trans-Cinnamic acid-induced leaf expansion involves an auxin-independent component

ABSTRACT

The phenylpropanoid pathway, the source of a large array of compounds with diverse functions, starts with the synthesis of trans-cinnamic acid (t-CA) that is converted by cinnamate-4-hydroxylase (C4H) into p-coumaric acid. We have recently shown that in Arabidopsis, exogenous t-CA promotes leaf growth by increasing cell expansion and that this response requires auxin signaling. We have also shown that cell expansion is increased in C4H loss-of-function mutants. Here we provide further evidence that leaf growth is enhanced by either t-CA or a t-CA derivative that accumulates upstream of C4H. We also show that this growth response pathway has two components: one that requires auxin signaling and another which employs a currently unknown mechanism.

KEYWORDS:

• Auxin
• trans-cinnamic acid
• phenylalanine ammonia-lyase
• cinnamate-4-hydroxylase
• leaf expansion

Acknowledgments

The ref3-1 and ref3-3 mutant seeds were provided by the Arabidopsis Biological Resource Center at Ohio State University. This work was supported by NIFA HATCH project (1009329) and by the Kentucky Tobacco Research and Development Center.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Kentucky Tobacco Research and Development Center [1]; National Institute of Food and Agriculture [HATCH project 1009329].