AUTHOR=Wang Lei , Tonsager Andrew J. , Zheng Wenguang , Wang Yingjun , Stessman Dan , Fang Wei , Stenback Kenna E. , Campbell Alexis , Tanvir Rezwan , Zhang Jinjiang , Cothron Samuel , Wan Dongli , Meng Yan , Spalding Martin H. , Nikolau Basil J. , Li Ling 

TITLE=Single-cell genetic models to evaluate orphan gene function: The case of QQS regulating carbon and nitrogen allocation

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1126139

DOI=10.3389/fpls.2023.1126139

ISSN=1664-462X

ABSTRACT=<p>We demonstrate two synthetic single-cell systems that can be used to better understand how the acquisition of an orphan gene can affect complex phenotypes. The Arabidopsis orphan gene, <italic>Qua-Quine Starch</italic> (<italic>QQS</italic>) has been identified as a regulator of carbon (C) and nitrogen (N) partitioning across multiple plant species. <italic>QQS</italic> modulates this important biotechnological trait by replacing NF-YB (Nuclear Factor Y, subunit B) in its interaction with NF-YC. In this study, we expand on these prior findings by developing <italic>Chlamydomonas reinhardtii</italic> and <italic>Saccharomyces cerevisiae</italic> strains, to refactor the functional interactions between QQS and NF-Y subunits to affect modulations in C and N allocation. Expression of <italic>QQS</italic> in <italic>C. reinhardtii</italic> modulates C (<italic>i.e.</italic>, starch) and N (<italic>i.e.</italic>, protein) allocation by affecting interactions between NF-YC and NF-YB subunits. Studies in <italic>S. cerevisiae</italic> revealed similar functional interactions between QQS and the NF-YC homolog (HAP5), modulating C (<italic>i.e.</italic>, glycogen) and N (<italic>i.e.</italic>, protein) allocation. However, in <italic>S. cerevisiae</italic> both the NF-YA (HAP2) and NF-YB (HAP3) homologs appear to have redundant functions to enable QQS and HAP5 to affect C and N allocation. The genetically tractable systems that developed herein exhibit the plasticity to modulate highly complex phenotypes. </p>