Genome-Wide Association Analysis Uncovers Genes Associated with Resistance to Head Smut Pathotype 5 in Senegalese Sorghum Accessions.

A newly documented pathotype 5 of the soil-borne fungus , causing head smut in sorghum, was tested against 153 unexplored Senegalese sorghum accessions. Among the 153 sorghum accessions tested, 63 (41%) exhibited complete resistance, showing no signs of infection by the fungus. The remaining 90 accessions (59%) displayed varying degrees of susceptibility.

Genetic Diversity and Classification of Pathotypes Using a Standard Set of Sorghum Differentials.

Anthracnose, incited by is the most destructive foliar disease of sorghum and, under severe conditions, yield losses can exceed 80% on susceptible cultivars. The hyper-variable nature of the pathogen makes its management challenging despite the occurrence of several resistant sources. In this study, the genetic variability and pathogenicity of 140 isolates of which were sequenced using restriction site-associated sequencing (RAD-Seq), resulted in 1244 quality SNPs.

Genetic and Pathogenic Variability among Isolates of Causing Sorghum Head Smut.

, the causal agent of sorghum ( (L.) Moench) head smut, is present in most sorghum-producing regions. This seed replacement fungal disease can reduce yield by up to 80% in severely infected fields.

A Genome-Wide Association Study of Nigerien and Senegalese Sorghum Germplasm of , the Causal Agent of Leaf Blight.

In Senegal, sorghum ranks third after millet and maize among dryland cereal production and plays a critical role in the daily lives of millions of inhabitants. Yet, the crop's productivity and profitability are hampered by biotic stresses, including , causing leaf blight. A total of 101 sorghum accessions collected from Niger and Senegal, SC748-5 and BTx623, were evaluated in three different environments (Kaymor, Kolda, and Ndiaganiao) in Senegal for their reactions against the leaf blight pathogen.

Specific PCR Detection of Fusarium oxysporum f. sp. vasinfectum California Race 4 Based on a Unique Tfo1 Insertion Event in the PHO Gene.

A highly virulent race 4 (Cal race 4) of Fusarium oxysporum f. sp. vasinfectum was identified in California cotton fields in 2001, and has since been found in increasing numbers of fields.

Virulence and Molecular Genotyping Studies of Sporisorium reilianum Isolates in Sorghum.

Head smut, caused by the fungal pathogen Sporisorium reilianum, has been reported with increasing frequency in the grain sorghum growing areas of Texas. To facilitate analysis of changes in pathogen virulence, four inoculation techniques were examined: soil and teliospore mixture, seed coating, media placement, and syringe injection. Of the four, syringe injection was determined to be the most effective.

Expression of pathogenesis-related protein PR-10 in sorghum floral tissues in response to inoculation with Fusarium thapsinum and Curvularia lunata.

Differences in grain mould disease levels among different sorghum varieties grown in the same environment imply that host genes play a role in controlling disease severity. The fungi most often recovered from naturally infected sorghum grain, Fusarium thapsinum and Curvularia lunata, were used to inoculate a set of resistant and susceptible cultivars at anthesis in both field and glasshouse trials. In the field, 12 cultivars were inoculated with a mixture of F.

Simple sequence repeat markers useful for sorghum downy mildew (Peronosclerospora sorghi) and related species.

Background: A recent outbreak of sorghum downy mildew in Texas has led to the discovery of both metalaxyl resistance and a new pathotype in the causal organism, Peronosclerospora sorghi. These observations and the difficulty in resolving among phylogenetically related downy mildew pathogens dramatically point out the need for simply scored markers in order to differentiate among isolates and species, and to study the population structure within these obligate oomycetes. Here we present the initial results from the use of a biotin capture method to discover, clone and develop PCR primers that permit the use of simple sequence repeats (microsatellites) to detect differences at the DNA level.

Stereoselective coupling of hemigossypol to form (+)-gossypol in moco cotton is mediated by a dirigent protein.

The terpenoid gossypol, a secondary metabolite found in the cotton plant, is synthesized by a free radical dimerization of hemigossypol. Gossypol exists as an atropisomeric mixture because of restricted rotation around the central binaphthyl bond. The dimerization of hemigossypol is regiospecific in cotton.

Characterization and genetic distance analysis of isolates of Peronosclerospora sorghi using AFLP fingerprinting.

Sorghum downy mildew, caused by the obligate oomycete Peronosclerospora sorghi, has been controlled through the use of resistant cultivars and seed treatment with metalaxyl. A recent outbreak in fields planted with treated seed revealed the presence of a metalaxyl-resistant variant. Here, PCR-based methods including amplification from RAPD primers and two systems of automated AFLP analysis have been used to detect DNA-level genetic variation among 14 isolates including metalaxyl-resistant and susceptible isolates, as well as representatives of common pathotypes 1 and 3 and a new pathotype.

Terpenoid aldehyde formation and lysigenous gland storage sites in cotton: variant with mature glands but suppressed levels of terpenoid aldehydes.

A new cotton variant with reduced levels of terpenoid aldehydes (sesquiterpenoids and sesterterpenoids (heliocides)) was isolated from the progeny of hemizygous cotton (Gossypium hirsutum cv. Coker 312) transformed with antisense (+)-delta-cadinene synthase cDNA. Southern analysis of leaf DNA digested with HindIII, Pst or KpnI restriction endonucleases did not detect any antisense cdn1-C1 DNA in the genome of the variant.

Reduced levels of cadinane sesquiterpenoids in cotton plants expressing antisense (+)-delta-cadinene synthase.

Cotton plants were transformed with an antisense construct of cdn1-Cl, a member of a complex gene family of delta-(+)cadinene (CDN) synthase. This synthase catalyzes the cyclization of (E,E)-farnesyl diphosphate to form CDN, and in cotton, it occupies the committed step in the biosynthesis of cadinane sesquiterpenoids and heliocides (sesterterpenoids). Southern analyses of the digestion of leaf DNA from R(o), T(o), and T(1) plants with Hind III, Pst I and Kpn I restriction enzymes show the integration of antisense cdn1-C1 cDNA driven by the CaMV 35S promoter into the cotton genome.

Cloning and expression of desoxyhemigossypol-6-O-methyltransferase from cotton (Gossypium barbadense).

Terpenoids play an important role in defense against insects and pathogens in cotton. These terpenoids contain phenolic groups. Metabolites in which the phenolic group has been converted to a methoxy group are less toxic to most insects and pathogens and thus may alter resistance.