Submitted to: Plant Physiology
Publication Type: Abstract Only
Publication Acceptance Date: June 2, 2000
Publication Date: N/A
Technical Abstract: Mineral nutrients (N, P, K etc.) are vital to plant growth and development. Globally, about $30 billion is spent annually on N fertilizer alone, and fertilizer inputs for the macronutrients P and K also constitute a major cost to agriculture. Also, soils deficient in micronutrients such as Fe and Zn cause significant limitations to agricultural production. Recent research on the molecular regulation of mineral nutrient acquisition has shown that deficiencies of specific nutrients upregulates the expression of key genes involved in nutrient acquisition. We have initiated a mineral nutrition genomics project to investigate changes in global gene expression associated with the imposition of specific mineral nutrient deficiencies, in order to begin to understand the molecular and physiological processes involved in the relationship between mineral status and acquisition. In the study presented here, we imposed specific deficiencies of the macro- and micronutrients N, S, P, K, Ca, Mg, Fe, Zn or Cu on hydroponically-grown tomato seedlings as well as an additional treatment of nitrate for a subset of the N-starved plants. All the treatments (except nitrate resupply) were pooled for RNA isolation and a subtraction was performed against control plants, while the RNA from plants given nitrate resupply was subtracted from N-starved plants. The subtracted mRNAs were used to construct two cDNA libraries. Redundant clones were identified, remaining cDNAs were chosen for sequencing and candidate clones are now being selected for construction of microarrays. These microarrays will be used study the effects of starvation/resupply of specific mineral nutrients on tomato gene expression and the findings will be discussed in the context of global control of mineral nutrient acquisition.