Phenolic acids (PAs) are potential antifungal agents of stored grain cereals. Previous studies have mostly focused on the action of single compounds, consequently providing limited information on their effect as mixtures. We tested the hypothesis that higher phytochemical diversity and concentration of phenolic acids provide better defense against pathogenic fungi of cereals. Five maize seed-borne fungi with different degrees of specialization as cereal pathogens were exposed in vitro to five phenolic acids found in cereal grains either alone or in combinations. We detected that the inhibitory effect of PAs depended on their concentration and the fungus specialization, but the tested hypothesis was not functional for any plant-fungal species relationship. Moreover, various PAs or PAs-mixtures were almost equally inhibitory against the fungal species. We also found that phytochemical diversity had a differential effect on the phytopathogens according to their degree of specialization. Thus, a high phytochemical diversity in high concentration would protect a plant against a fungal community, but not necessarily against a single-fungus species.

酚酸 (PA) 是储存谷物的潜在抗真菌剂。以前的研究主要集中在单一化合物的作用上，因此提供的关于它们作为混合物的作用的信息有限。我们检验了更高的植物化学多样性和酚酸浓度可以更好地防御谷物病原真菌的假设。5种不同专化程度的玉米种传真菌作为谷物病原体的体外暴露到谷物中发现的五种酚酸单独或组合。我们检测到 PA 的抑制作用取决于它们的浓度和真菌特化，但测试的假设对任何植物 - 真菌物种关系都不起作用。此外，各种 PA 或 PA 混合物对真菌物种的抑制作用几乎相同。我们还发现，根据植物病原体的专业化程度，植物化学多样性对它们有不同的影响。因此，高浓度的高植物化学多样性将保护植物免受真菌群落的侵害，但不一定免受单一真菌物种的侵害。