In vitro screening of siderophore-producing rice root endophytic bacteria from up-land paddies in north-western Vietnam for plant growth-promoting activities

Van Phuong Nguyen; Thi Phuong Nga Mai; Duc Chung Mai; Hoang Ha Chu; Tran Binh Le

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In vitro screening of siderophore-producing rice root endophytic bacteria from up-land paddies in north-western Vietnam for plant growth-promoting activities

Author: Van Phuong Nguyen ^{1
,

2} ; Thi Phuong Nga Mai ³ ; Duc Chung Mai ⁴ ; Hoang Ha Chu ⁵ ; Tran Binh Le ⁵
Author Information

1. Graduate University of Science and Technology (GUST), Vietnam Academy of Science and Technology (VAST), Hanoi 10000, Vietnam. &
2. Department of Life Sciences, University of Science and Technology of Hanoi (USTH), VAST, Hanoi 10000, Vietnam.
3. Department of Life Sciences, University of Science and Technology of Hanoi (USTH), VAST, Hanoi 10000, Vietnam.
4. Agricultural Genetics Institute, Hanoi 122000, Vietnam.
5. Institute of Biotechnology, VAST, Hanoi 10000, Vietnam.
Publication Type:Journal Article
Keywords: Rice root endophytic bacteria; Siderophore production; Plant growth-promoting traits; Upland rice; MALDI-TOF MS
MeSH: Oryza--microbiology; Siderophores; Plant Growth Regulators; Vietnam
From:Malaysian Journal of Microbiology 2022;18(1):17-26
CountryMalaysia
Language:English
Abstract: Aims:Endophytic bacteria (EB) living inside plant tissues possess different beneficial traits including siderophore production and other plant growth-promoting (PGP) activities. Siderophore-producing EB promote host plant growth by secreting ferrum in iron-deficient conditions. This study screened 19 siderophore producers in vitro, isolated from upland rice roots grown in mountain farms of Tung Village, Nậm Có Commune, Mù Cang Chải District, Yên Bái Province, Vietnam, for PGP traits, including phosphate solubilisation, indole-3-acetic acid (IAA), ammonia, gelatinase, amylase and catalase production.
Methodology and results:The bacteria were identified by Matrix assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF MS). All 19 isolates were identified as genera Pseudomonas, Enterobacter, Pantoe, Bacillus, Burkholderia, Staphylococcus, Ralstonia and Cronotacter. The isolates produced catalase and ammonia. The amount of ammonia ranged from 60.74 ± 0.14 to 466.72 ± 0.18 mg/L. Out of the 19 siderophore producers, 17 (89.47%) were able to solubilise phosphate with solubilisation index (PSI) ranging from 1.12 ± 0.07 to 2.14 ± 0.15. The qualitative assays identified 12 isolates (63.15%) positive for IAA production with a tryptophan concentration of 5 mM, whereas 15 (78.94%) and 17 (89.47%) isolates were positive for gelatin and starch hydrolysis, respectively. Especially, 7 isolates were found to be positive for all tested assays in vitro including Pseudomonas rhodesiae (NC2), Enterobacter asburiae (NC50), Pantoea ananatis (NC63), Bacillus cereus (NC64), Burkholderia cenocepacia (NC110), Staphylococcus sciuri (NC112) and Ralstonia pickettii (NC122).
Conclusion, significance and impact of study:This study serves as crucial findings of multi-trait plant growth-promoting endophytic bacteria isolated from upland rice root in north-western Vietnam. The seven potential isolates positive for all tested assays could be effective PGP bacteria for bio-inoculants.
Full text:20.2022my00021.pdf