Pushing forward white lupin as a local source for protein and nitrogen in Central Europe

White lupin (Lupinus albus L.) is a promising leguminous crop. Europe is fully dependent on protein and nitrogen fertilizer imports. This has tremendous negative effects both in Europe and the producing countries, such as loss of terrestrial biodiversity, pollution of freshwater, increase of greenhouse gases and soil acidification. Diverse crop-rotations with a substantial amount of pulses are a proven solution. The protein composition and yield potential of white lupin suggest that it could become the ‘Soy of the North’. Currently, the seed-borne pathogen Colletotrichum lupini is substantially impeding the cultivation of white lupin in Central Europe. We developed a DNA-based diagnostic test to identify and quantify the fungal pathogen in plants and seeds. This technique will allow us to improve our understanding of the Colletotrichum lupini life cycle and, thereby, lay the basis for an advanced resistance breeding approach

Suppression or Activation of Immune Responses by Predicted Secreted Proteins of the Soybean Rust Pathogen Phakopsora pachyrhizi

Rust fungi, such as the soybean rust pathogen Phakopsora pachyrhizi, are major threats to crop production. They form specialized haustoria that are hyphal structures intimately associated with host-plant cell membranes. These haustoria have roles in acquiring nutrients and secreting effector proteins that manipulate host immune systems. Functional characterization of effector proteins of rust fungi is important for understanding mechanisms that underlie their virulence and pathogenicity. Hundreds of candidate effector proteins have been predicted for rust pathogens, but it is not clear how to prioritize these effector candidates for further characterization. There is a need for high-throughput approaches for screening effector candidates to obtain experimental evidence for effector-like functions, such as the manipulation of host immune systems. We have focused on identifying effector candidates with immune-related functions in the soybean rust fungus P. pachyrhizi. To facilitate the screening of many P. pachyrhizi effector candidates (named PpECs), we used heterologous expression systems, including the bacterial type III secretion system, Agrobacterium infiltration, a plant virus, and a yeast strain, to establish an experimental pipeline for identifying PpECs with immune-related functions and establishing their subcellular localizations. Several PpECs were identified that could suppress or activate immune responses in nonhost Nicotiana benthamiana, N. tabacum, Arabidopsis, tomato, or pepper plants

The haustorial transcriptomes of Uromyces appendiculatus and Phakopsora pachyrhizi and their candidate effector families

Haustoria of biotrophic rust fungi are responsible for the uptake of nutrients from their hosts and for the production of secreted proteins, known as effectors, which modulate the host immune system. The identification of the transcriptome of haustoria and an understanding of the functions of expressed genes therefore hold essential keys for the elucidation of fungus–plant interactions and the development of novel fungal control strategies. Here, we purified haustoria from infected leaves and used 454 sequencing to examine the haustorial transcriptomes of Phakopsora pachyrhizi and Uromyces appendiculatus, the causal agents of soybean rust and common bean rust, respectively. These pathogens cause extensive yield losses in their respective legume crop hosts. A series of analyses were used to annotate expressed sequences, including transposable elements and viruses, to predict secreted proteins from the assembled sequences and to identify families of candidate effectors. This work provides a foundation for the comparative analysis of haustorial gene expression with further insights into physiology and effector evolution

Early insights into the genome sequence of Uromyces fabae

Uromyces fabae is a major pathogen of broad bean, Vicia faba. U. fabae has served as a model among rust fungi to elucidate the development of infection structures, expression and secretion of cell wall degrading enzymes and gene expression. Using U. fabae, enormous progress was made regarding nutrient uptake and metabolism and in the search for secreted proteins and effectors. Here, we present results from a genome survey of U. fabae. Paired end Illumina sequencing provided 53 Gb of data. An assembly gave 59,735 scaffolds with a total length of 216 Mb. K-mer analysis estimated the genome size to be 329 Mb. Of a representative set of 23,153 predicted proteins we could annotate 10,209, and predict 599 secreted proteins. Clustering of the protein set indicates families of highly likely effectors. We also found new homologs of RTP1p, a prototype rust effector. The U. fabae genome will be an important resource for comparative analyses with U. appendiculatus and P. pachyrhizi and provide information regarding the phylogenetic relationship of the genus Uromyces with respect to other rust fungi already sequenced, namely Puccinia graminis f. sp. tritici, P. striiformis f. sp. tritici, Melampsora lini, and Melampsora larici-populina

Successful Silencing of the Mycotoxin Synthesis Gene <i>TRI5</i> in <i>Fusarium culmorum</i> and Observation of Reduced Virulence in VIGS and SIGS Experiments

Crops constantly experience various biotic stresses during their life cycle, and Fusarium spp. remain one of the most serious groups of pathogens affecting plants. The ability to manipulate the expression of certain microorganism genes via RNAi creates the opportunity for new-generation dsRNA-based preparations to control a large number of diseases. In this study, we applied virus-induced gene silencing (VIGS), and spray-induced gene silencing (SIGS) to silence the trichothecene-producing gene TRI5 in F. culmorum as a means to reduce its aggressiveness on spring wheat. Treatment of the fungus with dsTRI5RNA in vitro reduced deoxynivalenol (DON) and 3-acetyldeoxynivalenol (3-A-DON) accumulations by 53–85% and 61–87%, respectively, and reduced TRI5 expression by 84–97%. VIGS decreased the proportion of infected wheat spikelets by 73%, but upregulation was observed for TRI5. SIGS on wheat leaves and ears using certain dsTRI5RNA amounts negatively impacted F. culmorum growth. However, when performing in vivo analyses of TRI5 mRNA levels, the upregulation of the gene was determined in the variants where fungal colonization was restricted, suggesting a compensatory reaction of the pathogen to RNAi

Suppression or Activation of Immune Responses by Predicted Secreted Proteins of the Soybean Rust Pathogen Phakopsora pachyrhizi

Rust fungi, such as the soybean rust pathogen Phakopsora pachyrhizi, are major threats to crop production. They form specialized haustoria that are hyphal structures intimately associated with host-plant cell membranes. These haustoria have roles in acquiring nutrients and secreting effector proteins that manipulate host immune systems. Functional characterization of effector proteins of rust fungi is important for understanding mechanisms that underlie their virulence and pathogenicity. Hundreds of candidate effector proteins have been predicted for rust pathogens, but it is not clear how to prioritize these effector candidates for further characterization. There is a need for high-throughput approaches for screening effector candidates to obtain experimental evidence for effector-like functions, such as the manipulation of host immune systems. We have focused on identifying effector candidates with immune-related functions in the soybean rust fungus P. pachyrhizi. To facilitate the screening of many P. pachyrhizi effector candidates (named PpECs), we used heterologous expression systems, including the bacterial type III secretion system, Agrobacterium infiltration, a plant virus, and a yeast strain, to establish an experimental pipeline for identifying PpECs with immune-related functions and establishing their subcellular localizations. Several PpECs were identified that could suppress or activate immune responses in nonhost Nicotiana benthamiana, N. tabacum, Arabidopsis, tomato, or pepper plants.This article is published as Qi, Mingsheng, James P. Grayczyk, Janina M. Seitz, Youngsill Lee, Tobias I. Link, Doil Choi, Kerry F. Pedley, Ralf T. Voegele, Thomas J. Baum, and Steven A. Whitham. "Suppression or activation of immune responses by predicted secreted proteins of the soybean rust pathogen Phakopsora pachyrhizi." Molecular plant-microbe interactions 31, no. 1 (2017): 163-174. doi: 10.1094/MPMI-07-17-0173-FI.</p

ニッケル製錬に関する研究． 特に本邦夏梅鉱に就て

種別: 卒業論

A high-throughput phenotyping tool to identify field-relevant anthracnose resistance in white lupin

The seed- and air-borne pathogen Colletotrichum lupini, the causal agent of lupin anthracnose, is the most important disease in white lupin (Lupinus albus) worldwide and can cause total yield loss. The aims of this study were to establish a reliable high-throughput phenotyping tool to identify anthracnose resistance in white lupin germplasm and to evaluate a genomic prediction model, accounting previously reported resistance QTLs, on a set of independent lupin genotypes. Phenotyping under controlled conditions, performing stem inoculation on seedlings, showed to be applicable for high-throughput and its disease score strongly correlated with field plot disease assessments (r = 0.95, p<0.0001) and yield (r = -0.64, p=0.035). Traditional 1-row field disease phenotyping showed no significant correlation with field plot disease assessments (r = 0.31, p=0.34) and yield (r = -0.45, p=0.17). Genomically-predicted resistance values showed no correlation with values observed under controlled or field conditions, and the parental lines of the RIL population used for constructing the prediction model exhibited a resistance pattern opposite to that displayed in the original (Australian) environment used for model construction. Differing environmental conditions, inoculation procedures or population structure may account for this result. Phenotyping a diverse set of 40 white lupin accessions under controlled conditions revealed eight accessions with improved resistance to anthracnose. The standardized area under the disease progress curves (sAUDPC) ranged from 2.1 to 2.8 compared to the susceptible reference accession with a sAUDPC of 3.85. These accessions can be incorporated into white lupin breeding programs. In conclusion, our data supports stem inoculation-based disease phenotyping under controlled conditions as a time-effective approach to identify field-relevant resistance which can now be applied to further identify sources of resistance and their underlying genetics

A Small Cysteine-Rich Protein from the Asian Soybean Rust Fungus, Phakopsora pachyrhizi, Suppresses Plant Immunity

The Asian soybean rust fungus, Phakopsora pachyrhizi, is an obligate biotrophic pathogen causing severe soybean disease epidemics. Molecular mechanisms by which P. pachyrhizi and other rust fungi interact with their host plants are poorly understood. The genomes of all rust fungi encode many small, secreted cysteine-rich proteins (SSCRP). While these proteins are thought to function within the host, their roles are completely unknown. Here, we present the characterization of P. pachyrhizi effector candidate 23 (PpEC23), a SSCRP that we show to suppress plant immunity. Furthermore, we show that PpEC23 interacts with soybean transcription factor GmSPL12l and that soybean plants in which GmSPL12l is silenced have constitutively active immunity, thereby identifying GmSPL12l as a negative regulator of soybean defenses. Collectively, our data present evidence for a virulence function of a rust SSCRP and suggest that PpEC23 is able to suppress soybean immune responses and physically interact with soybean transcription factor GmSPL12l, a negative immune regulator.This article is published as Qi, Mingsheng, Tobias I. Link, Manuel Müller, Daniela Hirschburger, Ramesh N. Pudake, Kerry F. Pedley, Edward Braun, Ralf T. Voegele, Thomas J. Baum, and Steven A. Whitham. "A small cysteine-rich protein from the Asian soybean rust fungus, Phakopsora pachyrhizi, suppresses plant immunity." PLoS pathogens 12, no. 9 (2016): e1005827, doi: 10.1371/journal.ppat.1005827.</p