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Date of Award
Doctor of Philosophy in Biological Sciences (PhD)
College, School or Department Name
Department of Biomedical Engineering
Excessive use of heavy metals in industrial applications has resulted in widespread contamination of the environment. Lead (Pb) is one of the heavy metals used extensively without realizing its toxic nature, in various household products such as paint, toys, water pipes etc. Lead also was released into the environment via the use of leaded gasoline and fertilizers. Lead is second most toxic substance only next to arsenic. The Consumer Product Safety Commission (CPSC) in the U.S. banned lead-based paint in 1977 in residential properties.Lead-based paint in pre1978 homes is currently the major source of lead poisoning in children. Soils of millions of homes in United States have high levels of lead as a result of deteriorating paint over the years. Lead laden dust is readily available for inhalation and ingestion, which cause severe health problems such as neurological, renal, gastrointestinal, developmental problems in children below six. Remediation of soils is crucial to abate the lead poisoning cases. Phytoremediation has been demonstrated as an economical and efficient alternative over physico-chemical remediation methods. Chrysopogon zizanioides (vetiver), a tropical grass plant is one of the primary choices for lead remediation due to various advantages such as hyperaccumulation ability, extensive root system, resilience to co-contaminants and different soil conditions. Lead has no biological role in plant systems and elicits toxic effects and various stress responses. Lead stress effects are poorly reported and molecular implications are completely unknown in hyperaccumulator plants such as vetiver. Our study aimed to unravel the biochemical mechanisms of lead stress, tolerance and hyperaccumulation in vetiver grass under hydroponic conditions. Using “omics” approach, we report the proteomic and metabolic profiling of lead stress in non-model hyperaccumulating vetiver plant and also compared metabolic changes with the susceptible maize plant. Metabolic changes mainly included significant increase in stress responsive amino acids, altered carbon metabolism and enhanced antioxidative mechanisms. Proteomic changes include increased expression of transporter proteins, lignin biosynthesis enzymes, antioxidative enzymes such as superoxide dismutase, and negatively impacted proteins related to photosynthesis, protein synthesis and phosphatases. These results could be useful in gaining insights for identifying potential targets for improving the remediation, tolerance and hyperaccumulation ability in vetiver through genetic engineering leading to more efficient phytoremediation practices.
Pidatala, Venkataramana R., "METABOLOMIC AND PROTEOMIC APPROACHES TO UNDERSTAND LEAD STRESS IN VETIVER GRASS (Chrysopogon zizanioides L. NASH)", Dissertation, Michigan Technological University, 2015.