Temporal expression profiles of defense-related genes involved in Lactuca sativa- Sclerotinia sclerotiorum interactions

Abstract

Sclerotinia sclerotiorum, a destructive fungal pathogen with an extensive host range infecting more than 400 plant species, causes lettuce drop on the leafy green lettuce that potentially have an enormous economic impact on lettuce cultivation worldwide. To gain insights into how lettuce regulates its defense pathways, gene expression profiles of five defense-related genes (LsPRB1, LsSOD, LsERF1, LsLTC1, and LsHPL1) triggered following infection of susceptible Mazandaran line 1 (ML1) and tolerant Jahrom (Jah) lettuce accessions by the S. sclerotiorum were compared by the real-time quantitative RT-PCR (RT-qPCR) approach. In the current study, we observed temporal and quantitative gene expression fluctuations between two examined accessions of L. sativa in response to S. sclerotiorum attack. All genes, except LsHPL1, were up-regulated earlier (24 hours after inoculation) in the Jah accession compared with the susceptible one. This data implies strong defense responses established in the tolerant accession to arrest the fungal growth, but it resulted in restricting lesion development rather than in preventing infection. This research contributes to a better understanding of the kinetics of lettuce reactions induced following S. sclerotiorum infection and may be employed to develop effective strategies to manage lettuce drop.