Understanding Soil Respiration: an integrated approach

Soil respiration is a key factor for understanding the responses of terrestrial ecosystems to climate change, and it is crucial to understand the effects of variation in biophysical regulators of soil respiration for assessing carbon balance of forested temperate ecosystem. One fundamental challenge for soil research is the spatial and temporal heterogeneity of soil processes. Therefore, we deployed a dense array of soil sensor in combination with minirhizotrons to study variation in soil temperature, moisture, root production, and rhizomorph production on soil respiration within natural spatial gradients at the James Reserve. We used Structural Equation Modeling (SEM) to find out which factors are significant to the soil respiration in various depths

Understanding Soil Respiration: an integrated approach

Soil respiration is a key factor for understanding the responses of terrestrial ecosystems to climate change, and it is crucial to understand the effects of variation in biophysical regulators of soil respiration for assessing carbon balance of forested temperate ecosystem. One fundamental challenge for soil research is the spatial and temporal heterogeneity of soil processes. Therefore, we deployed a dense array of soil sensor in combination with minirhizotrons to study variation in soil temperature, moisture, root production, and rhizomorph production on soil respiration within natural spatial gradients at the James Reserve. We used Structural Equation Modeling (SEM) to find out which factors are significant to the soil respiration in various depths

Strigolactone analog GR24 triggers changes in PIN2 polarity, vesicle trafficking and actin filament architecture

Strigolactones (SLs) are plant hormones that regulate shoot and root development in a MAX2-dependent manner. The mechanism underlying SLs' effects on roots is unclear. We used root hair elongation to measure root response to SLs. We examined the effects of GR24 (a synthetic, biologically active SL analog) on localization of the auxin efflux transporter PIN2, endosomal trafficking, and F-actin architecture and dynamics in the plasma membrane (PM) of epidermal cells of the primary root elongation zone in wildtype (WT) Arabidopsis and the SL-insensitive mutant max2. We also recorded the response to GR24 of trafficking (tir3), actin (der1) and PIN2 (eir1) mutants. GR24 increased polar localization of PIN2 in the PM of epidermal cells and accumulation of PIN2-containing brefeldin A (BFA) bodies, increased ARA7-labeled endosomal trafficking, reduced F-actin bundling and enhanced actin dynamics, all in a MAX2-dependent manner. Most of the der1 and tir3 mutant lines also displayed reduced sensitivity to GR24 with respect to root hair elongation. We suggest that SLs increase PIN2 polar localization, PIN2 endocytosis, endosomal trafficking, actin debundling and actin dynamics in a MAX2-dependent fashion. This enhancement might underlie the WT root's response to SLs, and suggests noncell autonomous activity of SLs in roots. © 2014 New Phytologist Trust

Arabidopsis response to low-phosphate conditions includes active changes in actin filaments and PIN2 polarization and is dependent on strigolactone signalling

© The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. Strigolactones (SLs) are plant hormones that regulate the plant response to phosphate (Pi) growth conditions. At least part of SL-signalling execution in roots involves MAX2-dependent effects on PIN2 polar localization in the plasma membrane (PM) and actin bundling and dynamics. We examined PIN2 expression, PIN2 PM localization, endosome trafficking, and actin bundling under low-Pi conditions: a MAX2-dependent reduction in PIN2 trafficking and polarization in the PM, reduced endosome trafficking, and increased actin-filament bundling were detected in root cells. The intracellular protein trafficking that is related to PIN proteins but unassociated with AUX1 PM localization was selectively inhibited. Exogenous supplementation of the synthetic SL GR24 to a SL-deficient mutant (max4) led to depletion of PIN2 from the PM under low-Pi conditions. Accordingly, roots of mutants in MAX2, MAX4, PIN2, TIR3, and ACTIN2 showed a reduced low-Pi response compared with the wild type, which could be restored by auxin (for all mutants) or GR24 (for all mutants except max2-1). Changes in PIN2 polarity, actin bundling, and vesicle trafficking may be involved in the response to low Pi in roots, dependent on SL/MAX2 signalling