Transgenic expression of plant-specific insert of potato aspartic proteases (StAP-PSI) confers enhanced resistance to Botrytis cinerea in Arabidopsis thaliana

FREY MARIA EUGENIA; D IPPÓLITO, SEBASTIAN; PEPE ALFONSO; GUEVARA MARIA GABRIELA; DALEO, GUSTAVO RAUL

PHYTOCHEMISTRY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2018 vol. 149 p. 1 - 11

0031-9422

The plant-specific insert of Solanum tuberosum aspartic proteases (StAP-PSI) has high structural similaritywith NK-lysin and granulysin, two saposin-like proteins (SAPLIPs) with antimicrobial activity. RecombinantStAP-PSI and some SAPLIPs show antimicrobial activity against pathogens that affect human andplants. In this work, we transformed Arabidopsis thaliana plants with StAP-PSI encoding sequence with itscorresponding signal peptide under the control of the cauliflower mosaic virus (CaMV) 35S promoter.Results obtained show that StAP-PSI significantly enhances Arabidopsis resistance against Botrytis cinereainfection. StAP-PSI is secreted into the leaf apoplast and acts directly against pathogens; thereby complementingplant innate immune responses. Data obtained from real-time PCR assays show that theconstitutive expression of StAP-PSI induces the expression of genes that regulate jasmonic acid signallingpathway, such as PDF1.2, in response to infection due to necrotrophic pathogens. On the other hand,according to the data described for other antimicrobial peptides, the presence of the StAP-PSI protein inthe apoplast of A. thaliana leaves is responsible for the expression of salicylic acid-associated genes, suchas PR-1, irrespective of infection with B. cinerea. These results indicate that the increased resistancedemonstrated by A. thaliana plants that constitutively express StAP-PSI owing to B. cinerea infectioncompared to the wild-type plants is a consequence of two factors, i.e., the antifungal activity of StAP-PSIand the overexpression of A. thaliana defense genes induced by the constitutive expression of StAP-PSI.We suggest that the use of this protein would help in minimizing the ecological and health risks thatarise from the use of pesticides.We suggest that the use of this protein would help in minimizing the ecological and health risks thatarise from the spreading of resistance of agriculturally important pathogens.