Banca de DEFESA: ÉRICO ATÍLIO DE PAIVA TELES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ÉRICO ATÍLIO DE PAIVA TELES
DATE: 02/03/2023
TIME: 13:00
LOCAL: Departamento de Solos, Sala 24
TITLE:

Selection and identification of halophilic and halotolerant bacteria that solubilize phosphate.

KEY WORDS:

Salt stress. Rhizobacteria. Phosphate solubilization.

PAGES: 50
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

Salinization severely affects agricultural production worldwide. This process occurs naturally, but is greatly aggravated and accelerated by human actions. Another issue that limits agricultural production is the low availability of phosphorus for plants in the soil. This occurs due to the high affinity of soluble phosphorus to other elements present in the soil, which reduces the efficiency of phosphate fertilizers. The rhizosphere of halophytic plants harbors several microorganisms that contribute for the establishment of these plants under saline stress, reducing the deleterious effects of salinity and through attributes of plant growth promotion. The use of phosphate-solubilizing bacterial inoculants has been considered a promising approach for establishing and increasing crop production under conditions of nutritional deficiency and/or other environmental stresses such as soil salinity. Thus, the aim of this work was to identify 47 bacterial isolates from the rhizosphere of halophyte plants by sequencing of the 16S rDNA gene in addition to evaluating their development in increasing concentrations of NaCl and classifying them according to salinity response and  phosphate solubilization activity in culture medium. Phosphate solubilization capacity was evaluated using the mineral phosphates CaHPO4 (dibasic calcium phosphate) and AlPO4 (aluminum phosphate) in solid and liquid culture media. The genera identified were Bacillus sp., Enterobacter sp., Halobacillus sp., Halomonas sp., Kushneria sp., Pantoea sp., Pseudomonas sp., Oceanobacillus sp. and Staphylococcus sp., and the most abundant among isolates were of the genera Enterobacter sp, Pseudomonas sp. and Bacillus sp. It was not possible to identify isolate 145, which had greater identity with sequences from non-cultivable bacteria deposited at the NCBI. 15 isolates from the genera Bacillus sp., Enterobacter sp., Halobacillus sp., Halomonas sp., Pantoea sp., Pseudomonas sp. and Staphylococcus sp. were classified as halophilic and 32 isolates of the genus Bacillus sp. Enterobacter sp., Halomonas sp., Kushneira sp., Pseudomonas sp., Oceanobacillus sp. and Staphylococcus sp. were classified as halotolerant. All isolates developed from colonies on solid medium containing insoluble phosphate as sources, but three of them did not show a solubilization halo in the medium with calcium phosphate. No halo was observed in the media containing aluminum phosphate. The isolates that developed the greatest ability to solubilize phosphorus from calcium phosphate were Kushneira sp. (102), Enterobacter sp. (186), isolate 145 and Bacillus sp. (120), 989.53 mg/L, 956.37 mg/L, 783, 82 mg/L and 757.60 mg/L, respectively. For the solubilization of aluminum phosphate, the isolates that presented the best results were Bacillus sp. (89), Oceanobacillus sp. (94), which raised soluble P by 61.10 mg/L and 45.82 mg/L, respectively. Pantoea sp. (150), Pseudomonas sp. (183) showed considerable solubilization activity for calcium aluminum phosphate, 436.04 mg/L and 23.89 mg/L for the first isolate and 376.49 mg/L and. 21.28 mg/L for the second. These results confirm that the rhizosphere of halophytic plants harbor bacteria from different taxa with phosphate solubilization capacity.

COMMITTEE MEMBERS:
Interno - 2213075 - EVERALDO ZONTA
Presidente - 1815763 - IRENE DA SILVA COELHO
Externa à Instituição - MARCIA REED RODRIGUES COELHO - EMBRAPA