RESUMEN
The biofortification approach has been widely used to enhance mineral nutrients in staple foods such as rice (Oryza sativa). In the present study, iron-solubilizing plant growth-promoting bacteria (PGPB) were evaluated for iron fortification of rice grains and NPK via field experiments. Inoculation of iron-solubilizing bacteria showed significant improvements in growth parameters, such as plant height, root and shoot dry weight, panicle length, grain yield, and nitrogen, potassium, phosphorus, and iron uptake. The mobilization of iron was ranged from 53.88% to 89.05% in rice grains compared to the uninoculated plants. The present study results revealed that application of PGPB strains is vital approach to combat the problem of iron deficiency in rice and subsequently in humans.
Asunto(s)
Oryza , Suelo , Humanos , Hierro/metabolismo , Disponibilidad Biológica , Bacterias/metabolismoRESUMEN
In this study, Cu-tolerant PGP bacteria were isolated from the contaminated soils of Tapi (Surat, Gujarat, India). From a set of 118 bacteria isolated from the contaminated soil, the isolate RBTS7 was found to be efficient in tolerating 0.3 g (w/v) Cu. The isolate was identified as Stenotrophomonas maltophilia, based on biochemical and 16S rRNA gene sequencing. Further, the isolate was also found to produce indole acetic acid (140 µg/ml) and siderophore, and solubilize potassium. Inoculation study was carried out in the presence and absence of Cu in the greenhouse. The results revealed that S. maltophilia enhanced plant growth and biomasses compared to control. In addition to plant growth attributes, the isolate also enhanced chlorophyll a and b (434.1 and 496.7%) contents and antioxidant properties such as proline (168.2%), total phenolic compounds (33.5%), and ascorbic acid oxidase (62.3%) compared to control with Cu and without Cu. Inoculation of S. maltophilia + Cu enhanced the uptake of Cu in maize root (77.4%) and stem (112.0%) compared to Cu-stressed control. The results clearly indicated the inoculation of S. maltophilia reduced the toxicity of Cu and in turn enhanced the plant growth and mobilization of Cu to the plant parts.
Asunto(s)
Contaminantes del Suelo , Stenotrophomonas maltophilia , Biodegradación Ambiental , Biofortificación , Clorofila A , Cobre , India , Raíces de Plantas , ARN Ribosómico 16S , Zea maysRESUMEN
In this study, chromium (Cr)-tolerant bacteria were test for their efficiency in alleviating Cr stress in Cicer arietinum plants. On the basis of 16S rRNA gene analysis, the isolates were identified belonging to genus Stenotrophomonas maltophilia, Bacillus thuringiensis B. cereus, and B. subtilis. The strains produced a considerable amount of indole-3-acetic acid in a medium supplemented with tryptophan. The strains also showed siderophore production (S2VWR5 and S3VKR17), phosphorus production (S1VKR11, S3VKR2, S3VKR16, and S2VWR5), and potassium solubilization (S3VKR2, S2VWR5, and S3VKR17). Furthermore, the strains were evaluated in pot experiments to assess the growth promotion of C. arietinum in the presence of chromium salts. Bacterization improved higher root and shoot length considerably to 6.25%-60.41% and 11.3%-59.6% over the control. The plants also showed increase in their fresh weight and dry weight in response to inoculation with Cr-tolerant strains. The accumulation of Cr was higher in roots compared to shoots in both control and inoculated plants, indicating phytostabilization of Cr by C. arietinum. However, phytostabilization was found to be improved manifold in inoculated plants. Apart from the plant attributes, the amendment of soil with Cr and Cr-tolerant bacteria significantly increased the content of total chlorophyll and carotenoids, suggesting the inoculant's role in protecting plants from deleterious effects. This work suggests that the combined activity of Cr-tolerant and plant growth-promoting (PGP) properties of the tested strains could be exploited for bioremediation of Cr and to enhance the C. arietinum cultivation in Cr-contaminated soils.
Asunto(s)
Bacillus/metabolismo , Cromo/metabolismo , Cicer/microbiología , Desarrollo de la Planta , Contaminantes del Suelo/metabolismo , Stenotrophomonas maltophilia/metabolismo , Estrés Fisiológico , Bacillus/genética , Biodegradación Ambiental , Cicer/efectos de los fármacos , Cicer/metabolismo , Medios de Cultivo/química , Ácidos Indolacéticos/metabolismo , Desarrollo de la Planta/fisiología , ARN Ribosómico 16S/genética , Microbiología del Suelo , Stenotrophomonas maltophilia/genéticaRESUMEN
Iron (Fe) is one of the essential micronutrients for all living organisms. Despite its abundance in most of the contaminated soil, it is usually in unavailable forms. The unavailable form of Fe could be mobilized to plants by the use of microorganisms. This study was carried out to show that the Fe-contaminated field soils could be used to accumulate Fe in the plant parts using bacterial inoculation. For this, from a set of bacterial isolates, four Fe-tolerant bacteria were selected and identified based on 16S rRNA gene sequencing. The Fe-tolerant bacteria belonged to the genus Bacillus toyonensis (MG430287), Rhodococcus hoagii (MG432495), Lysinibacillus mangiferihumi (MG432492), and Lysinibacillus fusiformis (MG430290). Screening of plant growth-promoting properties of these isolates revealed that all isolates were able to produce indole acetic acid (50.0-84.0 µg/ml), siderophore, and potassium solubilization (except R. hoagii). Pot assay using Fe-contaminated ((8.07-8.35 g kg-1) soils River Directorate of India) revealed that Fe-tolerant bacteria enhanced the growth of Brassica juncea and its biomass. Besides the improved plant growth, the inoculated plants also showed an overall percentage increase in the uptake of iron in root, stem, and leaf (57.91-128.31%) compared with uninoculated plants. In addition to enhanced plant growth attributes, the isolates also improved the total chlorophyll content and antioxidant properties such as total phenol, proline, and ascorbic acid oxidase. Thus, the results clearly indicated that these isolates could be used as a bioinoculant to improve the sequestration of Fe from the contaminated soils and alleviation of Fe stress in plants.