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Identification and characterisation of a previously unknown drought tolerance‐associated micro RNA in barley
Author(s) -
Zhou Hui,
Hussain Syed S.,
Hackenberg Michael,
Bazanova Natalia,
Eini Omid,
Li Jie,
Gustafson Perry,
Shi Bujun
Publication year - 2018
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13938
Subject(s) - biology , gene , promoter , transcription (linguistics) , tata box , transcription factor , transgene , genetics , microbiology and biotechnology , gene expression , linguistics , philosophy
Summary Drought is the most serious abiotic stress, and causes crop losses on a worldwide scale. The present study identified a previously unknown micro RNA (designated as hvu‐mi RX ) of 21 nucleotides (nt) in length in barley. Its precursor (designated pre‐mi RX ) and primary transcript (designated pri‐mi RX ) were also identified, with lengths of 73 and 559 nt, respectively. The identified upstream sequence of pri‐mi RX contained both the TATA box and the CAAT box, which are both required for initiation of transcription. Transient promoter activation assays showed that the core promoter region of pri‐mi RX ranged 500 nt from the transcription start site. In transgenic barley overexpression of the wheat DREB 3 transcription factor (Ta DREB 3) caused hvu‐mi RX to be highly expressed as compared with the same mi RNA in non‐transgenic barley. However, the high expression was not directly associated with Ta DREB 3. Genomic analysis revealed that the hvu‐mi RX gene was a single copy located on the short arm of chromosome 2 and appeared to be only conserved in Triticeae, but not in other plant species. Notably, transgenic barley that overexpressed hvu‐mi RX showed drought tolerance. Degradome library analysis and other tests showed that hvu‐mi RX targeted various genes including transcription factors via the cleavage mode. Our data provides an excellent opportunity to develop drought stress tolerant cereals using hvu‐mi RX .