Juice chemical properties of 24 sorghum cultivars under varying levels of sugarcane aphid (Melanaphis sacchari) infestation

Abstract

Sugarcane aphids [Melanaphis sacchari (Zehntner)] have become a significant pest of grain, forage, and sweet sorghum [Sorghum bicolor (L.) Moench] in the USA in recent years. However, the effects of sugarcane aphid damage on sweet sorghum juice quality have not been well studied. A three-year (2015–2017) field study was conducted at Tifton, GA to assess planting date effects (April, May, or June planting) and cultivar responses (24 cultivars) to sugarcane aphids in sorghum. Aphid damage ratings were measured in all three years and cumulative aphid days were measured in 2016 and 2017. Cumulative aphid days (ln scale) and damage ratings (relative marginal effect) were correlated in five of the six plantings. Stem juice was collected at maturity from seven plantings for chemical analyses, which included HPLC, fluorescence excitation-emission spectrophotometry with parallel factor analysis (EEM/PARAFAC), and cyclic voltammetry (CV). Aphid damage ratings and cumulative aphid days were negatively correlated with sugar-related traits, particularly brix and total sugars. In four plantings, significant negative correlations (r ≤ −0.493) between trans-aconitic acid concentration and aphid damage were observed. Fluorescence and electrochemical properties related to the presence of polyphenols also showed correlations with aphid damage, particularly in the resistant landrace No. 5 Gambela. These secondary metabolites may play a role in sugarcane aphid resistance or tolerance. Stability analysis revealed that the more tolerant cultivars were able to maintain high concentrations of total sugars and trans-aconitic acid across environments.

Registration of three sweet sorghum lines with high tolerance to sorghum aphid (Melanaphis sorghi)

“…The trans-aconitic acid concentration in the juice of GTS1903, GTS1904, and GTS1905 is significantly greater than that of Top 76-6. Recent research suggests that this compound may function in sorghum aphid resistance (Knoll et al, 2021). However, higher acidity may also affect the flavor of T A B L E 3 Genotyping of three sorghum aphid (SA) resistant sweet sorghum lines (GTS1903, GTS1904, and GTS1905) and two parental lines (A 1 N109, SA-susceptible and No.…”

“…Most of the sweet cultivars in use today are heirlooms or were developed by the USDA‐ARS at Meridian, MS, prior to 1983 (Murray et al., 2009). ‘Dale’ (PI 651495; Broadhead & Coleman, 1973) has shown some tolerance compared with other cultivars (Knoll et al., 2021), but it is still heavily damaged by sorghum aphid.…”

Time point- and plant part-specific changes in phloem exudate metabolites of leaves and ears of wheat in response to drought and effects on aphids

“…Interestingly, this organic acid showed lower concentrations under salt stress in shoots of Zea mays (Poaceae) [ 56 ] and led to reduced survival of the aphid Rhopalosiphum padi (Hemiptera: Aphididae) on an artificial diet [ 57 ]. Furthermore, a negative correlation between the concentration of trans -aconitic acid in the stem juice of different sorghum (Poaceae) cultivars and damage by the sugarcane aphid has been reported [ 58 ], highlighting that organic acids can impact aphid development.…”

Aconitic Acid Recovery from Renewable Feedstock and Review of Chemical and Biological Applications

“…High levels of aconitic acid production may also play a role in the resistance of some cereal plants such as corn, sorghum, and barnyard grass to aphids [ 89 ]. For instance, higher levels of TAA in sorghum leaves corresponded to decreased aphid burden and leaf damage, further implying that TAA functions as a defensive phytochemical [ 89 , 90 , 91 ].…”