Transcriptomic analysis of Ammopiptanthus mongolicus root
Fei Gao, Nan Liu, Zicheng Zhang, Yijun Zhou*, Jinchao Feng

College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China.
*Corresponding author：Tel: (+8610) 6893 2922; Fax: (+8610) 6893 6927; E-mail: queenzhou@263.net; zhouyijun@muc.edu.cn.

Abstract
Ammopiptanthus mongolicus, a super-xerophytic broadleaf evergreen wood, is an ecologically important foundation species in desert ecosystems and exhibits substantial drought tolerance in Mid-Asia desert. To investigate the molecular mechanism underlying the stress tolerance of Ammopiptanthus, we performed a high throughput transcriptome sequencing analysis of A. mongolicus root. A total of 672,002 sequencing reads were obtained from a 454 GS XLR70 Titanium pyrosequencer with a mean length of 279 bp. These reads were assembled into 29,056 unique sequences including 15,173 contigs and 13,883 singlets. In our assembled sequences, 1,827 potential simple sequence repeats (SSR) molecular markers were discovered. Based on sequence similarity with known plant proteins, the assembled sequences represent approximately 9,771 proteins in PlantGDB. Based on the Gene ontology (GO) analysis, hundreds of drought stress-related genes were found. We further analyzed the gene expression profiles of 27 putative genes involved in drought tolerance using quantitative real-time PCR (qRT-PCR) assay. Our sequence collection represents a major transcriptomic resource for A. mongolicus, and the large number of genetic markers predicted should contribute to future research in Ammopiptanthus genus. The potential drought stress related transcripts identified in this study provide a good start for further investigation into the drought adaptation in Ammopiptanthus.

Key Words: Ammopiptanthus mongolicus; root; drought stress