Targeted misexpression of NAC052, acting in H3K4 demethylation, alters leaf morphological and anatomical traits in Arabidopsis thaliana.

In an effort to identify genetic regulators for the cell ontogeny around the veins in Arabidopsis thaliana leaves, an activation-tagged mutant line with altered leaf morphology and altered bundle sheath anatomy was characterized. This mutant had a small rosette area with wrinkled leaves and chlorotic leaf edges, as well as enhanced chloroplast numbers in the (pre-)bundle sheath tissue. It had a bundle-specific promoter from the gene GLYCINE DECARBOXYLASE SUBUNIT-T from the C4 species Flaveria trinervia (GLDTFt promoter) inserted in the coding region of the transcriptional repressor NAC052, functioning in H3K4 demethylation, in front of an alternative start codon in-frame with the natural start codon.

Photosynthetic response to increased irradiance correlates to variation in transcriptional response of lipid-remodeling and heat-shock genes.

Plants have evolved several mechanisms for sensing increased irradiance, involving signal perception by photoreceptors (cryptochromes), and subsequent biochemical (reactive oxygen species, ROS) and metabolic clues to transmit the signals. This results in the increased expression of heat-shock response genes and of the transcription factor LONG HYPOCOTYL 5 (HY5, mediated by the cryptochrome photoreceptor 1, CRY1). Here, we show the existence of another response pathway in Arabidopsis.

Natural variation of YELLOW SEEDLING1 affects photosynthetic acclimation of Arabidopsis thaliana.

Exploiting genetic variation for more efficient photosynthesis is an underexplored route towards new crop varieties. This study demonstrates the genetic dissection of higher plant photosynthesis efficiency down to the genomic DNA level, by confirming that allelic sequence variation at the Arabidopsis thaliana YELLOW SEEDLING1 (YS1) gene explains natural diversity in photosynthesis acclimation to high irradiance. We use a genome-wide association study to identify quantitative trait loci (QTLs) involved in the Arabidopsis photosynthetic acclimation response.

Natural genetic variation for acclimation of photosynthetic light use efficiency to growth irradiance in Arabidopsis.

Plants are known to be able to acclimate their photosynthesis to the level of irradiance. Here, we present the analysis of natural genetic variation for photosynthetic light use efficiency (ΦPSII) in response to five light environments among 12 genetically diverse Arabidopsis (Arabidopsis thaliana) accessions. We measured the acclimation of ΦPSII to constant growth irradiances of four different levels (100, 200, 400, and 600 µmol m(-2) s(-1)) by imaging chlorophyll fluorescence after 24 d of growth and compared these results with acclimation of ΦPSII to a step-wise change in irradiance where the growth irradiance was increased from 100 to 600 µmol m(-2) s(-1) after 24 d of growth.