Weiler EW, Spanier K. Phytohormones in the formation of crown gall tumors.
PLANTA 1981;
153:326-337. [PMID:
24276937 DOI:
10.1007/bf00384251]
[Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/1981] [Accepted: 07/23/1981] [Indexed: 06/02/2023]
Abstract
Crown gall tumors were initiated in a variety of plant species by infection with Agrobacterium tumefaciens strain B6 and the concomitant changes in the tissue levels of phytohormones, mainly indole-3-acetic acid (IAA) and cytokinins, were analyzed. A comparison was made of these hormones with those produced by virulent and avirulent strains of the bacterium in liquid culture and with those of bacteria-free crown gall callus cultures. Specific radioimmunoassays were employed for hormone determinations. An assay for the quantitation of femto-mol amounts of isopentenyladenosine and related cytokinins was newly developed and is described in detail. The results can be summarized as follows: Virulence in strain B 6 is associated with the ability to release trans-zeatin and increased amounts of IAA into the surrounding environment. In many, but not all plants analyzed, the development of crown gall tumors is also associated with a sharp rise in the levels of trans-zeatin-type zytokinins and IAA (e.g., Euphorbia lathyris, Catharanthus roseus). Crown gall calli growing on hormone-free media varied greatly in their cytokinin levels. In a culture of Nicotiana tabacum, both trans-zeatin and isopentenyladenine or related cytokinins were not detected. Thus, tumor growth cannot be explained on the basis of elevated levels of IAA and/or cytokinins alone.
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