Constitutive expression of CEN-like protein 2, a TFL1 ortholog of pigeon pea (Cajanus cajan [L.] Millspaugh) delays flowering in transgenic tobacco plants.

Abstract

CEN-like protein 2 of pigeon pea, a candidate anti-florigen gene and a close homolog of AtTFL1 (Arabidopsis Terminal Flower1) of the PEBP family has been characterized through constitutive expression in tobacco. In-silico analysis helped to demonstrate the absence of a nuclear binding domain and the conserveness of substrate binding sites of this protein across angiosperms. Transgenic tobacco lines with 2-eightfold higher expressions of CEN-like protein 2 showed delayed flowering (26-32 days) along with significant morphological changes, including vegetative vigour, number and size of flowers, fruit setting, etc. Together, these findings showed that CEN-like protein 2 not only delays floral transition through repression but also regulates a variety of developmental traits. Expression profiling of upstream and downstream interacting pathway genes explained that their expression modulation led to a prolonged vegetative phase of over-expressed lines. Floral inducer genes like APETALA1 and LEAFY were drastically down-regulated in transgenic lines, reconfirming the role of the CEN-like 2 gene in floral regulation. In conclusion, precisely controlling CcCEN-like 2 gene expression may prove useful for refining pigeon pea breeding.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-025-01572-8.