Highly Branched Phenotype of the Petunia dad1-1 Mutant Is Reversed by Grafting

Laboratories have used this approach to test the roles of auxin and cytokinin in apical dominance by introducing auxin and cytokinin biosynthetic genes from Agrobacterium tumefaciens and Pseudomonas syringae pv savastanoi into tobacco, petunia, and Arabidopsis.The engineered increases in endogenous hormone levels produce a series of pleiotropic effects, but the experiments confirm that both cytokinin and auxin are important factors in either promotion or suppression of axillary bud growth

C. Napoli

2016

Scholarcy highlights

  • Laboratories have used this approach to test the roles of auxin and cytokinin in apical dominance by introducing auxin and cytokinin biosynthetic genes from Agrobacterium tumefaciens and Pseudomonas syringae pv savastanoi into tobacco, petunia, and Arabidopsis.The engineered increases in endogenous hormone levels produce a series of pleiotropic effects, but the experiments confirm that both cytokinin and auxin are important factors in either promotion or suppression of axillary bud growth
  • The important factor determining the extent of axillary bud growth appears to be the ratio of auxin to cytokinin rather than absolute levels of either hormone
  • Because auxin overexpression results in increased ethylene concentration, it is difficult to distinguish auxin-induced from ethylene-induced changes in plant growth and development
  • Axillary buds develop outside the immediate vicinity of the apical meristem, the shoot apex can control bud growth and development in crossed to transgenic plants inhibited in ethylene biosynthesis
  • The recessive dadl-1 allele conditions a highly branched phenotype that is visibly distinct from the wild type
  • The dadl-1 mutant is altered in the control of apical dominance for the earliest nodes on the plant, and the presence of the growing shoot has no discernible negative affect on axillary bud and accessory bud growth at this early stage of development

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