Identification of acid-resistant PGPR potential as stem rot antagonists and biofertilizers from peatlands of Central Kalimantan

Sweet corn (Zea mays L. saccharata) is a commodity of economic value, and cultivation constraints include stem rot disease by Fusarium sp. and acidic peat soil. To control this disease, farmers use destructive methods or using chemical pesticides that hurt the environment. Therefore, environmentally friendly control is needed, including using Plant Growth Promoting Rhizobacteria (PGPR). PGPR is a bacterium that lives around plant roots or in plant root tissue and has the potential as a biostimulant, biofertilizer, and bioprotectant. Peatlands are acidic and poor in nutrients. Therefore, soil amendments are needed. Therefore, it is necessary to identify and characterize PGPR which is capable of acting as a biofertilizer, biostimulant, and biofertilizer. This study aims to obtain rhizobacteria isolates that act as biofertilizers, biostimulants, and bioprotectants and are resistant to acid soils and study the role of indigenous PGPR in controlling corn stem rot disease in vitro. The research used descriptive, quantitative, and qualitative methods. PGPR isolates were obtained from peatlands in Kelampangan Village, Central Kalimantan, Indonesia. The results showed that six rhizobacteria isolates functioned as bioprotectants and were tolerant of acidity in peat soils, namely Pantoea stewartii, Burkholderia cepacia, Pseudomonas luteola, Bacillus cereus, Bacillus subtilis, and Brevibacillus laterosporus, and four isolates were able to inhibit the development of the Fusarium sp is Burkholderia cepacia, Bacillus cereus, Bacillus subtilis, and Brevibacillus laterosporus. Two isolates were found to be able to solubilize phosphate so that they have potential as biofertilizers, such as Burkholderia cepacia and Brevibacillus laterosporus.