Phenazine and 1-Undecene Producing Pseudomonas chlororaphis subsp. aurantiaca Strain KNU17Pc1 for Growth Promotion and Disease Suppression in Korean Maize Cultivars

Abstract

In this study, strain KNU17Pc1 was tested for its antifungal activity against Rhizoctonia solani AG-1(IA), which causes banded leaf and sheath blight (BLSB) of maize. KNU17Pc1 was tested further for its broad-spectrum antifungal activity and in vitro plant growth promoting (PGP) traits. In addition, the in vivo effects of KNU17Pc1 on reduction of BLSB severity and seedling growth promotion of two maize cultivars under greenhouse conditions were investigated. On the basis of multilocus sequence analysis (MLSA), KNU17Pc1 was confirmed as P. chlororaphis subsp. aurantiaca. The study revealed that KNU17Pc1 had strong in vitro antifungal activity and was effective toward all in vitro PGP traits except phosphate solubilization. In this study, for the first time, a strain of P. chlororaphis against Colletotrichum dematium, Colletotrichum gloeosporioides, Fusarium oxysporum f.sp. melonis, Fusarium subglutinans and Stemphylium lycopersici has been reported. Further biochemical studies showed that KNU17Pc1 was able to produce both types of phenazine derivatives, PCA and 2-OH-PCA. In addition, solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis identified 13 volatile organic compounds (VOCs) in the TSB culture of KNU17Pc1, 1-undecene being the most abundant volatile. Moreover, for the first time, Octamethylcyclotetrasiloxan (D4), dimethyl disulfide, 2-methyl-1,3-butadiene and 1-undecene were detected in P. chlororaphis. Furthermore, this study reported for the first time the effectiveness of P. chlororaphis to control BLSB of maize. Hence, further studies are necessary to test the effectiveness of KNU17Pc1 under different environmental conditions so that it can be exploited further for biocontrol and plant growth promotion.

Response of Soil Bacterial Community and Pepper Plant Growth to Application of Bacillus thuringiensis KNU-07

“…Our in vivo assays also showed that KNU-07 promoted the growth of pepper plants after inoculation into the soil. Strains of B. thuringiensis have been used to promote the growth of plants, and our findings are consistent with these reports [36][37][38]. Previous studies reported that PGPR strains possessing siderophore production play a great role in helping plants to acquire iron for plant growth [13].…”

Diffusible and Volatile Antifungal Compounds Produced by Pseudomonas chlororaphis subsp. aurantiaca ST-TJ4 against Various Phytopathogenic Fungi

“…The antifungal activity of 1-undecene against R. solani AG-1(IA), which causes banded leaf and sheath blight (BLSB) of maize, has been reported (Tagele et al, 2019). The volatile methyl siloxane octamethylcyclotetrasiloxane (D4) has been reported to have antibacterial and antifungal activity (Lin et al, 2014) and was found in the present study.…”

Insights into plant-beneficial traits of probiotic Pseudomonas chlororaphis isolates

“…subsp. aurantiaca KNU17Pc1 [53] and P. chlororaphis O6 (unpublished) when isolates are grown on rich medium. Other VOCs detected in both O6 (unpublished) and M71 [46] isolates include S-containing compounds, such as hydrogen sulfide, dimethyl sulfide and methanethiol.…”