RESUMO

The Thar Desert harsher environment harbors a limited diversity of life forms due to extreme conditions like low moisture of sandy soils and high soil temperature. In the present study, osmotolerant bacteria from the Thar soils were isolated and characterized. Bacteria were isolated from 20 soil samples (100g), collected from sand dunes, suspended in water and absolute alcohol. A total of 11 biochemical and morphological tests were carried out for generic identification of bacteria. Osmotic tolerance capacity of isolates was examined on glycerol, NaCl and alcohol; and sequencing of 16S rRNA gene was also performed for bacterial identification. 16S to 23S rRNA internal transcribed spacer analysis (RISA) was done for phylogenetic analysis of isolates. The soil suspended in water contained 2.5×10(6) bacteria/g of soil while alcohol suspended soil had 4.4×10(4) bacteria/g. The 24 bacterial isolates were found tolerant to 26% glycerol, 14% NaCl and 10% of alcohol, and 22 out of 24 isolates were found Gram positive. The results showed that 45.83% and 41.67% bacteria belong to Bacillus spp. and Corynebacterium spp., respectively, while Acinetobacter spp., Aeromonas spp. and Staphylococcus spp. were in equal proportion (4.16% each). Six isolates were selected for 16S rRNA gene sequencing and five were found 95% similar with Bacillus licheniformis whereas one isolate was identified as B. subtilis. All the isolates showed good growth up to 50°C with gradual reduction on subsequent increment of temperature. Out of 24 isolates, six could survive at 65°C while one isolate could grow at 63°C. Growth kinetic studies revealed that the reduction in generation time in solute(s) and temperature stress was more as compared to generation time in plain medium. This study suggests that virgin sand dunes may be a rich source of bacteria, tolerant to osmotrophic solutes, and can be examined for plant growth promotion activity in agriculture. Moreover, study might help to resolve the tactic adopted by microbes to defeat desiccation induced by various types of solutes.

El duro ambiente del desierto de Thar alberga una diversidad de formas de vida limitado debido a sus condiciones extremas, como el bajo contenido de humedad de los suelos arenosos y la alta temperatura del suelo. En el presente estudio, las bacterias osmotolerantes de los suelos de Thar, fueron aislados y caracterizados. Las bacterias fueron aisladas a partir de 20 muestras de suelo (100g), obtenidas de dunas de arena, suspendidas en agua y alcohol absoluto. Un total de 11 pruebas bioquímicas y morfológicas se llevaron a cabo para identificar géneros de bacterias: la capacidad de tolerancia osmótica de los aislados se examinó con glicerol, NaCl y alcohol, y la secuenciación de los genes 16S rRNA se realizó también para la identificación bacteriana. El análisis de espaciadores internos transcritos de 16S a 23S rRNA (RISA) se realizó para los aislamientos de análisis filogenéticos. El suelo suspendido en el agua contuvo 2.5×10(6) bacteria/g de suelo mientras que el suelo con alcohol suspendido presentó 4.4×104 bacteria/g. Los 24 aislados bacterianos se encontraron tolerantes a 26% glicerol, 14% NaCl y 10% de alcohol y 22 de los 24 aislados fueron grampositivas. Los resultados mostraron que 45.83% y 41.67% de las bacterias son Bacillus spp. y Corynebacterium spp., respectivamente, mientras que Acinetobacter spp., Aeromonas spp. y Staphylococcus spp. se presentaron en la misma proporción (4.16% cada uno). Seis aislamientos fueron seleccionados para secuenciación de genes 16S rRNA y 95% fueron similares a Bacillus licheniformis mientras que un aislamiento fue identificado como B. subtilis. Todos los aislamientos mostraron un buen crecimiento a 50º C con reducción gradual en el incremento subsiguiente de la temperatura. Fuera de 24 aislados, 6 podrían sobrevivir a 65ºC mientras que un aislado podría crecer a 63ºC. Estudios de crecimiento cinéticos revelaron que la reducción en el tiempo de generación en soluto (s) y estrés de temperatura fue mayor en comparación con el tiempo de generación en un medio simple. Este estudio sugiere que las dunas de arena virgen pueden ser una fuente rica de bacterias, tolerantes a los solutos osmotróficos y se pueden examinar para la promoción de crecimiento de plantas en la agricultura. Por otra parte, el estudio podría ayudar a resolver la táctica adoptada por los microorganismos para rechazar la desecación inducida por diversos tipos de solutos.

Assuntos

RESUMO

The Thar Desert, a very inhospitable place, accommodates only plant species that survive acute drought, unpredictable precipitation, and those can grow in the limited moisture of sandy soils. Capparis decidua is among one of the few plants able to grow well under these conditions. This species is highly exploited and has been naturally taken, as local people use it for various purposes like food, timber and fuel, although, no management or conservation efforts have been established. The present study was conducted in this arid area of Western Rajasthan (India) with the aim to obtain preliminary molecular information about this group of plants. We evaluated diversity among 46 samples of C. decidua using chemical parameters and random amplified polymorphic DNA (RAPD) markers. Fourteen chemical parameters and eight minerals (total 22 variables) of this species fruits were estimated. A total of 14 RAPD primers produced 235 band positions, of which 81.27% were polymorphic. Jaccard's similarity coefficients for RAPD primers ranged from 0.34 to 0.86 with a mean genetic similarity of 0.50. As per observed coefficient of variation, NDF (Neutral Detergent Fiber) content was found to be the most variable trait followed by starch and soluble carbohydrate. The Manhattan dissimilarity coefficient values for chemical parameters ranged between 0.02-0.31 with an average of 0.092. The present study revealed a very low correlation (0.01) between chemical parameters and RAPD-based matrices. The low correlation between chemical- and RAPD-based matrices indicated that the two methods were different and highly variable. The chemical-based diversity will assist in selection of nutritionally rich samples for medicinal purpose, while genetic diversity to face natural challenges and find sustainable ways to promote conservation for future use.

Assuntos

RESUMO

The Thar Desert, a very inhospitable place, accommodates only plant species that survive acute drought, unpredictable precipitation, and those can grow in the limited moisture of sandy soils. Capparis decidua is among one of the few plants able to grow well under these conditions. This species is highly exploited and has been naturally taken, as local people use it for various purposes like food, timber and fuel, although, no management or conservation efforts have been established. The present study was conducted in this arid area of Western Rajasthan (India) with the aim to obtain preliminary molecular information about this group of plants. We evaluated diversity among 46 samples of C. decidua using chemical parameters and random amplified polymorphic DNA (RAPD) markers. Fourteen chemical parameters and eight minerals (total 22 variables) of this species fruits were estimated. A total of 14 RAPD primers produced 235 band positions, of which 81.27% were polymorphic. Jaccard s similarity coefficients for RAPD primers ranged from 0.34 to 0.86 with a mean genetic similarity of 0.50. As per observed coefficient of variation, NDF (Neutral Detergent Fiber) content was found to be the most variable trait followed by starch and soluble carbohydrate. The Manhattan dissimilarity coefficient values for chemical parameters ranged between 0.02-0.31 with an average of 0.092. The present study revealed a very low correlation (0.01) between chemical parameters and RAPD-based matrices. The low correlation between chemical- and RAPD-based matrices indicated that the two methods were different and highly variable. The chemical-based diversity will assist in selection of nutritionally rich samples for medicinal purpose, while genetic diversity to face natural challenges and find sustainable ways to promote conservation for future use.

El desierto de Thar, un lugar muy inhóspito, alberga sólo a las especies de plantas capaces de resistir a condiciones de sequía extrema, a las precipitaciones impredecibles, y a las plantas que pueden crecer en la humedad limitada de los suelos arenosos. Capparis decidua se encuentra entre una las pocas plantas capaces de crecer bien en estas condiciones. Esta especie es altamente explotada y se ha tomado de forma natural, así los habitantes locales las han usado para varios propósitos, como alimento, madera y combustible, aunque sin ningún programa de manejo o esfuerzo por conservación. El presente estudio se llevó a cabo en esta zona árida del oeste de Rajastán (India) con el objetivo de obtener información molecular preliminar sobre este grupo de plantas. Se evaluó la diversidad entre 46 muestras de C. decidua usando parámetros químicos y marcadores de ADN polimórfico amplificado al azar (RAPD por sus siglas en inglés). Catorce parámetros químicos y ocho minerales (22 variables en total) de los frutos de esta especie fueron estimados. Un total de 14 cebadores para RAPD produjeron 235 posiciones de bandas, de las cuales 81.27% fueron polimórficas. El coeficiente de similitud de Jaccard para los cebadores del RAPD varió entre 0.34 y 0.86 con un promedio de similitud genética de 0.50. De acuerdo con el coeficiente de variación observado, se encontró que el contenido de NDF fue el rasgo más variable, seguido por el almidón y los carbohidratos solubles. Los valores del coeficiente de disimilitud de Manhattan para los parámetros químicos osciló entre 0.02-0.31 con un promedio de 0.092. El presente estudio reveló una correlación muy baja (0.01) entre los parámetros químicos y las matrices basadas en RAPD. La baja correlación entre las matrices químicas y la basada en RAPD indicó que los dos métodos fueron diferentes y altamente variables. El estudio de la diversidad basada en su química ayudará en la selección de muestras nutricionalmente ricas para fines medicinales, mientras que la diversidad genética ayudará a enfrentar los desafíos naturales y encontrar formas sostenibles para promover la conservación de esta plana para uso futuro.

Assuntos

RESUMO

The Thar Desert harsher environment harbors a limited diversity of life forms due to extreme conditions like low moisture of sandy soils and high soil temperature. In the present study, osmotolerant bacteria from the Thar soils were isolated and characterized. Bacteria were isolated from 20 soil samples (100 g), collected from sand dunes, suspended in water and absolute alcohol. A total of 11 biochemical and morphological tests were carried out for generic identification of bacteria. Osmotic tolerance capacity of isolates was examined on glycerol, NaCI and alcohol; and sequencing of 16S rRNA gene was also performed for bacterial identification. 16S to 23S rRNA internal transcribed spacer analysis (RISA) was done for phylogenetic analysis of isolates. The soil suspended in water contained 2.5 x 10(6) bacteria/g of soil while alcohol suspended soil had 4.4 x 10(4) bacteria/g. The 24 bacterial isolates were found tolerant to 26% glycerol, 14% NaCI and 10% of alcohol, and 22 out of 24 isolates were found Gram positive. The results showed that 45.83% and 41.67% bacteria belong to Bacillus spp. and Corynebacterium spp., respectively, while Acinetobacter spp., Aeromonas spp. and Staphylococcus spp. were in equal proportion (4.16% each). Six isolates were selected for 16S rRNA gene sequencing and five were found 95% similar with Bacillus licheniformis whereas one isolate was identified as B. subtilis. All the isolates showed good growth up to 50 degrees C with gradual reduction on subsequent increment of temperature. Out of 24 isolates, six could survive at 65 degrees C while one isolate could grow at 63 degrees C. Growth kinetic studies revealed that the reduction in generation time in solute(s) and temperature stress was more as compared to generation time in plain medium. This study suggests that virgin sand dunes may be a rich source of bacteria, tolerant to osmotrophic solutes, and can be examined for plant growth promotion activity in agriculture. Moreover, study might help to resolve the tactic adopted by microbes to defeat desiccation induced by various types of solutes.

Assuntos