Cytochrome b Gene-Based Assay for Monitoring the Resistance of Colletotrichum spp. to Pyraclostrobin

Abstract

Resistance to pyraclostrobin due to a single nucleotide polymorphism at 143rd amino acid position on the cytochrome b gene has been a major source of concern in red pepper field infected by anthracnose in Korea. Therefore, this study investigated the response of 24 isolates of <i>C. acutatum</i> and <i>C. gloeosporioides</i> isolated from anthracnose infected red pepper fruits using agar dilution method and other molecular techniques such as cytochrome b gene sequencing, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and allele-specific polymerase chain reaction (PCR). The result showed that four isolates were resistant to pyraclostrobin on agar dilution method and possessed GCT (alanine) codon at 143rd amino acid position, whereas the sensitive isolates possessed GGT (glycine). Furthermore, this study illustrated the difference in the cytochrome b gene structure of <i>C. acutatum</i> and <i>C. gloeosporioides</i>. The use of cDNA in this study suggested that the primer Cacytb-P2 can amplify the cytochrome b gene of both <i>C. acutatum</i> and <i>C. gloeosporioides</i> despite the presence of various introns in the cytochrome b gene structure of <i>C. gloeosporioides</i>. The use of allele-specific PCR and PCR-RFLP provided clear difference between the resistant and sensitive isolates. The application of molecular technique in the evaluation of the resistance status of anthracnose pathogen in red pepper provided rapid, reliable, and accurate results that can be helpful in the early adoption of fungicide-resistant management strategies for the strobilurins in the field.

Identification and Characterization of Diplodia parva and Diplodia crataegicola Causing Black Rot of Chinese Quince

“…To date, the resistance of various pathogens to pyraclostrobin fungicides has been reported ( Fernández-Ortuño et al, 2012 ; He et al, 2021 ). However, this drawback is not limited to pyraclostrobin fungicides; resistance to pathogens, such as Colletotrichum gloeosporioides to thiophanate-methyl has also been reported ( Ali et al, 2019 ; Isa and Kim, 2022 ). To solve this challenge, the continuous spraying of a particular fungicide system should be reduced and replaced instead with alternatively replacing the fungicides to establish a better systematic control system.…”