Yucasin and cinnamic acid inhibit IAA and flavonoids biosynthesis minimizing interaction between maize and endophyte Aspergillus nomius

Abstract

Chemical crosstalk between plant roots and associated microbes is imperative for the initiation of symbiosis. Phenolics, flavonoids and indole-3-acetic acid (IAA) are acclaimed as signaling molecules in developing plant-microbe symbiosis. The role of IAA and flavonoids in establishing a symbiotic relationship between Aspergillus nomius wlg2 and maize roots have also been observed during the present study. The isolate A. nomius wlg2 and maize roots have secreted flavonoids and IAA that helped in A. nomius-maize association. However, the suppression of either flavonoids or IAA secretion reduced the endophyte colonization of the maize roots by 77% and 67%, respectively. The main flavonoids secreted by maize were identified as luteolin, calycosin, phenolics cis-caftaric acid, and caffeoyl-d-glucose. The identified flavonoids were most likely to be involved in the root-endophyte association. To establish a plant-microbe interaction, the complex chemical dialogue is necessary for which IAA and flavonoids play a central role.