Biochemical changes in sunflower plants due to seed treatment/spray application with biocontrol agents

The application of Trichoderma harzianum and Pseudomonas fluorescens led to increases in dry matter content, starch, total soluble sugars (TSS) and reducing Sugar contents in leaves of sunflower (Helianthus annuus) when done as seed treatment or coupled with spray. There was a significant increase in TSS and reducing sugars in stein tissue after treatment with biocontrol agents. The content of total phenols in leaves increased after treatment at 30 and 60 days after sowing (DAS) and at 30 DAS in stein tissues. Biocontrol agents increased the activities of phenylalanine ammonia lyase (PAL) in leaves and stein tissue after 30 DAS and significantly reduced total phenolic content and PAL activity in the stein at 60 DAS. Following treatment with biocontrol agents, seed lipid content increased, the proportion of linoleic acid increased and that of oleic acid decreased. Application of biocontrol agents to sunflower plants initiated certain biochemical changes. which can be considered to be part of the plant's defense response.