Perturbation of cell cycle regulation triggers plant immune response via activation of disease resistance genes

Abstract

The Arabidopsis gene OSD1 (Omission of the Second Division) and its homolog UVI4 (UV-B-Insensitive 4) are negative regulators of anaphase-promoting complex/cyclosome (APC/C), a multisubunit ubiquitin E3 ligase that regulates the progression of cell cycles. Here we report the isolation of an activation tagging allele of OSD1 as an enhancer of a mutant of BON1 (BONZAI1), a negative regulator of plant immunity. Overexpression of OSD1 and UVI4 each leads to enhanced immunity to a bacterial pathogen, which is associated with increased expression of disease resistance (R) genes similar to the animal NOD1 receptor-like immune receptor genes. In addition, the reduction of function of one subunit of the APC complex APC10 exhibited a similar phenotype to that of overexpression of OSD1 or UVI4, indicating that altered APC function induces immune responses. Enhanced immune response induced by OSD1 overexpression is dependent on CYCB1;1, which is a degradation target of APC/C. It is also associated with up-regulation of R genes and is dependent on the R gene SNC1 (Suppressor of npr1-1, constitutive 1). Taken together, our findings reveal an unexpected link between cell cycle progression and plant immunity, suggesting that cell cycle misregulation could have an impact on expression of genes, including R genes, in plant immunity.

Casein Kinase 1γ1 Inhibits the RIG-I/TLR Signaling Pathway through Phosphorylating p65 and Promoting Its Degradation

“…RIG-I itself initially was identified as a protein involved in cell proliferation and differentiation (17). Many studies indicated that there were cross-talks between cell cycle regulation and immune response (18,19). To identify the novel proteins involved in the regulation of RIG-Imediated immune signaling as well as the cell cycle pathway, we screened a set of protein kinases that play important roles in the control of cell cycle using an IFN-b luciferase reporter assay.…”

A Secreted Effector Protein ofUstilago maydisGuides Maize Leaf Cells to Form Tumors

“…We hypothesize that this reflects the reduced activation of cell division and, consequently, limited tumor expansion in the mutant-infected leaves. Recent work by Bao et al (2013) found an unexpected link between cell cycle progression and plant immunity, suggesting that cell cycle misregulation impacts the expression of R genes. Also, DNA repair proteins have been shown to be directly involved in the regulation of gene expression during plant defense responses (Song et al, 2011).…”

The Maize MID-COMPLEMENTING ACTIVITY Homolog CELL NUMBER REGULATOR13/NARROW ODD DWARF Coordinates Organ Growth and Tissue Patterning

“…Interestingly, cell wall synthesis inhibition triggers pathogen response pathways and inhibits cell division and expansion (Hamann, 2015). Disturbance of the cell cycle is also known to trigger pathogen responses (Bao et al, 2013). Cell wall synthesis CSDL mutants, warty and slender leaf, have overlapping phenotypes with nod-1, including reduced organ size, defects in cell division, and abnormal stomata differentiation (Hunter et al, 2012;Yoshikawa et al, 2013).…”