Proteomic Analysis of Rhizoctonia solani Identifies Infection-specific, Redox Associated Proteins and Insight into Adaptation to Different Plant Hosts

Abstract

Rhizoctonia solani is an important root infecting pathogen of a range of food staples worldwide including wheat, rice, maize, soybean, potato and others. Conventional resistance breeding strategies are hindered by the absence of tractable genetic resistance in any crop host. Understanding the biology and pathogenicity mechanisms of this fungus is important for addressing these disease issues, however, little is known about how R. solani causes disease. This study capitalizes on recent genomic studies by applying mass spectrometry based proteomics to identify soluble, membrane-bound and culture filtrate proteins produced under wheat infection and vegetative growth conditions. Many of the proteins found in the culture filtrate had predicted functions relating to modification of the plant cell wall, a major activity required for pathogenesis on the plant host, including a number found only under infection conditions. Other infection related proteins included a high proportion of proteins with redox associated functions and many novel proteins without functional classification. The majority of infection only proteins tested were confirmed to show transcript up-regulation during infection including a thaumatin which increased susceptibility to R. solani when expressed in Nicotiana benthamiana. In addition, analysis of expression during infection of different plant hosts highlighted how the infection strategy of this broad host range pathogen can be adapted to the particular host being encountered. Data are available via ProteomeXchange with identifier PXD002806.

Salicylic acid‐dependent immunity contributes to resistance against Rhizoctonia solani, a necrotrophic fungal agent of sheath blight, in rice and Brachypodium distachyon

“…These results suggest that R. solani probably uses the biotrophic stage in a short window of time for early infection; SA‐induced defense responses could attenuate the infection at this point to combat the disease. This result is consistent with the recent finding that R. solani expresses secreted proteinaceous effectors during infection as potential virulence factors (Zheng et al ., ; Anderson et al ., ). The JA‐induced susceptibility of B. distachyon to R. solani might be attributed to the antagonistic interaction between SA and JA, based on observations mainly in Arabidopsis (Kunkel & Brooks, ).…”

“…oryzae ( Xoo ) via the promotion of SCW reinforcement in rice, and the cesa4 rice mutant, as well as the RNAi transgenic rice lines for OsCESA4 , 7 and 9 , compromised the Xa4 ‐mediated race‐specific resistance to Xoo (Hu et al ., ). From the culture filtrates of vegetative and infection samples of R. solani AG‐8, many proteins with predicted function relating to lignin catabolism were detected, and were thought to be involved in the modification of the host cell wall (Anderson et al ., ). Therefore, SCW reinforcement might be a crucial event in SA‐induced R. solani resistance in B. distachyon .…”

Optimization of CTAB-based RNA Extraction for in planta Fusarium oxysporum f. sp. cubense Gene Expression Study

“…Fusarium-specific endogenous control, translation elongation factor 1α (FoTEF1α) was successfully quantified in cDNA synthesised from RNA for both LiCl- precipitated Foc and infected root samples ( Figure 6(d)). Using our method, PCR amplification of FoTEF1α showed high integrity (Figures 4(c) and 6(c)), despite the number of Foc cells attached to the banana roots being very low during the early stages of infection (Anderson et al 2016). Amplification of another Foc-specific effector gene, FocSIX1, from sampled infected roots proved the prospect of this optimised method to be used for in planta pathogenic gene expression studies.…”

Cereal Root Interactions with Soilborne Pathogens—From Trait to Gene and Back

“…A proteomics approach was used to identify R. solani AG-8 genes induced in the presence of wheat seedlings [12]. This interaction represented the susceptibility response of the host, and the pathogenic response for R. solani.…”

“…These pathogens are problems in the dryland production regions of the Pacific Northwest, USA (PNW), Australia, Europe, China, Southeast Asia, India, and other parts of the world [2][3][4][5][6][7]. Furthermore, a body of knowledge is accumulating about the cellular and molecular interactions between these hosts and pathogens that are helping to elucidate the basis of susceptibility and resistance, e.g., References [8][9][10][11][12][13].…”