Changes in β-1,3-glucanase mRNA levels in peach in response to treatment with pathogen culture filtrates, wounding, and other elicitors

The response of three different peach, Prunus persica (L.) Batsch, genotypes to bacterial and fungal culture filtrates (CFs), wounding, and sterile nutrient broth (NB) treatments were studied by evaluating β-1,3-glucanase mRNA levels. Northern blot analysis was conducted using the 3′ end of a peach β-1,3-glucanase gene, PpGns1, as a probe. Autoradiographs were analyzed using a Stratagene Eagle Eye II gel documentation system. Analysis of the accumulation of mRNAs encoded by β-1,3-glucanase demonstrated that activation trends were different among the three peach genotypes. All genotypes, 'Evergreen', 'Stark's Earliglo', and 'White Lady', showed an increase in β-1,3-glucanase mRNA following treatment with CF of the bacterial pathogen Xanthomonas campestris pv. pruni. Two genotypes, 'Evergreen' and 'White Lady', showed an increase in mRNA levels following treatment with CF of the bacterial pathogen Pseudomonas syringae pv. syringae, and two genotypes, 'Evergreen' and 'Stark's Earliglo', showed an increase in mRNA levels following treatment with CF of the fungal pathogen Monilinia fructicola. Differences in induction patterns were observed between bacterial and fungal culture filtrate treatments. Wounding induced high levels of β-1,3-glucanase mRNA in one genotype, 'White Lady'; while, treatment with a sterile nutrient broth showed an increase in mRNA in another genotype, 'Evergreen'. The use of gene-specific primers in RT-PCR indicated that PpGns1 and a second closely-related gene family member, PpGns2, were transcriptionally active, and were differentially regulated.