Browsing by Author "Akköprü, A."

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Characterization of Endophytic Bacteria Isolated From Various Cultivated Plants and Determination of Their Antagonistic Effects on Plant Pathogenic Bacteria
(Centenary University, 2020) Babier, Y.; Akköprü, A.
This study aims to characterize endophytic bacteria (EB) isolated from various cultivated plants and to identify isolates that have an antagonistic effect against some plant pathogenic bacteria. For this purpose, 191 endophyte bacteria (EB) were isolated from root, stem, shoot, and leaf tissues, which were subjected to intensive surface sterilization of samples taken from seedling and the vegetative period from some cultivated plants widely grown in Van province and its vicinity. In-vitro characterizations of these isolates were made in terms of nitrogen fixation ability, phosphate solubility ability, aminocyclopropane-1-carboxylate deaminase (ACC-d) production ability, indole-3-acetic acid (IAA) production ability and siderophore production ability which are PGPR markers. It was determined that 58.9% of the isolates were gram (-), and 41.1% were gram (+). It was revealed that EB isolates with codes V33K1, V35Y1, V34G1, V17G2, V30Y3, V38K1, V17K1, and V36Y2 showed activity in all other categories besides nitrogen fixation. Twenty-five isolates were active in 3 different categories, 59 isolates were in 2 different categories, and 67 isolates were active in only one category. In contrast, 21 isolates were not active in any category. It was also determined that isolate V30Y3 and V30G2 had an antagonistic effect against seven different plant pathogenic bacterial isolates. The 16s rDNA sequence analysis of the isolates selected according to weighted grading scores and antagonistic effects identified the isolates with codes V40K2, V30Y3, V30G2, V31Y4, V33K2 as Bacillus velezensis (MN186863), Bacillus megaterium (MN187955), Pseudomonas caspiana (MN128080), Pantoea sp. (MT249279) and Bacillus sp. (MT249109), respectively. © 2020, Centenary University. All rights reserved.
The Effect of Some Endophytic Bacteria on Seedling Growth and Physiological Properties of Salvia Officinalis L
(Centenary University, 2023) Uçar, C.P.; Selem, E.; Tunçtürk, R.; Tunçtürk, M.; Akköprü, A.
In order to meet the demand for medicinal sage (Salvia officinalis L.), which is an important economic product, harvesting from nature has economic value. However, it may not always be of the desired standard and quality. Also, the harvesting from nature endangers their natural population causing their genetic base to decline. For this reason, it is important to produce it in an agrosystem and to increase yield in a sustainable way. In this study, the effects of eleven endophyte bacteria (EB) isolates applications on the development, morphology, and physicochemical properties of Salvia officinalis L. were investigated by climate chamber experiments. Peat+perlite+soil (1:1:2) mixture was used as the growing medium and EB was applied two times by soaking method. Effects of EB applications on shoot/root length, root/stem fresh and dry weight, Dualex values (Nitrogen balance index (NBI), flavonol, anthocyanin, and chlorophyll), leaf area, leaf temperature and color values (L*, a) *, b * C and Hue° were examined. All EB applications increased the plant height and leaf area. Also, the majority of EB isolates enhanced the root dry weight. The effect of EB applications on flavonol and chlorophyll content was not found statistically significant. However, there was a statistically significant increase in the nitrogen balance index (NBI). It was also observed that EB applications caused changes in plant color. According to the results obtained, it has been seen that it is possible to produce environmentally friendly and sustainable medicinal sage with appropriate plant-bacteria combinations. © 2023, Centenary University. All rights reserved.
Effects of Endophytic Bacteria on Disease and Growth in Plants Under Biotic Stress
(Centenary University, 2018) Akköprü, A.; Çakar, K.; Husseini, A.
The aim of this study was to reveal the effects of four endophytic bacteria (EB) (Ochrobactrum sp. CB36/1, Pantoea agglomerans CC37/2, Bacillus thuringiensis CA41/1 and Pseudomonas fluorescens CC44) on the plant development of tomato and pepper and the effects against bacterial spot disease caused by Xanthomonas euvesicatoria (Xe) in both hosts. EB applied on tomato and pepper seedlings cultivated in a sterile peat growing medium in a climate chamber in two different periods to the roots. The pathogen inoculated on the leaves by spraying. Disease severity was measured by different scales for tomatoes and peppers, and plant development parameters were determined at the end of the study. The antagonistic effects of EB against Xe and 1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase activities were determined with in vitro studies. The effect of endophytic bacteria on tomato and pepper varied according to the host plant x endophyte x pathogen combination. While no bacteria were effective against the pathogen in vitro, Ochrobactrum sp. CB36/1 inhibited the disease severity by 37% in tomato plants, but this effect was not observed in pepper. Tomato and especially pepper plants under disease stress had root and shoot fresh and dry weight increased by 28% to 128% by EB. The measurable effects of EB under biotic stress were determined to be higher than in stress-free conditions. In conclusion, the endophytic bacteria used in the study have potential for use within sustainable integrated agricultural concept framework, with their effects determined to vary according to the host, pathogen and endophytic bacteria. © 2018, Centenary University. All rights reserved.
The Fire Blight Problem on Apples in Lake Van Basin: The Status and Incidence of the Disease
(Centenary University, 2017) Kipçak, C.; Akköprü, A.
The aim of the study is to determine the incidence and prevalence of Erwinia amylovora causative agent of fire blight disease on apple trees in Lake Van basin. Surveys were carried out in 41 apple orchards from Van, Bitlis, Edremit, Gevas, Tatvan, Adilcevaz, Ahlat, Ercis, Muradiye districts in Lake Van basin between May and July 2015. Identification of the isolates was performed by biochemical and molecular detection methods by G1-F/G2-R primer pair and pathogenicity tests. The general incidence and prevalence of fire blight was detected 0.23% and 36%, respectively. The highest disease incidence was detected as 6% in Edremit district. The highest disease prevalence was detected at the rate of 66.6% in Ercis district. Although fire blight disease prevalence was high throughout the basin, the disease prevalence was low due to use of tolerant varieties, good growing practices and climate conditions. © 2017, Centenary University. All rights reserved.
Plant Growth–promoting Rhizobacteria: Their Potential as Biological Control Agents in Sustainable Agriculture
(Elsevier, 2024) Rezaee Danesh, Y.; Pellegrini, M.; Akköprü, A.; Farda, B.; Boyno, G.; Djebaili, R.
Microorganisms as biological control agents have received special attention in recent years. Biological control is a sustainable and environmentally friendly method and offers a valid alternative to chemical pesticides. Biological control agents have high adaptability to environmental conditions and various synergistic mechanisms based on the host plant. The role of beneficial soil bacteria that live around the root or the rhizosphere and improve plant growth, known as plant growth–promoting rhizobacteria (PGPRs), is very important. PGPRs directly (dissolving of minerals, nitrogen fixation, production of plant hormones such as auxins, gibberellins, and cytokinins) or indirectly (production of several substances such as antibiotics, siderophores, lytic enzymes, volatile organic compounds, hydrogen cyanide, and also competitions) improve plant growth. PGPRs also stimulate the induced systemic resistance (ISR) in plants, thereby increasing the resistance of plants against various pathogens by jasmonic acid (JA) and ethylene (ET) signaling pathways. The ISR was described for different PGPRs species, including Pseudomonas spp., Bacillus spp., and Burkholderia spp. The decrease in disease severity in various host plants has been described by numerous researches. This chapter focuses on the potential of PGPRs as suitable biocontrol agents and the mechanisms involved in sustainable plant disease management. © 2024 Elsevier Inc. All rights reserved.