Small RNA changes in synthetic Brassica napus.
Small RNAs and microRNAs were found to vary extensively in synthetic Brassica napus and subsequent generations, accompanied by the activation of transposable elements in response to hybridization and polyploidization. Resynthesizing B. napus by hybridization and chromosome doubling provides an approach to create novel polyploids and increases the usable genetic variability in oilseed rape. Although many studies have shown that small RNAs (sRNAs) act as important factor during hybridization and polyploidization in plants, much less is known on how sRNAs change in synthetic B. napus, particularly in subsequent generations after formation. We performed high-throughput sequencing of sRNAs in S1-S4 generations of synthetic B. napus and in the homozygous B. oleracea and B. rapa parent lines. We found that the number of small RNAs (sRNAs) and microRNAs (miRNAs) doubled in synthetic B. napus relative to the parents. The proportions of common sRNAs detected varied from the S1 to S4 generations, suggesting sRNAs are unstable in synthetic B. napus. The majority of miRNAs (67.2 %) were non-additively expressed in the synthesized Brassica allotetraploid, and 33.3 % of miRNAs were novel in the resynthesized B. napus. The percentage of miRNAs derived from transposable elements (TEs) also increased, indicating transposon activation and increased transposon-associated miRNA production in response to hybridization and polyploidization. The number of target genes for each miRNA in the synthesized Brassica allotetraploid was doubled relative to the parents, enhancing the complexity of gene expression regulation. The potential roles of miRNAs and their targets are discussed. Our data demonstrate generational changes in sRNAs and miRNAs in synthesized B. napus.
Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
Ying
Y
Fu
Engineering Research Center of South Upland Agriculture of Ministry of Education, College of Agronomy and Biotechnology, Southwest University, Chongqing, China.|Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Agronomy College, Jiangxi Agricultural University, Nanchang, 330045, China.
Meili
M
Xiao
Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
Huasheng
H
Yu
Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Annaliese S
AS
Mason
Engineering Research Center of South Upland Agriculture of Ministry of Education, College of Agronomy and Biotechnology, Southwest University, Chongqing, China.
Jiaming
J
Yin
Engineering Research Center of South Upland Agriculture of Ministry of Education, College of Agronomy and Biotechnology, Southwest University, Chongqing, China.
Jiana
J
Li
Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
Dongqing
D
Zhang
Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Agronomy College, Jiangxi Agricultural University, Nanchang, 330045, China. fudhui@163.com.
Donghui
D
Fu
D029688:Brassica napus / Q000235:genetics* / Q000378:metabolism; D004251:DNA Transposable Elements; D006824:Hybridization, Genetic; D035683:MicroRNAs / Q000378:metabolism*
D004251:DNA Transposable Elements; D035683:MicroRNAs
High-throughput sequencing; Polyploid; Resynthesized Brassica napus; miRNAs; sRNAs