A novel plant-based functional biosensor for precision agricultureWe explore and consolidate the novel idea of plant based sensors, a new approach where the plants are used as sensors and the output is based directly on the plant response. The majority of biosensors used in agricultural practice today are based on indirect sensing of environmental conditions and inference of plant parameters from measured environmental parameters. We applying a new approach, leading to a viable paradigm for future technology, in which the biosensor measures plant sensing directly. Our biosensor is composed of amalgamated technology, comprising a biological component- the plant itself, and an electrical or optical component- a sensing modality which includes an array of electrodes connected directly to the plant. The project will ultimately result in the production of an agriculture oriented Internet of Things (Agro-IoT) unit comprised of the biosensor and including the front-end, microprocessor, memory and communication, and power system. This will allow for real-time stress data integration in large settings.
Induction of plant innate immunity by a fungal effector (MAMP)Plant resistance against disease involves inducible defense mechanisms. One aspect of the plant defense response is the induction of programmed cell death known as hypersensitive response (HR). Our research focuses on understanding the signal transduction pathway by which a fungal protein effector (MAMP) induces innate immunity in plants. We address this question from several angles: We use genetic approach to isolate the plant gene controlling the plant response to the fungal protein by positional cloning (map based cloning) and microarray (chip technology). We identified of a novel gene family from tomato (LeEix). The LeEix genes belong to an extracellular leucine-rich repeat (LRR) receptor-like proteins (RLPs) represent a unique class of cell-surfac receptors, as they lack a functional cytoplasmic domain. Using silencing and complementation techniques in intransgenic plants we showed that both genes are capable of binding the fungal effector independently. However, only LeEix2 is capable of transmitting the signal to induce the plant innate immunity response.
The fungal effector EIX (MAMP) triggers a defense response via the LeEix2 receptor, in an endocytosis-dependent process. We study the signal transduction pathways that lead to the induction of defense responses using molecular genetic tools. We demonstrated that the EIX effector triggers internalization of the RLP LeEix2 receptor. Treatment with endocytosis, actin or microtubule inhibitors greatly reduced the internalization of LeEix2. Our data indicate a distinct endosomal signaling mechanism for induction of defense responses in this RLP system. Endocytosis is an essential process by which the eukaryotic cell internalizes exogenous material. Studies in mammalian cells have revealed that endocytosis is a complex molecular process depending on regulated interactions between a variety of proteins and lipids through specific modules. One such module is the Eps15 homology (EH) domain, a conserved modular protein-interaction domain found in several endocytic proteins. We isolated and characterized two plant EH-domain-containing proteins (AtEHD1 and AtEHD2). We show that the two proteins are involved in endocytosis in plant systems and demonstrated that the Arabidopsis EHD proteins function similarly to previously identify mammalian EHDs. Our laboratory study the involvement of the plant EHD proteins in the signaling pathway involved in the induction of plant defense responses. We found that AtEHD2 interact with the cytoplasmic domain of LeEix2 in planta in the BiFC system and its over-expression inhibits the induction of plant defense responses. Additionally, we demonstrated that plant EHD2 binds to LeEix2 and is an important factor in its internalization and in regulation of the induction of defense responses in the case of LeEix2, Cf4 and Cf9 resistant genes, but does not appear to be involved in the FLS2 system. Our results suggest that various endocytosis pathways are involved in the induction of plant defense responses. Targeted nucleases are powerful tools for mediating genome alteration with high precision. Currently, we are using the CRISPR-CAS9 technology to edit the tomato genome in order to identify genes involved in the signaling process that induces innate immunity in tomato. We are using genome-scale CRISPR-Cas9 knockout screen in tomato to identify genes essential for plant innate immunity. Ensuring global food security, and ensuring it is socially, economically and environmentally sustainable, is perhaps the most important societal issue we face. Our long-term goals are to generate plants that show high resistance to pathogens to help increase food productivity for global food security.
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