Antifungal Proteins during Sorghum Grain Development and Grain Mould Resistance

Abstract

Proteins potentially inhibitory to the growth of grainmoulding fungi in vitro have been identified from sorghum seeds. However, their role in vivo during fungi infection is still not clear. The objective of the present study was to evaluate the presence of antifungal proteins (AFPs) during grain development. Suren˜o (a grain mould-resistant line), RTx430 (a grain mouldsusceptible) and their F 1 hybrid, were planted at two moisture levels. Caryopses were collected from each genotype every 7 days after anthesis (DAA) during development and maturity of the grain. Significant levels of grain mould occurred naturally. Levels of four AFPs (sormatin, chitinases, b-1,3-glucanases and ribosomal-inactivating proteins) were determined using the immunoblotting technique. During grain development (7-35 DAA), Suren˜o and the F 1 hybrid showed higher levels of sormatin and chitinase than RTx430. RIPs levels in Suren˜o and the F 1 hybrid were higher than those in RTx430 after 21 DAA. Sormatin, chitinases, b-1,3-glucanases and RIPs levels in Suren˜o and in the F 1 hybrid were higher than those of RTx430 after grain physiological maturity. AFPs are associated with grain mould resistance because Suren˜o and the F1 hybrid induce and/or retain higher AFPs levels under grain mould infection pressure than did RTx430. 566RODRIGUEZ-HERRERA et al.

Inoculation strategies to assess biological interactions betweenFusariumandAlternariaspecies infecting sorghum

“…RTx430 has been shown to be highly susceptible to grain mold diseases (Rodriguez-Herrera et al 2006) but no published data of response of 'Wheatland' to grain mold disease has been found. Other genotypes used in different bioassays included very early maturing lines N246 and N247, BTx631, which lacks the purple wound response, and Tx2911 and Tx2927, reported to have resistance to grain mold diseases (National Plant Germplasm System, USDA-ARS; http://www.ars-grin.gov/npgs/).…”

“…Each bioassay was conducted using 'Wheatland' and RTx430, since these elite sorghum genotypes have been commonly used in breeding programs and in other research on sorghum and grasses in general (Rodriguez-Herrera et al 2006). RTx430 has been shown to be highly susceptible to grain mold diseases (Rodriguez-Herrera et al 2006) but no published data of response of 'Wheatland' to grain mold disease has been found.…”

Effect of genotype and environment on flavonoid concentration and profile of black sorghum grains

“…Grain weathering scores were from 1 to 9, where 1 was sorghum free of damage by weathering and 9 was completely weathered sorghum (Rodriguez-Herrera et al, 2000). The evaluation was performed by an experienced pathologist.…”