Proteomic Profiles Reveal the Function of Different Vegetative Tissues of Moringa oleifera

Moringa oleifera is a rich source of bioactive compounds and is widely used in traditional medicine and food for its nutritional value; however, the protein and peptide components of different tissues are rarely discussed. Here, we describe the first investigation of M. oleifera proteomes using mass spectrometry and bioinformatics methods. We aimed to elucidate the protein profiles of M. oleifera leaves, stem, bark, and root. Totally 202 proteins were identified from four vegetative organs. We identified 101 proteins from leaves, 51 from stem, 94 from bark and 67 from root, finding that only five proteins existed in both four vegetative parts. The calculated pI of most of the proteins is distributed in 5-10 and the molecular weight distributed below 100 kDa. Functional classification analysis revealed that proteins which are involved in catalytic activities are the most abundant both in leaves, stem, bark and root. Identification of several heat shock proteins in four vegetative tissues might be adaptive for resistance to high temperature environmental stresses of tropical or subtropical areas. Some enzymes involved in antioxidant processes were also identified in M. oleifera leaves, stem, bark and root. Among the four tissues studies here, leaves protein content and molecular diversity were the highest. The identification of the flocculating protein MO2.1 and MO2.2 in the bark and root provides clue to clarify the antimicrobial molecular mechanisms of root and bark. This study provides information on the protein compositions of M. oleifera vegetative tissues that will be beneficial for potential drug and food supplement development and plant physiology research.