Down-regulation of TM29, a tomato SEPALLATA homolog, causes parthenocarpic fruit development and floral reversion.
We have characterized the tomato (Lycopersicon esculentum Mill.) MADS box gene TM29 that shared a high amino acid sequence homology to the Arabidopsis SEP1, 2, and 3 (SEPALLATA1, 2, and 3) genes. TM29 showed similar expression profiles to SEP1, with accumulation of mRNA in the primordia of all four whorls of floral organs. In addition, TM29 mRNA was detected in inflorescence and vegetative meristems. To understand TM29 function, we produced transgenic tomato plants in which TM29 expression was down-regulated by either cosuppression or antisense techniques. These transgenic plants produced aberrant flowers with morphogenetic alterations in the organs of the inner three whorls. Petals and stamens were green rather than yellow, suggesting a partial conversion to a sepalloid identity. Stamens and ovaries were infertile, with the later developing into parthenocarpic fruit. Ectopic shoots with partially developed leaves and secondary flowers emerged from the fruit. These shoots resembled the primary transgenic flowers and continued to produce parthenocarpic fruit and additional ectopic shoots. Based on the temporal and spatial expression pattern and transgenic phenotypes, we propose that TM29 functions in floral organ development, fruit development, and maintenance of floral meristem identity in tomato.
Ampomah-Dwamena
Charles
C
HortResearch, Private Bag 92169, Auckland, New Zealand.
Morris
Bret A
BA
Sutherland
Paul
P
Veit
Bruce
B
Yao
Jia-Long
JL
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D005638:Fruit / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics / Q000502:physiology; D010641:Phenotype; D010802:Phylogeny; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D026161:MADS Domain Proteins; C121158:SEP3 protein, Arabidopsis; C470667:TM29 protein, Lycopersicon esculentum; D014157:Transcription Factors