The non-traditional growth regulator pectimorf is an elicitor of defense responses and protects Arabidopsis against Botrytis cinerea

Pectimorf is a non-traditional growth regulator produced in Cuba by partial enzymatic degradation of the cell wall of citrus fruit rinds. It is mainly composed of oligogalacturonides (OGs) and is currently used for in vitro micropropagation of different crops. Since OGs are known to elicit plant defence responses and are able to protect plants against fungal infection, we have investigated whether Pectimorf also has elicitor properties in Arabidopsis thaliana. The activity of Pectimorf was similar to that observed with similar doses of OGs in different bioassays (induction of gene expression, elicitation of oxidative burst, activation of MAP kinases). Furthermore, Pectimorf pre-treatments increased resistance of Arabidopsis leaves against infection by Botrytis cinerea. Pectimorf, as previously observed with OGs, also showed antagonistic effects with exogenous auxin. Taken together, these data indicate that Pectimorf is a potent elicitor of plant innate immunity and may be used as an inexpensive natural product to protect crops against diseases.