms of different drought-tolerant Gleditsia sinensis seedlings under drought stress

Supplementary Material 1

Root Interactions in a Maize/Soybean Intercropping System Control Soybean Soil-Borne Disease, Red Crown Rot

<div><p>Background</p><p>Within-field multiple crop species intercropping is well documented and used for disease control, but the underlying mechanisms are still unclear. As roots are the primary organ for perceiving signals in the soil from neighboring plants, root behavior may play an important role in soil-borne disease control.</p><p>Principal Findings</p><p>In two years of field experiments, maize/soybean intercropping suppressed the occurrence of soybean red crown rot, a severe soil-borne disease caused by <i>Cylindrocladium parasiticum</i> (<i>C. parasiticum</i>). The suppressive effects decreased with increasing distance between intercropped plants under both low P and high P supply, suggesting that root interactions play a significant role independent of nutrient status. Further detailed quantitative studies revealed that the diversity and intensity of root interactions altered the expression of important soybean <i>PR</i> genes, as well as, the activity of corresponding enzymes in both P treatments. Furthermore, 5 phenolic acids were detected in root exudates of maize/soybean intercropped plants. Among these phenolic acids, cinnamic acid was released in significantly greater concentrations when intercropped maize with soybean compared to either crop grown in monoculture, and this spike in cinnamic acid was found dramatically constrain <i>C. parasiticum</i> growth <i>in vitro</i>.</p><p>Conclusions</p><p>To the best of our knowledge, this study is the first report to demonstrate that intercropping with maize can promote resistance in soybean to red crown rot in a root-dependent manner. This supports the point that intercropping may be an efficient ecological strategy to control soil-borne plant disease and should be incorporated in sustainable agricultural management practices.</p></div

Root interactions between soybean and maize plants in the field.

<p>Root interactions were measured as the total root length in the upper 20: 80 kg P₂O₅ ha⁻¹ added as calcium superphosphate, LP: no P fertilizer added. ISC1: maize/soybean intercropping with 20 cm spacing; ISC2: maize/soybean intercropping with 5 cm spacing. All the data are the mean of four replicates ± SE. F value from Two-way ANOVA: 8.35 for P treatment (<i>P</i><0.05), 159.08 for cultivation mode (<i>P</i><0.001), 1.99 for interaction (not significant). Bars with different letter(s) vary significantly among treatments as determined by Duncan's multiple range test (<i>P</i><0.05).</p

<i>C. parasiticum</i> growth as affected by root exudates.

<p>A, growth performance, B, colony diameter, C, sporulation. LP, 15 µM P; HP, 500 µM P. MS: soybean monoculture; MC: maize monoculture; ISC: maize/soybean intercropping. F value from Two-way ANOVA: colony diameter, 685.62 for P treatment (<i>P</i><0.001), 1119.75 for cultivation mode (<i>P</i><0.001), 12.73 for interaction (<i>P</i><0.001); sporulation, 38.33 for P treatment (<i>P</i><0.001), 116.49 for cultivation mode (<i>P</i><0.001), 1.02 for interaction (not significant). Each bar represents the mean of four replicates ± SE. Bars with different letter(s) vary significantly among treatments as determined by Duncan's multiple range test (<i>P</i><0.05).</p

Disease severity of soybean red crown rot in sand culture.

<p>A, disease incidence, B, disease index, C, CFU. LP, 15 µM P; HP, 500 µM P. All of the data are the means of four replicates ±SE. Bars with different letter(s) vary significantly among the different inoculation treatments as determined by Duncan's multiple range test (<i>P</i><0.05).</p

Expression of eight defense-related (<i>PR</i>) genes in soybean roots.

<p>LP: 15 µM P; HP: 500 µM P. Soybean roots were inoculated with <i>C. parasiticum</i> (see Materials and Methods for details). Solid barrier: eliminate root interactions and exudates movement between the roots of the two plant species; mesh barrier: prevent root intermingling of two species while permitting root exudates exchange; no barrier: allow roots and exudates to completely interact. Each bar represents the mean of three replicates ± SE.</p

Additional file 4: Figure S1. of Development of high-lysine rice via endosperm-specific expression of a foreign LYSINE RICH PROTEIN gene

Amino acid content in T14 generation of PA110 and PA64S. (JPG 1752 kb

Effect of 5 different phenolic acids on the growth and sporulation of <i>C. parasiticum</i>.

<p>A, colony diameter, B, number of spores. Each bar represents the mean of four replicates ± SE.</p

Concentrations of phenolic acids (µg·pot⁻¹) in root exudates from different treatments at the flowering stage as detected by HPLC.

<p>Note: LP, 15 µM P; HP, 500 µM P. MS, soybean monoculture; MC, maize monoculture; ISC, maize/soybean intercropping. -, not detectable. All the data are the mean of four replicates ± SE. Data with the same letter represent no significant differences among the different cultivation modes at the same P level as determined by Duncan's multiple range test or a <i>t</i>-test (<i>P</i><0.05).</p