Differential gene expression of two potato cultivars in response to infection with ralstonia solanacearum

Abstract EN

Bacterial wilt, caused by Ralstonia solanacearum (Rs), is one of the most important plant diseases, especially on potato.

In this study, the molecular mechanisms of potato resistance against Rs were compared between cv.

Diamant (susceptible) and cv.

Lady Bedford (partially resistant).

The results indicated that potato cv.

Lady Bedford was significantly more resistant (24.3% wilt) to Rs than cv.

Diamant (83.8% wilt).

The inoculated cv.

Diamant plants exhibited the highest decrease in photosynthetic pigment compared to the cv.

Lady Bedford.

Three differentiated expressed cDNA fragments that present in inoculated plants of the partially resistant cv.

Lady Bedford were selected for sequencing and identified as 1-D-deoxyxylulose 5-phosphate synthase gene (StDXS1), polyphenol oxidase (PPO) gene and WRKY transcription factor (StWRKY) from potato genome.

The expression level of the POD (peroxidase), PPO, StWRKY and StDXS1 genes were induced by inoculation with Rs compared to the non-infected plants.

The highest gene expression level on the two cultivars was recorded at 12, 24, 24 and 12 hpi for the four genes, respectively, and it was significantly higher in the partially resistant cultivar than the susceptible one.

POD and PPO, enzymes activity significantly increased After inoculation with Rs in the both cultivars.

cv.

Lady Bedford had a higher enzymes activity and peaked at 12 and 24 hpi for POD and PPO, respectively, while, cv.

Diamant peaked at 6 and 12 hpi for the same enzymes.

These clear transcriptional responses suggested that these genes and enzymes participates in the basal defense of potato to Rs.