Lily Bennett
Year: 2017
Faculty Advisor: Michelle Heck

“Role of hemocyanin in variation in CLas transmission between ACP isofemale lines”

Project Summary:

Diaphorina citri or the Asian Citrus Psyllid (ACP), is the insect vector of the citrus greening bacterial pathogen, ‘Candidatus Liberibacter asiaticus’ (CLas). Citrus greening is a fatal citrus disease to which all commercial citrus varieties are susceptible. Hemocyanin, an immunity and metabolism protein of the ACP, is highly upregulated in psyllids reared on CLas infected plants. Variation in CLas transmission in psyllids was previously analyzed in isofemale lines collected from different field sites in Florida by culturing the psyllid lines in growth chambers and characterizing the psyllids for CLas acquisition and transmission. We hypothesize that variation in ACP immunity gene sequence and or expression contributes to variation in the ability of the insect to acquire and transmit CLas.

To test this hypothesis, we analyzed the sequence of the hemocyanin coding region in the ACP lines with the highest (L8) and lowest (L16) rates of CLas transmission. The different color morphs were also analyzed and the blue psyllids were found to have lower levels of transmission of the CLas bacteria. The best and the worst transmitting lines as well as the different color morphs of the psyllid were analyzed for genetic differences through DNA and RNA sequencing as well as differences in expression of the hemocyanin protein through western blotting to help characterize what makes psyllids a poor or strong transmitter of the CLas bacteria. Hemocyanin levels were also analyzed through copper analysis. This characterization of hemocyanin helps to further explain how psyllids transmit CLas and may help to eventually find a way to stop the transmission of the citrus greening disease.

My Experience:

In this internship I learned what working in a lab is like. I learned many molecular biology techniques which will help me with my future lab work during my undergraduate career and beyond. I have become even more interested in plant biology research, especially as it pertains to agricultural applications. I appreciated the weekly seminars because they exposed me to many different fields of plant biology research in a way that I wouldn’t be exposed to through other means. This internship further confirmed my desire to go into scientific research as a career.