The role of genes encoding pericycle-specific expression in development of lateral roots and salinity tolerance

Salinity stress is a contributing factor to lowering crop yield due to the accumulation of sodium ions in the shoot and interfering with photosynthesis as well as a range of other independent processes. During the early stages of plant development, lateral roots develop from the pericycle, the cell layer enclosing the vascular tissue. The pericycle is important for processes regulating water and ion transport. Previously, we observed that Arabidopsis high-affinity potassium transporter (HKT1) contributes to salt tolerance and lateral root development. Here, we hypothesize that other genes with pericycle-specific expression are key to lateral root development under salt conditions. Apart from Arabidopsis’ one HKT1 gene, two HKT1 genes (HKT1;1 and HKT1;2) have been identified in tomato, however, their tissue-specific expression has yet to be determined. In this study, we aimed to determine the tissue-specific expression of HKT1;1 and HKT1;2 through cloning their respective promoters into GreenGate expression vectors. In the future, these constructs will be transformed into Agrobacterium rhizogenes and ultimately induce hairy root transformations in tomatoes to localize the pericycle-specific expression of HKT1;2. Additionally, we screened 47 Arabidopsis mutants targeting genes with pericycle-specific expression. The mutants were evaluated for root architecture with and without salt stress. 13 mutants with altered salt stress resilience underwent further screening in PhenoSite Facility at BTI. The results collected within this study will increase our understanding of genes that are specifically expressed in the pericycle, and their contribution to salt stress resilience. This and future studies will further contribute to a more targeted approach to cultivating crops with low-quality water and in areas with no or limited access to freshwater.

I am extremely grateful for the opportunity to work in Magda Julkowska’s lab at BTI and Cornell University this summer. I came to Ithaca lacking a lot of microbiology laboratory experience and I was excited to be out of my comfort zone and to learn everything I could. Over the past ten weeks, my discomfort in new challenges such as cloning via the GreenGate method and the use of R for data analysis has pushed me to become a better biologist. Magda went to great lengths to ensure my experience was the best it could be and it shines in the bittersweet sentiment I am feeling as my time here comes to an end. She has been an amazing mentor; she encouraged me to learn while supporting me and making it okay to make mistakes. My time here has nurtured and simultaneously tested my passion for plant sciences, and I am emerging from it more confident than ever that plant biology is the field I aim to persue.