Análisis de la expresión diferencial de genes involucrados en la interacción planta de papafitoplasma “Mexican potato purple top”

Abstract

The "Mexican potato purple top" (MPPT) Phytoplasma” was identified affecting the potato crop in Mexico, causing great losses in production. The study and control of these pathogens is difficult because they are obligate parasites. However, genes coding for virulence proteins (SAP11 and SAP30) have been identified in AY-WB phytoplasma genome, altering plant cell physiology and modulate the host plant defense. It would be interesting to determine if these phytoplasma-secreted proteins are conserved between different strains and species. Additionally, our working group has a library of cDNAs of differentially expressed genes in potato plants in vitro in response to MPPT phytoplasma infection. The aim of this study was to determine the level of expression of genes associated with potato plants in response to MPPT phytoplasma infection. The results of RT-PCR suggest that virulence genes SAP11 and SAP30 are not conserved in MPPT phytoplasma. Real-time PCR was used to determinate the level of expression of ten differentially expressed genes in potato plants in vitro in response to phytoplasma infection MPPT. An overexpression was observed of four genes coding for proteins involved in cell defense/stress response (SAP6, Zn finger, EREB and HSP90) one gene coding for a transcription factor (WRKY) and one gene for an unknown function protein. Three genes presented no change in their relative expression; two of them encode proteins involved in cell defense/stress response (ABC Transporter and MCP In) and another one coding for a metabolism protein (MDAR). One gene coding for a protein involved in cell defense/stress response decreased their level of expression (Membrane protein). On the other hand, there were no detectable levels of expression of genes for MDAR, MCP-In and Membrane protein in symptomatic plants compared to asymptomatic plants. Genes coding for SAP6, Zn finger, HSP90, EREB, WRKY, ABC transporter and an unknown function protein showed an induction in their relative expression, so they may be involved in defense mechanisms in potato plants and symptoms presence.