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POSTERS: Plant defense response

Age Related Resistance in Arabidopsis in Response to Tobacco Mosaic Virus Infection
Madhu Kappagantu - University of Maryland. Tamara Collum- University of Maryland College Park, James Culver- University of Maryland, Matthew Brandon- University of Maryland

Age related resistance (ARR) is a phenomenon in which older plants are able to better cope with infections compared to younger plants and is often associated with a particular stage in the life cycle of the plants like flowering or leaf maturity. Arabidopsis- Tobacco mosaic virus (TMV) is an ideal system to study if adult plants deploy ARR towards viral infections. Previously, it was shown TMV interacts with the phloem specific auxin/indole acetic acid responsive protein 26 (IAA26) and disrupts its localization, thus altering the phloem transcriptome. In this study, wild type Arabidopsis shahdara, IAA26-knockout and -overexpression lines were used to investigate the effect of the TMV-IAA26 interaction on ARR. To test if Arabidopsis plants show higher levels of resistance towards TMV infection, 10 plants one week before flowering and one week after flowering were inoculated with TMV. Samples were collected one week after inoculation and quantitative polymerase chain reaction (qPCR) analysis was performed. Results showed that transcript levels of TMV were 12 fold higher in younger plants before flowering compared to older plants after flowering. However, none of the host resistance genes tested i.e. pathogenesis related protein 1 (PR1), Jasmonate ZIM domain 1 (JAZ1) and Pectinesterase 5 (PME 5) showed significant difference before and after flowering, which indicate that there are other defense response pathways involved in ARR in Arabidopsis challenged with TMV.