2. Materials and methods2.1 Isolati

2. Materials and methods
2.1 Isolation of endophytic bacteria.
The rice plants were collected from different three types of rice farm; 1 year, 3 years organic rice
farms, and conventional rice farm in Udon Thani, Thailand. The healthy rice plants were carefully
removed, washed under tap water to remove soil and separated to three parts; root, lower stem (5-10 cm.
from root) and higher stem (10-15 cm. form root). All rice tissues were put in beaker, soaked in distilled
water and drained. After that rice tissues were rinsed in 70% ethyl alcohol for 30 seconds and then
sterilized with 0.2% HgCl2 for 3 minutes for root and lower stem, 5 minutes for higher stem. The tissues
were then washed ten times with sterile water, cut into small pieces and homogenized in a blender
containing 90 ml sterile distilled water. Macerated tissues were diluted into 10-1 dilution by adding 9
volumes of sterile distilled water. Serial dilution was made up to 10-5 dilution by taking 1 ml of wellshaken
suspension and adding into 9 ml water blank tubes. 100