Stress-responsive microRNAs in Populus
Article first published online: 28 JUN 2008
© 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd
The Plant Journal
Volume 55, Issue 1, pages 131–151, July 2008
How to Cite
Lu, S., Sun, Y.-H. and Chiang, V. L. (2008), Stress-responsive microRNAs in Populus. The Plant Journal, 55: 131–151. doi: 10.1111/j.1365-313X.2008.03497.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Received 8 January 2008; revised 29 February 2008; accepted 11 March 2008; published online 19 May 2008.
- Populus trichocarpa;
- abiotic stress;
- cold stress;
MicroRNAs (miRNAs), a group of small non-coding RNAs, have recently become the subject of intense study. They are a class of post-transcriptional negative regulators playing vital roles in plant development and growth. However, little is known about their regulatory roles in the responses of trees to the stressful environments incurred over their long-term growth. Here, we report the cloning of small RNAs from abiotic stressed tissues of Populus trichocarpa (Ptc) and the identification of 68 putative miRNA sequences that can be classified into 27 families based on sequence homology. Among them, nine families are novel, increasing the number of the known Ptc-miRNA families from 33 to 42. A total of 346 targets was predicted for the cloned Ptc-miRNAs using penalty scores of ≤2.5 for mismatched patterns in the miRNA:mRNA duplexes as the criterion. Six of the selected targets were validated experimentally. The expression of a majority of the novel miRNAs was altered in response to cold, heat, salt, dehydration, and mechanical stresses. Microarray analysis of known Ptc-miRNAs identified 19 additional cold stress-responsive Ptc-miRNAs from 14 miRNA gene families. Interestingly, we found that individual miRNAs of a family responded differentially to stress, which suggests that the members of a family may have different functions. These results reveal possible roles for miRNAs in the regulatory networks associated with the long-term growth of tree species and provide useful information for developing trees with a greater level of stress resistance.