Lingxue Cao ^1* Kailin Shi ² Yongyi Liu ² Xiaonan Xie ² Xizhe Sun ² Wentong Dong ³ Congya Wang ⁴ Lisong Ma ^2*

• ¹ College of Forestry, Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees, Ministry of Education, Central South University Forestry and Technology, Changsha, Hunan Province, China
• ² State Key Laboratory of North China Crop Improvement and Regulation, Agricultural University of Hebei, Baoding, China
• ³ Key Lab of Non-wood Forest Products of State Forestry Administration, College of Forestry, Central South University of Forestry and Technology, Changsha, Hunan Province, China
• ⁴ Hunan Tianhua Tea-oil Technology, Changsha, China

Camellia anthracnose is caused by multiple Colletotrichum species, resulting in severe yield losses of oil-tea Camellia. Colletotrichum fructicola is one of the major anthracnose pathogens of oil-tea Camellia worldwide. However, developing unique molecular markers for the rapid and accurate detection of Colletotrichum fructicola from diverse Colletotrichum species, as well as early monitoring and effective control of the disease, remains largely unexplored. In this study, Colletotrichum fructicola-specific molecular markers were developed for rapid and accurate detection of C. fructicola among Camellia anthracnose causing fungal pathogens. C. fructicola-specific genes were obtained using a BLAST search of the sequences of predicted genes in C. fructicola against the genome sequences of Colletotrichum fungal pathogens. Using DNA-based conventional and quantitative PCR, three C. fructicola-specific genes with the ability to distinguish C. fructicola from other oil-tea Camellia anthracnose-related Colletotrichum species, including Colletotrichum camelliae, Colletotrichum gloeosporioides, and Colletotrichum siamense, and oil-tea Camellia fungal pathogens belonging to the genus Neopestalotiopsis, Pestalotiopsis and Alternaria, were validated as molecular markers. In addition, these three molecular markers were highly sensitive to detecting C. fructicola using DNA extracted from the inoculated leaves of oil-tea Camellia. These findings enable us to rapidly and uniquely detect the Camellia anthracnose disease caused by Colletotrichum fructicola, which will equip farmers with an effective tool for monitoring Camellia anthracnose disease in the field and taking timely control measurements in advance.