Differential gene expression during floral transition in pineapple

Area of Science:

• Plant Biology
• Molecular Biology
• Genetics

Background:

• Commercial flowering in pineapple and ornamental bromeliads is induced using ethylene or its analogs.
• Ethylene treatment triggers a shift from vegetative to floral meristem in the plant apex.
• Morphological changes are observed within 8–10 days, with flowering occurring 8–10 weeks later.

Purpose of the Study:

• To investigate the molecular mechanisms underlying ethylene-induced flowering in pineapple.
• To identify differentially expressed genes (DEGs) and key regulatory pathways involved in floral transition.
• To develop a model for ethylene response in pineapple flowering.

Main Methods:

• Gene expression profiling across eight sampling stages (6 hours to 8 days post-treatment).
• Analysis of differential gene expression (DE) following ethylene application.
• Prediction of target genes for ethylene response transcription factors (ERTFs).

Main Results:

• Over 7961 genes showed differential expression post-ethylene treatment.
• Three ERTFs were upregulated, targeting genes like CONSTANS-like 3 (CO), WUSCHEL, APETALA1/FRUITFULL (AP1/FUL), and jasmonic acid synthesis genes.
• Genes including FLOWERING LOCUS T (FT), TERMINAL FLOWER (TFL), AGAMOUS-like APETELAR (AP2), and SEPETALA (SEP) rapidly increased within 2–3 days.

Conclusions:

• Ethylene directly promotes vegetative-to-flower transition in pineapple via AP1/FUL, interacting with SPL, FT, TFL, SEP, and AP2.
• Pineapple has lost the flowering repressor FLOWERING LOCUS C.
• Identified candidate genes offer targets for genetic manipulation to understand their role in floral transition.