Calcium is essential for plant growth and development. The researcher studied plants with mutations (knockouts) in genes that encode cation exchangers (CAX) involved in calcium transport. Specifically, the researcher analyzed plants with triple knockouts (TKO) of CAX genes under various stress conditions, such as heavy metals, osmotic stress, and oxidative stress. Preliminary results showed that the TKO lines did not differ substantially from single and double mutants. Surprisingly, the TKO mutants exhibited a slight increased growth rate in many of the stress conditions tested, raising the question of whether these transporters actually impair plant growth.

1. Phenotypical analysis of CAX mutants in Arabidopsis thaliana
Brookens, Claire E., Kutztown University of Pennsylvania, Class of 2017.
Kendal Hirschi Ph.D. Department of Pediatrics-Nutrition, Children's Nutrition Research Center,
Baylor College of Medicine
Calcium is as important to plant growth and development as the electron is to electricity.
Dr. Hirschi’s lab works on a family of cation exchangers (CAX) from the model plant Arabidopsis
thaliana to determine how plans partition and utilize calcium. This summer I worked on
phenotyping plants with cax gene mutations (knockouts). My focus was phenotyping mutant
with three knockouts (TKO) of the CAXs to explore their role in various stress conditions (heavy
metals, osmotic, oxidative and altered levels of growth hormones). This was done by comparing
various single, double and triple mutants and controls on media infused with stress conditions
then using imagine software to analyze plant responses to the environmental perturbations.
Preliminary results suggest that the TKO lines are not substantially different from the single and
double mutants. Surprisingly, the TKO mutants did show a slight increased rate of growth on
many of the media conditions tested. Raising the question, do these transporters actually impair
plant growth? Moving forward the lab would like to test additional conditions on the mutant lines
and investigate the growth phenotype discovered in the TKO.