Enhancement of the Aroma Compound 2-Acetyl-1-pyrroline in Thai Jasmine Rice (Oryza sativa) by Rhizobacteria under Salt Stress

Thai jasmine rice (Oryza sativa L. KDML105), particularly from inland salt-affected areas in Thailand, is both domestically and globally valued for its unique aroma and high grain quality. The key aroma compound, 2-acetyl-1-pyrroline (2AP), has undergone a gradual degradation due to anthropogenic soil salinization driven by excessive chemical input and climate change. Here, we propose a cheaper and an ecofriendly solution to improve the 2AP levels, based on the application of plant growth-promoting rhizobacteria (PGPR). In the present study, nine PGPR isolates from rice rhizosphere were investigated for the 2AP production in liquid culture and the promotion potential for 2AP content in KDML105 rice seedlings under four NaCl concentrations (0, 50, 100, and 150 mM NaCl). The inoculation of 2AP-producing rhizobacteria resulted in an increase in 2AP content in rice seedling leaves with the maximum enhancement from Sinomonas sp. ORF15-23 at 50 mM NaCl (19.6 µg·kg−1), corresponding to a 90.2% increase as compared to the control. Scanning electron microscopy confirmed the colonization of Sinomonas sp. ORF15-23 in the roots of salinity-stressed KDML105 seedlings. Our results provide evidence that Sinomonas sp. ORF15-23 could be a promising PGPR isolate in promoting aroma level of Thai jasmine rice KDML105 under salt stress.

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Isolation and Characterization of Indigenous Plant Growth-Promoting Rhizobacteria and Their Effects on Growth at the Early Stage of Thai Jasmine Rice (Oryza sativa L. KDML105)

Arabian Journal for Science and Engineering ◽

10.1007/s13369-017-2999-8 ◽

2017 ◽

Vol 43 (7) ◽

pp. 3359-3369 ◽

Cited By ~ 2

Author(s):

Thanakorn Saengsanga

Keyword(s):

Oryza Sativa ◽

Oryza Sativa L ◽

Early Stage ◽

Plant Growth Promoting Rhizobacteria ◽

Isolation And Characterization ◽

Indigenous Plant ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Jasmine Rice

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Isolation and identification of salt-tolerant plant-growth-promoting rhizobacteria and their application for rice cultivation under salt stress

Canadian Journal of Microbiology ◽

10.1139/cjm-2019-0323 ◽

2020 ◽

Vol 66 (2) ◽

pp. 144-160 ◽

Cited By ~ 2

Author(s):

Shahnaz Sultana ◽

Sumonta C. Paul ◽

Samia Parveen ◽

Saiful Alam ◽

Naziza Rahman ◽

...

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Oryza Sativa L ◽

Plant Growth Promoting Rhizobacteria ◽

Salt Resistance ◽

Salt Tolerant ◽

Isolation And Identification ◽

Enhanced Expression ◽

Plant Growth Promoting ◽

Growth Promoting

Growth and productivity of rice are negatively affected by soil salinity. However, some salt-tolerant rhizosphere-inhabiting bacteria can improve salt resistance of plants, thereby augmenting plant growth and production. Here, we isolated a total of 53 plant-growth-promoting rhizobacteria (PGPR) from saline and non-saline areas in Bangladesh where electrical conductivity was measured as >7.45 and <1.80 dS/m, respectively. Bacteria isolated from saline areas were able to grow in a salt concentration of up to 2.60 mol/L, contrary to the isolates collected from non-saline areas that did not survive beyond 854 mmol/L. Among the salt-tolerant isolates, Bacillus aryabhattai, Achromobacter denitrificans, and Ochrobactrum intermedium, identified by comparing respective sequences of 16S rRNA using the NCBI GenBank, exhibited a higher amount of atmospheric nitrogen fixation, phosphate solubilization, and indoleacetic acid production at 200 mmol/L salt stress. Salt-tolerant isolates exhibited greater resistance to heavy metals and antibiotics, which could be due to the production of an exopolysaccharide layer outside the cell surface. Oryza sativa L. fertilized with B. aryabhattai MS3 and grown under 200 mmol/L salt stress was found to be favoured by enhanced expression of a set of at least four salt-responsive plant genes: BZ8, SOS1, GIG, and NHX1. Fertilization of rice with osmoprotectant-producing PGPR, therefore, could be a climate-change-preparedness strategy for coastal agriculture.

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Overexpression of GSK3-like Kinase 5 (OsGSK5) in rice (Oryza sativa) enhances salinity tolerance in part via preferential carbon allocation to root starch

Functional Plant Biology ◽

10.1071/fp16424 ◽

2017 ◽

Vol 44 (7) ◽

pp. 705 ◽

Cited By ~ 7

Author(s):

Maysaya Thitisaksakul ◽

Maria C. Arias ◽

Shaoyun Dong ◽

Diane M. Beckles

Keyword(s):

Oryza Sativa ◽

Salt Stress ◽

Salinity Tolerance ◽

Carbon Allocation ◽

Oryza Sativa L ◽

Rice Seedling ◽

Shoot Biomass ◽

Salt Shock ◽

Seedling Roots ◽

Root Starch

Rice (Oryza sativa L.) is very sensitive to soil salinity. To identify endogenous mechanisms that may help rice to better survive salt stress, we studied a rice GSK3-like isoform (OsGSK5), an orthologue of a Medicago GSK3 previously shown to enhance salinity tolerance in Arabidopsis by altering carbohydrate metabolism. We wanted to determine whether OsGSK5 functions similarly in rice. OsGSK5 was cloned and sequence, expression, evolutionary and functional analyses were conducted. OsGSK5 was expressed highest in rice seedling roots and was both salt and sugar starvation inducible in this tissue. A short-term salt-shock (150 mM) activated OsGSK5, whereas moderate (50 mM) salinity over the same period repressed the transcript. OsGSK5 response to salinity was due to an ionic effect since it was unaffected by polyethylene glycol. We engineered a rice line with 3.5-fold higher OsGSK5 transcript, which better tolerated cultivation on saline soils (EC = 8 and 10 dS m–2). This line produced more panicles and leaves, and a higher shoot biomass under high salt stress than the control genotypes. Whole-plant 14C-tracing and correlative analysis of OsGSK5 transcript with eco-physiological assessments pointed to the accelerated allocation of carbon to the root and its deposition as starch, as part of the tolerance mechanism.

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