QUIRKY interacts with STRUBBELIG and PAL OF QUIRKY to regulate cell growth anisotropy during Arabidopsis gynoecium development

Abstract

Organ morphogenesis largely relies on cell division and elongation, which need to be both coordinated between cells and orchestrated with cytoskeleton dynamics. However, components that bridge the biological signals and the effectors that define cell shape remain poorly described. We have addressed this issue through the functional characterisation of QUIRKY (QKY), previously isolated as being involved in the STRUBBELIG (SUB) genetic pathway that controls cell-cell communication and organ morphogenesis in Arabidopsis. QKY encodes a protein containing multiple C2 domains and transmembrane regions, and SUB encodes an atypical LRRreceptor-like kinase. We show that twisting of the gynoecium observed in qky results from the abnormal division pattern and anisotropic growth of clustered cells arranged sporadically along the gynoecium. Moreover, the cortical microtubule (CMT) network of these cells is disorganised. A cross to botero, a katanin mutant in which the normal orientation of CMTs and anisotropic cell expansion are impaired, strongly reduces silique deviation, reinforcing the hypothesis of a role for QKY in CMT-mediated cell growth anisotropy. We also show that QKY is localised at the plasma membrane and functions in a multiprotein complex that includes SUB and PAL OF QUIRKY (POQ), a previously uncharacterised PB1-domaincontaining protein that localises both at the plasma membrane and in intracellular compartments. Our data indicate that QKY and its interactors play central roles linking together cell-cell communication and cellular growth.

The C2-domain protein QUIRKY and the receptor-like kinase STRUBBELIG localize to plasmodesmata and mediate tissue morphogenesis in Arabidopsis thaliana

“…Although the presence of SUB is not constrained to PD, localization of QKY appears to be restricted to PD. With respect to the subcellular localization of QKY, our results differ from a recent study, that reported QKY to be present at the PM (Trehin et al, 2013). Trehin et al, however, used a nonfunctional reporter carrying EGFP at the C terminus of QKY.…”

“…On selective medium, yeast growth was observed when QKYΔPRT_C was combined with the ICD of SUB (Fig. 7D), demonstrating that QKY can interact with the ICD of SUB in this assay, extending previous results (Trehin et al, 2013).…”

“…Previous genetic data indicated that QKY contributes to SUBmediated signaling (Fulton et al, 2009;Trehin et al, 2013). Supporting this notion, we found that the expression patterns of QKY and SUB largely overlap in young flowers and ovules (supplementary material Fig.…”

“…Recent efforts have resulted in the identification of additional genetic components of SUB signaling, including QUIRKY (QKY) (Fulton et al, 2009;Trehin et al, 2013). Plants lacking SUB or QKY activities display very similar phenotypes at the gross morphological and cellular levels.…”

Characterization of Multiple C2 Domain and Transmembrane Region Proteins in Arabidopsis

“…including mctp1-1 (ftip1-1) (Liu et al, 2012), mctp15 (qky-14) (Trehin et al, 2013), and mctp6-1 370 show the late-flowering phenotype (Fig. 10, A-D (Liu et al, 2012) (Fig.…”