Authors: Andrew McAuley, Marie de Gracia Coquerel, Sydney Cabana, Nabil Chowdhury, Dr. Marina Ascunce
Faculty Mentor: Dr. Marina Ascunce
College: College of Agricultural and Life Sciences
The citrus industry in Florida and worldwide is been seriously affected by citrus greening or Huanglongbing (HLB) disease. The causal agent, Candidatus Liberibacter asiaticus (CLas), is an unculturable bacterium that it is transmitted by an invasive insect, the citrus psyllid, upon feeding on citrus leaves. As crop losses reach up to 90%, Florida growers are desperate, resulting in the spraying of human antibiotics streptomycin (STR) and oxytetracycline (OTC) on citrus groves to treat HLB. Because soil microbiota represents a natural source of antibiotic resistance genes in the environment, the ongoing and widespread antibiotic applications in citrus-growing areas of Florida are expected to select for antibiotic resistance bacteria (ARB) and possibly for horizontal transfer of antibiotic-resistance genes (ARGs) within the microbial community. We hypothesize that after antibiotic application on citrus trees, there will be an increase in the frequency and diversity of ARBs and ARGs in the citrus environment. Sampling of the roots, leaves, and soil of citrus trees in fields that have had antibiotic applications and a field that did not have antibiotic applications were done. DNA extractions, PCRs, and high-throughput 16S amplicon sequencing were conducted. An initial assessment of the microbial taxonomic diversity will be discussed.