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Parental transposable element loads influence their dynamics in young Nicotiana hybrids and allotetraploids
Author(s) -
Mhiri Corinne,
Parisod Christian,
Daniel Julien,
Petit Maud,
Lim K. Yoong,
Dorlhac de Borne François,
Kovarik Ales,
Leitch Andrew R.,
Grandbastien MarieAngèle
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15484
Subject(s) - transposable element , biology , ploidy , genome , genetics , genome evolution , plant evolution , evolutionary biology , gene
Summary The genomic shock hypothesis suggests that allopolyploidy is associated with genome changes driven by transposable elements, as a response to imbalances between parental insertion loads. To explore this hypothesis, we compared three allotetraploids, Nicotiana arentsii , N. rustica and N. tabacum , which arose over comparable time frames from hybridisation between increasingly divergent diploid species. We used sequence‐specific amplification polymorphism (SSAP) to compare the dynamics of six transposable elements in these allopolyploids, their diploid progenitors and in corresponding synthetic hybrids. We show that element‐specific dynamics in young Nicotiana allopolyploids reflect their dynamics in diploid progenitors. Transposable element mobilisation is not concomitant with immediate genome merger, but occurs within the first generations of allopolyploid formation. In natural allopolyploids, such mobilisations correlate with imbalances in the repeat profile of the parental species, which increases with their genetic divergence. Other restructuring leading to locus loss is immediate, nonrandom and targeted at specific subgenomes, independently of cross orientation. The correlation between transposable element mobilisation in allopolyploids and quantitative imbalances in parental transposable element loads supports the genome shock hypothesis proposed by McClintock.