University of Arkansas, Fayetteville Division of Agriculture


Aphids are a group of sap-feeding insects that attack most of the world’s crops. The loss of function of fatty acid desaturase7 (FAD7) in Solanum lycopersicum (tomato plant) induces aphid resistance that is dependent upon the accumulation of plant defense hormones such as salicylic acid (SA). Tomato lacks most of the genetic resources found in the model plant Arabidopsis (Arabidopsis thaliana). There is an analogous fad7-1 line of Arabidopsis; however, the line has a background mutation, the glabra-1 (gl1), that causes the absence of trichomes (small hairs), which are essential to plant defense. In order to study aphid resistance, a single mutant line of fad7-1 mutants were developed using cross breeding between the fad7-1/gl1 mutant and wild-type plants. Homozygous fad7-1 mutants were then identified using the Kasajima DNA extraction method, followed by the use of single nucleotide polymorphism-polymerase chain reaction (SNP-PCR) primers using allele-specific PCR. A phenotypic screening was then performed to screen out the plants with the glabra-1 mutation using the presence or absence of trichomes. Two single Arabidopsis fad7-1 mutant lines were identified, and subsequently verified using a bioassay to be aphid resistant relative to other genotypes as seen in tomato.