14-3-3 Lambda Protein Affects Anthocyanin Production in Arabidopsis thaliana during Drought Stress

Plants evolve to adapt to environmental stresses, including changes at the genetic and molecular levels. For bioengineers to utilize genetic manipulation to build tolerance into crops, a better understanding of the mechanism is needed. Published studies have demonstrated that 14-3-3 Lambda (14-3-3 Lambda) protein affect the phenylpropanoid (Pp) biosynthetic pathway and alters production of flavonoids and downstream compounds of importance for stress tolerance. The 14-3-3 family of proteins binds to many different client proteins and serves as signaling scaffolds. In this study 14-3-3 Lambda knockout mutants were used to investigate changes in metabolite accumulation in the downstream Pp pathway. Amongst them are anthocyanins which are important antioxidants involved in a variety of plant functions including stress response. Investigating how drought stress influenced anthocyanin production identified nodes in the Pp pathway affected by 14-3-3 Lambda. A metabolomics analysis employing high resolution mass spectrometry (HRMS) and metabolomics software was used to identify metabolites in 14-3-3 knockout which changed relative to wild-type A. thaliana (Columbia-0) during drought stress. The metabolites Cy-3-p-coumaurolysinapoylsophoroside-5-diglucoside, 3-caffeoylferuloylsophoroside- 5-succinoylglucoside, 3-caffeoylferuloylsophoroside-5-malonyldiglucoside, 3-feruloylsophoroside-5-succinoyl glucoside, petunidin-3,5-O-diglucoside and malvidin-3-O-p-coumarylmonoglucoside show significant differences in their profiles ranging from 18- to > 500-fold between the Col-0 and 14-3-3 Lambda knockout in wet and dry groups. The findings suggest that 14-3-3 Lambda interacts along the CHS, and CHI nodes, which in turn regulate the downstream production of specific anthocyanins. The interaction of 14-3-3 Lambda with CHS was confirmed using co-immunoprecipitation and co-localization studies. This study supports the hypothesis that manipulation of gene expression of 14-3-3 Lambda can lead to development of drought tolerance in plants.