A large presence/absence variation in the promotor of the ClLOG gene determines trichome elongation in watermelon.

population with significant variations in trichome length was undertaken. A 1.84-Mb candidate region on chromosome 10 was associated with trichome length. Resequencing and fine-mapping analyses indicated that a 12-kb structural variation in the promoter of Cla97C10G203450 (ClLOG) led to a significant expression difference in this gene in watermelon lines with different trichome lengths. In addition, a virus-induced gene silencing analysis confirmed that ClLOG positively regulated trichome elongation. These findings provide new information and identify a potential target gene for controlling multicellular trichome elongation in watermelon.