Phenolic acids in the plow layer soil of strawberry fields and their effects on the occurrence of strawberry anthracnose

Abstract

Phenolic allelochemicals have been found in both natural and managed ecosystems, where they cause numerous ecological and economic problems. Whether these problems can be mediated by some other specific phenolic acid components is unknown. In this study, we identified phenolic acids and their concentrations in plow layer soil, rhizosphere soil and decomposing strawberry (Fragaria ananassa Duch.‘Benihoppe’.) plants susceptible to strawberry anthracnose crown rot. We also assessed the effects of exogenously added phenolic acids at varying concentrations on Colletotrichum gloeosporioides, the pathogen causing strawberry anthracnose crown rot, conidial germination and colony growth. Finally, we verified the occurrence of strawberry anthracnose crown rot and the changes in root structure in response to phenolic acids. Ten phenolic acids were identified in soil samples. The concentrations of p-coumaric acid (PA) and ferulic acid (FA) were higher than other phenolic acids. Relatively high concentrations of PA and FA could increase the occurrence of strawberry seedling anthracnose crown rot. However, when the concentrations of PA and FA were higher than respectively certain critical concentration, they could reduce the degree of the disease. Meanwhile, high concentration of FA seriously inhibited the growth of root. The trans-cinnamic acid (TA) content could be regulated to control the occurrence of strawberry anthracnose crown rot without affecting root growth. Overall, diverse phenolic acids in plow soil had different influence on strawberry anthracnose crown rot. The effects of phenolic acids were concentration-dependent and C. gloeosporioides was more sensitive to phenolic acids concentration than root.