Isolation and Screening of Phosphate and Potassium Solubilizing Endophytic Bacteria in Maize (Zea mays L.)

Abstract

Maize (Zea mays L.) is a functional food source in Indonesia after rice and wheat. Increasing maize productivity can be done by developing a proper environment and nutritional availability during cultivation. The use of endophytic bacteria as biofertilizers is one prospective approach in reducing the synthetic fertilizers in the soil, and improving the absorption of macronutrients, such as nitrogen, phosphate, and potassium, as well. This study aimed to obtain phosphate solubilizing bacteria (PSB) and potassium solubilizing bacteria (KSB). The samples of maize leaves, stems, and roots were isolated using a serial dilution method and selected on a Pikovskaya (PKV) and Aleksandrov medium. A total of 10 PSB isolates were obtained from PKV selective agar media. The highest density was obtained in the root (8.3x10 5 CFU.mL-1), stems (5.7x10 5 CFU.mL-1), and leaves (4.6x10 5 CFU.mL-1), respectively. Meanwhile, the diversity index of the PSB ranges from 0.7 to 0.78, indicates that the diversity index is high. Four isolates from PSB (AP1.3, AP3.1, AP1.2, and AP1.4) were selected as KSB because of the clear zone formed in Aleksandrov's medium. The highest production of phosphate and potassium was obtained by AP1.3 with value 12.11 µg.mL-1 and 8.38 µg.mL-1 at 72h and 15d, respectively. Therefore, these isolates potential to be used as an organic fertilizer (biofertilizers).

Minerals solubilizing and mobilizing microbiomes: A sustainable approach for managing minerals’ deficiency in agricultural soil

“…from corn soil has been reported for solubilization of potassium sources glauconite and muscovite in culture broth (Baghel et al, 2020). Two potassium solubilizing bacteria, Bacillus licheniformis and Pseudomonas azotoformans , isolated from the rhizospheric rice soil, had increased K availability under optimal conditions (Azizah et al, 2021).…”

Isolation and plant growth promoting properties of bacterial endophytes from wild plant (Wedelia urticifolia) of south Gujarat region

“…Endophytic bacteria A. calcoaceticus and Burkholderia sp. isolated from soybean cultivars showed significant growth promotion of plant by solubilization of mineral phosphate [28][29][30] .…”

“…Thus, the plate screening method fails where the clear zone is inconspicuous or absent. This may be because of the varying diffusion rates of different organic acids secreted by an organism [29] . Phosphate solubilizing activity is determined by microbial biochemical ability to produce ~ 46 ~ and release organic acids, which their carboxylic groups chelate the cations (Mainly Ca) bound to phosphate converting them into soluble forms [17] .…”

Biossolubilização De Rochas E Resíduos De Rochas Como Fontes Alternativas De Fertilizantes Para a Agricultura

“…É possível notar a mudança na coloração após o período de incubação de 48h. O uso do corante azul de bromotimol demonstrou ser eficaz na identificação preliminar de microrganismos capazes de solubilizar potássio, o que também foi corroborado por diversos estudos anteriores (PARMAR; SINDHU, 2013;RAJAWAT et al, 2016;AZIZAH et al, 2020;BOUBEKRI et al, 2021;ONYEWENJO et al, 2021).…”

“…No presente estudo, em todos os ensaios houve diminuição do valor pH e, consequentemente aumento das concentrações de potássio, sugerindo produção de ácidos orgânicos pelas estirpes testadas. Os resultados obtidos foram satisfatórios quando comparados aos resultados recentes obtidos na literatura (AZIZAH et al, 2020;SUN et al, 2020;BOUBEKRI et al, 2021;YONGMEI;PANPAN 2021;CHINACHANTA;SHUTSRIRUNG, 2021).…”