A tomato HD-Zip homeobox protein, LeHB-1, plays an important role in floral organogenesis and ripening.
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.
Lin
Zhefeng
Z
Plant Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
Hong
Yiguo
Y
Yin
Mingan
M
Li
Chunyang
C
Zhang
Ke
K
Grierson
Don
D
D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D035264:Flowers / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D020868:Gene Silencing; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding
D018398:Homeodomain Proteins; D010940:Plant Proteins; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase