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Foletto M.P.,State University of Maringa | Kagami F.,State University of Maringa | Voll E.,Brazilian Agricultural Research Corporation Embrapa Soybean | Kern-Cardoso K.A.,State University of Maringa | And 5 more authors.
Allelopathy Journal | Year: 2012

This study investigated the allelopathic potential of both aqueous fraction of Bracharia ruziziensis L. straws and trans-aconitic acid, a component of aqueous fraction on growth and physiological processes of the weed Ipomoea triloba L. Both aqueous fraction and aconitic acid at 250-2000 ppm concentrations influenced the germination and growth of I. triloba and caused similar changes in the respiratory activity of primary roots. They reduced KCN-sensitive respiration and increased the KCN-insensitive respiration. The highest concentration of both aqueous fraction and trans-aconitic acid increased the malondialdehyde and conjugated diene content in the primary roots of seedlings. The oxygen consumption from citrate oxidation in mitochondria isolated from primary roots was not affected. Thus, the water soluble compounds of B. ruziziensis were phytotoxic to I. triloba, inducing perturbations in respiratory activity and lipid peroxidation. Although trans-aconitic acid exerted similar effects to the aqueous fraction, it is not the main compound responsible for the effects of aqueous fraction in I. triloba, because its content is very little in this fraction.

Rodrigues F.A.,Brazilian Agricultural Research Corporation Embrapa Soybean | Fuganti-Pagliarini R.,Brazilian Agricultural Research Corporation Embrapa Soybean | Marcolino-Gomes J.,Brazilian Agricultural Research Corporation Embrapa Soybean | Marcolino-Gomes J.,State University Londrina | And 9 more authors.
BMC Genomics | Year: 2015

Background: Since drought can seriously affect plant growth and development and little is known about how the oscillations of gene expression during the drought stress-acclimation response in soybean is affected, we applied Illumina technology to sequence 36 cDNA libraries synthesized from control and drought-stressed soybean plants to verify the dynamic changes in gene expression during a 24-h time course. Cycling variables were measured from the expression data to determine the putative circadian rhythm regulation of gene expression. Results: We identified 4866 genes differentially expressed in soybean plants in response to water deficit. Of these genes, 3715 were differentially expressed during the light period, from which approximately 9.55 % were observed in both light and darkness. We found 887 genes that were either up- or down-regulated in different periods of the day. Of 54,175 predicted soybean genes, 35.52 % exhibited expression oscillations in a 24 h period. This number increased to 39.23 % when plants were submitted to water deficit. Major differences in gene expression were observed in the control plants from late day (ZT16) until predawn (ZT20) periods, indicating that gene expression oscillates during the course of 24 h in normal development. Under water deficit, dissimilarity increased in all time-periods, indicating that the applied stress influenced gene expression. Such differences in plants under stress were primarily observed in ZT0 (early morning) to ZT8 (late day) and also from ZT4 to ZT12. Stress-related pathways were triggered in response to water deficit primarily during midday, when more genes were up-regulated compared to early morning. Additionally, genes known to be involved in secondary metabolism and hormone signaling were also expressed in the dark period. Conclusions: Gene expression networks can be dynamically shaped to acclimate plant metabolism under environmental stressful conditions. We have identified putative cycling genes that are expressed in soybean leaves under normal developmental conditions and genes whose expression oscillates under conditions of water deficit. These results suggest that time of day, as well as light and temperature oscillations that occur considerably affect the regulation of water deficit stress response in soybean plants. © 2015 Rodrigues et al.

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