Synchronization of Developmental Processes and Defense Signaling by Growth Regulating Transcription Factors

Abstract

Growth regulating factors (GRFs) are a conserved class of transcription factor in seed plants. GRFs are involved in various aspects of tissue differentiation and organ development. The implication of GRFs in biotic stress response has also been recently reported, suggesting a role of these transcription factors in coordinating the interaction between developmental processes and defense dynamics. However, the molecular mechanisms by which GRFs mediate the overlaps between defense signaling and developmental pathways are elusive. Here, we report large scale identification of putative target candidates of Arabidopsis GRF1 and GRF3 by comparing mRNA profiles of the grf1/grf2/grf3 triple mutant and those of the transgenic plants overexpressing miR396-resistant version of GRF1 or GRF3. We identified 1,098 and 600 genes as putative targets of GRF1 and GRF3, respectively. Functional classification of the potential target candidates revealed that GRF1 and GRF3 contribute to the regulation of various biological processes associated with defense response and disease resistance. GRF1 and GRF3 participate specifically in the regulation of defense-related transcription factors, cell-wall modifications, cytokinin biosynthesis and signaling, and secondary metabolites accumulation. GRF1 and GRF3 seem to fine-tune the crosstalk between miRNA signaling networks by regulating the expression of several miRNA target genes. In addition, our data suggest that GRF1 and GRF3 may function as negative regulators of gene expression through their association with other transcription factors. Collectively, our data provide new insights into how GRF1 and GRF3 might coordinate the interactions between defense signaling and plant growth and developmental pathways.

GROWTH REGULATING FACTOR5 Stimulates Arabidopsis Chloroplast Division, Photosynthesis, and Leaf Longevity

“…This implies that an altered steady state has been reached in the cytokinin signaling pathway in 35S:GRF5 and grf5-1 plants, which could explain the increased sensitivity of 35S:GRF5 plants to cytokinin-driven stimulation of cell division and leaf longevity. Recently, analysis of the root transcript profiles of the grf1 grf2 grf3 triple mutant and plants overexpressing rGRF1 or rGRF3 revealed a significant overlap with a robust set of cytokinin-responsive genes, defined as the golden list, including ARR9 (Bhargava et al, 2013;Liu et al, 2014b). Moreover, GRF1 and GRF3 transcript levels were reduced in 2-week-old ahk2 ahk3 double mutant plants, corroborating that GRFs and cytokinins interact (Liu et al, 2014b).…”

Sp-miR396a-5p acts as a stress-responsive genes regulator by conferring tolerance to abiotic stresses and susceptibility to Phytophthora nicotianae infection in transgenic tobacco

“…8). GRF1 is also involved in basal disease resistance by positively regulating TGA1 and TGA4 and negatively regulating TGA3 and TGA7 (Kesarwani et al 2007;Shearer et al 2012;Liu et al 2014). This feature further suggested that overexpression of SpmiR396a-5p increased transgenic plants susceptibility to P. nicotianae infection.…”

The Arabidopsis miR396 mediates pathogen-associated molecular pattern-triggered immune responses against fungal pathogens

“…Fungal perception impinges on the activity of MIR396 promoters leading to a gradual decline in mature miR396 levels and a concomitant increase of miR396 target expression during the normal course of PTI. MiR396 targets can regulate growth and stress responses2425262728, MIM396 plants grow and develop normally. This result is in agreement with the minor changes observed in the global transcriptome in non-pathogen challenged MIM396 plants.…”