Assistant Research Scientist, Texas A&M University, TX
The white sugarcane aphid (Melanaphis sacchari) has emerged as a devastating pest of sorghum in southern U.S. The main threat of this insect pest is related to the high production of honeydew, the aphid excretion. Honeydew is high in sugars promoting the development of sooty mold. Honeydew production is such that this sticky substance can clog up the mechanical combine, hampering harvest and causing up to 100% yield loss. The newness of this pest and the scarcity of control measures pose a serious threat to sorghum production in Texas. Sorghum, a monocot, is used as a grain and feed for animals and is also being developed for bioenergy production. Moreover, sorghum is an important crop adapted to drought, and tropical and subtropical areas. The emergence of this new pest and the speed of its invasion are a threat to U.S. agriculture. Aphid-plant interaction studies have focused mainly in dicots. However, it is becoming obvious that attention should be paid to monocots as the responses to biotic and abiotic stresses differ between these two groups. Our long-term research question is to understand sorghum-aphid interactions. The specific question of this project is to unveil early sorghum responses to aphid infestation. Sorghum aphids are able to readily colonize and develop large populations on sorghum. Plant responses are therefore not sufficient to stop this insect pest.
In collaboration with Devin Tillman, we are studying the sorghum transcriptomic response to aphid infestation. We compared leaf tissue from infested (treatment) and un-infested (control) plants. Four-week-old plants were infested with 25 aphids. After 1 day, aphids will be removed and middle leaves will be collected and flash-frozen for transcriptomic analyses. Control plants were mock-infested and treated similarly. Plant responses to insect infestation are fast and temporally dynamic. By assessing plant responses after 24h, we will monitor early plant defenses. This transcriptome study will represent the initiation of molecular research in this system. It will result in 1) increased knowledge on monocot-aphid interactions, and 2) improved understanding of the aphid-sorghum interaction specifically which will pave the way for screening for potentially resistance in the sorghum germplasm.
Materials are under development.
Materials are under development.
