Primary Action of Indole-3-acetic Acid in Crown Gall Tumors

Abstract

Exogenously added indole-3-acetc acid at a cocentratin of 100 mrom sim tes D-e uptake (or 3-0-methyl-D-glcoSe Uptake) by 25% In crown tmos Induced on potato tuber tissue by Agrobaam tac1If strain C 58. The titration of the e IAA with the axln a g t 2 pthe add at 100 micromolas reduoes n-gluose uptake by about 80%. The appart ihib constant K,is 21 m ors. Other auxin angi liJke 1-naphthoxyacetic acd and 2-(p-c rophenoxy)-2-methylpropionic acid show similar effects. The uptalke of the amino acids lencin methionie tryptophan, lysine, and aspartic acid is also inhibited by 2-naphtlcetic acid to sidr degees. The auxis 1-naphthaleneacetic acid and 2-aphthoxyacetic acid at co tri betwee 10 and 100 micromolars inhibit solute uptake only slhtly (hibition less than 20%). The Impact of the results on the ptted role of indole-3-acetic acid as a modifier of the electrochemical proton gradient acoss the pmlemma in crown pHl tumor tisue discd.

Auxin synthesis in Agrobacterium tumefaciens and A. tumefaciens-transformed plant tissue

“…tumefaciens transformed tobacco tissue cultures [33] although the conversions were not confirmed enzymatically . In contrast, the indoleacetaldoxime pathway seems to be characteristic only of Brassicaceae, Rosedaceae and Tovariaceae.…”

The three-dimensional structure of vascular tissues in Agrobacterium tumefaciens-induced crown galls and in the host stems of Ricinus communis L.

“…It has been suggested that, upon expression of the T-DNA, the increase in auxin synthesis (Weiler and Spanier 1981;Malsy et al 1992) stimulates the plasma-membrane-located H + ATPase, as is known from various other sensitive cells and tissues (Altabella et al 1990). This has been assumed to result in membrane hyperpolarization and hence in an increase in the proton motive force (A~H +) that energizes hexose uptake (Rausch et al 1984(Rausch et al , 1994. Measurements of electrical membrane parameters, however, did not confirm this assumption (Malsy et al 1992).…”

A mutation in the indole-3-acetic acid biosynthesis pathway of Pseudomonas syringae pv. syringae affects growth in Phaseolus vulgaris and syringomycin production

“…syringae is also associated with the induction of the hypersensitive response in tobacco (6). Bacterially derived sources of IAA could have a direct effect on plant plasmalemma function, as this phytohormone can modify the electrochemical proton gradient across the plant plasma membrane (44). Mutations in hrp genes disrupt the activation of the K+ efflux, eliminate the ability to induce a hypersensitive response, and restrict in planta bacterial multiplication (6,29).…”