Gene Disruption of an Arabinofuranosidase/β-Xylosidase Precursor DecreasesSclerotinia sclerotiorumVirulence on Canola Tissue

Abstract

Although Sclerotinia sclerotiorum (Lib.) de Bary has been studied extensively, there are still aspects of this important phytopathogen's ability to cause disease in susceptible plants that remain unclear. A recent comprehensive proteome-level investigation of this fungus identified a number of proteins whose functions in disease initiation and progression have not been clearly established. Included among these proteins was an arabinofuranosidase/beta-xylosidase precursor whose role as a potential virulence factor had not been investigated previously. This article describes the generation of gene-disrupted mutant S. sclerotiorum unable to produce this arabinofuranosidase/beta-xylosidase precursor as well as the comparison of the virulence of this mutant with that of wild-type mycelia on susceptible canola leaves and stems. At all time points tested, the degree of necrosis was observed to be significantly greater on the plant tissue inoculated with wild-type mycelia. To our knowledge, this is the first report that clearly demonstrates that this arabinofuranosidase/beta-xylosidase precursor is a virulence factor for S. sclerotiorum.

Plant Surface Cues Prime Ustilago maydis for Biotrophic Development

“…While filament and appressorium formation were not affected by the triple deletion (Figure 3B and C), appressoria of the mutant strain had a reduced penetration efficiency on maize plants (Figure 3D), which most likely explains the reduced virulence. In Sclerotinia sclerotiorum a GH54 arabinofuranosidase, Ssaxp, is required for full virulence on canola plants [63] and in M. oryzae a GH51 as well as a GH62 enzyme are induced during appressorium formation [12]. We consider it likely that also in those fungi arabinofuranosidases are involved in the plant penetration process.…”

Deficiency of the melanin biosynthesis genes SCD1 and THR1 affects sclerotial development and vegetative growth, but not pathogenicity, in Sclerotinia sclerotiorum

“…Thus, the efficiency of gene replacement will be improved because only transformants that contain the two successfully integrated overlapping marker fragments will grow on selective media. In this study, we obtained a gene knockout efficiency of 50% for SCD1 and 63% for THR1 , similar to the efficiencies obtained from other studies (Feng et al ., ; Yajima et al ., ).…”

“…The primer pair ACT1F/ACT1R was used for Actin amplification as the reference control. In addition, extracted total RNA was also used directly as a template to avoid the false positive caused by DNA contamination (Yajima et al, 2009).…”

Transcriptome analysis of the plant pathogen Sclerotinia sclerotiorum interaction with resistant and susceptible canola (Brassica napus) lines

“…S. sclerotiorum is known to produce several pectinases, including both endo-(Sspg1, Sspg3, Sspg5, and Sspg6) and exo-(Ssxpg1 and Ssxpg2) polygalacturonases [9]. Apart from polygalacturonases, gene disruption mutants of an arabinofuranosidase/β-xylosidase precursor (Ssaxp) and an endo-β-1, 4-xylanase (SsXyl1) showed either reduction or loss of virulence, indicating their importance as virulence factors [10,11].…”