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Sequence and functional analysis of MIR319 promoter homologs from Brassica juncea reveals regulatory diversification and altered expression under stress
Key message Extensive regulatory divergence during development, abiotic stress and ABA regime observed amongst promoter homologs and homeologs of MIR319 from Brassica juncea . Gene duplication followed by sub-functionalization, neo-functionalization, and pseudogenization are routes to functional and...
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Published in: | Molecular genetics and genomics : MGG 2021-05, Vol.296 (3), p.731-749 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Key message
Extensive regulatory divergence during development, abiotic stress and ABA regime observed amongst promoter homologs and homeologs of
MIR319
from
Brassica juncea
.
Gene duplication followed by sub-functionalization, neo-functionalization, and pseudogenization are routes to functional and adaptive diversification. The influence of polyploidy on protein-coding genes is well investigated but little is known about their impact on transcriptional regulation of
MIRNA
gene family. The present study was therefore performed with an aim to uncover regulatory diversification of
MIR319
homologs and homeologs in
Brassica juncea.
We employed comparative genomics to identify and isolate six promoter homologs of
MIR319
from
B. juncea
. Regulatory diversification was studied using analysis of reporter activity driven by
BjMIR319
promoters in a heterologous system employing promoter–reporter fusion constructs.
MIR319
is known to play important roles in leaf and flower development, and multiple stress responses. Reporter activity was therefore monitored during development, hormonal and stress regimes. In-silico analyses revealed differential distribution of
cis
-regulatory motifs and functional analysis revealed distinct spatiotemporal expression patterns. The significance of presence of selected
cis
-regulatory motifs corresponding to heat, cold, salt and ABA stress were further functionally validated. It was observed that promoter of
Bj
-MIR319a-A01 was upregulated in response to cold and salt stress, while promoter of
Bj
-MIR319c-A04 (D1) and
Bj
-MIR319c-A05 (FL) were downregulated in response to high temperature. In summary, comparative analysis of homologous promoters from
Brassica juncea
, an allopolyploid revealed extensive sequence and functional diversity. Spatiotemporal activity of reporter gene driven by
BjMIR319
promoter was distinct, and partially overlapping with from those reported previously for
A. thaliana
. The present study clearly demonstrates regulatory divergence amongst promoter homologs of
MIR319
in
Brassica juncea
during development and stress response, and underlines the urgent need for dissection of promoter function and detailed characterization including identification of interacting
trans-
factors.
Genbank accession numbers
: MT379853-MT379858. |
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ISSN: | 1617-4615 1617-4623 |
DOI: | 10.1007/s00438-021-01778-x |