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A tomato HD-Zip homeobox protein, LeHB-1, plays an important role in floral organogenesis and ripening
Article first published online: 4 APR 2008
© 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd
The Plant Journal
Volume 55, Issue 2, pages 301–310, July 2008
How to Cite
Lin, Z., Hong, Y., Yin, M., Li, C., Zhang, K. and Grierson, D. (2008), A tomato HD-Zip homeobox protein, LeHB-1, plays an important role in floral organogenesis and ripening. The Plant Journal, 55: 301–310. doi: 10.1111/j.1365-313X.2008.03505.x
- Issue published online: 8 JUL 2008
- Article first published online: 4 APR 2008
- Received 24 January 2008; revised 11 March 2008; accepted 17 March 2008.
- HD-Zip homeobox protein;
- floral organogenesis;
Ethylene is required for climacteric fruit ripening. Inhibition of ethylene biosynthesis genes, 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase, prevents or delays ripening, but it is not known how these genes are modulated during normal development. LeHB-1, a previously uncharacterized tomato homeobox protein, was shown by gel retardation assay to interact with the promoter of LeACO1, an ACC oxidase gene expressed during ripening. Inhibition of LeHB-1 mRNA accumulation in tomato fruit, using virus-induced gene silencing, greatly reduced LeACO1 mRNA levels, and inhibited ripening. Conversely, ectopic overexpression of LeHB-1 by viral delivery to developing flowers elsewhere on injected plants triggered altered floral organ morphology, including production of multiple flowers within one sepal whorl, fusion of sepals and petals, and conversion of sepals into carpel-like structures that grew into fruits and ripened. Our findings suggest that LeHB-1 is not only involved in the control of ripening but also plays a critical role in floral organogenesis.