Menu:
Contact Details:
Saul Burdman, Ph.D.
Phone: +972 8 9489369
Fax: +972 8 9466794
Email:
saulb@agri.huji.ac.il
The Department of Plant Pathology and Microbiology
The Robert H. Smith Faculty of Agriculture, Food and Environment
The Hebrew University of Jerusalem
Research in the lab
Research in our lab is in the area of plant-bacteria interactions. Plants are our main suppliers of food and fibers. In their environment, either natural or agricultural, plants interact with other organisms, including bacteria. The outcome of these interactions can be beneficial or detrimental. The basic understanding of both kinds of interactions is of fundamental importance for agriculture, to manage conditions for promotion of higher crop yields, while minimizing negative impacts on the environment.
The successful establishment of plant-associated bacteria in their host plants and their ecological performance depends on complex processes that require the coordinated expression of a plethora of genes, whose identity and mode of action are largely unknown. Research in our lab aims to enlarge our understanding of the molecular basis of both detrimental and beneficial interactions between plants and bacteria. In other words, the major goal of our group is to contribute at deciphering the mechanisms that are required by a plant-associated bacterium to be a successful organism at both lifestyles.
Lab founders: Nadia, Tal, Dafna, Avital, Anu and Saul (2004)
Bacteria as causal agents of plant diseases
It is estimated that about 20,000 different species of fungi and thousands of viruses cause diseases on plants. In contrast, there are few hundreds of plant pathogenic bacterial species or subspecies. Nevertheless, almost every agricultural crop suffers at least from one important bacterial disease, and there are some crops for which a bacterium is the most important pathogen. For instance, Xanthomonas axonopodis pv. citri, the causal agent of citrus bacterial canker lead to the erradication of millions of citrus trees in Florida, Sao Paulo and other parts of the world. As an other example, there are some places in the world where pears and apples cannot be cultivated due to a bacterium, Erwinia amylovora, which causes the fire blight disease in a wide range of plants from the Rosaceae family.
A pear flower burnt by Erwinia amylovora, the fire blight pathogen
(courtesy of Dafna
Blachinsky)
The importance of bacterial plant diseases is increasing in recent years, partially because of the lack of efficient methods to control them. In addition, most phytopathogenic bacteria are seedborne, namely, they can colonize, survive and be transmitted by seeds. In times of world globalization and technological advances, every crop can be cultivated in almost every part of the world. Well, plant diseases are also being globalized, mainly by spreading pathogens worldwide by seeds. One such example is Acidovorax avenae subsp. ciitrulli (Aac), a pathogen we are investigating in our lab. Aac is the causal agent of bacterial fruit blotch disease of cucurbits, one of the most serious threats to the watermelon and melon industry worldwide. This pathogen gained importance in the late 80s' after several outbreaks in the US. In just a few years the pathogen spread to many parts of the world mainly through watermelon and melon seeds, and today it is a serious threat in several countries at the Americas, Europe, Asia, the Middle East, and Australia.
A watermelon fruit affected by A. avenae subsp. citrulli
(Burdman et al., Plant Disease 2005).
Last, most plant pathogenic bacteria are easy to work with. They are (basically) unicellular, possess a relatively simple (prokaryotic) cell structure, grow relatively fast, and many of them are relatively easily manipulable by molecular tools. In addition, the genomes of most important plant pathogenic bacteria have already been sequenced. Those reasons make plant pathogenic bacteria, important models for basic research of plant-pathogen interactions. Hopefully, improving our undertanding of plant pathogenesis at the basic level will contribute to the development of more efficient means to control bacterial plant diseases.