In Vitro Study of Biocontrol Potential of Rhizospheric Pseudomonas aeruginosa against Pathogenic Fungi of Saffron (Crocus sativus L.)

Abstract

Plant rhizosphere soil contains a large number of plant-growth promoting rhizobacteria, which can not only resist the invasion of pathogenic microorganisms and protect plants from damage, but also promote the growth and development of plants. In this study, Pseudomonas aeruginosa strain YY322, isolated and screened from the rhizosphere soil of saffron (Crocus sativus L.), was found through a plate confrontation experiment to show highly effectual and obvious antagonistic activity against the pathogens of saffron, including Fusarium oxysporum, Fusarium solani, Penicillium citreosulfuratum, Penicillium citrinum and Stromatinia gladioli. In addition, the volatile organic compounds of strain YY322 had great antagonistic activity against these pathogens. Observation under a scanning electron microscope and transmission electron microscope reflected that strain YY322 had a significant effect on the hyphae and conidia of F. oxysporum and F. solani. Through the detection of degrading enzymes, it was found that P. aeruginosa can secrete protease and glucanase. The plant growth promoting performance was evaluated, finding that strain YY322 had the functions of dissolving phosphorus, fixing nitrogen, producing siderophore and producing NH3. In addition, whole genome sequencing analysis indicated that the YY322 genome is comprised of a 6,382,345-bp circular chromosome, containing 5809 protein-coding genes and 151 RNA genes. The P. aeruginosa YY322 genome encodes genes related to phenazine (phzABDEFGIMRS), hydrogen cyanide(HCN) (hcnABC), surfactin (srfAA), salicylate (pchA), biofilm formation (flgBCDEFGHIJKL, motAB, efp, hfq), and colonization (minCDE, yjbB, lysC). These results collectively indicated the role of P. aeruginosa YY322 in plant growth enhancement and biocontrol mechanisms. All in all, this study provides a theoretical basis for P. aeruginosa as the PGPR of saffron, paving the way for the subsequent development and utilization of microbial fertilizer.

An Evaluation of Aluminum Tolerant Pseudomonas aeruginosa A7 for In Vivo Suppression of Fusarium Wilt of Chickpea Caused by Fusarium oxysporum f. sp. ciceris and Growth Promotion of Chickpea

“…PGPR Pseudomonas aeruginosa was reported to be the dominant bacteria from the rhizosphere of sorghum, paddy, tobacco, tea, and maize crops in India [ 166 ]. Recently, the Pseudomonas aeruginosa strain RTE4, isolated from the tea plant rhizosphere [ 167 ]; tomato plant rhizosphere associated Pseudomonas aeruginosa strain CQ-40 [ 168 ] and Pseudomonas aeruginosa FG106 [ 169 ]; and saffron rhizosphere Pseudomonas aeruginosa strain YY322 [ 170 ], have been reported as PGPR with multiple beneficial phenotypes and biocontrol activities in the plants.…”

Antagonism of Rhizosphere Streptomyces yangpuensis CM253 against the Pathogenic Fungi Causing Corm Rot in Saffron (Crocus sativus L.)

“…In this study, the CM253 strain was isolated from the rhizosphere soil of healthy crocus sativus , which had significant antagonistic effects on four C. sativus pathogens. We previously isolated Pseudomonas aeruginosa , which also had an obvious antagonistic effect on the pathogenic fungi of saffron [ 36 ]. There have been numerous studies on the prevention and control of crocus corm rot and the advancement of crocus yields and quality by beneficial strains.…”

Rhizosphere microorganisms of Crocus sativus as antagonists against pathogenic Fusarium oxysporum

“…Some rhizosphere microbes, including Pseudomonas aeruginosa , Brevibacterium frigoritolerans , Alcaligenes faecalis subsp. phenolicus , and Bacillus aryabhattai , were found to have plant growth properties and effectively control the growth of pathogenic fungi of C. sativus ( Hu et al., 2021 ; Rasool et al., 2021 ). In this study, the microbial structure related to rot disease resistance in the rhizosphere of C .…”

“…The most severe disease of C. sativus is corm rot, leading to more than 50% mortality ( Di Primo et al., 2002 ). Corm rot can be caused by various pathogens, but Fusarium oxysporum infection is the main cause ( Hu et al., 2021 ). Various methods to manage plant rot diseases include chemical pesticide application, soil improvement technology, breeding of resistant varieties, and field rotation ( Eshel et al., 2000 ; Shang et al., 2021 ; Dong et al., 2022 ; Wohor et al., 2022 ), but these methods are cumbersome with low efficiency and may cause severe environmental pollution.…”