Multi-omics analysis reveals a link between Brassica -specific miR1885
and rapeseed tolerance to low temperature
Abstract
Brassica crops include various edible vegetable and plant oil
crops, and their production is limited by low temperature. The key
regulators of low-temperature resistance in Brassica remain
largely unexplored. To identify post-transcriptional regulators of plant
response to low temperature, we performed small RNA profiling, and found
that 16 known miRNAs responded to cold treatment in Brassica
rapa. The cold response of seven of those miRNAs were further confirmed
by qRT-PCR and/or northern blotting analyses. In parallel, a genome-wide
association study of 220 accessions of Brassica napus identified
four candidate MIRNA genes, all of which were cold-responsive, at the
loci associated with low temperature resistance. Specifically, these
large-scale data analyses revealed a link between miR1885 and the plant
response to low temperature in both B. rapa and B. napus.
Using 5′ rapid amplification of cDNA ends approach, we validated that
miR1885 can cleave its putative target gene transcripts,
Bn.TIR.A09 and Bn.TNL.A03, in B. napus.
Furthermore, overexpression of miR1885 in B. napus decreased the
mRNA abundance of Bn.TIR.A09 and Bn.TNL.A03 and resulted
in increased sensitivity to low temperature. Knocking down of miR1885 in
B. napus led to increased mRNA abundance of its targets and
improved rapeseed tolerance to low temperature. Together, our results
suggested that the loci of miR1885 and its targets could be potential
candidates for the molecular breeding of low temperature-tolerant
Brassica crops.