Wulff B.B.H.,Norwich Research Park |
Horvath D.M.,Two Blades Foundation |
Ward E.R.,Norwich Research Park
Current Opinion in Plant Biology | Year: 2011
Crop disease remains a major cause of yield loss and emerging diseases pose new threats to global food security. Despite the dearth of commercial development to date, progress in using our rapidly expanding knowledge of plant-pathogen interactions to invent new ways of controlling diseases in crops has been good. Many major resistance genes have now been shown to retain function when transferred between species, and evidence indicates that resistance genes are more effective when deployed in a background containing quantitative resistance traits. The EFR pattern-recognition receptor, present in only the Brassicaceae, functions to provide bacterial disease control in the Solanaceae. Knowledge of how transcription activator-like effectors bind DNA is leading to new methods for triggering disease resistance and broader applications in genome engineering. © 2011 Elsevier Ltd. Source
Agency: GTR | Branch: BBSRC | Program: | Phase: Research Grant | Award Amount: 467.98K | Year: 2014
Plant disease causes significant yield losses in agriculture. Wheat and potato are two of the most important crops worldwide, including India and the UK. Among the most damaging diseases of wheat are the rusts. Stripe rust occurs wherever the crop is grown causing average yearly yield losses of up to 10% in some regions. Stem rust was until the green revolution associated with regular crop failures and famine. The resistance introduced then has now been broken by new strains of the fungus, which started appearing in Africa 14 years ago. The potato late blight disease, the cause of the Great Irish Potato famine in the 1840s, is still a serious impediment to potato cultivation today. Pesticides can control these diseases but they are expensive, at odds with sustainable intensification of agriculture, and in developing countries and for subsistence farmers, they are simply unaffordable. Wild relatives of domesticated crops contain many useful disease resistance (R) genes. Introducing this natural resistance is an elegant way of managing disease. However, traditional methods for introducing R genes typically involve long breeding trajectories to avoid linkage drag, i.e. the simultaneous introduction of deleterious traits. Furthermore, R genes tend to be overcome by the pathogen within a few seasons when deployed one at a time. Our long-term strategy is to isolate, by molecular cloning, as many new R genes as possible, and introduce them in combinations using GM methods. Molecular cloning makes it possible, indeed straightforward, to put several new genes together in the same location in the genome, allowing breeders to work with them as a single gene and avoiding linkage drag. Moreover, from first principles, a pyramid of R genes with distinct specificities should be more durable. Traditional map-based cloning of R genes, however, is still challenging. First, large tracts of plant genomes are inaccessible to map-based genetics due to lack of recombination. Second, most R genes belong to a structural class of genes called NB-LRRs, which tend to reside in complex clusters, and many hundreds of NB-LRRs populate a typical plant genome. The scientist therefore frequently delimits a map interval containing multiple NB-LRRs and must find out which confers the resistance of interest. An approach, which has been successfully used to narrow down the candidate list to a single NB-LRR, is mutagenesis and screening for susceptible mutants. This creates discrete variations whereby a simple comparison of mutant and wildtype can identify the R gene. We propose a strategy that will significantly increase the rate of R gene identification. In a first step of our workflow, we will screen large numbers of mutagenized plants for susceptible mutants. In a second step, we will use a state-of-the art sequencing technique recently implemented in our lab to selectively capture and sequence all the NB-LRRs in a plant genome. This will allow us to rapidly and cheaply compare wildtype with mutants to identify and clone resistance genes. The outputs of this research will be three-fold: (i) using known controls we will implement our generic strategy to isolate R genes from complex genomes, (ii) we will apply this strategy to identify novel R genes from potato and wheat (against late blight and wheat rusts respectively), and (iii) we will test our key wheat rust R genes in Indian and UK environments. We envisage that not only will our strategy significantly accelerate R gene cloning, it could also be used to pursue R genes not amenable to standard genetics, e.g. in low- or non-recombinogenic regions of the genome including centromeres, alien introgressed segments, and translocations. In wheat, this would allow accessing a plethora of useful R genes currently unusable due to linkage to deleterious yield-depressing alleles.
Two Blades Foundation | Date: 2012-07-12
Two Blades Foundation | Date: 2015-11-23
Methods are provided for enhancing the resistance of plants to bacterial pathogens. The methods involve transforming a plant with a polynucleotide molecule comprising a plant promoter operably linked to a nucleotide sequence that encodes a plant receptor that binds specifically with bacterial elongation factor-Tu. Further provided are expression cassettes, transformed plants, seeds, and plant cells that are produced by such methods.
Two Blades Foundation | Date: 2015-02-20
Methods are provided for identifying a plant disease resistance (R) gene for a plant disease of interest. The methods involve using bait sequences to select a subgroup of nucleic acids from a group of nucleic acids that are derived from a mutagenized plant that is susceptible to the plant disease of interest but that was produced by mutagenizing a plant that is resistant to the disease of interest. The bait sequences are designed to hybridize to one or more genes from at least one plant R gene family. The methods further involve sequencing the subgroup of nucleic acids to obtain a collection of nucleic acid sequences, comparing such nucleic acid sequences with corresponding sequences of one or more genes that are derived from a resistant plant, and identifying at least one nucleic acid sequence derived from the mutagenized plant that is not identical in sequence to a corresponding sequence from the resistant plant. Further provided are related methods for identifying a gene associated with a phenotypic change for a trait of interest in plants and other organisms.