YGL8 gene encodes a chloroplast targeted-UMP kinase. Mutation in YGL8 gene cause negative impact on the expression of chloroplast genome-encoded thylakoid membrane constitutive genes. Reduced expression of those genes affects the grana lamella structure and reduced level of chlorophyll, resulting in the yellowish phenotype, a reduced photosynthetic rate and poor yield (Zhu et al., 2016).