Comprehensive analysis of GIR family genes and characterization of their expression profiles during cotton fiber development

Authors: FENG, XIAOXU - Chinese Academy Of Agricultural Sciences; CHENG, HAILIANG - Chinese Academy Of Agricultural Sciences; ZUO, DONGYUN - Chinese Academy Of Agricultural Sciences; ZHANG, YOUPING - Chinese Academy Of Agricultural Sciences; WANG, QIAOLIAN - Chinese Academy Of Agricultural Sciences; LU, LIMIN - Chinese Academy Of Agricultural Sciences; LI, SHUYAN - Chinese Academy Of Agricultural Sciences; Yu, John; SONG, GUOLI - Chinese Academy Of Agricultural Sciences

Submitted to: Planta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2021
Publication Date: 12/19/2021
Citation: Feng, X., Cheng, H., Zuo, D., Zhang, Y., Wang, Q., Lu, L., Li, S., Yu, J., Song, G. 2021. Comprehensive analysis of GIR family genes and characterization of their expression profiles during cotton fiber development. Planta. 255. Article 23. https://doi.org/10.1007/s00425-021-03737-7.
DOI: https://doi.org/10.1007/s00425-021-03737-7

Interpretive Summary: Cotton is the most important crop that produces natural fiber for the textile industry. Genetic improvement of fiber yield and quality continues to be effective, but it requires understanding of specific genetic mechanisms for successful cotton breeding programs. Cotton fibers share many similarities with arabidopsis trichomes and root hairs, which provide a framework for investigating fiber initiation and elongation in cotton. In this study, sets of arabidopsis genes were identified and analyzed in cotton genomes. These regulatory genes belong to the group called GL2-interacting repressors (GIRs). Variation in gene sequences and expression levels was observed and the impact on fiber development was assessed in both diploid and tetraploid cottons. One of the genes, named GaFzl in diploid cotton Gossypium arboreum, appeared to code for a nuclear-membrane protein with strong self-activating effect. This gene and other GIR members may play a desired role in cotton fiber development. The expression files of these genes lead to our understanding in their potential exploitation for improved fiber yeild and quality.

Technical Abstract: Cotton fiber development shares similar formation of Arabidopsis thaliana trichomes and root hairs. GL2-interacting-repressors (GIRs) in A. thaliana were identified during the development of root hairs. However, understanding of the GIR genes in cotton remained elusive and specific information was needed for cotton fiber improvement. In this study, 21 GIR family genes were identified from diploid cotton Gossypium arboreum, and they were characterized for phylogenetic relationship, gene structure, chromosome distribution, and evolutionary dynamics. Most GIR family genes were not differentially expressed between a wild type and a fuzzless mutant of cotton. One of the family members, Ga08G0121, previously reported as GaFzl, exhibited significant accumulated expression in the isogenic line DPL972 at fiber and fuzz initiation stages. Further investigation on the GaFzl gene revealed remarkable expression patterns in G. arboreum although the expression level of GaFzl in tetraploid cotton G. hirsutum did not show any noticeable difference. The change of GaFzl expression in G. arboreum did not alter any expression pattern of other known fiber-associated genes. These expression patterns revealed that the regulatory pathway of fuzz initiation and development in G. arboreum was distinguished from that in G. hirsutum. Changes to gene sequences and expression levels of 21 GIR family members may have impact on fiber and fuzz development. GaFzl appears to code for a nuclear-membrane protein that is a truncated transcription factor or transcriptional activity domain. GaFzl and GIR family may function at the downstream of the MYB-bHLH-WD complex to control fiber and fuzz development. The study enhances our understanding of the GIR family genes for genetic improvement of cotton fiber.