| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1488-1 | ||||
Resumo:The invasive weed Cyperus haspan, commonly known as "tiririca" ranks among the top 10 most aggressive global weeds, infesting a variety of crops such as soybeans and maize, where it competes for vital resources including water, light, and nutrients. Its remarkable resilience in diverse and challenging climate and soil conditions underscores its robust nature. This study aimed to isolate and characterize bacteria from both the rhizospheric soil and bulbs of Cyperus haspan, with the objective to assess their capacity for nutrient solubilization and the production of plant growth hormones. A total of 43 bacteria were isolated, divided into two groups: those from rhizospheric soil (30) and root endophytes (13). In vitro tests included inorganic phosphate solubilization (IPS), which was evaluated using the NBRIP medium and categorized isolates as having low (SI up to 2), moderate (SI between 3 and 4), or high (SI > 4) solubilization capacity. For the production of the plant growth hormone indole-3-acetic acid (IAA), isolated colonies were inoculated in a liquid TSA 10% (Tripcase Soy Agar) medium with the addition of L-tryptophan. The cultures were incubated in the absence of light at 28°C for 24 hours. Subsequently, 500µL of the bacterial culture were mixed with 500µL of the Salkowski reagent and incubated for 30 minutes at 28°C, in the absence of light, to detect IAA production using a colorimetric method. The bacteria were also identified as Gram-positive and Gram-negative through Gram staining. Results demonstrated that 51.16% of the bacteria exhibited positive results for IPS, with 72.73% originating from the rhizosphere and 27.27% from endophytic sources. Among these, 68.18% were classified as having a moderate solubilization capacity, and 31.82% as having a low capacity. Concerning IAA-producing bacteria, concentrations ranged from 0 (bacteria that did not produce IAA) to 129.65 µg/mL, with an average of 42.51 µg/mL. Gram staining identified 51.22% of the bacteria as Gram-positive and 48.78% as Gram-negative. Based on these findings, bacteria exhibiting the greatest potential for phosphate solubilization and IAA production will be selected for germination tests, involving the inoculation of these microorganisms into seeds. This research has the potential to contribute to the development of new biological products aimed at enhancing crop productivity. Palavras-chave: Rhizospheric microorganisms, Bacterial isolation, Plant growth promotion, Nutrient solubilization, Microbial characterization Agência de fomento:Fundação Araucária e Biopark Educação | |||||