- Drought-Tolerance of Wheat Improved by Rhizosphere Bacteria from Harsh Environments: Enhanced Biomass Production and Reduced Emissions of Stress Volatiles.
- A Simplified Method for Gene Knockout and Direct Screening of Recombinant Clones for Application in Paenibacillus polymyxa.
The general research area is molecular microbial ecology. I have studied biofilm forming Paenibacillus polymyxa plant interactions for a wide variety of plants. The bacteria are good biocontrol agents, which induce systemic resistance and enhance abiotic stress tolerance.
These studies have lead to the understanding of the complexity of the plant microbe interactions and necessity to study the natural isolates from the regions where microbes have coevolved with plant root. These microorganisms may hold solutions to various global problems facing our society e.g. shortage of resources shortage of fertile soils, loss of biodiversity and climate change. Natural isolates differ from the highly subcultured laboratory representatives.
Hence we study the natural isolates from the rhizosphere of wild progenitors of cereals at ‘Evolution Canyon’ (PIC1) and from the from ponderosa pine at Mt. Lemmon (PIC2).
The ‘Evolution Canyon’ represent local, microcosmic, natural laboratory designated by the Institute of Evolution, Haifa University.
The canyon slopes present abiotic and biotic contrasts locally, permitting the pursuit of observations and experiments across diverse taxa sharing sharp microecological subdivisions. Higher solar radiation received by the “African ” south-facing slopes in canyons north of the equator than by the opposite “European” north-facing slopes is associated with higher abiotic stress.
Mt. Lemmon in the Santa Catalina Mountains, situated within the Sonoran desert of Arizona, was formed 12 million years ago when the western North American continent was being stretched. The rocks of the Catalinas are primarily granite and hard, banded, metamorphic Catalina gneiss, creating nutrient deprivation stress. Temperature extremes expose the tress to heat and drought in summer and due to high elevation at 2,800 meters, cold in winter. Being located at 32º N, as well as high elevation exposes plants to high UV radiation stress.
In these unique ecological laboratories drought, heat, UV radiation, and nutritional deprivation have been stress factors along with evolutionary selection forces occurring over millennia. Hence these laboratories facilitate the generation of theoretical testable and predictable models of biodiversity and genome evolution as well as practical solution for our agro-ecological systems under global change.
Collaboration and students
FP-7-2009-IRISES Biocontrol and Bioremediation agents and their role in Agriculture and Forest health ( B.R. Glick, University of Waterloo, Department of Biology, Cheryl L. Patten, University of New Brunswick, Canada)
Yoav Bashan, the University of Arizona, Department of Soil Water and Environmental Science
Jonas Bergguist, Uppsala University, Department of Physical and Analytical Chemistry
Emmanuelle Gothlied, Uppsala University, Department of Physics and Astronomy
Seong-Bin Kim postdoctoral student ( Prof. S-H. Park) Korea Research Institute of Bioscience and Biotechnology (KRIBB)
Ameraswar Vangala, PhD student
Srisailam Marukapula, PhD student with Prof. R. Finlay
Islam A Abd El-Daim, PhD student.
General project areas
- Microbial distribution in the rhizosphere of wild progenitors of cereals (wild barley, emmer wheat) and ponderosa pine. Read the paper Bacterial Distribution in the Rhizosphere of Wild Barley under Contrasting Microclimates here.
- Molecular and biochemical interactions in the rhizosphere; natural isolate genetic manipulation.
- Method development for plant abiotic and biotic stress alleviation. Quantitative relationships between the intensity of stress and strength of rhizobacterially primed plant response are studied in order to assess the ability of the bacteria to reduce plant environmental stress as well as pathogen stress.
Plant response to a particular type of stress is usually composed of stress specific adaptive responses but also responses that confer to unspecific basic protection. The unspecific early signaling events largely determine the capacity of plants to orchestrate a successful adaptive response. This initial basic response is reestablishing homeostasis, repair damaged cellular components and reprogram metabolism.
We use interdisciplinary approach and advanced techniques (high resolution microscopy, immunotagging, comparative/ functional genomics) to investigate some of the factors so that we can improve our understanding of these complex interactions. Our research is directed towards the design and carrying out of functional screens for metabolic functions and isolation, characterization of microbial genes which encode products that are involved in the microbial stress tolerance enhancement and stimulation of plant growth in general.
Drought and heat in summer, flooding in spring and autumn, poor agricultural soils and nutrient deprivation will be the major abiotic factors limiting crop production in Sweden during the climate change. At the same time, as a secondary result of climate change the pathogen attacks to agriculturally important plants are about to increase as well. The situation challenges us to find sustainable practical solutions to complex stress situations i.e. there various environmental stress factors are affecting simultaneously. Hence our basic research is correlated to applied research to find practical solutions for sustainable growth.