Towards understanding the function of JOINTLESS gene in tomato inflorescence

The lack of fruit abscission is a trait of great agronomical value. In tomato, the jointless phenotype,
referring to the lack of abscission zone (AZ) in the flower pedicel, has been obtained by two
independent mutations, named jointless (j) and jointless-2 (j-2). The corresponding genes encode
MADS-box transcription factors, as shown in 2000 for J (Mao et al. 2000) and very recently for J-2,
known as SlMBP21 (Gomez-Roldan et al., 2017). Similar to the quartet model of MADS-box protein
complexes regulating floral organ formation, J and J-2 interact with MADS-box partners, among
which MACROCRALYX (MC), to regulate AZ formation (Liu et al. 2014). In addition to - or in
connection with - AZ formation, J acts during the building of the inflorescence to regulate meristem
fate. Indeed j mutants produce leafy inflorescences characterized by faster flower maturation and
resumption of vegetative meristems (Périlleux et al. 2014). For these traits, j is epistatic to j-2. The
involvement of J in the regulation of meristem fate is consistent with the roles of its closest homologs
in Arabidopsis, AGAMOUS LIKE 24 (AGL24) and SHORT VEGETATIVE PHASE (SVP). Our goal is
to identify J targets in order to unravel its multiple functions in the tomato inflorescence.