Complementation of Vitamin B6 Mutations in Arabidopsis thaliana and Saccharomyces cerevisiae with a Ripening Related SlPDX1 cDNA from Tomato

Ethylene is an important plant hormone that regulates many physiological processes in plants, including ripening in climacteric fruit. Understanding the molecular events that regulate the biosynthesis and signal transduction of this hormone then is of great importance, not only for tomato (Solanum lycopersicum), the model system for fruit ripening, but for many other species of economic importance. ACC synthase is the rate limiting step of ethylene biosynthesis and its activity requires vitamin B6 as a co-factor. SlPDX1 encodes a putative enzyme involved with the biosynthesis of this co-factor in tomato. Tomato plants were previously generated using RNAi to silence SlPDX1. The resulting plants exhibit a delay and inhibition of ripening and reduced ethylene. In addition, both vitamin B6 and ethylene treatment rescues the inhibition of ripening phenotype, resulting in normally ripened fruit. Our main goal was to determine if the SlPDX1 sequence encodes an active enzyme by complemention of vitamin B6 biosynthetic mutations in either A. thaliana or S. cerevisiae. We amplified SlPDX1 from tomato fruit RNA using RT-PCR, and the resulting amplicons were sequenced then ligated into appropriate plasmid vectors for expression in both A. thaliana and S. cerevisiae. The subsequent constructs were deployed for the appropriate species, the results of which will be reported and discussed.

My Experience

During my time here, I’ve learned techniques that I otherwise might not have been exposed to. I’ve grown an appreciation for Boyce Thompson Institute’s mission and plant research as a whole. It was incredibly rewarding when hard work and patience got me the results I needed but I learned that getting results is a process. Working full-time on a project has taught me how to deal with roadblocks when they arise by reflecting on past work to circumvent the problem. This program has reinforced my interest in scientific research.