Identification of Early Tomato Fruit Ripening Loci by QTL-seq

QTL-seq has been successfully studied in identifying major QTLs, markers, and candidate genes associated with traits that are important for crop improvement. Tomato earliness is an economically important trait and is a major current research focus recently. This paper reports the identification of tomato early ripening fruit locus facilitated by QTL-seq using a novel next-generation sequencing technology. Two DNA pools of phenotypes of F2 offspring from crosses between the Bone ММ (early ripening fruit, P1) and 071-440 (late ripening fruit, P2) cultivars of (Solanum lycopersicum) were bulked for sequencing and alignment analysis. Sequencing results revealed 434 SNP markers on chromosome 11, a candidate QTL at position 52,048,208 bp (named er-fruit) and a candidate gene, Solyc11g071510.1.1. The “er-fruit” as confirmed by the traditional QTL method was related to the early fruit ripening trait in tomato. Additionally, BLAST analysis to known homologies for Solyc11g071510.1.1 gene encodes glycoside hydrolases (GHs). GHs are functionally associated with cell wall degradation, fruit softening and ripening. Thus, GHs may be important in fruit softening, stimulating early fruit ripening in tomato. Our results confirmed that QTL-seq is effective method to identify candidate QTL loci, candidate genes and candidate markers.