Rice (Oryza sativa) is the primary staple food source for more than half of the world's population. Proteins are active macromolecules and central to understanding biological molecular processes. Hence, it is necessary to study all protein forms of plant genes so that their biological functions and roles in regulating important traits such as yield, quality, and responses to environmental stresses can be determined. Although there have been significant advances over the years, a big gap still exists between the number of protein-coding genes (PCGs) and proteins detected with sufficient experimental evidence (Legrain et al., 2011). Therefore, one of the major objectives of proteomics is to detect the proteins without sufficient experimental evidence, also known as the missing proteins (MPs), mainly by using mass spectrometry (MS)-based experimental approaches (Horvatovich et al., 2015).