@phdthesis{11879,
  abstract     = {As the overall global mean surface temperature is increasing due to climate change, plant
adaptation to those stressful conditions is of utmost importance for their survival. Plants are
sessile organisms, thus to compensate for their lack of mobility, they evolved a variety of
mechanisms enabling them to flexibly adjust their physiological, growth and developmental
processes to fluctuating temperatures and to survive in harsh environments. While these unique
adaptation abilities provide an important evolutionary advantage, overall modulation of plant
growth and developmental program due to non-optimal temperature negatively affects biomass
production, crop productivity or sensitivity to pathogens. Thus, understanding molecular
processes underlying plant adaptation to increased temperature can provide important
resources for breeding strategies to ensure sufficient agricultural food production.
An increase in ambient temperature by a few degrees leads to profound changes in organ growth
including enhanced hypocotyl elongation, expansion of petioles, hyponastic growth of leaves and
cotyledons, collectively named thermomorphogenesis (Casal & Balasubramanian, 2019). Auxin,
one of the best-studied growth hormones, plays an essential role in this process by direct
activation of transcriptional and non-transcriptional processes resulting in elongation growth
(Majda & Robert, 2018).To modulate hypocotyl growth in response to high ambient temperature
(hAT), auxin needs to be redistributed accordingly. PINs, auxin efflux transporters, are key
components of the polar auxin transport (PAT) machinery, which controls the amount and
direction of auxin translocated in the plant tissues and organs(Adamowski & Friml, 2015). Hence,
PIN-mediated transport is tightly linked with thermo-morphogenesis, and interference with PAT
through either chemical or genetic means dramatically affecting the adaptive responses to hAT.
Intriguingly, despite the key role of PIN mediated transport in growth response to hAT, whether
and how PINs at the level of expression adapt to fluctuation in temperature is scarcely
understood.
With genetic, molecular and advanced bio-imaging approaches, we demonstrate the role of PIN
auxin transporters in the regulation of hypocotyl growth in response to hAT. We show that via
adjustment of PIN3, PIN4 and PIN7 expression in cotyledons and hypocotyls, auxin distribution is modulated thereby determining elongation pattern of epidermal cells at hAT. Furthermore, we
identified three Zinc-Finger (ZF) transcription factors as novel molecular components of the
thermo-regulatory network, which through negative regulation of PIN transcription adjust the
transport of auxin at hAT. Our results suggest that the ZF-PIN module might be a part of the
negative feedback loop attenuating the activity of the thermo-sensing pathway to restrain
exaggerated growth and developmental responses to hAT.},
  author       = {Artner, Christina},
  isbn         = {978-3-99078-022-0},
  issn         = {2663-337X},
  keywords     = {high ambient temperature, auxin, PINs, Zinc-Finger proteins, thermomorphogenesis, stress},
  pages        = {128},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Modulation of auxin transport via ZF proteins adjust plant response to high ambient temperature}},
  doi          = {10.15479/at:ista:11879},
  year         = {2022},
}

@article{10015,
  abstract     = {Auxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies have revealed that, beyond transcriptional reprogramming, alternative auxincontrolled mechanisms regulate root growth. Here, we explored the impact of different concentrations of the synthetic auxin NAA that establish growth-promoting and -repressing conditions on the root tip proteome and phosphoproteome, generating a unique resource. From the phosphoproteome data, we pinpointed (novel) growth regulators, such as the RALF34-THE1 module. Our results, together with previously published studies, suggest that auxin, H+-ATPases, cell wall modifications and cell wall sensing receptor-like kinases are tightly embedded in a pathway regulating cell elongation. Furthermore, our study assigned a novel role to MKK2 as a regulator of primary root growth and a (potential) regulator of auxin biosynthesis and signalling, and suggests the importance of the MKK2
Thr31 phosphorylation site for growth regulation in the Arabidopsis root tip.},
  author       = {Nikonorova, N and Murphy, E and Fonseca de Lima, CF and Zhu, S and van de Cotte, B and Vu, LD and Balcerowicz, D and Li, Lanxin and Kong, X and De Rop, G and Beeckman, T and Friml, Jiří and Vissenberg, K and Morris, PC and Ding, Z and De Smet, I},
  issn         = {2073-4409},
  journal      = {Cells},
  keywords     = {primary root, (phospho)proteomics, auxin, (receptor) kinase},
  publisher    = {MDPI},
  title        = {{The Arabidopsis root tip (phospho)proteomes at growth-promoting versus growth-repressing conditions reveal novel root growth regulators}},
  doi          = {10.3390/cells10071665},
  volume       = {10},
  year         = {2021},
}

@article{9986,
  abstract     = {Size control is a fundamental question in biology, showing incremental complexity in plants, whose cells possess a rigid cell wall. The phytohormone auxin is a vital growth regulator with central importance for differential growth control. Our results indicate that auxin-reliant growth programs affect the molecular complexity of xyloglucans, the major type of cell wall hemicellulose in eudicots. Auxin-dependent induction and repression of growth coincide with reduced and enhanced molecular complexity of xyloglucans, respectively. In agreement with a proposed function in growth control, genetic interference with xyloglucan side decorations distinctly modulates auxin-dependent differential growth rates. Our work proposes that auxin-dependent growth programs have a spatially defined effect on xyloglucan’s molecular structure, which in turn affects cell wall mechanics and specifies differential, gravitropic hypocotyl growth.},
  author       = {Velasquez, Silvia Melina and Guo, Xiaoyuan and Gallemi, Marçal and Aryal, Bibek and Venhuizen, Peter and Barbez, Elke and Dünser, Kai Alexander and Darino, Martin and Pӗnčík, Aleš and Novák, Ondřej and Kalyna, Maria and Mouille, Gregory and Benková, Eva and Bhalerao, Rishikesh P. and Mravec, Jozef and Kleine-Vehn, Jürgen},
  issn         = {1422-0067},
  journal      = {International Journal of Molecular Sciences},
  keywords     = {auxin, growth, cell wall, xyloglucans, hypocotyls, gravitropism},
  number       = {17},
  publisher    = {MDPI},
  title        = {{Xyloglucan remodeling defines auxin-dependent differential tissue expansion in plants}},
  doi          = {10.3390/ijms22179222},
  volume       = {22},
  year         = {2021},
}