Abstract
Ten fungal strains that cause apple ring rot disease (Physalospora piricola Nose) were used to study the role of ribosomal DNA-internal transcribed spacer (rDNA-ITS) in classifying and identifying the pathogen Botryosphaeria berengeriana de Not f. sp. piricola (Nose) Koganezawa et Sakuma, and the correlation between sequence mutations and biological characteristics, and pathogenicity. We used an effective method to screen for conidiospore induction in in vitro cultures of the pathologic pathogens. PCR amplification and clone sequencing were performed for the rDNA-ITS region and used to construct a phylogenetic tree. The growth status, sporulation ability, and phylogenetic effect of different strains were determined. The influence of culture medium types, pH, temperature and light, and the effect of mycelia scraping were investigated. Based on the 582-bp and 583-bp cloned fragments, the results show that there are two significant sequence variations in the ITS1 region, and there were variant bases found in the sequences from five strains. All ten strains were shown to be in theâ sub-variety of Botryosphaeria berengeriana f. sp. piricola (Nose) using homology comparisons. The strains with a higher degree of variation performed better in terms of biological characteristics and were more pathogenic than the strains with less variation. The variations in the ITS1 region might have more predictive power. The appropriate developmental conditions for ring rot colonies were determined to be 25-30°C on a potato-based medium at a pH 5.0-7.0. Alternating irradiation of 12 h/d black light and 12 h/d fluorescent light and scrape treatment of fungal mycelia were best able to induce conidiosporangia and sporulation.
Highlights
Apple is one of the most important fruit species and is economically important worldwide [1]
Apple ring rot disease (Physalospora piricola Nose.), which is one type of fungal disease caused by Botryosphaeria berengeriana de Not f. sp. piricola (Nose) Koganezawa & Sakuma, is widely distributed in warm apple growing regions of the world [2]
Fungi strains: Ten pathogenic strains of apple ring rot disease were collected in Henan province and Liaoning province from a variety of tissues or cultivars and from different districts (Table 1), and isolate purified by Zhengzhou Fruit Research Institute, China Academy of Agricultural Science (CAAS)
Summary
Apple is one of the most important fruit species and is economically important worldwide [1]. Apple ring rot disease (Physalospora piricola Nose.), which is one type of fungal disease caused by Botryosphaeria berengeriana de Not f. The incidence of ring rot disease in major apple yielding regions has been increasing sharply due to the expansion of the planted areas and prolonged planting, which has resulted in a significant loss of apple production. Natural selection and evolution allow the pathogens to adapt themselves to variations in different plant species, environmental changes and prevention methods [9]. This adaptation adversely affects pathogenesis research, pathological changes, pathogen isolation and identification, disease control, and screening for diseaseresistant cultivars [10,11]
Sign-in/Register to view highlights & summary 
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call