Abstract
Salicylic acid (SA) and root associated
Pseudomonas fluorescens
are known inducers of systemic resistance and influence plant defense responses including reprogramming of cellular mechanisms in response to biotic stress. However, integration of SA, tricyclazole and bioagent
P. fluorescens
in the integrated disease management practices is not clearly understood. With this rationale the present study was carried out to understand the effects of integration of an anti-penetrant tricyclazole, signaling molecule SA and
P. fluorescens
UBSPF-10 in modulation of defense cascades and enhancing suppression of
Bipolaris sorokiniana
in bread wheat (
Triticum aestivum
L.). Results showed that exogenous application of SA (100 mg L
−1
) alone and in combination with tricyclazole (750 mg L
−1
) and
P. fluorescens
UBSPF-10 significantly increased activation and accumulation of phenylalanine ammonia lyase (PAL), peroxidase, β 1,3-glucanase and chitinase activities in wheat leaves challenged with
B. sorokiniana
compared to individually treated and control plants
.
The influence of combined applications of SA, tricyclazole and
P. fluorescens
UBSPF-10 on lignin content in plant leaves was investigated and it was observed that the combined treatment resulted significant increase in the acid-soluble lignin content in wheat possibly leading to enhanced suppression of disease progression and severity. Furthermore, correlation analysis clearly indicated that enhanced accumulation of lignin in plant cells significantly reduces pathogen infection and invasion of tissue leading to reduction in disease development compared to other treatments. Therefore, it is concluded that combined application of SA, tricyclazole and
P. fluorescens
UBSPF-10 played an important role in suppression of
B. sorokiniana
development in wheat plants in a cooperative manner and thus, could be used in the integrated disease management practices of wheat.