Transcriptome analysis of Ammopiptanthus mongolicus root under drought stress
Total RNA extraction, mRNA purification, and cDNA library construction were conducted by LC Sciences (Houston, TX, USA). In brief, total RNA was obtained from roots using the total RNA purification kit (LC Sciences, Houston, TX, USA) as instructed, treated with RNAase free DNAase, and re-purified with the RNeasy kit (Qiagen, Valencia, CA, USA) following the manufacturer’s protocol. Equal quantity of RNA from both CK and T samples were blended for cDNA library construction.     cDNA synthesis was performed using SMART II™ cDNA Synthesis kit (Clontech Laboratories, Inc., Mountain View, CA, USA) following manufacturer’s recommendations. Double stranded cDNA was separated on a 2% agarose gel, and the cDNA with a length no less than 100 bp was separated by gel extraction. The concentration of cDNA was determined using Bioanalyzer 2100 (Agilent Technologies, Inc. Waldbronn, Germany). Approximately 5 µg of cDNA sample was sheared via sonication into small fragments, and then Roche GS-FLX 454 pyrosequencing was conducted according to the manufacturer’s recommendations.