|PAUDYAL, SULOCHANA - Oklahoma State University|
|Armstrong, John - Scott|
|GILES, KRISTOPHER - Oklahoma State University|
|HOBABK, WYATT - Oklahoma State University|
|AIKEN, ROB - Kansas State University|
|PAYTON, MARK - Oklahoma State University|
Submitted to: Planta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2020
Publication Date: 7/3/2020
Citation: Paudyal, S., Armstrong, J.S., Giles, K., Hobabk, W., Aiken, R., Payton, M. 2020. Differential responses of sorghum genotypes to sugarcane aphid feeding. Planta. 252(14):1-9. https://doi.org/10.1007/s00425-020-03419-w.
Interpretive Summary: This study details the physiological response of sugarcane aphids feeding on resistant and susceptible sorghums. The results provide evidence that known resistant sorghums are able to maintain/increase photosynthetic capacity and compensate under feeding pressure when compared to susceptible genotypes.
Technical Abstract: Knowledge of the physiological response of sorghum, (Sorghum bicolor (L.) Moench), to sugarcane aphid (SCA), Melanaphis sacchari (Zehnter) feeding will provide baseline information on defense responses and resistance mechanisms. This study documented the impact of SCA feeding on seven sorghum genotypes through differentiating chlorophyll content, photosynthetic rate, stomatal conductance, and carbon assimilation for 14-d post-infested sorghum. Carbon assimilation (A/Ci) curves were recorded at 3, 6, 9, and 15 d after aphid introduction to understand the pattern of physiological response of resistant and susceptible sorghums over time. Chlorophyll loss of resistant genotypes was significantly lower (greater than or equal to 10% loss) than the susceptible indicating tolerance. Most resistant genotypes compensated to aphid feeding by either increasing or maintaining photosynthetic rate and stomatal conductance. Carbon assimilation curves over time showed that infested resistant plants had delayed photosynthetic decreases, whereas susceptible plants displayed accelerated photosynthetic senescence. This research also investigated the influence of aphid density (0, 50, 100, 200 nymphs/plant) on the photosynthetic rates of 28-d-old resistant and susceptible sorghums measured at 72-h post-infestation. Although, there were no visual symptoms in susceptible sorghums, photosynthetic rates were impaired when infested with less than or equal to 100 SCA. However, resistant plants were able to compensate when infested with greater than or equal to 100 aphids. Differences between physiological responses of infested susceptible and resistant genotypes imply that resistant sorghum plants can tolerate some physiological impacts of SCA injury and maintain photosynthetic integrity.