Location: Wheat, Sorghum and Forage ResearchTitle: Association of post-flowering non-senescence (stay-green) and dhurrin levels in response to stalk rot pathogens in sorghum bicolor
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/13/2020
Publication Date: 8/3/2020
Citation: Funnell-Harris, D.L., Sattler, S.E., Oneill, P.M., Bernhardson, L.F., Kilts, M., Khasin, M. 2020. Association of post-flowering non-senescence (stay-green) and dhurrin levels in response to stalk rot pathogens in sorghum bicolor. [abstract]. Plant Health 2020 (virtual). Accepted poster.
Technical Abstract: Sorghum (Sorghum bicolor (L.) Moench) is a diverse C4 crop used for grain- or juice-based bioethanol, with potential for lignocellulosic biofuels. Although drought-tolerant, sorghum is vulnerable to stalk rots caused by Fusarium thapsinum and Macrophomina phaseolina, especially during water-stress. Lines with post-flowering non-senescence (Stay-green), associated with drought and stalk rot resistance, were shown to have high levels of the cyanogenic glycoside dhurrin, unlikely to be a pathogen resistance factor. Lines with reported field stalk rot resistance, Stay-green with high dhurrin levels, or stalk rot-susceptibility and senescent, were screened in a greenhouse for response to the two pathogens. Of the four most resistant lines, Plant Introduction (PI) 534133 is known as Stay-green with high dhurrin levels and PI267379 as field resistant; there is little information on PI533882 and PI534053. Dhurrin assays using HPLC of greenhouse-grown leaves showed that PI267379 had significantly less dhurrin than all other lines while PI533882 and PI534053 had levels similar to PI534133 and a Stay-green check, PI656029. Dhurrin levels of field-grown leaves from the most resistant lines were similar to greenhouse-grown leaves; PI534053 and PI534133 had levels similar to a Stay-green check. Field-grown lines were scored at maturity for senescence with a 1 (non-senescent) to 5 (completely senescent) scale. PI534133 was non-senescent (1.2) while the other three resistant lines had low (2.0-2.4) senescence. The most resistant line, PI267379, had low field senescence and low dhurrin.