Maize-corn leaf aphid interaction: Role of Mir1

Maize (Zea mays L.), is one of the major cereal crops cultivated throughout the world with the U.S. producing over 40% of the crop annually. At the same time, maize is also attacked by a plethora of insect pests, which dramatically decreases its yield. The maize genotype, Mp708, developed by classical plant breeding confers enhanced resistance to corn leaf aphid [CLA; Rhopalosiphum maidis] compared to B73 and Tx601 genotypes. Both choice and no-choice tests showed a heightened CLA population on the B73 and Tx601 genotypes as compared to Mp708 plant. Feeding by CLA triggers the rapid accumulation of the Maize insect resistance1 (Mir1) transcripts, which encodes a cysteine protease. In addition, our preliminary findings of feeding behavior studies using Electrical Penetration Graph (EPG) suggest that Mp708’s resistance to CLA is phloem-localized. Our next goal is to quantify callose deposition, which might be getting activated in the phloem cells after CLA infestation reducing the feeding.