| Description |
How would our world change if salt tolerance could be engineered in plants? The Arabidopsis mutant bps1-2 has been shown to respond differently on salt media than a nonmutated plant would. In normal conditions, the bps1-2 mutant will arrest development in the root and shoot shortly after germination. However, supplementation of growth media with higher than normal concentrations of salt caused these mutant plants to grow larger, indicating a partial rescue of the molecular defect that causes stunted growth in the bps1-2 mutant. This strange phenomenon suggests that bps1-2 could have a role in salt signaling. Because soil salinity is increasing as land is used, demand for plants with salt tolerance is also increasing. However, most plants, Arabidopsis included, prefer very low concentrations of salt, and undergo physiological changes if growing in the presence of salt. Unlike the bps1-2 mutant, normal Arabidopsis seedlings will show decreased growth when grown on media containing salt. Thus, the growth exhibited by bps1-2 mutants on salt is unexpected. This project aimed to quantify the partial rescue of the bps1-2 mutant phenotype in the presence of salt, investigate more of the conditions of this partial rescue, and identify possible models for this interaction between bps 1-2 mutants and salt. The quantitative proof of partial rescue of the phenotype was determined through a series of dry weight experiments. Seedlings were dried in an oven for 48 hours and the weight of the plants' biomass was determined. Quantitative results matched what had qualitatively been observed - not only does salt partially rescue the mutant phenotype, but potassium chloride rescues the phenotype to a greater degree than sodium chloride. Other conditions of the partial rescue were examined in transfer experiments, aimed at discovering if bps1-2 mutants need a constant input of salt or merely salt during germination to partially rescue. Mutants were transferred from media with salt to media without salt, and vice versa. Only mutants transferred from general media to media containing potassium chloride exhibited partial rescue of the phenotype. Finally, bps1-2 was crossed with several other mutants that are involved in salt signaling pathways. These crosses could shed light on the potential involvement of bps1-2 in salt signaling pathways. A potential model is proposed of how bps1-2 interacts with proteins involved in maintaining salt balance within Arabidopsis. If involved in salt tolerance, bps1-2 could be an important key in battling soil salinity. |
