Heavy metals and gene expression in plant stomata

Abstract

Stomata are structures that regulate leaf gas exchange with the atmosphere, allowing the entrance of CO2 to promote photosynthesis and the exit of O2 as a byproduct. Many studies have documented the changes caused by environmental stress in the number of stomata on plant leaves and in the opening and closing of these plant structures. Opening and closing of stomata is regulated by environmental and physiological factors, such as hormones, however, many molecular and genetic details have not been revealed. The purpose of this research is to understand the genetic and molecular basis of the environmental stress on plant stomata. We are focused on the effect of heavy metals on the expression of the following genes from Arabidopsis thaliana: stomatal closure-related actin binding protein 1 (SCAB1), actin 2 (ACT2), myosin (MYOATP), metallothionein 2B (MT2B), and nine-cis-epoxycarotenoid dioxygenase 3 (NCED3). Plants were exposed to cadmium and total RNA from whole plant and plant stomata was isolate. Different bioinformatics tools were used to assess and identify specific oligonucleotide sequences for these genes. cDNA was obtained and gene expression was determined by real time PCR. Preliminary results showed changes in the expression of SCAB1, ACT2, MYOATP, MT2B and NCED3 due to exposure to cadmium. Experiments are underway to establish a relationship between the opening and closing of stomata due exposition to cadmium.