Multi-responses of O-methyltransferase genes to salt stress and fiber development of Gossypium species

Background O-methyltransferases (OMTs) are an important group of enzymes that catalyze the transfer of a methyl group from S-adenosyl-L-methionine to their acceptor substrates. OMTs are divided into several groups according to their structural features. In Gossypium species, they are involved in phenolics and flavonoid pathways. Phenolics defend the cellulose fiber from dreadful external conditions of biotic and abiotic stresses, promoting strength and growth of plant cell wall. Results An OMT gene family, containing a total of 192 members, has been identified and characterized in three main Gossypium species, G. hirsutum, G. arboreum and G. raimondii. Cis-regulatory elements analysis suggested important roles of OMT genes in growth, development, and defense against stresses. Transcriptome data of different fiber developmental stages in Chromosome Substitution Segment Lines (CSSLs), Recombination Inbred Lines (RILs) with excellent fiber quality, and standard genetic cotton cultivar TM-1 demonstrate that up-regulation of OMT genes at different fiber developmental stages, and abiotic stress treatments have some significant correlations with fiber quality formation, and with salt stress response. Quantitative RT-PCR results revealed that GhOMT10_Dt and GhOMT70_At genes had a specific expression in response to salt stress while GhOMT49_At, GhOMT49_Dt, and GhOMT48_At in fiber elongation and secondary cell wall stages. Conclusions Our results indicate that O-methyltransferase genes have multi-responses to salt stress and fiber development in Gossypium species and that they may contribute to salt tolerance or fiber quality formation in Gossypium.

Automated summary

O-methyltransferases (OMTs) in Gossypium species play important roles in phenolics and flavonoid pathways, defending cellulose fiber and promoting plant cell wall strength and growth. Analysis of a 192-member OMT gene family in G. hirsutum, G. arboreum, and G. raimondii reveals their involvement in growth, development, defense against stresses, and their correlations with fiber quality and salt stress response. Specific OMT genes show responses to salt stress and fiber development stages, suggesting their potential contributions to salt tolerance and fiber quality formation in Gossypium.