“…It was found that these proteins show different patterns of distribution in the xylem during biofilm formation [ 127 ]. Furthermore, haemagglutinin adhesion and MopB, an outer membrane protein, have been studied in X. fastidiosa [ 120 , 128 , 129 , 130 ]. While the role of the protein (MopB) is not well known, it is well established that the outer membrane proteins (OMPs) in Gram-negative bacteria play vital roles such as (1) keeping the structural integrity of the outer membrane (OM), (2) recognition proteins, (3) transportation, (4) membrane pores, (5) membrane-bound enzymes or components of signal cascades [ 131 , 132 , 133 , 134 ], (6) stress resistance (implicated are Escherichia coli OmpA and OprF in Pseudomonas aeruginosa ) [ 135 , 136 , 137 ], (7) pathogenesis (for example, OmpA in Escherichia coli and OspC in Borrelia burgdorferi ) [ 134 , 138 , 139 ], and (8) agglutination.…”