IAA and flavonoids modulates the association between maize roots and phytostimulant endophytic Aspergillus fumigatus greenish

Abstract

ABSTRACTThe association between microbes and plant roots involves a complex chemical dialogue featured by IAA and flavonoids in addition to other signals. Current study is focused on the role of IAA and flavonoids as essential elements of the chemical dialogue between an endophytic fungus and maize roots. The strain was isolated from the leaves of Withania somnifera and was identified as Aspergillus fumigatus greenish by 18S rDNA sequence. Culture filtrate of the strain contained phyotstimulant (IAA, ammonia and ACC) and signaling compounds including IAA, flavonoids and flavonols. The strain effectively colonized the maize roots and enhanced its growth. In order, to determine the effect of IAA and flavonoids on the ability of the endophyte to colonize maize roots, we inhibited the release of IAA and flavonoids in maize separately which reduced the colonization of endophyte in maize root to 66% and 55% of the untreated control. Similarly, application of IAA in combination with endophyte enhanced root colonization by 90% in zone of cell division, 66% in the zone of elongation and 30% in the zone of maturation. These findings determined that IAA and flavonoids are among the key players of the complex chemical dialogue between plant root and fungal endophyte.