Paper 2

Molecular Events Leading to Adventitious Root Initiation in The

Hypocotyls of Phaseolus Vulgaris L;

G.R. Kantharaj, S. Mahadevan & G. Padmanabhan;

Dept. of Biochemistry, Indian Institute of Science, Bangalore 560012

(Indian Cell Biology, 24, 1978).

Synopsis

Phaseolus vulgaris hypocotyls when treated with IBA for 30 minutes induce new roots in hormone concentration dependent manner. IBA induced RNA synthesis and protein synthesis from 30 minutes after treatment to one hr, showed substantial increased Protein synthesis in the presence of Actinomycin-D suggested that the increased protein synthesis is due to IBA induced activation of translation machinery. Following this observation Poly-A RNA was measured and found no increase in mRNA.  But the increase in poly-A RNA and protein synthesis later 60 minutes after is due to increased mRNA synthesis. Coinciding with the increase in translatable mRNA with the appearance of 55-58KD and 135 KD proteins, among the others, were found as prominent bands.  The high molecular weight 135KD protein appears at 36hrs and disappears later, which coincides with the root primordial formation in the pericyclic region between exarch xylem elements in the vascular bundle.  The 55-58KD protein has been identified as tubulin dimers by immunoprecipitation.  However, it was not possible to identifiable 135Kd transient protein.  This we consider it as a regulatory protein for triggering the root primordial initiation. Work on this is in progress.

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