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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Crop Germplasm Research » Research » Publications at this Location » Publication #354783

Research Project: Identification of Resistance in Sorghum to Fungal Pathogens and Characterization of Pathogen Population Structure

Location: Crop Germplasm Research

Title: Responses of Johnsongrass against sorghum anthracnose isolates

Author
item Ahn, Ezekiel - Texas A&M University
item Prom, Louis
item Odvody, Gary - Texas A&M University
item Magill, Clint - Texas A&M University

Submitted to: Journal of Plant Pathology & Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2018
Publication Date: 7/31/2018
Citation: Ahn, E., Prom, L.K., Odvody, G., Magill, C. 2018. Responses of Johnsongrass against sorghum anthracnose isolates. Journal of Plant Pathology & Microbiology. 9:442. https://10.4172/2157-7471.1000442.
DOI: https://doi.org/10.4172/2157-7471.1000442

Interpretive Summary: Johnsongrass is a weed found in most production fields and if not controlled can cause significant yield loss to the main crop. This weed is genetically similar to sorghum, the fifth most important cereal crop worldwide. Due to this similarity to sorghum, there is a possibility that Johnsongrass may have resistance genes to anthracnose, a fungal disease that can cause significant yield loss on sorghum. In this study, three isolates of the sorghum anthracnose pathogen were inoculated on 26 Johnsongrass cultivars. The study showed that Johnsongrass cultivars responded differently when challenged with the sorghum anthracnose pathogen. The work is significant because it showed that some of the Johnsongrass cultivars could be used as an alternate source of anthracnose resistance genes for sorghum.

Technical Abstract: Johnsongrass is a creeping perennial weed that interferes with crop productivity. Due to genetic similarity to sorghum, Johnsongrass is considered to have potential as an alternate source of pathogen resistance genes for sorghum. In order to test this hypothesis, sorghum isolates of anthracnose (Colletotrichum sublineolum P. Henn.) were inoculated onto twenty-six Johnsongrass cultivars collected from across the southern U.S. by using an excised leaf method. Upon inoculation with a C. sublineolum sorghum isolate, different Johnsongrass cultivars showed different degrees of infection. Moreover, three different C. sublineolum isolates caused different responses on the same Johnsongrass cultivar. -Expression of defense response related genes, including Beta-1,3-glucanase??, chalcone synthase 8 (CHS8), pathogen induced chitinase, flavonoid-3'-hydroxylase, pathogenesis related protein-10 (PR-10), and thaumatin-like protein, were measured 24 hrs and 48 hrs post inoculation in selected Johnsongrass cultivars by Real-Time qRT-PCR. The results revealed that levels of defense responses varied among cultivars, but were not sufficient to establish a basis for resistance. When the same Johnsongrass cultivars were inoculated in a greenhouse study with conidia of Colletotrichum sublineolum isolate FSP53 from sorghum, some showed evidence of a hypersensitive response. However, successful reproduction of the pathogen as detected by formation of acervuli and setae was seen only on SH1116 and on only one leaf of this cultivar.