Potential of acetoin-Producing Rizobacteria from rhisospheres of plants of Graminae grown in Merauke Indonesia to promote the growth of rice

Abstract Acetoin (3-hydroxybutan-2-butanone) is a volatile compound produced by bacteria that function as a plant growth promoting agent. Acetoin plays an important role in stimulating the process of plant organogenesis (morphogenesis) for faster formation of plant organs and faster plant growth. Besides being able to increase the growth, acetoin can also induce plant resistance, increase the formation of the number of branches, roots and flowers so that acetoin can increase crop productivity. This study aims to isolate and identify acetoin-producing rhizobacteria which can promote the growth of rice plants. Rhizobacteria isolation was carried out from the rhizospheres of plants of Graminae grown in Merauke, Indonesia. Identification was made molecularly through 16S rRNA gene analysis. This study obtained four rhizobacteria isolates that produce acetoin which act as a promoter for rice plant growth, namely isolates Pd13, Rg21, Pd7, and Bb7. These four rhizobacteria isolates can increase the number of lateral roots of rice seedlings aged 14 days after planting with percentage of increase by 60.68%; 40.24%: 32.61%, and 19.56% compared to controls. The identification results show that the species of isolates of rhizobacteria are Myroides odoratimimus Pd13 and Bb7, Providencia vermicola Rg21, and Serratia marcescens Pd7. They have the potential to be developed as a promoter for plant growth and increase the yield of rice plants, especially in Marauke Papua, Indonesia. Keywords: Rizobacteria, acetoin, growth promotion, rice yield