Volume: 4, 2025
4th International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: P006
DOI: https://doi.org/10.24326/ICDSUPL4.P006
Published online: 9 April 2025
ICDSUPL, 4, P006 (2025)
Cellular mechanisms of oat resistance to powdery mildew conditioned by the Pm4 gene
Weronika Grzelak1*, Aleksandra Nucia1, Sylwia Okoń1
1 Institute of Plant Genetics, Breeding and Biotechnology, Akademicka 15, 20-950 Lublin, Poland
* Corresponding author: weronika.grzelak@up.lublin.pl
Abstract
Oat (Avena sativa L.) is one of the most important cereal crops worldwide, with its cultivation expanding due to its health-promoting properties. Unfortunately, oat production is threatened by powdery mildew, a disease that causes yield losses ranging from 10% to 40%. This disease is caused by the obligate biotrophic fungus Blumeria graminis f. sp. avenae. Fortunately, oats possess genetic resistance mechanisms, including the Pm4 gene, which originates from Avena barbata. According to the literature, there is no evidence of Pm4-mediated resistance being overcome by the pathogen, suggesting its potential for improving oat resistance to powdery mildew. However, the precise mechanisms by which Pm4 functions remain unknown. Understanding these mechanisms is crucial for gene pyramiding with other resistance genes to enhance and stabilize oat resistance. To investigate the effect of Pm4 on plant defense mechanisms triggered at the cellular level, we conducted studies on four isolates of Blumeria graminis f. sp. avenae. We infected two oat genotypes: one carrying the Pm4 gene (resistant) and another susceptible to powdery mildew. The plants were examined under a light microscope at 8, 12, 24, and 48 hours post-inoculation to compare differences in pathogen development. We analyzed fungal structures such as primary and secondary germ tubes, appressoria, infection hyphae, haustoria, and mycelial hyphae to assess plant susceptibility. Additionally, plant responses were observed before and 48 hours after pathogen penetration using a fluorescence microscope to identify resistance-related structures, including papillae, encasements, and dead cells, indicative of activated defense mechanisms. Our research confirms that the Pm4 gene plays a crucial role in oat resistance to Blumeria graminis f. sp. avenae. Pathogen structures such as appressoria, infection hyphae, haustoria, and mycelial hyphae developed less extensively in resistant plants compared to susceptible ones. Moreover, Pm4-carrying plants exhibited a higher occurrence of defensive structures such as papillae, encasements, and dead cells, indicating the activation of plant defense mechanisms.
Keywords: plant disease, plant resistance, oat resistance, powdery mildew
How to cite
W. Grzelak, A. Nucia, S. Okoń, 2025. Cellular mechanisms of oat resistance to powdery mildew conditioned by the Pm4 gene. In: 4th International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL4.P006