Auxin canalization and vascular tissue formation by TIR1/AFB‐mediated auxin signaling in Arabidopsis

Abstract

Plant survival depends on vascular tissues, which originate in a self-organizing manner as strands of cells co-directionally transporting the plant hormone auxin. The latter phenomenon (also known as auxin canalization) is classically hypothesized to be regulated by auxin itself via the effect of this hormone on the polarity of its own intercellular transport. Correlative observations supported this concept, but molecular insights remain limited.In the current study, we established an experimental system based on the model Arabidopsis thaliana, which exhibits auxin transport channels and formation of vasculature strands in response to local auxin application.Our methodology permits the genetic analysis of auxin canalization under controllable experimental conditions. By utilizing this opportunity, we confirmed the dependence of auxin canalization on a PIN-dependent auxin transport and nuclear, TIR1/AFB-mediated auxin signaling. We also show that leaf venation and auxin-mediated PIN repolarization in the root require TIR1/AFB signaling.Further studies based on this experimental system are likely to yield better understanding of the mechanisms underlying auxin transport polarization in other developmental contexts.

Strigolactones inhibit auxin feedback on PIN-dependent auxin transport canalization

“…Young Arabidopsis plants with inflorescence stems having primary tissue architecture (vascular bundles separated by interfascicular parenchyma sectors) were used for analyzing vasculature regeneration and formation after wounding or from local application of compounds according to method described in previous study 41 , 68 . Briefly, first step was aimed to obtain a closed ring of active vascular cambium and secondary tissue architecture in immature inflorescence stems; second step was to analyze regeneration of incised vascular cambium and formation of new vessels in wounded stems.…”

Cellular requirements for PIN polar cargo clustering in Arabidopsis thaliana

“…This process underlies a plethora of developmental processes, such as embryonic axis establishment, root and shoot tropisma, meristem activities, and root and shoot organogenesis (Adamowski & Friml, 2015). Polarly localized members of the plant‐specific family of PIN‐FORMED (PIN) auxin transporters regulate both the rate and the directionality of this auxin transport that is essential to connect polarities at the individual cell level and the tissue and organ levels (Wiśniewska et al ., 2006; Sauer et al ., 2006a; Glanc et al ., 2018; Skokan et al ., 2019; Mazur et al ., 2020; Zhang et al ., 2020). In animal, cell polarity is regulated through several conserved factors (Crumbs, Scribble and PAR) that are absent in known plant genomes (Geldner, 2009; Kania et al ., 2014), and tight junctions separating the polar domains between neighboring epithelial cells (Nelson & Beitel, 2009).…”

Unraveling the Roles of Vascular Proteins Using Proteomics

“…The Altered Phloem Development (APD) transcription factor is required for phloem formation [ 79 ]. Auxin receptor protein TIR1/AFB mediates PIN repolarization, and plays roles in the regeneration of vascular strands and leaf venation [ 80 ]. Calmodulin-signal–related proteins, such as phloem protein 1 (PP1) and PP2, function in the blocking of damaged sieve tubes.…”