SYNERGISTIC ON AUXIN AND CYTOKININ 1 positively regulates growth and attenuates soil pathogen resistance

Abstract

Plants as non-mobile organisms constantly integrate varying environmental signals to flexibly adapt their growth and development. Local fluctuations in water and nutrient availability, sudden changes in temperature or other abiotic and biotic stresses can trigger changes in the growth of plant organs. Multiple mutually interconnected hormonal signaling cascades act as essential endogenous translators of these exogenous signals in the adaptive responses of plants. Although the molecular backbones of hormone transduction pathways have been identified, the mechanisms underlying their interactions are largely unknown. Here, using genome wide transcriptome profiling we identify an auxin and cytokinin cross-talk component; SYNERGISTIC ON AUXIN AND CYTOKININ 1 (SYAC1), whose expression in roots is strictly dependent on both of these hormonal pathways. We show that SYAC1 is a regulator of secretory pathway, whose enhanced activity interferes with deposition of cell wall components and can fine-tune organ growth and sensitivity to soil pathogens.

Cytokinin Signaling Downstream of the His-Asp Phosphorelay Network: Cytokinin-Regulated Genes and Their Functions

“…Auxin and cytokinin action are closely interwoven and each of the two hormone influences the status of the other at multiple layers and through multiple signaling pathways, mostly in an antagonistic fashion ( Dello Ioio et al, 2008 ; Müller and Sheen, 2008 ). Components of that largely unknown network continue to be discovered, such as SYAC1 very recently ( Hurný et al, 2020 ).…”

Hormonal Regulation and Crosstalk of Auxin/Cytokinin Signaling Pathways in Potatoes In Vitro and in Relation to Vegetation or Tuberization Stages

“…In this way, these two hormones determine, to a large extent, the overall plant phenotype. Other important plant traits including organogenesis and resistance to biotic and abiotic stresses are also auxin-/CK-dependent [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. In the 21st century, great progress has been achieved in dissecting the molecular mechanisms of auxin and CK perception and signal transduction [ 2 , 20 , 21 , 22 , 23 , 24 , 25 ].…”

Auxin and Cytokinin Interplay during Leaf Morphogenesis and Phyllotaxy

“…Moreover, the in-depth analysis of auxins and CKs pathways has revealed that multiple players are involved in the crosstalk of these two hormones, fine-tuning their levels of auxins and cytokinins in plants [ 6 ]. The cytokinins biosynthesis is positively modulated by auxins via direct control of the ISOPENTENYL TRANSFERASE (IPT) genes transcript accumulations, which is mediated by the AUXIN RESPONSE FACTOR 19 (ARF19) transcription factor [ 5 ].…”

“…In this regard, the available literature with the recent findings sheds light on the involvement of both auxin and cytokinin pathway genes in leaf development in plants. However, the available literature is not sufficient for understanding the underlying molecular mechanisms [ 6 , 10 ].…”