Biology subjects

MARTINEZ GARCIA, j.

Publications and source records attributed to MARTINEZ GARCIA, j..

2 recordsLinked to original sources

bioRxiv2022

Temporal and spatial frameworks supporting plant responses to vegetation proximity

After perception of vegetation proximity by the phytochrome photoreceptors, shade-avoider plants initiate a set of responses known as the Shade Avoidance Syndrome (SAS). The shade-induced de-repression of active phytochrome B (phyB) releases the repression imposed over the PHYTOCHROME INTERACTING FACTORs (PIFs). In Arabidopsis thaliana seedlings, this mechanism triggers rapid and massive changes in gene expression, increases auxin production in a SHADE AVOIDANCE 3-dependent manner and promotes hypocotyl elongation. Other components, such as phyA and ELONGATED HYPOCOTYL 5 (HY5), also participate in the shade regulation of the hypocotyl elongation response repressing it. However, it is less clear how phyA and HY5 interact with PIFs to regulate this response. Our physiological, genetic, cell biology and transcriptomic analyses showed that these components are organized in two main branches, and incorporate into the model for the regulation of shade-induced hypocotyl elongation the temporal and spatial functional importance of the various SAS regulators analyzed in here. They also indicated that PIFs and HY5, belonging to separate branches, target common genes whose expression is rapidly modulated by shade. This transcriptional relationship, however, changes after longer shade-treatments, suggesting that it is a dynamic convergence point to modulate the hypocotyl elongation.

plant biology↗

bioRxiv2020

Light quality signals generated by vegetation shade facilitate acclimation to reduced light quantity in shade-avoider plants

O_LIWhen growing in search for light, plants can experience continuous or occasional shading by other plants. Plant proximity causes a decrease in the ratio of red to far red light (low R:FR) due to the preferential absorbance of red light and reflection of far red light by photosynthetic tissues of neighboring plants. This signal is often perceived before actual shading causes a reduction in photosynthetically active radiation (low PAR). C_LIO_LIHere we investigated elongation, photosynthesis and photoacclimation responses in several Brassicaceae species to explore the possible connections between low R:FR and low PAR. C_LIO_LIA negative correlation was found in shade-tolerant Cardamine hirsuta and shade-avoider Arabidopsis thaliana seedlings (e.g., shade-tolerance was associated with a good adaptation to low PAR but a poor or null response to low R:FR exposure). However, they could be genetically uncoupled. Most interestingly, exposure to low R:FR of shade-avoider plants improved their photoacclimation to low PAR by triggering changes in photosynthesis-related gene expression, pigment accumulation and chloroplast ultrastructure. C_LIO_LIThese results indicate that low R:FR signaling unleashes molecular, metabolic and developmental responses that allow shade-avoider plants (including most crops) to adjust their photosynthetic capacity in anticipation of eventual shading by nearby plants. C_LI

plant biology↗