QTL detection and candidate gene analysis of the anthracnose resistance locus in tea plant (Camellia sinensis)

• Anthracnose resistance QTLs in tea plants were investigated using the BJG×LJ43 population. • Two anthracnose resistance QTLs, qARChr1 and qARChr13 , were identified through BSA-seq analysis. • A nuclear-localized ERF transcription factor (CsERF105) within the qARChr1 locus was found to positively regulate anthracnose resistance. Anthracnose is a devastating disease caused by Colletotrichum that significantly affects the yield and economic value of the tea plant ( Camellia sinensis ). However, few studies have addressed the genetic mechanism of anthracnose resistance (AR). This study investigated the QTL associated with AR in a ‘Longjing 43’בBaijiguan’ (LJ43×BJG) population. The field surveys conducted in this study led to the identification of several QTLs for AR on the linkage map. One major QTL ( qAR-12.4 ) accounted for 12% of the phenotypic variance explained over two years. The BSA-seq results also revealed two genomic regions, qARChr1 on chromosome 1 and qARChr13 on chromosome 13, which showed strong correlations with AR. Time-course RNA-seq was performed on LJ43 and BJG inoculated with anthracnose at 0, 24, and 48 hours to screen for candidate genes. The results showed the gradual post-inoculation expression of a nuclear-localized ERF transcription factor ( CsERF105 ) within the qARChr1 locus in BJG but not in LJ43. The AR of BJG was significantly reduced after feeding with CsERF105 -specific antisense oligonucleotides, suggesting that CsERF105 may be a positive regulator. The findings of this study add to our general knowledge of the genetic factors involved in the tea plant's AR and potential breeding targets.