TERMINAL FLOWER‐1/CENTRORADIALIS inhibits tuberisation via protein interaction with the tuberigen activation complex

Abstract

SUMMARY Potato tuber formation is a secondary developmental programme by which cells in the subapical stolon region divide and radially expand to further differentiate into starch‐accumulating parenchyma. Although some details of the molecular pathway that signals tuberisation are known, important gaps in our knowledge persist. Here, the role of a member of the TERMINAL FLOWER 1/CENTRORADIALIS gene family (termed StCEN) in the negative control of tuberisation is demonstrated for what is thought to be the first time. It is shown that reduced expression of StCEN accelerates tuber formation whereas transgenic lines overexpressing this gene display delayed tuberisation and reduced tuber yield. Protein–protein interaction studies (yeast two‐hybrid and bimolecular fluorescence complementation) demonstrate that StCEN binds components of the recently described tuberigen activation complex. Using transient transactivation assays, we show that the StSP6A tuberisation signal is an activation target of the tuberigen activation complex, and that co‐expression of StCEN blocks activation of the StSP6A gene by StFD‐Like‐1. Transcriptomic analysis of transgenic lines misexpressing StCEN identifies early transcriptional events in tuber formation. These results demonstrate that StCEN suppresses tuberisation by directly antagonising the function of StSP6A in stolons, identifying StCEN as a breeding marker to improve tuber initiation and yield through the selection of genotypes with reduced StCEN expression.

Transcription factor StABI5-like 1 binding to the FLOWERING LOCUS T homologs promotes early maturity in potato

“…Interestingly, StCEN was also observed to physically interact with StABL1, but StFD or StFDL1 could not interact with StABL1 in the Y2H interaction ( Supplemental Figure S8 ). Because StCEN suppresses both flowering and tuberization and binds components of TAC ( Zhang et al, 2020) . It is likely that StCEN also act as inhibitors of the aTAC/aFAC complexes.…”

“…StSP6A together with StFDL1 (FD homolog in potato) form a tuberigen activation complex (TAC) to induce tuberization in a 14-3-3-dependent manner ( Teo et al, 2017 ). StCEN suppresses tuberization by directly antagonizing the function of StSP6A in TAC ( Zhang et al, 2020) . StBRC1b interacts with StSP6A to block its inducing activity in aerial axillary meristems ( Michael et al, 2021 ).…”

Genome-Wide Identification of PEBP Gene Family Members In Potato and Their Phylogenetic Relationships and Expression Patterns Under Heat Stress

“…Arabidopsis FT is a owering promoter, but the AtTFL1 plays as a owering repressor [18]. StCEN1 T37143 can repress tuber formation, whereas StSP6A PGSC0003DMT400060057 is the core inducer of tuberization [20]. Within the FT gene group, the downregulation of StPEBP14 and StPEBP15 was associated with upregulation of StPEBP8 suggests there might be a activity switch among FT gene members under heat stress (Table 2).…”

Decoupling the molecular regulation of perenniality and flowering in bulbous barley (Hordeum bulbosum)

“…Another potential route for a perennial life habit to evolve is through modifications in genes expression that promote bulb formation and development. In H. bulbosum, bulb formation is induced by a shift in day-length similarly to onion and potato (Lee et al, 2013;Zhang et al, 2020), and develops from the bottom of the shoot meristem (Leshem, 1971). Unlike onion and potato where transition to flowering inhibits the development of the storage organ, in H. bulbosum flowering and bulb formation are coupled and occur simultaneously.…”