Environmental sensing, hormonal crosstalk and molecular control of mango flowering in Mangifera indica L.

Mango is an evergreen perennial whose flowering depends on the developmental competence of a mature flush and on environmental conditions that alter the balance between vegetative growth and reproductive transition. This review focuses on temperature and light sensing, water status, source-sink signals, hormonal crosstalk and molecular regulators of flowering in Mangifera indica. Direct mango evidence is separated from association studies and from functional tests performed in heterologous Arabidopsis systems. Cool conditions can promote floral induction, but the response is cultivar- and stage-dependent: controlled experiments include inductive regimes near 19 –15 °C during the day and 15 –10 °C at night, whereas a 13 °C treatment produced almost complete flowering and 25 °C produced none in potted ‘Tommy Atkins’ trees. Moderate pre-induction water deficit can also promote flowering in some low-latitude cultivars, while severe or late stress is damaging. Fruit load, sugars, circadian transcripts and plant age are associated with flowering competence or FT/TFL1 expression, but direct evidence that these variables alter ABA levels during mango floral induction remains limited. Gibberellin and ABA responses are therefore best interpreted as tissue- and treatment-specific. Recent studies extend the molecular framework from FLOWERING LOCUS T (FT), TERMINAL FLOWER 1 (TFL1), SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), APETALA1 (AP1), LEAFY (LFY) and SHORT VEGETATIVE PHASE (SVP) to the ABA-responsive ABSCISIC ACID INSENSITIVE 5-like7 (MiABI5-like7)-MiFT3 module, GIBBERELLIN INSENSITIVE DWARF1 (MiGID1) and SLENDER RICE-like DELLA (MiSLR) genes, and allelic CONSTANS-LIKE (COL) MiCOL14B modules. The resulting model is a competence-gated network in which environmental signals, growth restraint and florigenic or anti-florigenic pathways converge on bud fate. Floral induction is a competence-gated response to cool temperature, mature shoots and water status. Gibberellin and abscisic acid interact, but direct mango evidence is tissue- and treatment-specific. FT/TFL1, SOC1/AP1/LFY/SVP, CO/COL and circadian modules are organized by evidence strength. MiABI5-like7-MiFT3 and allelic MiCOL14B studies refine the current flowering model. Chemical growth retardants are mechanistic probes and require cultivar- and site-specific validation.