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A tomato HD‐Zip homeobox protein, LeHB‐1, plays an important role in floral organogenesis and ripening
Author(s) -
Lin Zhefeng,
Hong Yiguo,
Yin Mingan,
Li Chunyang,
Zhang Ke,
Grierson Don
Publication year - 2008
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2008.03505.x
Subject(s) - sepal , ripening , biology , organogenesis , petal , homeobox , microbiology and biotechnology , gene , botany , stamen , biochemistry , gene expression , pollen
Summary 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.