Complex and shifting interactions of phytochromes regulate fruit development in tomato

Suresh Kumar Gupta, Sulabha Sharma, Parankusam Santisree, Himabindu Vasuki Kilambi, Klaus Appenroth, Yellamaraju Sreelakshmi, Rameshwar Sharma*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Tomato fruit ripening is a complex metabolic process regulated by a genetical hierarchy. A subset of this process is also modulated by light signalling, as mutants encoding negative regulators of phytochrome signal transduction show higher accumulation of carotenoids. In tomato, phytochromes are encoded by a multi-gene family, namely PHYA, PHYB1, PHYB2, PHYE and PHYF; however, their contribution to fruit development and ripening has not been examined. Using single phytochrome mutants phyA, phyB1 and phyB2 and multiple mutants phyAB1, phyB1B2 and phyAB1B2, we compared the on-vine transitory phases of ripening until fruit abscission. The phyAB1B2 mutant showed accelerated transitions during ripening, with shortest time to fruit abscission. Comparison of transition intervals in mutants indicated a phase-specific influence of different phytochrome species either singly or in combination on the ripening process. Examination of off-vine ripened fruits indicated that ripening-specific carotenoid accumulation was not obligatorily dependent upon light and even dark-incubated fruits accumulated carotenoids. The accumulation of transcripts and carotenoids in off-vine and on-vine ripened mutant fruits indicated a complex and shifting phase-dependent modulation by phytochromes. Our results indicate that, in addition to regulating carotenoid levels in tomato fruits, phytochromes also regulate the time required for phase transitions during ripening.

Original languageEnglish
Pages (from-to)1688-1702
Number of pages15
JournalPlant, Cell and Environment
Issue number7
StatePublished - Jul 2014
Externally publishedYes


  • Carotenoids
  • Fruit ripening
  • Photoreceptors


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