title: Selection of Reliable Reference Genes for Gene Expression Analysis under Abiotic Stresses in the Desert Biomass Willow,Salix psammophila.
abstract: Salix psammophilais a desert shrub willow that has extraordinary adaptation to abiotic stresses and plays an important role in maintaining local ecosystems. Moreover,S. psammophilais regarded as a promising biomass feedstock because of its high biomass yields and short rotation coppice cycle. However, few suitable reference genes (RGs) for quantitative real-time polymerase chain reaction (qRT-PCR) constrain the study on normalization of gene expression inS. psammophilauntil now. Here, we investigated the expression stabilities of 14 candidate RGs across tissue types and under four abiotic stress treatments, including heat, cold, salt, and drought treatments. After calculation of PCR efficiencies, three different software, NormFinder, geNorm, and BestKeeper were employed to analyze systematically the qRT-PCR data, and the outputs were merged by RankAggreg software. The optimal RGs selected for gene expression analysis wereEF1α (Elongation factor-1 alpha) andOTU(OTU-like cysteine protease family protein) for different tissue types,UBC(Ubiquitin-conjugating enzyme E2) andLTA4H(Leukotriene A-4 hydrolase homolog) for heat treatment,HIS(Histone superfamily protein H3) andARF2(ADP-ribosylation factor 2) for cold treatment,OTUandACT7(Actin 7) for salt treatment,UBCandLTA4Hfor drought treatment. The expression ofUBC,ARF2, andVHAC(V-type proton ATPase subunit C) varied the least across tissue types and under abiotic stresses. Furthermore, the relative genes expression profiles of one tissue-specific geneWOX1a(WUSCHEL-related homeobox 1a), and four stress-inducible genes, includingHsf-A2(Heat shock transcription factors A2),CBF3(C-repeat binding factor 3),HKT1(High-Affinity K+Transporter 1), andGST(Glutathione S-transferase), were conducted to confirm the validity of the RGs in this study. These results provided an important RGs application guideline for gene expression characterization inS. psammophila.
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry Beijing, China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of ForestryBeijing, China; Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry UniversityNanjing, China.
authors.forename: Huixia
authors.initials: H
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry Beijing, China.
authors.forename: Xiaojiao
authors.initials: X
authors.lastname: Han
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry Beijing, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry Beijing, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of ForestryBeijing, China; Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry UniversityNanjing, China.
authors.forename: Mengzhu
authors.initials: M
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of ForestryBeijing, China; Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry UniversityNanjing, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Hu
keywords: Salix psammophila; abiotic stresses; quantitative real-time PCR; reference genes; tissue types