APS Homepage

POSTERS: Molecular plant-microbe interactions

Understanding the molecular basis of Phytophthora cinnamomi-plant interactions using Nicotiana benthamiana as model system
Aidan Shands - University of California, Riverside. Rodger Belisle- University of California, Riverside, Lukas Mueller- Boyce Thompson Institute, Liliana Cano- University of Florida, Prashant Hosmani- Boyce Thompson Institute, Patricia Manosalva- University of California, Riverside, Aureliano Bombarely- Un

Phytophthora cinnamomi (Pc), the causal agent of phytophthora root rot, is the major constraint of avocado production worldwide. Despite its economic importance, the molecular basis of plant immunity and Pc pathogenicity are largely unknown. Functional genomic studies in avocado are challenging due to limitations associated with tree biology and lack of efficient transformation assays and a reference genome. A detached leaf Pc inoculation assay using Nicotiana benthamiana was used to conduct a dual RNAseq study at 6, 12, 24, 36, and 48 hours post inoculation (hpi). Genes involved in hormone signaling, oxidative stress, production of antimicrobial compounds, as well as receptor-like kinases, NLRs, transcription factors such as WRKY, and pathogenesis-related proteins were differentially expressed at different infection stages. Approximately, 53% of the Pc predicted RXLR effectors were expressed in planta and several effectors exhibited a dynamic expression during the infection. The peak for RXLR effector expression in planta occurs at the biotrophic stages of infection (24 hpi), which is consistent with the pathogen haustorium formation. Transient overexpression of host genes and pathogen effectors are being conducted in N. benthamiana followed by Pc inoculation to determine their effects in plant immunity and pathogenesis respectively. The information gained using this system can be translated to avocado using biotechnology or marker assisted selection.