A novel role for STOMATAL CARPENTER 1 in stomata patterning

Abstract

BackgroundGuard cells (GCs) are specialised cells within the plant epidermis which form stomatal pores, through which gas exchange can occur. The GCs derive through a specialised lineage of cell divisions which is specified by the transcription factor SPEECHLESS (SPCH), the expression of which can be detected in undifferentiated epidermal cells prior to asymmetric division. Other transcription factors may act before GC specification and be required for correct GC patterning. Previously, the DOF transcription factor STOMATAL CARPENTER 1 (SCAP1) was shown to be involved in GC function, by activating a set of GC–specific genes required for GC maturation and activity. It is thus far unknown whether SCAP1 can also affect stomatal development.ResultsHere we show that SCAP1 expression can also be observed in young leaf primordia, before any GC differentiation occurs. The study of transgenic plants carrying a proSCAP1:GUS-GFP transcriptional fusion, coupled with qPCR analyses, indicate that SCAP1 expression peaks in a temporal window which is coincident with expression of stomatal patterning genes. Independent scap1 loss-of-function mutants have a reduced number of GCs whilst SCAP1 over expression lines have an increased number of GCs, in addition to altered GC distribution and spacing patterns. The study of early markers for stomatal cell lineage in a background carrying gain–of–function alleles of SCAP1 revealed that, compared to the wild type, an increased number of protodermal cells are recruited in the GC lineage, which is reflected in an increased number of meristemoids.ConclusionsOur results suggest an early role for SCAP1 in GC differentiation. We propose that a function of SCAP1 is to integrate different aspects of GC biology including specification, spacing, maturation and function.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0851-z) contains supplementary material, which is available to authorized users.

Regulation of Gene Expression of Methionine Sulfoxide Reductases and Their New Putative Roles in Plants

“…In summary, 11 of the TFs (PDF2, SBF, WUSCHEL, TESMIN/TSO1-like CXC, KANADI1, GLK, DOF5.7, LHY, repressor AS1/AS2, GBF1, STK) that were predicted to bind the promoter regions of most of the analyzed Msrs act in plant growth and regulation. Studies have demonstrated that the above TFs are involved in shoot development [40], lateral root formation and development [41], embryo development [40], leaf development [42,43], stomata patterning [44], chloroplast development [45], the development of reproductive tissues [46], early embryogenesis [47], seedling development [48], senescence [49], the regulation of circadian rhythms [50], and cell-cycle-dependent transcription-enabling plant growth [47]. Interestingly, seven of the TFs that are listed in Table 2 (WUSCHEL, DIVARICITA, BELLRINGER, HB32 and HB34, RAP2.7, CRABS CLAW, ODO1) control the flowering process by regulating floral development [51,52], fragrance [53], and nectary development [54] and the initiation and repression of flowering [47,49,55,56].…”

Expression Pattern and Functional Analyses of Arabidopsis Guard Cell-Enriched GDSL Lipases

“…Moreover, the stomatal density and index of ggl7ggl14ggl26 triple mutant were not different from those in ggl14 ( Supplementary Figures S6A , B ), suggesting that GGL7 and GGL26 are not involved in stomatal density. It has been reported that some guard cell-expressed genes affect stomatal patterning and shape ( Lee et al, 2013 ; Negi et al, 2013 ; Castorina et al, 2016 ; Rui et al, 2017 ). We found that the one-spacing rule in these single, double, and triple mutants was not disrupted (data not shown), suggesting that these GGLs are not involved in this stomatal developmental process.…”

Stomatal development and genetic expression in Arabidopsis thaliana L.

“…Antagonistically, Castorina et al (2016) performed comprehensive analysis of the control of SCAP1 expression during leaf development and found that the transcriptional component SCAP1 is essential in the genetic pathway of stomatal production and might be a key regulator involving SCAP1 mediated down regulation of EPF2 activation. SCAP1 plays a spatially distinct role in the GC maturation, as well as has the fundamental role in GC patterning and function.…”