Differential expression of the brassinosteroid receptor-encoding BRI1 gene in Arabidopsis

Abstract

the wild phenotype, expression from the photosynthesisassociated CAB3 and the vasculature-specific SUC2 and ATHB8 promoters resulted in plants with varying morphogenic defects. Our results reveal complex differential regulation of BRI1 expression, and suggest that by influencing the distribution and abundance of the receptor this regulation can enhance or attenuate BR signalling.

Characterization of photomorphogenic responses and signaling cascades controlled by phytochrome‐A expressed in different tissues

“…In order to ensure tissue/cell‐type specific localization of the functional phyA‐YFP photoreceptor in planta , we expressed the fusion protein under the control of PHYA , MERISTEM LAYER 1 ( ProML1 ), SUCROSE (SUC)/H + SYMPORTER 2 ( ProSUC2 ) and CHLOROPHYLL A/B BINDING PROTEIN 3 ( ProCAB3 ) promoters in the phyA‐201 mutant. The ProPHYA promoter is known to be ubiquitously expressed in seedlings (Somers & Quail, ; Hall et al ., ), whereas the ProCAB3 , ProML1 and ProSUC2 promoters had been routinely used in the past to express proteins of interest exclusively in mesophyll, epidermal or companion cells, respectively (Sessions et al ., ; Srivastava et al ., ; Hategan et al ., ). For this study we raised 15–20 independent transgenic lines for each construct, and selected those which segregated the transgenes as a single Mendelian trait.…”

Local and Systemic Effects of Brassinosteroid Perception in Developing Phloem

“…Leaves typically appeared less elongated but slightly broader than in wild type, although total leave area was similar (Fig- ures 2E and 2F). This was possibly related to the continued activity of the CVP2 promoter throughout leaf development, as compared with native BRI1 expression, which gradually decreases in postmeristematic, maturating leaf areas [20,24]. Rosettes thus appeared more compact than in wild type, also because petiole elongation was not fully restored (Figures 2E and 2M).…”

“…Brassinosteroids are secreted steroid phytohormones that are perceived by the extracellular domain of the receptors and thereby trigger an intracellular signaling cascade that determines the nuclear abundance of the downstream effectors BRASSINAZOLE-RESISTANT 1 (BZR1) and BRI1-EMS-SUPPRESSOR 1 (BES1), two homologous transcription factors that were isolated through dominant alleles that partially suppress bri1 single-mutant phenotypes [15][16][17]. Protophloem differentiation is one of the few instances where BRI1, BRL1, and BRL3 are fully redundant, because it is only observed in bri 3 mutants, likely because of overlapping expression patterns (that is, whereas BRI1 is expressed in all root tissues, BRL1 is only expressed in the vascular cylinder and BRL3 only in the phloem) [14,[18][19][20][21]. By contrast, severe dwarfism and patterning defects are already observed in bri1 mutants, whereas brl1 or brl3 single mutants or brl1 brl3 double mutants appear essentially wild type [14,[22][23][24].…”

Crosstalk of the Brassinosteroid Signalosome with Phytohormonal and Stress Signaling Components Maintains a Balance between the Processes of Growth and Stress Tolerance

“…Expression of the BRI1 gene is under developmental, organ-specific and diurnal regulation [ 46 ]. It is known that BRs attenuate expression of the BRI1 gene [ 47 ], whereas auxin promotes transcription of the gene [ 48 , 49 ].…”