AUTHOR=Rabeler Christina , Chen Mingjie , Kaplinsky Nick 

TITLE=BUMPY STEM Is an Arabidopsis Choline/Ethanolamine Kinase Required for Normal Development and Chilling Responses

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.851960

DOI=10.3389/fpls.2022.851960

ISSN=1664-462X

ABSTRACT=<p>Phospholipid biosynthesis is a core metabolic pathway that affects all aspects of plant growth and development. One of the earliest step in this pathway is mediated by choline/ethanolamine kinases (CEKs), enzymes in the Kennedy pathway that catalyze the synthesis of the polar head groups found on the most abundant plant phospholipids. The Arabidopsis genome encodes four <italic>CEK</italic>s. <italic>CEK1-3</italic> have been well characterized using viable mutants while <italic>CEK4</italic> encodes an essential gene, making it difficult to characterize its effects on plant development and responses to the environment. We have isolated an EMS-induced allele of <italic>CEK4</italic> called <italic>bumpy stem</italic> (<italic>bst</italic>). <italic>bst</italic> plants are viable, allowing the effects of decreased <italic>CEK4</italic> function to be characterized throughout the Arabidopsis life cycle. <italic>bst</italic> mutants have a range of developmental defects including ectopic stem growths at the base of their flowers, reduced fertility, and short roots and stems. They are also sensitive to cold temperatures. Supplementation with choline, phosphocholine, ethanolamine, and phosphoethanolamine rescues <italic>bst</italic> root phenotypes, highlighting the flow of metabolites between the choline and ethanolamine branches of the Kennedy pathway. The identification of <italic>bst</italic> and characterization of its phenotypes defines new roles for <italic>CEK4</italic> that go beyond its established biochemical function as an ethanolamine kinase.</p>