Perception of strigolactones and the coordinated phytohormonal regulation on rice (Oryza sativa) tillering is affected by endogenous ascorbic acid.

Phytohormones play a key role in regulating tiller number. Ascorbic acid (Asc)-phytohormone interaction plays a pivotal role in the regulation of senescence. We analysed the relationship between Asc and the enzyme concentrations and gene transcript abundances related to the signal perception of strigolactones (SLs), the contents of four phytohormones (abscisic acid, ABA; jasmonic acid, JA; indole acetic acid, IAA; cytokinin, CTK), the enzyme concentrations and gene transcript abundances related to the synthesis or transportation of these four phytohormones. Our results showed that Asc deficiency leads to the upregulation of enzyme concentrations, gene transcript abundances related to the SL signal perception, ABA synthesis and IAA transport. The altered level of Asc also leads to a change in the contents of ABA, JA, IAA and CTK. These findings support the conclusion that Asc or Asc/DHA play an important role in the signal perception and transduction of SLs, and Asc may affect the coordinated regulation of SL, IAA and CTK on rice (Oryza sativa ) tillering.