Figures (4)  Tables (1)

    • Figure 1. 

      Cell wall–related mechanical properties control the polarity of PIN-FORMED proteins (PINs). Cell walls transmit mechanical signals to regulate PIN polarity, maintained by PM nanodomain compartmentalization and PIN clustering. The cell wall also regulates PIN trafficking via calcium and kinase signaling. PM, plasma membrane.

    • Figure 2. 

      Cell wall sensing hijacks the brassinosteroid (BR) receptor. The canonical BR signaling and xylem cell fate regulation cascades can be activated by a pectin-based signal. PSKR1, Phytosulfokine Receptor 1; RLP44, Receptor-Like Protein 44; BAK1, BRI1-Associated Receptor Kinase 1; BRI1, Brassinosteroid Insensitive 1; BIN2 (GSK3), BR-insensitive 2 (Glycogen Synthase Kinase3); OsWAK11, rice Cell Wall Associated receptor-like Kinase 11; AtRFO1, resistance to Fusarium oxysporum 1; BSU1, BRI1 Suppressor 1; BZR1, Brassinazole-Resistant 1; BES1, BRI1-EMS-suppressor 1; GSK3, Glycogen Synthase Kinase-3; PINs: PIN-FORMED proteins.

    • Figure 3. 

      Cell wall–derived chemical and mechanical signals regulate jasmonic acid (JA), salicylic acid (SA), and abscisic acid (ABA) content via PM-localized receptor like–kinases (RLKs). PEP, Plant Elicitor Peptide; PEPR, PEP Receptor; RALF, Rapid Alkalinization Factor; LRX, Leucine-Rich Repeat Extension; FER, FERONIA; MIK2, LRR-RK Male Discoverer 1-Interacting RLK 2; WAK, Wall-Associated Kinase; MCA1, Mechanosensitive Channel in Arabidopsis1; NIA1/2, Nitrate Reductase 1/2; THE1, Theseus; GEF, Guanine Nucleotide Exchange Factors; ROP, Small GTPase Rho Of Plants; ABI2, Abscisic Acid Insensitive2; RLP12, Receptor-Like Protein 44; BAK1, BRI1-Associated Receptor Kinase 1; BKK1, BAK1-Like 1; BIK1, Botrytis-Induced Kinase 1; FEI2, FEI LRR Receptor Like Kinase2; MYC2, MYC2 transcription factor.

    • Figure 4. 

      Cell wall status regulates ethylene pathway signaling. Cell wall information is relayed to 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor of ethylene (ET), to initiate ET-independent signaling. ACS, ACC synthase; FLA4, Fasciclin-Like Arabinogalactan Protein 4; GLR, Glutamate Receptor-Like; MCA1, Mechanosensitive Channel in Arabidopsis1; FEI1/2, FEI LRR Receptor Like Kinase1/2; THE1, Theseus1.

    • Receptor Co-receptor Ligand/stimulus Downstream Biological function Ref.
      THE1 NA Cell wall damage (mechanical) Ca2+ channels (MCA1); Regulates JA and SA Salt tolerance [45, 57]
      FER LRX proteins RALF peptides Ca2+ signals; Activates ABA; Regulates JA, SA Growth-defense balance;
      salt tolerance      		 [9, 67, 75, 78]
      MIK2 BAK1 PEPs/microbial patterns Acts in parallel to THE1; Negative regulator of JA/SA Pathogen defense [45, 66]
      WAKs NA Pectin Regulators of JA and SA; MAPK cascades Pathogen defense [45]
      PEPR1/2 BAK1; BIK1 Plant elicitor peptides MAPK cascades, Ca2+ influx; Regulators of JA/SA Pathogen defense [45, 66]
      LRR-RLK FEI2 SOS5/FLA4 NA Interacts with ACS5/9; Regulates ACC Root development; salt stress response [60, 86]
      RLP44 BRI1 Pectin status Integrate cell wall status with BR and PSK signaling;
      A key integrator of JA/SA/ABA      		 Regulate vasculature differentiation [44, 48]
      PSKR1

      Table 1. 

      RLKs in JA, SA, and ABA Signaling