Endofit ve epifit bakterilerin turunçgillerde sorun olan bazı fungal patojenlere karşı in vitro biyokontrol etkinliklerinin belirlenmesi
Yükleniyor...
Dosyalar
Tarih
2022
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Hatay Mustafa Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Ülkemiz için stratejik bir ürün olan turunçgil (Citrus spp.) türleri, ekonomik ihracat değerleri ve yaygın yerel tüketimleri nedeniyle Türkiye' de önemli bir meyve olarak kabul edilmektedir. Antraknoz (Colletotrichum spp.), Fusarium solgunluğu ve kuru kök çürüklüğü (Fusarium spp.) ve ekşi çürüklük (Geotrichum citri-aurantii) gibi fungal hastalıklar turunçgillerde ciddi verim ve kalite kayıplarına neden olur. Bu tür hastalıklarla mücadelede güvenilir ve çevre dostu yöntem olarak büyük potansiyel kontrol stratejilerinden biri de antagonist ve bitki gelişimini teşvik eden bakteriyel izolatların kullanıldığı biyolojik mücadeledir. Bu çalışmada, sağlıklı turunçgil ağaçlarından elde edilen endofit ve epifit bakteri izolatların izolasyonu, tanılanması ve G. citri-aurantii, C. gloeosporioides ve F. solani'ye karşı in vitro antagonistik potansiyellerinin belirlenmesinin yanı sıra bitki gelişimini teşvik etmede ve antagonistik etkinlikte rol oynayan olası mekanizmalarının karakterize edilmesi amaçlanmıştır. Sağlıklı ağaçların toprak altı ve üstü bölgelerinden elde edilen 48 izolat MALDI-TOF MS ile tanılanmıştır. İkili kültür testlerinde Bacillus vallismortis YGL73ep, Bacillus cereus YGK25en ve Pseudomonas chlororapsis YGM82ep izolatları G. citri-aurantii'nin misel gelişimini %73.3-77.2 oranlarında; Bacillus thuringiensis YGT22en, Bacillus vallismortis YGL73ep, Bacillus cereus YGK25en ve Pseudomonas chlororaphis YGM82ep izolatları C. gloeosporioides'in misel gelişimini %65.5-72.7 oranlarında; Bacillus subtilis YGS5en, Bacillus cereus YGK25en, ve Pseudomonas chlororapsis YGM82ep izolatları F. solani'nin misel gelişimini %71.1-66.1 oranlarında engelleyen en güçlü antagonist izolatlar olarak belirlenmiştir. Etkili antagonist bakteri izolatlarından olan Pseudomonas chlororapsis YGM82ep, Bacillus vallismortis 73YGep, Bacillus thuringiensis 22YGen ve Bacillus cererus 25YGen tarafından üretilen uçucu organik bileşiklerin (VOC's) in vitro ikili kültür testlerinde test edilen hastalık etmenlerinin misel gelişimlerini önemli ölçüde engellediği gözlenmiştir. Test edilen 25 bakteri izolatın, 20 tanesi siderofor, 24 tanesi amonyak, 19 tanesi protease, 5 tanesi ise HCN üretiminde pozitif olarak kayıt edilmiştir. Test edilen 25 bakteri izolatının 21'i 1.84-69.68 µg/ml konsantrasyon aralığında değişen miktarda IAA üretmiş olup, 7 izolat fosforu çözebilme yeteneğinde olduğu belirlenmiştir. İzolatlar arasında Pseudomonas koreensis YGL72ep, Pseudomonas chlororaphis YGM82ep ve Bacillus simplex YGS12ep en fazla IAA üreten, Rahnella aquatilis YGP63ep, Raoultella ornithinolytica YGP64en ve Pseudomonas koreensis YGL72ep ise en fazla fosforu çözen izolatlar olarak belirlenmiştir. Sonuç olarak güçlü antagonistik ve PGP etkinlikleri gösteren, özellikle Bacillus spp. ve Pseudomonas chlororaphis izolatların Geotrichum citri-aurantii, Colletotrichum gloeosporioides ve Fusarium solani tarafından neden olunan hastalıkların baskılanmasında biyolojik mücadele etmeni olarak geliştirilebilmesinin yanısıra biyogübre olarakta kullanılma potansiyeline sahip olabileceği belirlenmiştir.
Citrus (Citrus spp.) species, as a strategic crop, are considered an important fruit due to the economic value of exports and local consumption in Turkey. Fungal diseases such as anthracnose (Colletotrichum spp.), Fusarium wilt and dry root rot (Fusarium spp.) and sour rot (Geotrichum citri-aurantii) cause serious yield and quality losses during cultivation and storage periods. In recent years, priority has been given to researching alternative methods to chemical pesticides with diseases. One of the promising control strategies that show great potential as a reliable environmentally friendly method in the management of such diseases is biological control using antagonist and plant growth promoting bacterial biocontrol agents. Multiple aims of this study were to isolate and identify of endophytic and epiphytic bacterial isolates obtained from healthy citrus trees, to determine their in vitro antagonistic activities against Geotrichum citri-aurantii, Colletotrichum gloeosporioides and Fusarium solani as well as to characterize mechanisms potentially involved in promoting plant growth and antagonistic activities. Total of 48 bacterial isolates were obtained from the rhizosphere and endosphere of healthy trees and identified by MALDI-TOF MS analysis. In dual culture assay, Bacillus vallismortis YGL73ep, Bacillus cereus YGK25en and Pseudomonas chlororapsis YGM82ep isolates were found as the most effective antagonistic bacterial isolates against Geotrichum citri-aurantii (73.33-77.22% inhibition); Bacillus thuringiensis YGT22en, Bacillus vallismortis YGL73ep, Bacillus cereus YGK25en and Pseudomonas chlororaphis YGM82ep against Colletotrichum gloeosporioides (65.56-72.78% inhibition); Bacillus subtilis YGS5en, Bacillus cereus YGK25en and Pseudomonas chlororaphis YGM82ep against Fusarium solani (71.11-66.11% inhibition). Volatile organic compounds (VOCs), produced by the efficient isolates such as Pseudomonas chlororapsis YGM82ep, Bacillus vallismortis 73YGep, Bacillus thuringiensis 22YGen and Bacillus cererus 25YGen, significantly inhibited mycelial growth of tested fungal disease agents in vitro dual culture tests. Among the tested 25 bacterial isolates, 20 isolates were positive for siderophore production, 24 isolates for ammonium production, 19 isolates for protease and 5 isolates for HCN production. Of the 25 bacterial isolates tested, 21 isolates produced varying amounts of IAA in the concentration range of 1.84-69.68 µg/ml, and 7 isolates were found to be capable of solubilising phosphorus. Among the isolates, Pseudomonas koreensis YGL72ep, Pseudomonas chlororaphis YGM82ep and Bacillus simplex YGS12ep produced a relatively large amount of IAA and Rahnella aquatilis YGP63ep, Raoultella ornithinolytica YGP64en ve Pseudomonas koreensis YGL72ep solubilised phosphate. In conclusion, the strong antagonistic and PGP traits displayed by effective isolates of Bacillus spp. and Pseudomonas chlororaphis may be developed as biological control agent in the suppression disease caused by Geotrichum citri-aurantii, Colletotrichum gloeosporioides and Fusarium solani as well as their potentials as a biofertilizer.
Citrus (Citrus spp.) species, as a strategic crop, are considered an important fruit due to the economic value of exports and local consumption in Turkey. Fungal diseases such as anthracnose (Colletotrichum spp.), Fusarium wilt and dry root rot (Fusarium spp.) and sour rot (Geotrichum citri-aurantii) cause serious yield and quality losses during cultivation and storage periods. In recent years, priority has been given to researching alternative methods to chemical pesticides with diseases. One of the promising control strategies that show great potential as a reliable environmentally friendly method in the management of such diseases is biological control using antagonist and plant growth promoting bacterial biocontrol agents. Multiple aims of this study were to isolate and identify of endophytic and epiphytic bacterial isolates obtained from healthy citrus trees, to determine their in vitro antagonistic activities against Geotrichum citri-aurantii, Colletotrichum gloeosporioides and Fusarium solani as well as to characterize mechanisms potentially involved in promoting plant growth and antagonistic activities. Total of 48 bacterial isolates were obtained from the rhizosphere and endosphere of healthy trees and identified by MALDI-TOF MS analysis. In dual culture assay, Bacillus vallismortis YGL73ep, Bacillus cereus YGK25en and Pseudomonas chlororapsis YGM82ep isolates were found as the most effective antagonistic bacterial isolates against Geotrichum citri-aurantii (73.33-77.22% inhibition); Bacillus thuringiensis YGT22en, Bacillus vallismortis YGL73ep, Bacillus cereus YGK25en and Pseudomonas chlororaphis YGM82ep against Colletotrichum gloeosporioides (65.56-72.78% inhibition); Bacillus subtilis YGS5en, Bacillus cereus YGK25en and Pseudomonas chlororaphis YGM82ep against Fusarium solani (71.11-66.11% inhibition). Volatile organic compounds (VOCs), produced by the efficient isolates such as Pseudomonas chlororapsis YGM82ep, Bacillus vallismortis 73YGep, Bacillus thuringiensis 22YGen and Bacillus cererus 25YGen, significantly inhibited mycelial growth of tested fungal disease agents in vitro dual culture tests. Among the tested 25 bacterial isolates, 20 isolates were positive for siderophore production, 24 isolates for ammonium production, 19 isolates for protease and 5 isolates for HCN production. Of the 25 bacterial isolates tested, 21 isolates produced varying amounts of IAA in the concentration range of 1.84-69.68 µg/ml, and 7 isolates were found to be capable of solubilising phosphorus. Among the isolates, Pseudomonas koreensis YGL72ep, Pseudomonas chlororaphis YGM82ep and Bacillus simplex YGS12ep produced a relatively large amount of IAA and Rahnella aquatilis YGP63ep, Raoultella ornithinolytica YGP64en ve Pseudomonas koreensis YGL72ep solubilised phosphate. In conclusion, the strong antagonistic and PGP traits displayed by effective isolates of Bacillus spp. and Pseudomonas chlororaphis may be developed as biological control agent in the suppression disease caused by Geotrichum citri-aurantii, Colletotrichum gloeosporioides and Fusarium solani as well as their potentials as a biofertilizer.
Açıklama
Anahtar Kelimeler
Ziraat, Agriculture
