Auxin Response Factors (ARFs) are potential mediators of auxin action in tomato response to biotic and abiotic stress (Solanum lycopersicum)

Abstract

Survival biomass production and crop yield are heavily constrained by a wide range of environmental stresses. Several phytohormones among which abscisic acid (ABA), ethylene and salicylic acid (SA) are known to mediate plant responses to these stresses. By contrast, the role of the plant hormone auxin in stress responses remains so far poorly studied. Auxin controls many aspects of plant growth and development, and Auxin Response Factors play a key role in the transcriptional activation or repression of auxin-responsive genes through direct binding to their promoters. As a mean to gain more insight on auxin involvement in a set of biotic and abiotic stress responses in tomato, the present study uncovers the expression pattern of SlARF genes in tomato plants subjected to biotic and abiotic stresses. In silico mining of the RNAseq data available through the public TomExpress web platform, identified several SlARFs as responsive to various pathogen infections induced by bacteria and viruses. Accordingly, sequence analysis revealed that 5’ regulatory regions of these SlARFs are enriched in biotic and abiotic stress-responsive cis-elements. Moreover, quantitative qPCR expression analysis revealed that many SlARFs were differentially expressed in tomato leaves and roots under salt, drought and flooding stress conditions. Further pointing to the putative role of SlARFs in stress responses, quantitative qPCR expression studies identified some miRNA precursors as potentially involved in the regulation of their SlARF target genes in roots exposed to salt and drought stresses. These data suggest an active regulation of SlARFs at the post-transcriptional level under stress conditions. Based on the substantial change in the transcript accumulation of several SlARF genes, the data presented in this work strongly support the involvement of auxin in stress responses thus enabling to identify a set of candidate SlARFs as potential mediators of biotic and abiotic stress responses.

Transcriptome analysis of Phytophthora infestans and Colletotrichum coccodes in tomato to reveal resistance mechanisms

“…Based on another study, auxin is as an active player in plant defense against pathogens (Navarro et al, 2006). Our findings agreed with Bouzroud et al (2018) and Saidi and Hajibarat (2019) that suggested auxin could be implicated in pathogen infections through ARFs.…”

“…Solyc05g008850.3 was down regulated during all the stage-specific tissues such as hypodermis, outer epidermis, parenchyma, seed, locular tissue, endocarp, leaf, flower, columella, generative cell, radical pericarp, ovary wall, fruit, placenta, pericarp, leaflet, inner pericarp, ovule, callus, pistil, placenta, vascular tissue, roots, floral meristem, sympodial inflorescence meristem, and shoot apex. ARF plays a critical role in the transcriptional activation or repression of auxinresponsive genes or IAA through direct binding to their promoters (Bouzroud et al, 2018). Auxin is implicated in plant developmental processes and response to environmental stresses .…”

Interaction of roses with a biotrophic and a hemibiotrophic leaf pathogen leads to differences in defense transcriptome activation

“…A downregulated or disturbed auxin pathway may enhance susceptibility, as in the case for Arabidopsis mutants and their defense response to necrotrophic fungi (Llorente et al 2008). Bouzroud et al (2018) describe auxin responsive factors (ARFs) as part of biotic and abiotic stress signaling in Solanum. The role of ethylene as a defense regulator has been well established, primarily due to its function as a signaling molecule in the defense against necrotrophic pathogens in combination with jasmonic acid.…”

Distinct Evolutionary Origins of Intron Retention Splicing Events in NHX1 Antiporter Transcripts Relate to Sequence Specific Distinctions in Oryza Species

“…In the PCRe, an AuxRE and a GCC_box_AP2_EREBP cis-motif are also conserved in seven Oryza species. HLH, NAC and AP2/EREBP transcription factors have well-documented roles under salinity stress (Zhang and Shi, 2013;Chen et al, 2016), while AuxRE bind Auxin Response Factors (ARFs) which are known to be induced in response to salinity (Qi et al, 2012;Bouzroud et al, 2018). The cladogram derived from the order of predicted cis-elements reveals that Oryza species with AA genomes have a distinct pattern of cis-elements that are distinct from BB, FF and KKLL genome types.…”