Plants are sessile organisms that must gauge stressful conditions to ensure survival and reproductive success. In nature, plants often encounter chronic or recurring abiotic stresses, such as heat stress, although the strategies to cope with high temperature are poorly understood in woody plants. In a recent study, researchers from Zhejiang Agriculture and Forestry University investigated the potential roles of microRNAs (miRNAs) in heat stress response in Betula luminifera.

Using next-generation deep sequencing, they identified a total of 206 miRNAs, comprising 115 known and 84 novel miRNAs, and seven potential miRNA candidates. Of these miRNAs, 98 (57 known and 41 novel miRNAs) were differentially expressed under heat stress. A total of 101 miRNA-target pairs consisting of 44 miRNAs and 71 target genes were verified by degradome sequencing. Target annotation suggested that these miRNAs might be important in the regulation of specific stress-responsive genes, including many transcription factors and a series of genes encoding important enzymes of functional proteins targeted by miRNAs.

 

Further functional analysis suggested these target genes were related to protein synthesis, transport and turnover, cell wall organization, protein folding, antioxidation, defense response, and modulation of attenuated plant growth and development under heat stress. The expression patterns of 15 randomly selected miRNAs derived from quantitative reverse transcription PCR had similar trends as those derived from high-throughput sequencing, as well as the expression patterns of six target genes under heat stress.

These results improve our understanding of the miRNA-mediated regulatory network of heat stress response in B. luminifera, which will contribute to improving heat stress-resistant breeding in woody plants.

 

Reference
Y. Pan, M. Niu, J. Liang, E. Lin, Z. Tong, J. Zhang (2017) Identification of heat-responsive miRNAs to reveal the miRNA-mediated regulatory network of heat stress response in Betula luminifera Trees doi: 10.1007/s00468-017-1575-x [abstract]

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