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Random RNAi Screening for Negative Regulators of Drought Resistance in Arabidopsis
Department of Plant and Soil Sciences
Many regions of the world are facing long-term droughts that threaten agricultural productivity and sustainability. The genes that are responsible for drought resistance can be divided into two general families: a family of genes that enhances drought resistance and a family of negative regulating genes whose expression will reduce drought resistance. Over-expressing positive and suppressing negative regulators will improve drought resistance.
Currently, T-DNA disruption and enhanced tagging are the two major bioengineering approaches used to dissect these drought-related genes. However, the T-DNA disruption approach cannot screen for lethal genes and the screening is time consuming. Enhanced tagging has similar drawbacks for screening lethal or toxic genes. In contrast, the RNAi approach will offer a new strategy to overcome these problems and has clear advantages.
In the proposed studies, we will generate a single-strand 21 nucleotide (nt) small RNA expression library that will cover the entire Arabidopsis genome. This small RNA expression library will be used for the large-scale transformation of Arabidopsis plants. The T0 transformants will be directly used to screen for the negative regulators of drought resistance under drought conditions. The proposed experiments are expected to establish a better approach for screening negative regulators of abiotic resistance in plants, and discover new genes that regulate drought resistance. These results will have implications for the improvement of agricultural plants growing under drought conditions.
2009 Project Description
We completed this project and conclude that the success for random RNAi in plants depends on a novel and reasonable approach for the designing of a random library. The original proposed approach must be changed for a new endeavor. We are currently working to develop a new approach to resume this project by submitting a new proposal.
1. A few approaches for random RNAi have been developed and tested for application studies;
2. trained a few students; and
3. published a few papers.
Xiaoyun Jia, Wang-Xia Wang, Ligang Ren, Qi-Jun Chen, Venugopal Mendu, Benjamin Willcut, Randy Dinkins, Xiaoqing Tang, and Guiliang Tang (2009) Differential and dynamic regulation of miR398 and its targets in response to ABA and salt stress in Populus tremula and Arabidopsis thaliana. Plant Molecular Biology 71: 51-59.
Xiaoyun Jia, Ligang Ren, Qi-Jun Chen, Runzhi Li and Guiliang Tang (2009) UV-B responsive microRNAs in Populus tremula. J. of Plant Physiology 166: 2046-2057.
Ricky Lewis, Venugopal Mendu, David McNear, and Guiliang Tang (2009) Roles of microRNAs in Plant Abiotic Stress, Molecular Techniques in Crop Improvement. 2nd Edition, edited by S. Mohan Jain and D.S. Brar. Springer Netherlands, pp 357-372.
Mian Gu, Ke Xu, Aiqun Chen, Yiyong Zhu, Guiliang Tang, and Guohua Xu (2010) Expression Analysis Suggests Potential Roles of microRNAs for Phosphate and Arbuscular Mycorrhizal Signaling in Solanum lycopersicum. Physiol Plant.138(2):226-37.
Xiaoyun Jia, Venugopal Mendu, and Guiliang Tang (2010) An array platform for identification of stress-responsive miRNAs in plants, "Methods in Molecular Biology; Plant Stress Tolerance- Methods and Protocols" edited by Ramanjulu Sunkar, Oklohoma State University, Stillwater, OK, USA. HUMANA PRESS.