Characterization and fine mapping of a yellow leaf gene regulating chlorophyll biosynthesis and chloroplast development in cotton (Gossypium arboreum)

•MutMap is an effective method for identifying loci for etiolated leaf.•Mutant gene Gachlh exhibited a lower chlorophyll content and the yellow-leaf phenotype.•Gachlh could not bind properly to GaCHLD, which prevented the assembly of Mg-chelatase.•Gachlh affected the tetrapyrrole pathway, leading to failure of chlorophyll synthesis.