In contrast, the low abundant proteins (L-L) were largely associated with bacterial infection and immunity pathways, which included a ubiquitin C protein (UBC; K08770), a phospholipase D (PLD1; K01115), a tubulin (TUBA; K07374), a DNA-directed RNA polymerase (RPC3; K03023), and a guanine nucleotide exchange factor (RASGRP3; K12362). The gene discussed is PLD1; the disease is bacterial infectious disease.