Blankenberg

Brian P. Dilkes

Clint Chapple

Conn

Dunstan

Elizabeth M. Buescher

Elliot Brown

Ganjewala

Kartikeya Krothapalli

Mitchell R. Tuinstra

Schappert

Seigler

Williams-Carrier

Xu Li

Abstract
               Whole genome sequencing has allowed rapid progress in the application of forward genetics in model species. In this study, we demonstrated an application of next-generation sequencing for forward genetics in a complex crop genome. We sequenced an ethyl methanesulfonate-induced mutant of Sorghum bicolor defective in hydrogen cyanide release and identified the causal mutation. A workflow identified the causal polymorphism relative to the reference BTx623 genome by integrating data from single nucleotide polymorphism identification, prior information about candidate gene(s) implicated in cyanogenesis, mutation spectra, and polymorphisms likely to affect phenotypic changes. A point mutation resulting in a premature stop codon in the coding sequence of dhurrinase2, which encodes a protein involved in the dhurrin catabolic pathway, was responsible for the acyanogenic phenotype. Cyanogenic glucosides are not cyanogenic compounds but their cyanohydrins derivatives do release cyanide. The mutant accumulated the glucoside, dhurrin, but failed to efficiently release cyanide upon tissue disruption. Thus, we tested the effects of cyanide release on insect herbivory in a genetic background in which accumulation of cyanogenic glucoside is unchanged. Insect preference choice experiments and herbivory measurements demonstrate a deterrent effect of cyanide release capacity, even in the presence of wild-type levels of cyanogenic glucoside accumulation. Our gene cloning method substantiates the value of (1) a sequenced genome, (2) a strongly penetrant and easily measurable phenotype, and (3) a workflow to pinpoint a causal mutation in crop genomes and accelerate in the discovery of gene function in the postgenomic era.</jats:p

Elizabeth M Buescher

Brian P Dilkes

Mitchell R Tuinstra

Crossref

Genetics

Forward Genetics by Genome Sequencing Reveals That Rapid Cyanide Release Deters Insect Herbivory of <i>Sorghum bicolor</i>

Forward Genetics by Genome Sequencing Reveals That Rapid Cyanide Release Deters Insect Herbivory of
                    Sorghum bicolor

Forward Genetics by Genome Sequencing Reveals That Rapid Cyanide Release Deters Insect Herbivory of Sorghum bicolor

Abstract

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