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Post‐transcriptional transgene silencing and consequent tospovirus resistance in transgenic lettuce are affected by transgene dosage and plant development
Author(s) -
Pang ShengZhi,
Ja FuhJyh,
Carney Kim,
Stout John,
Tricoli David M.,
Quemada Hector D.,
Gonsalves Dennis
Publication year - 1996
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1996.9060899.x
Subject(s) - transgene , gene silencing , biology , gene , virus , genetically modified crops , tospovirus , rna interference , microbiology and biotechnology , genetics , tomato spotted wilt virus , plant virus , rna
Summary Transgenic lettuce plants expressing the nucleocapsid (N) protein gene of the lettuce isolate of tomato spotted wilt virus (TSWV‐BL) were protected against TSWV isolates via transgenic N protein when the protein accumulated at high levels or via an N transgene silencing mechanism activated by its overexpression. In a transgenic lettuce line, post‐transcriptional gene silencing was activated at a relatively earlier developmental stage in homozygous than in hemizygous progenies. As a result, the homozygous progenies generally showed a uniform suppression of N protein accumulation and consequently high levels of virus resistance in all leaves of the silenced plants. in contrast, N protein accumulated at high levels in the lower leaves of the hemizygous progenies and at much reduced levels (due to transgene silencing) in the successive leaves, resulting in moderate levels of virus resistance. It was also observed that the timing of the N transgene silencing in both homozygous and hemizygous plants was affected by environmental factors.