Author(s)

Qing Miao¹, Peng Deng², Sukumar Saha³, Johnie N. Jenkins³, Chuan-Yu Hsu⁴, Ibrokhim Y. Abdurakhmonov⁵, Zabardast T. Buriev⁵, Alan Pepper⁶, Din-Pow Ma^1*

¹Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS, USA.
²Department of Pharmacology, Weill Cornell Medical College, New York, NY, USA.
³USDA-ARS, Crop Science Research Laboratory, Mississippi State, MS, USA.
⁴Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS, USA.
⁵Center of Genomics and Bioinformatics, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan.
⁶Department of Biology, Texas A & M University, College Station, TX, USA.

Silencing phytochrome A1 gene (PHYA1) by RNA interference in Upland cotton (Gossypium hirsutum L. cv. Coker 312) had generated PHYA1 RNAi lines with improved fiber quality (longer, stronger and finer fiber). To reveal molecular mechanisms that govern fiber development with positive fiber traits, a study of global gene expression profiling of 10-DPA fibers in a PHYA1 RNAi line and its parent Coker 312 was conducted by high-throughput RNA sequencing. A comparative analysis of transcriptomes between the two lines had identified 142 genes that were differentially expressed in the 10-DPA fiber of the RNAi line. Gene Ontology analysis showed that these differentially expressed genes were mainly involved in metabolic pathways, heterocyclic/organic cyclic compound binding and multiple enzyme activities, and cell structures which were reported to play important roles in fiber development. Twenty-eight KEGG pathways were mapped for the 142 genes, and the pathways related to glycolysis/gluconeogenesis and pyruvate metabolism were the most abundant and followed by cytochrome P450-involved pathways, suggesting that fiber improvement could be through the regulation of proteins involved in cytochrome P450 pathways. Genes encoding WRKY transcription factors, sucrose synthase, xyloglucan endotransglucosylase hydrolase, udp-glucuronate: xylan alpha-glucuronosyltransferase, and genes involved in lipid metabolism and ABA/brassinosteroid signal transduction pathways were found differentially expressed in the RNAi line. These genes have direct impacts on cotton fiber quality. The results of this study elucidate molecular signatures and possible mechanisms of fiber improvement in the background of PHYA1 RNAi in cotton and should help for future fine-tuning and programming of cotton fiber development.

Fiber Development, Phytochrome A1, RNA Interference, RNA-Seq, Transcriptome

Miao, Q. , Deng, P. , Saha, S. , Jenkins, J. , Hsu, C. , Abdurakhmonov, I. , Buriev, Z. , Pepper, A. and Ma, D. (2017) Transcriptome Analysis of Ten-DPA Fiber in an Upland Cotton (Gossypium hirsutum) Line with Improved Fiber Traits from Phytochrome A1 RNAi Plants. American Journal of Plant Sciences, 8, 2530-2553. doi: 10.4236/ajps.2017.810172.