Identification of differentially expressed genes in Malus domestica after application of the non-pathogenic bacterium Pseudomonas fluorescens Bk3 to the phyllosphere

Abstract

Biological control of plant diseases by the application of antagonistic micro-organisms to the plant phyllosphere is only marginally understood. Suppression subtractive hybridization (SSH) was used for the identification of genes expressed after application of the non-pathogenic bacterium Pseudomonas fluorescens Bk3 to the phyllosphere of the apple scab-susceptible cultivar Malus domestica cv. Holsteiner Cox. In total, 157 expressed sequence tag (EST) clones were obtained. The sequencing of 113 ESTs which have a significantly elevated transcript level and the comparison of the obtained sequences with databases revealed similarities to different classes of pathogenesis-related proteins, for example, RNase-like PR10 protein and endochitinase, or similarities to proteins expressed under stress conditions that could have a protective function, for example, a germin-like protein, glutathione S-transferase, thioredoxin-like proteins, and heat shock proteins. In addition, several transcripts were identified that code for proteins which have a crucial role at different stages of pathogen recognition and in signalling pathways or an as yet unknown function in plant defence. The results show that a number of transcripts encoding proteins/enzymes which are known to be up-regulated after pathogen infection are also up-regulated after the application of a non-pathogenic bacterium to a M. domestica cultivar. The expression of these proteins might increase the plant resistance towards pathogen infection and damage.

Differential gene expression, induced by salicylic acid and Fusarium oxysporum f. sp. lycopersici infection, in tomato

“…On the basis of the number of PCR cycles required for equal amplifi cation of the corresponding PCR products, from the subtracted and unsubtracted cDNA samples, it was estimated that the subtracted libraries were 64-fold enriched for differentially expressed genes. One of the main advantages of SSH is that it normalizes the cDNA abundance, so that cDNAs encoded by genes that are expressed infrequently, but nonetheless differentially, can be identifi ed readily (Diatchenko et al, 1996;Kürkcüoglu et al, 2006).…”

Germin and Germin-like Proteins: Evolution, Structure, and Function

“…tomato is regulated by ABA. Relevant recent information by Kûrkcûoglu et al (2007) indicate that ESTs rapidly upregulated after the application of a nonpathogenic bacterium Pseudomonas fluorescens Bk3 to Malus domestica include those encoding GLPs.…”

Evaluation of Reference Genes for the Relative Quantification of Apple stem grooving virus and Apple mosaic virus in Apple Trees

“…Finally, 5 lL of the PCR product were run in 1.5% agarose gel colored by Sybrgreen (Sigma-Aldrich) and visualized under UV light. Seven reference genes such as GAPDH [3], 18S rRNA [3], S19 [3], Ubiquitine [2], Rubisco [4], RNA polymerase [4] and b-actine [9] as well as for the two viruses ASGV and ApMV [12] were chosen. These internal genes are known as the most stable expression in apple tissues Table 1.…”