Expression Profiling Soybean Response to Pseudomonas syringae Reveals New Defense-Related Genes and Rapid HR-Specific Downregulation of Photosynthesis

Abstract

Transcript profiling during susceptible (S) and hypersensitive response-associated resistance (R) interactions was determined in soybean (Glycine max). Pseudomonas syringae pv. glycinea carrying or lacking the avirulence gene avrB, was infiltrated into cultivar Williams 82. Leaf RNA was sampled at 2, 8, and 24 h postinoculation (hpi). Significant changes in transcript abundance were observed for 3,897 genes during the experiment at P < or = 0.000005. Many of the genes showed a similar direction of increase or decrease in abundance in both the S and R responses, but the R response generally showed a significantly greater degree of differential expression. More than 25% of these responsive genes had not been previously reported as being associated with pathogen interactions, as 704 had no functional annotation and 378 had no homolog in National Center for Biotechnology Information databases. The highest number of transcriptional changes was noted at 8 hpi, including the downregulation of 94 chloroplast-associated genes specific to the R response. Photosynthetic measurements were consistent with an R-specific reduction in photosystem II operating efficiency (phiPSII) that was apparent at 8 hpi for the R response with little effect in the S or control treatments. Imaging analyses suggest that the decreased phiPSII was a result of physical damage to PSII reaction centers.

Response to biotic and oxidative stress in Arabidopsis thaliana: Analysis of variably phosphorylated proteins

“…This finding is in fairly good accordance with the observed down-regulation of primary carbon metabolism transcripts during basal defense [82]. In fact, it has been proposed that chloroplasts may be key players in plant defense and a loss of photosystem functionality can lead to ROS overproduction and to a decreased sugar availability to pathogens [83]. These findings may suggest that the observed quantitative changes in these phosphoproteins should reflect transcriptional phenomena more than being related to an augmented phosphorylation of a specific class of enzymes.…”

Recent Advances in Legume-Microbe Interactions: Recognition, Defense Response, and Symbiosis from a Genomic Perspective

“…The responses of the soybean 'Williams 82' to avirulent and virulent strains of the bacterial pathogen P. syringae pv glycinea, differing in the presence or absence of avrB, were investigated using a 27,648 cDNA array (Zou et al, 2005). Only 45 genes were specific to the susceptible response.…”

Picturing pathogen infection in plants

“…glycinea inducing hypersensitive response (HR) on soybean causes a decrease in Φ PSII , together with an increase in NPQ. Conversely, little changes were observed for a virulent strain able to establish a compatible interaction on the same host [45]. In contrast, Bonfig and collaborators [31] reported a decrease on maximum F V /F M , Φ PSII and NPQ in Arabidopsis plants infected with either virulent or avirulent P. syringae pv.…”

“…Imaging analysis of the changes of photosynthesis parameters during bacterial challenge in both compatible and incompatible interactions has been object of special attention [31,33,34,45,46]. An avirulent strain of Pseudomonas syringae pv.…”