STUDIES ON IMPORTANT PROTEINS OF CANDIDATUS LIBERIBACTER ASIATICUS TOWARDS DEVELOPING POTENTIAL INHIBITOR MOLECULES

Abstract

Citrus greening, often called huanglongbing (HLB), is a very destructive disease that affects citrus trees all over the world. Candidatus Liberibacter asiaticus (CLas), a phloem-restricted Gram-negative bacterium that has been difficult to cultivate, is a culprit for this deadly disease. Diaphorina citri, an Asian citrus psyllid, is the means by which CLas is transmitted. CLas is the most widespread and virulent strain that affects citrus plants. The infected plants gradually develop the symptoms such as yellow leaves, twig dieback, premature defoliation, and fruit abortion followed by eventual death of plants. CLas infection causes callose accumulation in the phloem, which indicates that many HLB symptoms may be caused by impaired phloem transport. The current management strategies include treating the plants with insecticides, biologically and chemically controlling the psyllid population and removing the infected plants. However, these strategies are unable to stop the spread of HLB. Therefore, it is necessary to develop an effective strategy to control and manage the HLB disease. The most potential strategies to control HLB disease might be to develop potential inhibitor molecules against essential proteins of CLas, critical for the survival of bacteria. Availability of genome sequence of CLA makes it easier to select key proteins critical for survival of the bacteria and then screening, designing and testing the potential molecules against these proteins/enzymes can be developed as antimicrobial compounds for controlling this serious disease. The proteome analysis reveals a lot of potential drug targets including, but not limited to, periplasmic amino acid binding proteins, ATIC enzyme of de-novo pathway of nucleotide metabolism, transcriptional regulators etc. The potential inhibitor molecules can be tested for their efficacies on HLB infected citrus plants under controlled conditions. And the current investigations focus specifically on two periplasmic amino acid binding proteins and ATIC enzyme as a drug target.