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

Abdul Hafeez,Hǎihóng Shāng,Qí Zhāng,Muharam Ali,Wànkuí Gǒng,Yǒulù Yuán,Yùzhēn Shí,Àiyīng Liú,Ruìxián Liú,Abdul Razzaq,Muhammad S Iqbal,Xiǎoyīng Dèng,Qún Gě,Jǔwǔ Gōng,Jùnwén Lǐ

doi:10.1186/s12870-020-02786-6

Abstract

BackgroundO-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.ResultsAn 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.ConclusionsOur 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.

Highlights

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
While GhOMT33_Dt, which was identified on chromosome Dt02, coded the largest protein of 969 aa with a molecular weight of 108.296 kDa among all OMT members in three Gossypium species
The results showed that each clade of OMT genes were symmetrically distributed within Gossypium species (Fig. 2a), while in A. thaliana and T. cacao, OMT genes were identified in cluster forms (Fig. 2b)

Summary

Introduction

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. Some studies have shown that secondary cell wall of fibers of flax (Linum usitatissimum L.), ramie (Boehmeria nivea L.), and Spanish broom (Spartium junceum L.) contain phenolics along with cellulose. Their fibers are known for their physical properties such as length and strength and have been used for textile purposes. Lignin and phenolics defend the cellulose fiber against dreadful conditions and increase the ability of response to biotic and abiotic stresses, and influence the growth and strength of plant cell walls [8]. The initial OMT cDNA was described in 1991 [11], a series of OMT cDNAs have been cloned from diverse plants species, including Zea mays, Arabidopsis thaliana, Iris hollandica, and Nicotiana tabacum [12]

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