Expression analysis of miRNAs and highly-expressed small RNAs in two rice subspecies and their reciprocal hybrids.
Heterosis, or hybrid vigor, is the phenomenon whereby progeny of two inbred lines exhibit superior agronomic performance compared with either parent. We analyzed the expression of miRNAs and highly expressed small RNAs (defined according to Solexa sequencing results) in two rice (Oryza sativa) subspecies (japonica cv. Nipponbare and indica cv. 93-11) and their reciprocal hybrids using microarrays. We found that of all the 1141 small RNAs tested, 140 (12%, 140 of 1141) and 157 (13%, 157 of 1141) were identified being significantly differentially expressed in two reciprocal hybrids, respectively. All possible modes of action, including additive, high- and low- parent, above high- and below low-parent modes were exhibited. Both F1 hybrids showed non-additive expression patterns, with downregulation predominating. Interestingly, 15 miRNAs displayed stark opposite expression trends relative to mid-parent in reciprocal hybrids. Computational prediction of targets of differentially expressed miRNAs showed that they participated in multifaceted developmental pathways, and were not distinguishable from the targets of non-differentially expressed miRNAs. Together, our findings reveal that small RNAs play roles in heterosis and add a new layer in the understanding and exploitation of molecular mechanisms of heterosis.
Chen
Fangfang
F
Graduate Program in Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
He
Guangming
G
He
Hang
H
Chen
Wei
W
Zhu
Xiaopeng
X
Liang
Manzhong
M
Chen
Liangbi
L
Deng
Xing Wang
XW
D003433:Crosses, Genetic; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D006823:Hybrid Vigor / Q000235:genetics; D006824:Hybridization, Genetic; D053858:Metabolic Networks and Pathways / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D012275:Oryza / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics* / Q000378:metabolism; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity
D035683:MicroRNAs; D018749:RNA, Plant