Forward and reverse genetics to identify genes involved in the age‐related resistance response in Arabidopsis thaliana

Abstract

SUMMARY Age-related resistance (ARR) occurs in numerous plant species, often resulting in increased disease resistance as plants mature. ARR in Arabidopsis to Pseudomonas syringae pv. tomato is associated with intercellular salicylic acid (SA) accumulation and the transition to flowering. Forward and reverse genetic screens were performed to identify genes required for ARR and to investigate the mechanism of the ARR response. Infiltration of SA into the intercellular space of the ARR-defective mutant iap1-1 (important for the ARR pathway) partially restored ARR function. Inter- and intracellular SA accumulation was reduced in the mutant iap1-1 compared with the wild-type, and the SA regulatory gene EDS1 was also required for ARR. Combining microarray analysis with reverse genetics using T-DNA insertion lines, four additional ARR genes were identified as contributing to ARR: two plant-specific transcription factors of the NAC family [ANAC055 (At3g15500) and ANAC092 (At5g39610)], a UDP-glucose glucosyltransferase [UGT85A1 (At1g22400)] and a cytidine deaminase [CDA1 (At2g19570)]. These four genes and IAP1 are also required for ARR to Hyaloperonospora parasitica. IAP1 encodes a key component of ARR that acts upstream of SA accumulation and possibly downstream of UGT85A1, CDA1 and the two NAC transcription factors (ANAC055, ANAC092).

Of the nine cytidine deaminase like genes in Arabidopsis thaliana eight are pseudogenes and only one is required to maintain pyrimidine homeostasis in vivo

“…It has been claimed that CDA is involved in the age-related resistance response of Arabidopsis (Carviel et al, 2009), because plants compromised in CDA showed reduced resistance to the virulent bacterium Pseudomonas syringae pv tomato and to the downy mildew fungus Hyaloperonospora parasitica. Additionally, CDA was transcriptionally induced in leaves by Pseudomonas spp.…”

Arabidopsis Defense against Botrytis cinerea: Chronology and Regulation Deciphered by High-Resolution Temporal Transcriptomic Analysis

“…However, recent studies have indicated that this family of TFs also plays crucial roles in the response to biotic stress. Transgenic lines with reduced or increased expression of ANAC002, ANAC019, ANAC055, ANAC081, and ANAC092 have altered susceptibility to pathogen infection (Delessert et al, 2005;Bu et al, 2008;Carviel et al, 2009;Wang et al, 2009;Wu et al, 2009) and all are differentially expressed following B. cinerea infection. Binding sites for NAC TFs are significantly overrepresented in a cluster of genes induced between 18 and 24 HAI with additional enrichment in clusters with similar expression profiles.…”

Promoter Analysis of a Powdery Mildew Induced Vitis vinifera NAC Transcription Factor Gene

“…ATAF1 was found to negatively regulate the defense reactions against necrotrophic fungal pathogens [1]. Over expression of OsNAC gene increased drought resistance in rice [8,9]. Most NAC gene in their promoter region conserved with hormonal and fungal elicitor responsive motifs [10,11].…”