Vitamin B6 Is Under a Tight Balance During Disease Development by Rhizoctonia solani on Different Cultivars of Potato and on Arabidopsis thaliana Mutants

Abstract

Vitamin B6 is well recognized as an essential antioxidant and plays a role in stress responses. Co-expression of plant and pathogen-derived vitamin B6 genes is critical during disease development of R. solani. However, little is known about the functionality of vitamin B6 vitamers during plant-R. solani interactions and their involvement in disease tolerance. Here, we explored the possible involvement of vitamin B6 during disease progression of potato cultivars of different susceptibility levels to R. solani. A distinct pattern of gene expression, pyridoxine (PN) concentration, and fungal biomass was found in the susceptible cv. Russet Burbank and tolerant cv. Chieftain. Accumulation of reactive oxygen species (ROS) in R. solani mycelia or plant tissues applying non-fluorescence or fluorescence methods was related to up-regulation in the vitamin B6 pathway and is indicative of oxidative stress. Russet Burbank was susceptible to R. solani, which was linked to reduced amounts of VB6 content. Prior to infection, constitutive PN levels were significantly higher in Russet Burbank by 1.6-fold compared to Chieftain. Upon infection with R. solani, PN levels in infected tissues increased more in Chieftain (1.7-fold) compared to Russet Burbank (1.4fold). R. solani AG3 infection of potato sprouts in both cultivars significantly activates the fungal and plant vitamin B6 and glutathione-S-transferase (GST) genes in a tissuespecific response. Significant fold increases of transcript abundance of the fungal genes ranged from a minimum of 3.60 (RsolSG3GST) to a maximum of 13.91 (RsolAG3PDX2) in the surrounding necrotic lesion tissues (zone 1). On the other hand, PCA showed that the top plant genes STGST and STPDX1.1 were linked to both tissues of necrotic lesions (zone 2) and their surrounding areas of necrotic lesions. Functional characterization of Arabidopsis pdx1.3 mutants challenged with R. solani provided evidence into the role of the vitamin B6 pathway in the maintenance of plant tolerance during disease progression. Overall, we demonstrate that the production of vitamin VB6 is under tight control and is an essential determinant of disease development during the interaction of R. solani with potato cultivars.

Deciphering Aphanomyces eutieches-pea-biocontrol bacterium interactions through untargeted metabolomics

“…In our study, ve VB6 metabolites (2-Methyl-3-hydroxy-5-formylpyridine-4-carboxylic acid, 4-Pyridoxic acid, Isopyridoxal, Pyridoxamine, Pyridoxamine phosphate) levels were lower in PT compared to control, and three metabolites (4-Pyridoxic acid, Isopyridoxal, and Pyridoxamine phosphate) content were higher in PBBT relative to PT (Table 1). Similar to our study, A. solani infection resulted in 37% reduction of VB6 content in Arabidopsis (Samsatly et al 2020). VB6 contents in Arabidopsis were lower in response to Pst DC3000 or B. cinerea infection (Zhang et al 2015).…”

Natural Variation in Vitamin B1 and Vitamin B6 Contents in Rice Germplasm

“…Exogenous vitamin B 1 provision could induce expression of defense-related genes and “prime” plants for enhanced resistance upon subsequent pathogen challenge ( Ahn et al, 2005 , 2007 ; Boubakri et al, 2012 ; Huang et al, 2016 ). Mutants impaired in vitamin B 6 metabolism are hyper-sensitive to abiotic stress and are susceptible to pathogen challenge ( Vanderschuren et al, 2013 ; Zhang et al, 2015 ; Samsatly et al, 2020 ). Despite this body of evidence, relatively little is known about the molecular dialog between stress signaling and vitamin metabolism.…”

Genome analysis and hyphal movement characterization of the hitchhiker endohyphalEnterobactersp. fromRhizoctonia solani

“…En-Cren also contains homologous genes for B1 and B12 biosynthesis and transportation pathways and a gene cluster for lipopolysaccharide biosynthesis proteins, an O-antigen ligase, and glycosyltransferases. Recent studies on the function of vitamin B6 in the oxidative stress regulation and disease development of Rhizoctonia solani are also worth noting [88], [89], especially as we also identified an En-Cren unique gene related to vitamin B6 oxidation. A transcriptomic study on free-living and fungus-associated En-Cren on different nutrient media may identify differentially expressed bacterial genes for fungal surface colonization or invasion and provide more comprehensive insight into pathways involved in bacterial-fungal interactions.…”