Defence mechanisms in rape seed participating in plant- pathogen interaction and induced resistance
Protection of crop plants against various diseases is undoubtedly of great importance.The efficiency of plant defence mechanisms against pathogens depends on the ability of the plant to recognise the pathogen early in the infection process. The recognition is followed by the expression of a number of defence responses and it was recently shown that various natural elicitors as well as some chemical compounds were capable of switching the same defence responses as pathogens. Thus, there appears to be great potential to further exploit induced disease resistance as an additional tool to control plant diseases within an integrated control strategy. In the presented project we would like to fructify the results of our currently finishing common research (grant no. 522/00/1332) on the characterization of plant phospholipases in connection to induced responses in the tobacco cell cultures as a model system. The acquired knowledge and methodology will be utilized in the study of defence mechanisms of Brassica napus against its important fungal pathogen Leptosphaeria maculans, and compared with the effect of some known elicitors and chemical inducers of induced resistance. The contribution to the recognition of the molecular basis of defence mechanisms in Brassica napus elicited by both pathogen and resistance inducers would deepen the knowledge of early events in pathogenesis, especially the action of phospholipases in the signal transduction and the role of PR-proteins in induced resistance in rape.
Role of multiple phospholipase forms in plant defense mechanism
Plants respond to attack by pathogens with a de novo production of compounds reducing or inhibiting the growth and multiplication of the invader, and in many cases, resulting in induced resistance (systemic acquired resistance, SAR) to subsequent infections. The speed of plant response to attack determines the efficacy of the plant defence and is crucial for the establishment of resistance. Thus the basic knowledge of the molecular mechanisms involved in plant's early response to pathogen attack and/or SAR inducers is obviously of great importance. Phospholipid-derived molecules are emerging as second messengers in plant defence signaling are produced by phospholipases C, D and A2. The aim of the project is to elucidate the role of multiple forms of PLC and/or PLD in the early events leading to the induced resistance in plants and to find out the level of their involvement in the pathway. Chemical inducers of systemic response, elicitors and pathogens, suspension cell cultures and T-DNA mutant lines of Arabidopsis will be used as experimental system. Specific marker pathogenesis related genes will be used for detection of ISR/SAR establisment and pharmacological approach using inhibitors of individual members of phospholipid signaling will show their roles in the process. Expression of single PLD and PLC genes and in planta study of T-DNA mutants will elucidate the involvement of different isoforms in signal transduction leading to PR-protein production and SAR establishment.
Role of plant phospholipide - cytoskeleton signaling in aluminum toxicity
Aluminum (Al) is highly cytotoxic metal to plants and animals as well and is responsible for significant losses in world crop production. The molecular base of Al toxicity is still far from being understood. Plant cell cytoskeleton appears to be extremely sensitive to Al. Moreover, Al seems to impact phospholipases in plant cells. The important role of phospholipases in regulation of cytoskeletal dynamics in animal organisms is now evident. On the other hand, there are no information about relationship between phospholipid-cytoskeleton signalling and Al toxicity in plant cells. The first part of the project is focused on the study of an effect of Al on the activities of phospholipases and effect of phospholipase inhibitors and /or lipid mediators on cytoskeleton organization in Al-treated and non-treated tobacco cells. In the second part of the project indirect and direct interactions of phospholipases with cytoskeleton in Al-treated and nontreated tobacco cells will be studied.