Meet Dr. Amit Levy, a BARD Senior Research Fellow from the University of Florida, hosted by Prof. Yotam Zait at Hebrew University. Dr. Levy is looking for potential cures for citrus greening disease, through anatomical and physiological studies, he aims to uncover mechanisms that could lead to future treatments.
Tell us about your BARD research fellowship and your main focus on agricultural challenges?
“ I received the BARD research fellowship to come to Israel and study the Orri Mandarin. In Florida, where I work, the citrus industry has been severely hurt by a disease called citrus greening or Huanglongbing (HLB). This disease is caused by an intracellular gram-negative bacteria called Candidatus Liberibacter asiaticus (CLas). Once a sensitive tree gets the disease there is no cure and it will eventually die.
This disease reduced the citrus production in Florida by more than 90%. While most commercial citrus varieties are highly susceptible, there are also some varieties that get the CLas bacteria but don’t develop a disease. This phenomenon is called tolerance. Studying the mechanisms that lead to tolerance can provide us with possible treatments and solutions to fight against this disease. One variety that seem to have this tolerance is the Israeli Orri mandarin, and the goal of my BARD research fellowship is to study the Orri mandarin stress response and gain preliminary data on possible mechanisms that can generate its tolerance.”
What key outcomes do you expect from your research during the fellowship?
“First, I expect to identify some unique characteristics that Orri possess that could provide its HLB tolerance. I am comparing Orri to another mandarin- Murcott- that we know from Florida that is very sensitive to HLB. We are focusing on anatomical and physiological differences between the two varieties. My second desired outcome is to improve my knowledge in plant physiology.”
How has this fellowship strengthened your collaboration with Israeli researchers or institutions?
“For me this is one of the nicest outcomes of this fellowship. First and foremost, with my hosting lab, the lab of Dr. Yotam Zait at the Faculty of Agriculture, Food and Environment in Rehovot. This is a collaborative work that we are building and carrying out together, and I am using Yotam’s unique physiological expertise and knowledge for my research. Then there are other researchers in the institute, including the microscopy facility people.
Beyond this, I have been getting to know many people working on citrus in Israel, including researchers from Volcani and Migal and also extension agents and growers. I gave a seminar for citrus agents and have been advising the Israeli government plant protection agents on controlling the insect that transmits the disease. I have been collaborating with Ilana Stein from the Eastern Region Research and Development Center on the anatomy of Orri. I have seminars planned in Tel Aviv University and Bar Ilan University and hope to increase my collaboration with those institutes as well.”
How do you see the collaboration between Israeli and US researchers in this field (Citrus Greening) evolving in the future?
“With Dr. Zait, I hope we will develop a long-lasting collaboration and relationship between our labs and that our results from this sabbatical will lead to a joint grant proposal (that get funded!). I am also hoping to have more collaborations with Israeli scientists. I am also hopeful to continue to collaborate with the microscopy Facility in Rehovot, and we already have some projects planned. Lastly, the insect that transmits citrus greening is already widespread in Israel, and there is a high possibility that the disease will follow. I am hoping to stay connected with the industry in Israel and use my knowledge and experience to contribute to Israel’s response if the disease arrives.”
What methodologies or technologies are you using during this fellowship?
“For the cell biology and anatomy work we are we are sectioning the tissue samples and use different staining or immunolocalization techniques for identifying various cellular components and then use light or fluorescence microscopy for visualization. For the physiological work, we use lysimeters to conduct a drought experiment and measure transpiration. We use the LiCor to measure photosynthesis and stomatal conductance. We will also measure stable isotopes to learn about the water use efficiency, and chlorophyll fluorescence to measure the tolerance of the photosynthetic system to damage caused from access radiation.”
What specific mechanisms of HLB tolerance in Orri Mandarin have been identified so far?
“So far, we found a difference in the phloem response to abiotic stress between the two varieties. We found that Orri responding stronger by depositing callose at the sieve plates compared to the Murcott mandarin.
We also looked at the anatomy of the two varieties and saw that Orri has many more fibers in the stem, again pointing to a stronger and durable variety. We are now comparing the physiological response of the two varieties to drought stress. “
