Cellulose is the main structural compound of the plant cell wall and the most abundant biopolymer on
Earth (Bar‐On et al 2018). The essential role of cellulose in plant development and defence highlights the
importance of understanding how its synthesis is regulated and will provide new tools to improve crop
tolerance to biotic and abiotic stresses.
We identified that Tetratricopeptide Thioredoxin‐Like (TTL) proteins function as scaffold components of
brassinosteroid signalling components (Amorim‐Silva et al 2019) and as new components of the
Cellulose Synthase Complex (CSC) and describe its unique dynamic association with the CSC under
cellulose‐deficient conditions (Kesten, García‐Moreno, Amorim‐Silva et al 2022). The TTL‐CESA
interaction at the plasma membrane significantly increased under conditions that cause reduced
cellulose content, such as salt stress and structural alterations of the CSCs. The relocalization of cytosolic
TTLs to the active CSCs allows cellulose synthesis, mediated by a stress‐resilient cortical microtubule
array and the stabilization of the CSCs at the plasma membrane. TTLs carry this out by interacting with
Cellulose Synthase 1 and promoting the polymerization of microtubules, thus maintaining the stability
and integrity of the complex. We propose that TTLs act as bridges connecting stress‐mediated cell wall
modification with the regulation of cellulose biosynthesis.
We are currently investigating novel components involved in TTL function and how this protein family is
regulated. Recently, we have identified the 14‐3‐3 proteins as interactors of TTL3. The 14‐3‐3s are a
family of proteins conserved in eukaryotes that target a wide number of proteins (Huang et al 2022). An
Arabidopsis line overexpressing 14‐3‐3λ present phenotypes under stress consistent with defects in
cellulose biosynthesis. This study will elucidate a possible role of 14‐3‐3 proteins in TTL regulation and
cellulose biosynthesis.This work was funded by the Spanish Ministry for Science and Innovation (MCIN/AEI/10.1 0 9/ 011000110 ) and the Andalusian Research Plan cofinanced by the European
Union(PAI I 2020-PY20_0008 and UMA20- E ERJA-02 ) to M.A.B.; V.A.-S. was supported by an Emerging Investigator research project (UMA20- E ERJA-007) and cofinanced by the
“Programa Operativo E ER 201 -2020” and by the “Consejeria de Economia y Conocimiento de la Junta de Andalucia”. R.P.M. was supported by the Andalusian PRE OC_01
fellowship. A.M. was supported by Shanghai Center for Plant Stress Biology.
Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
