Indole Acetic Acid-Producing and Phosphate-Solubilizing Bacteria From the Rhizosphere of Clove (Syzygium Aromaticum L.) in Bali, Indonesia

Abstract

Clove plants are routinely fertilized with synthetic fertilizer to increase yield. The use of synthetic fertilizer reduces soil productivity. Biofertilizer can be used as an alternative for increasing soil fertility. The goal of this study was to determine the potency of bacteria isolates capable of producing indole acetic acid (IAA) hormone and solubilizing phosphate, and to identify bacteria species from the rhizosphere of clove plants. Soil samples were collected from the clove plants’ rhizosphere, environmental parameters were measured, the potency of IAA-producing and phosphate-solubilizing bacteria was analyzed, and bacteria were molecularly identified. After 48 hours of incubation, isolate TCKI 5 from Karangasem produced the highest IAA hormone levels (19.64 ppm), and isolate TCBP 6 from Buleleng had the highest index of solubilizing phosphate (1.91). A compatibility test between the three best isolates of IAA hormone-producing and phosphate-solubilizing bacteria revealed that TCKI 5 was able to associate with TCBP 6. Isolate TCKI 5 was identified as Leclercia adecarboxylata C107 with a 99.92% similarity, and isolate TCBP 6 as Burkholderia cepacia GJ8 with a 99.61% similarity.
 Keywords: Bacteria, clove, Indole Acetic Acid, phosphate, rhizosphere