Postdoctoral Research Associate University of Georgia Athens, Georgia
Body of Abstract: Chlorophylls are the major light-capturing pigments found in plants that allow them to photosynthesize. Despite extensive knowledge on photosynthesis and the function of chlorophyll, not all regulatory steps have been elucidated. Using QTL-seq and linkage-based mapping approaches, we identified a major chlorophyll content index (CCI) QTL on chr04 explaining 39.6 PVE% in the F2 population. Genetic analysis showed that the locus was controlled by a single recessive locus, which was named CCI4.1. Further finemapping and progeny testing narrowed the CCI4.1 locus to 31.51 kbp, containing four genes. The two most likely candidate genes are Solyc04g010285, encoding a plant-specific protein of unknown biochemical function with high similarity to AT3G55240 in Arabidopsis and Solyc04g010290, encoding a member of the Core-2/I-branching beta-1,6-N-acetylglucosaminyltransferase family protein. Furthermore, plants carrying the homozygous BGV007936 allele of CCI4.1 featured larger leaf cells and lower chlorophyll content in terms of SPAD, chl a, chl b and chl a+b compared to the BGV007900 allele. The results from the CRISPR-Cas9 knockout editing of Solyc04g010285 demonstrated higher CCI whereas the knockout editing of Solyc04g010290 showed smaller cells with no changes in CCI. This research is supported by USDA AFRI grant 2020-67013-3091.