Transcriptome sequencing and whole genome expression profiling of chrysanthemum under dehydration stress.
BACKGROUND
Chrysanthemum is one of the most important ornamental crops in the world and drought stress seriously limits its production and distribution. In order to generate a functional genomics resource and obtain a deeper understanding of the molecular mechanisms regarding chrysanthemum responses to dehydration stress, we performed large-scale transcriptome sequencing of chrysanthemum plants under dehydration stress using the Illumina sequencing technology.


RESULTS
Two cDNA libraries constructed from mRNAs of control and dehydration-treated seedlings were sequenced by Illumina technology. A total of more than 100 million reads were generated and de novo assembled into 98,180 unique transcripts which were further extensively annotated by comparing their sequencing to different protein databases. Biochemical pathways were predicted from these transcript sequences. Furthermore, we performed gene expression profiling analysis upon dehydration treatment in chrysanthemum and identified 8,558 dehydration-responsive unique transcripts, including 307 transcription factors and 229 protein kinases and many well-known stress responsive genes. Gene ontology (GO) term enrichment and biochemical pathway analyses showed that dehydration stress caused changes in hormone response, secondary and amino acid metabolism, and light and photoperiod response. These findings suggest that drought tolerance of chrysanthemum plants may be related to the regulation of hormone biosynthesis and signaling, reduction of oxidative damage, stabilization of cell proteins and structures, and maintenance of energy and carbon supply.


CONCLUSIONS
Our transcriptome sequences can provide a valuable resource for chrysanthemum breeding and research and novel insights into chrysanthemum responses to dehydration stress and offer candidate genes or markers that can be used to guide future studies attempting to breed drought tolerant chrysanthemum cultivars.
Department of Ornamental Horticulture, China Agricultural University, Beijing 100193, China. hongbo1203@163.com.
Yanjie
Y
Xu
Shan
S
Gao
Yingjie
Y
Yang
Mingyun
M
Huang
Lina
L
Cheng
Qian
Q
Wei
Zhangjun
Z
Fei
Junping
J
Gao
Bo
B
Hong
D000040:Abscisic Acid / Q000096:biosynthesis; D001483:Base Sequence; D053898:Biosynthetic Pathways / Q000235:genetics; D031202:Chrysanthemum / Q000201:enzymology / Q000235:genetics* / Q000502:physiology*; D030541:Databases, Genetic; D003681:Dehydration; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant / Q000235:genetics*; D058977:Molecular Sequence Annotation; D011392:Proline / Q000096:biosynthesis; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism; D059467:Transcriptome / Q000235:genetics*
D012333:RNA, Messenger; D014157:Transcription Factors; D000040:Abscisic Acid; D011392:Proline; D011494:Protein Kinases