Genetic variation for induced and basal resistance against leaf pathogen Pseudomonas syringae pv. tomato DC3000 among Arabidopsis thaliana accessions

Abstract

In Arabidopsis thaliana, significant efforts to determine the effect of naturally occurring variation between phenotypically divergent accessions on different biotic or abiotic stresses are underway. Although it is usually assumed that induced systemic resistance (ISR) against pathogen will covary with plant genetic variation, this assumption has not been tested rigorously in previous experiments. Here, we investigated heritable variation in resistance as well as Penicillium simplicissimum GP17-2-mediated ISR to the bacteria Pseudomonas syringae pv. tomato DC3000 (Pst) among a worldwide collection of accessions of A. thaliana. In this study, 75 Arabidopsis accessions were screened against the bacteria Pst following induction and non-induction treatment and their resistance levels were determined by measuring three components of A. thaliana resistance (infected leaf number, disease severity and pathogen growth). We observed extensive quantitative variation in the number of infected leaves, severity of disease symptoms and the bacterial population size among 75 accessions of A. thaliana infected with Pst. On the contrary, about a two-third of the accessions (49 accessions) showed a reduction in infected leaf number, disease severity and pathogen proliferation after treatment with GP17-2, indicating that GP17-2 induction of resistance is ecotype specific in Arabidopsis. The level of suppression was more pronounced for percent disease severity and pathogen proliferation than for number of infected leaves in ISR-inducible accessions. Accessions non-responsive to GP17-2 treatment generally appeared to be associated with higher basal resistance to infection by Pst. Future study with these parental lines employing a variety of crossing schemes may facilitate identification of major trait loci responsible for GP17-2-mediated ISR in Arabidopsis.

Diverse mechanisms of resistance to Pseudomonas syringae in a thousand natural accessions of Arabidopsis thaliana

“…To select for robustly resistant accessions, we performed our screen under high humidity that simulates disease‐conducive conditions (Xin et al ., ). Of the 14 Pst DC3000‐resistant accessions identified in this screen, two accessions, Est‐1 and Ra‐0, had already been shown in previous studies to be more resistant to Pst DC3000 infection (Todesco et al ., ; Hossain & Sultana, ), further validating the results of our screen. Other accessions that had been observed before to be resistant to Pst DC3000 (Kover & Schaal, ; Perchepied et al ., ; Hossain & Sultana, ) were not resistant in our screen, probably because our disease‐conducive (e.g.…”

Role of ethylene signalling in growth and systemic resistance induction by the plant growth‐promoting fungus Penicillium viridicatum in Arabidopsis

“…PGPF are non‐pathogenic, filamentous, saprophytic rhizosphere fungi that significantly enhance the growth of plants (Hyakumachi, ). PGPF from the genera of Fusarium , Penicillium , Phoma , Trichoderma and sterile fungi have been the subject of multiple studies because of their high protective abilities against a variety of plant diseases (Hossain & Sultana, ; Hossain, Sultana, Kubota, Koyama, & Hyakumachi, ; Kojima, Hossain, Kubota, & Hyakumachi, ; Shoresh et al., ; Sultana, Hossain, Kubota, & Hyakumachi, ). In recent years, several PGPF Penicillium spp.…”

“…Although Penicillium spp. are very effective in eliciting ISR against fungi, bacteria and viruses (Elsharkawy et al., ; Hossain & Sultana, ; Madi & Katan, ), underlying signalling pathways and the associated defences have yet to be conclusively defined in many cases. Various studies have instead highlighted that signalling pathways and regulated defences have been wide ranging and distinctively depend on eliciting microorganisms and the interacting pathogens.…”

Genetic Interaction between Arabidopsis Qpm3.1 Locus and Bacterial Effector Gene hopW1-1 Underlies Natural Variation in Quantitative Disease Resistance to Pseudomonas Infection

“…Our and others’ studies have documented substantial variation in disease resistance to P. syringae infection among Arabidopsis natural populations ( Kover and Schaal, 2002 ; Perchepied et al, 2006 ; Fan et al, 2008 ; Hossain and Sultana, 2015 ). Based on our previous work ( Fan et al, 2008 ), we used two Arabidopsis accessions, Aa-0 and Gie-0, in combination with the reference accession Col-0, to further investigate the genetic and molecular basis of this variation.…”