Transposable elements(TEs)usually occupy largest fractions of plant genome and are also the most variable part of the structure.Although traditionally it is hallmarked as"junk and selfish DNA",today more and...Transposable elements(TEs)usually occupy largest fractions of plant genome and are also the most variable part of the structure.Although traditionally it is hallmarked as"junk and selfish DNA",today more and more evidence points out TE’s participation in gene regulations including gene mutation,duplication,movement and novel gene creation via genetic and epigenetic mechanisms.The recently sequenced genomes of diploid cottons Gossypium arboreum(AA)and Gossypium raimondii(DD)together with their allotetraploid progeny Gossypium hirsutum(At At Dt Dt)provides a unique opportunity to compare genome variations in the Gossypium genus and to analyze the functions of TEs during its evolution.TEs accounted for 57%,68.5%and67.2%,respectively in DD,AA and At At Dt Dt genomes.The 1,694 Mb A-genome was found to harbor more LTR(long terminal repeat)-type retrotransposons that made cardinal contributions to the twofold increase in its genome size after evolution from the 775.2 Mb D-genome.Although the 2,173 Mb At At Dt Dt genome showed similar TE content to the A-genome,the total numbers of LTR-gypsy and LTR-copia type TEs varied significantly between these two genomes.Considering their roles on rewiring gene regulatory networks,we believe that TEs may somehow be involved in cotton fiber cell development.Indeed,the insertion or deletion of different TEs in the upstream region of two important transcription factor genes in At or Dt subgenomes resulted in qualitative differences in target gene expression.We suggest that our findings may open a window for improving cotton agronomic traits by editing TE activities.展开更多
基金the National Natural Science Foundation of China(90717009)the Chinese National Basic Research Program of the Ministry of Science and Technology of China(2010CB126000)
文摘Transposable elements(TEs)usually occupy largest fractions of plant genome and are also the most variable part of the structure.Although traditionally it is hallmarked as"junk and selfish DNA",today more and more evidence points out TE’s participation in gene regulations including gene mutation,duplication,movement and novel gene creation via genetic and epigenetic mechanisms.The recently sequenced genomes of diploid cottons Gossypium arboreum(AA)and Gossypium raimondii(DD)together with their allotetraploid progeny Gossypium hirsutum(At At Dt Dt)provides a unique opportunity to compare genome variations in the Gossypium genus and to analyze the functions of TEs during its evolution.TEs accounted for 57%,68.5%and67.2%,respectively in DD,AA and At At Dt Dt genomes.The 1,694 Mb A-genome was found to harbor more LTR(long terminal repeat)-type retrotransposons that made cardinal contributions to the twofold increase in its genome size after evolution from the 775.2 Mb D-genome.Although the 2,173 Mb At At Dt Dt genome showed similar TE content to the A-genome,the total numbers of LTR-gypsy and LTR-copia type TEs varied significantly between these two genomes.Considering their roles on rewiring gene regulatory networks,we believe that TEs may somehow be involved in cotton fiber cell development.Indeed,the insertion or deletion of different TEs in the upstream region of two important transcription factor genes in At or Dt subgenomes resulted in qualitative differences in target gene expression.We suggest that our findings may open a window for improving cotton agronomic traits by editing TE activities.
