SYNERGISTIC EFFECT OF THE STEROID BIOSTIMULANT AND FUNGICIDE ON THE PHYTOPATHOGENIC FUNGUS Fusarium oxysporum sp. vasinfectum D.T. Babaeva, N.R. Khashimova, A.A. Akhunov, R.R. Shixnazarov Institute of Bioorganic Chemistry named after academician A.S. Sadykov, Academy of Sciences of Uzbekistan, 83 Mirzo Ulugbek street, 100125, Tashkent, Uzbekistan. e-mail: dildora.babaeva.11@mail.ru
Both biotic and abiotic stress inhibits the growth potential of all crops, and the
mechanisms and strategies for mitigating these effects are still poorly understood.
Cotton plants are grown in many fields of our republic, but the areas of plant infection
with phytopathogenic fungi are expanding, which directly hinders the growth and
development of cotton.
Fusarium fungi mainly cause root rot and wilting diseases in the
cotton plant, causing a sharp decrease in the volume of cotton production and fiber
quality. Plant biostimulants based on natural materials have received considerable
attention by both the scientific community and commercial enterprises especially in the
last two and a half decades. Many natural-based biostimulants contain biologically active
compounds that participate in the form of signaling molecules and can directly affect
plant metabolic processes. It is unclear what effects soil or foliar application of the
unspecified product will have on plants. Optimizing the use of biostimulants requires
accurate information about the rate and time. Therefore, using biostimulants with
unknown dosages and the efficiency of functional compounds in plants requires
determining what processes lead to them.
C-6580 cotton variety seeds were treated with DAG-1 biostimulator based on
glycyrrhizic acid of steroidal nature, P-4 fungicide, and their composition with four-fold
reduced P-4 fungicide. The activities of peroxidase (PO), phenylalanine ammonia-lyase
(PAL) enzymes, and cellulose content were studied in pretreated 7-day-old cotton
seedlings and roots under the influence of the cultural liquid of the phytopathogenic
fungus
F. oxysporum f. sp. vasinfectum . According to the results of the study, control
(water) and
F. oxysporum f. sp. medium , it was found that the enzyme activities were
the most active in samples grown under the influence of DAG-1, DAG-1+P-4
composition. In samples treated with a complex with a reduced fungicide content,
separately
F. oxysporum f. sp. vasinfectum and fungicide P-4 and its complex with a
bioregulator did not show PO activity in the root compared to the control, but under the
influence of DAG-1, the activity of PO and FAL in the shoot and root showed high
results. The cell wall is considered to be the first barrier that pathogens must overcome
to colonize plant tissuesThe increase in the contents of cellulose in response to biotic
stress indicates the activation of protective processes. It was found that in
F. oxysporum f.sp. vasinfectum fungus medium, the amount of cellulose in the roots of seedlings treated
with the usual dose of P-4 fungicide was higher than the control. A sharp increase in the
amount of cellulose indicates the activation of lignin synthesis and the formation of a
mechanical barrier against phytopathogens due to the synergism of biostimulant DAG-1
and P-4 fungicide.
The obtained results confirmed that the drug DAG-1 is universal due to its
stimulating properties, participation in complex biochemical processes in plants, as well
as synergistic compatibility with P-4 fungicide.