Isolation and screening of calcareous and non calcareous soil rhizobacteria producing osmoprotectant and indol acetic acid in Gunung Kidul, Yogyakarta, Indonesia

Ahmad Yunus, Sudadi, W. S. Dewi, Yekti Maryani

Abstract: Gunung Kidul regency is geographically divided into calcareous and non calcareous soils. Calcareous soil has limitations including mostly hilly terrain, deep hardpan layer, calcareous stone and shallow cultivated layer. Furthermore, it has disadvantageous climate such as long dry season, short rainy season and high temperature. Therefore, this research aimed to isolate rhizobacteria. Sampling of soil was conducted in 6 types of soil on different sites in Gunung Kidul with calcareous and non calcareous soils, during the dry season. Rhizobacteria isolates were tested on media M63 added with 0.3M NaCl. Then, the rhizobacteria isolates were tested on resistance to osmotic stress on media M63 added with NaCl concentrations of 0.3M, 0.5M, 0.7M, 0.9M and 1M. There were 15 isolates obtained having resistance to M63 + 0.3M NaCl. Calcareous isolates having resistance to osmotic stress are from strains A124-k and Ver5-k. Isolate of strain Al24-k can produce glycine betaine of 9.7756 mg/g cell and isolate of Ver5-k can produce glycine betaine of 11.1221 mg/g cell. Non calcareous isolates having resistance to osmotic stress are from strains Ul24-a and Ul16-k. Isolate of strain Ul16-k can produce glycine betaine of 5,6616 mg/g cell and isolate of Ul24-a can produce glycine betaine of 7,9152 mg/g cell. Strain Al24-k isolate form IAA 7.089,3185 ppm/g cell, while strain Ver5-k forms 9.619,9582 ppm/g cell, Ull6-k forms 6.713,4572 ppm/g cell and Ul24-a forms 6.673,0378 ppm/g cell. Calcareous isolates strains A124-k and Ver5-k produce glycine betaine and IAA higher than non calcareous isolates strains Ul16-k and Ul24-a.

Keywords: calcareous soils; glycine betaine; IAA; osmotic stress; rhizobacteria

Date published: 2019-02-08