Effect of waxy (Low Amylose) on Fungal Infection of Sorghum Grain

Authors

Deanna L. Funnell-Harris, University of Nebraska-LincolnFollow
Scott E. Sattler, University of Nebraska-LincolnFollow
Patrick M. O'Neill, University of Nebraska-Lincoln
Kent M. Eskridge, University of Nebraska-LincolnFollow
Jeffrey F. Pedersen, University of Nebraska-LincolnFollow

ORCID IDs

Kent M. Eskridge

Date of this Version

1-2015

Citation

Funnell-Harris, D. L., Sattler, S. E., O’Neill, P. M., Eskridge, K. M., and Pedersen, J. F. 2015. Effect of waxy (low amylose) on fungal infection of sorghum grain. Phytopathology 105:786-796.

Comments

U.S. government work.

Abstract

Loss of function mutations in waxy, encoding granule bound starch synthase (GBSS) that synthesizes amylose, results in starch granules containing mostly amylopectin. Low amylose grain with altered starch properties has increased usability for feed, food, and grain-based ethanol. In sorghum, two classes of waxy (wx) alleles had been characterized for absence or presence of GBSS: wx^a (GBSS^-) and wx^b (GBSS+, with reduced activity). Field-grown grain of wild-type; waxy, GBSS^-; and waxy, GBSS⁺ plant introduction accessions were screened for fungal infection. Overall, results showed that waxy grains were not more susceptible than wild-type. GBSS^- and wild-type grain had similar infection levels. However, height was a factor with waxy, GBSS⁺ lines: short accessions (wx^b allele) were more susceptible than tall accessions (undescribed allele). In greenhouse experiments, grain from accessions and near-isogenic wx^a, wx^b, and wildtype lines were inoculated with Alternaria sp., Fusarium thapsinum, and Curvularia sorghina to analyze germination and seedling fitness. As a group, waxy lines were not more susceptible to these pathogens than wildtype, supporting field evaluations. After C. sorghina and F. thapsinum inoculations most waxy and wild-type lines had reduced emergence, survival, and seedling weights. These results are valuable for developing waxy hybrids with resistance to grain-infecting fungi.