Comprehensive Analysis of Respiratory Burst Oxidase Homologs (Rboh) Gene Family and Function of GbRboh5/18 on Verticillium Wilt Resistance in Gossypium barbadense

Abstract

Respiratory burst oxidase homologs (Rbohs) play a predominant role in reactive oxygen species (ROS) production, which is crucial in plant growth, differentiation, as well as their responses to biotic and abiotic stresses. To date, however, there is little knowledge about the function of cotton Rboh genes. Here, we identified a total of 87 Rbohs from five sequenced Gossypium species (the diploids Gossypium arboreum, Gossypium raimondii, and Gossypium australe, and the allotetraploids Gossypium hirsutum and Gossypium barbadense) via BLAST searching their genomes. Phylogenetic analysis of the putative 87 cotton Rbohs revealed that they were divided into seven clades. All members within the same clade are generally similar to each other in terms of gene structure and conserved domain arrangement. In G. barbadense, the expression levels of GbRbohs in the CladeD were induced in response to a fungal pathogen and to hormones (i.e., jasmonic acid and abscisic acid), based upon which the main functional member in CladeD was discerned to be GbRboh5/18. Further functional and physiological analyses showed that the knock-down of GbRboh5/18 expression attenuates plant resistance to Verticillium dahliae infection. Combined with the molecular and biochemical analyses, we found less ROS accumulation in GbRboh5/18-VIGS plants than in control plants after V. dahliae infection. Overexpression of GbRboh5/18 in G. barbadense resulted in more ROS accumulation than in control plants. These results suggest that GbRboh5/18 enhances the cotton plants' resistance against V. dahliae by elevating the levels of ROS accumulation. By integrating phylogenetic, molecular, and biochemical approaches, this comprehensive study provides a detailed overview of the number, phylogeny, and evolution of the Rboh gene family from five sequenced

Glutathione Metabolism in Plants under Stress: Beyond Reactive Oxygen Species Detoxification

“…Successive reduction reactions from O 2 can lead to the production of O 2 ●− , (superoxide radical), H 2 O 2 (hydrogen peroxide) and • OH (hydroxyl radical) [ 34 , 38 ]. Plant cells also possess Ca 2+ -regulated Respiratory Burst Oxidase Homologs (RBOHs) at the plasma membrane [ 39 , 40 ] ( Figure 1 ). These enzymes use intracellular NADPH to reduce O 2 to O 2 ●− in the apoplastic space.…”

“…After dismutation, O 2 ●− generates the more stable H 2 O 2 . The activity of this pathway is strongly associated with plant response to pathogens and their effectors [ 39 , 40 , 41 ]. Other important sources of ROS can be found in the glyoxysome and the peroxisome ( Figure 1 ).…”

The Respiratory Burst Oxidase Homolog Protein D (GhRbohD) Positively Regulates the Cotton Resistance to Verticillium dahliae

“…To analyze the exon-intron distributions of the Rbohs gene, the gene structure display server (GSDS) was utilized. Next, conserved motifs were predicted using the MEME9 tool [ 44 ]. The positional information of a given cotton Rbohs was obtained from parsed general feature format (GFF) files, and downloaded from the Cotton Gene website.…”

Calcium-Dependent Protein Kinase GhCDPK28 Was Dentified and Involved in Verticillium Wilt Resistance in Cotton

“…ClustalX 2.0 was used to compare the amino acid sequences of CDPKs identified in cotton and Arabidopsis . After conducting a model test, MEGAX software was used to construct the maximum likelihood (ML) phylogenetic tree with the best substitution model ( Chang et al, 2020 ).…”