Banca de DEFESA: LILIANDRA BARRETO EMIDIO GOMES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LILIANDRA BARRETO EMIDIO GOMES
DATE: 15/12/2022
TIME: 13:30
LOCAL: Departamento de Solos da UFRRJ
TITLE:

Use of inoculant produced in co-cultivation of two species of diazotrophic bacteria for the purpose of promoting the growth of maize 

KEY WORDS:

Growth promoting bacteria, Simultaneous cultivation, plant phytohormones

PAGES: 30
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Microbiologia e Bioquímica do Solo
SUMMARY:

The selection of diazotrophic bacteria for crops of agricultural importance makes it possible to reduce the loss of nitrogen fertilizers and increase productivity gains. The promotion of plant growth by stimulating the absorption of nutrients, especially those with greater mobility in the soil, is an important alternative to increase the income of rural producers. This research sought to employ different microbiological techniques to clarify the establishment and efficiency of mixed inoculants (co-cultivation), comparing them to individual inoculants of diazotrophic bacteria selected for application in sugarcane. The objective was to evaluate the efficiency of an inoculants containing Gluconacetobacter diazotrophicus (Gd-BR11281) and Paraburkholderia tropica (Pt-BR11366) co-cultivated in the initial development and in the root architecture of corn used as a model plant for plant promotion and to analyze the production of phytohormone in the co-cultivation compared to the individual growth of the two strains. The establishment of inoculated bacteria was also observed using the FISH and qPCR technique. Complementing the study, bioassays were carried out with different concentrations of growth regulators such as AIA, GA3 and Zeatin in the initial growth of corn roots and comparison with the effects of inoculation and quantification of phytohormone production by the strains studied through the technique of monitoring of selected ions by GC-MS. The experiments in a greenhouse were evaluated for mass gains and root parameters. The two strains adapted well to the culture conditions and despite the different metabolism there was no growth inhibition between them, being possible to produce the inoculant from the simultaneous cultivation. Pt-BR11366 obtained a 10 times higher growth compared to Gd-BR11281. The bioassays showed that 40 µM of AIA and 20 µM of GA3 and Zeatin stimulate root growth in corn, compared to the control being compared to the co-culture and to the supernatant, without the presence of cells. These showed increments of 69 and 84% for length, 47 and 50% for the parameters projected area and surface area and 28 and 22% for volume, respectively. In addition, the root growth responses of the co-culture and the supernatant were like the responses of the best concentration of the tested phytohormones. These results were corroborated by the quantification of phytohormones, which showed that the simultaneous cultivation has a higher concentration of AIA (19.6 ng/mL), GA3 (20.5 nm/mL) and Zeatin (10.7 nm/mL) than the individual cultures and supernatant extraction intensified these concentrations: AIA (29.8 ng/mL), GA3 (29.1 nm/mL) and Zeatin (14.3 nm/mL). The FISH technique allowed the visualization of the strains inside the roots and proving that the inoculated bacteria establish themselves inside the plant and that both cohabit the same niches, preferring the regions of the apoplast, root surface, tip, root hairs and root differentiation zones. secondary. Corn inoculated with the two co-cultured bacteria differed from the treatment with them applied separately, being superior to the control. 

COMMITTEE MEMBERS:
Presidente - ***.052.847-** - VERONICA MASSENA REIS - EMBRAPA
Interna - 1815763 - IRENE DA SILVA COELHO
Externo à Instituição - CARLOS HENRIQUE SALVINO GADELHA MENESES - UEPB
Externo à Instituição - LUIS HENRIQUE DE BARROS SOARES - EMBRAPA
Externo à Instituição - STEFAN SCHWAB - EMBRAPA