Choripetalous corolla: A graft-transmissible phenotypic trait in Salpiglossis sinuata
Abstract
A choripetalous trait that spontaneously appeared in Salpiglossis sinuata R. et P. is graft-transmissible and permanently modifies the phenotype of normal salpiglossis scions grafted onto rootstocks expressing it. This response suggests the presence of a graft-transmissible virus or mycoplasma-like-organism (MLO); however, evidence from polyacrylamide gel electrophoresis of proteins and nucleic acids, enzyme-linked immunosorbent assays, and transmission electron microscopy has been negative. The choripetalous condition persists through asexual propagation; although sectors of stems or corollas occasionally revert to the normal phenotype. This revertant sectoring of choripetalous plant tissues is suggestive of transposable element activity or restricted movement of a low-infectivity pathogen. In vitro callus cultures, established from choripetalous flower pedicels, should not be expected to affect a pathogen-induced, variant phenotype; yet primarily phenotypically normal regenerants are produced. Genomic shock associated with an undisclosed microorganism may result in the initial exposure of the choripetalous phenotype via transposition of a stable transposable element. Further genomic rearrangements during meiosis and in vitro organogenesis may account for reversions to normal phenotype of nearly all sexual progeny and callus culture regenerants, respectively.
Degree
Ph.D.
Advisors
Erickson, Purdue University.
Subject Area
Genetics
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