Overexpression of a Homeobox Gene, LeT6, Reveals Indeterminate Features in the Tomato Compound Leaf1

AUTOR(ES)

Janssen, Bart-Jan

FONTE

American Society of Plant Physiologists

RESUMO

The cultivated tomato (Lycopersicon esculentum) has a unipinnate compound leaf. In the developing leaf primordium, major leaflet initiation is basipetal, and lobe formation and early vascular differentiation are acropetal. We show that engineered alterations in the expression of a tomato homeobox gene, LeT6, can cause dramatic changes in leaf morphology. The morphological states are variable and unstable and the phenotypes produced indicate that the tomato leaf has an inherent level of indeterminacy. This is manifested by the production of multiple orders of compounding in the leaf, by numerous shoot, inflorescence, and floral meristems on leaves, and by the conversion of rachis-petiolule junctions into “axillary” positions where floral buds can arise. Overexpression of a heterologous homeobox transgene, kn1, does not produce such phenotypic variability. This indicates that LeT6 may differ from the heterologous kn1 gene in the effects manifested on overexpression, and that 35S-LeT6 plants may be subject to alterations in expression of both the introduced and endogenous LeT6 genes. The expression patterns of LeT6 argue in favor of a fundamental role for LeT6 in morphogenesis of leaves in tomato and also suggest that variability in homeobox gene expression may account for some of the diversity in leaf form seen in nature.

Documentos Relacionados

• Clausa, a Tomato Mutant with a Wide Range of Phenotypic Perturbations, Displays a Cell Type-Dependent Expression of the Homeobox Gene LeT6/TKn21
• Ectopic Expression of the Maize Homeobox Gene Liguleless3 Alters Cell Fates in the Leaf1
• CONDITION OF CHLOROPHYLL IN THE LEAF1
• LeCTR1, a Tomato CTR1-Like Gene, Demonstrates Ethylene Signaling Ability in Arabidopsis and Novel Expression Patterns in Tomato1
• Nucleotide sequence of Xenopus homeobox gene, En-1.