ISOLATION AND DETERMINATION OF SOME CHARACTERISTICS OF ENDOPHYTIC BACTERIA IN Houttuynia cordata Thunb IN SOC TRANG PROVINCE

Abstract

Background: Houttuynia cordata Thunb is a medicinal plant that has many therapeutic properties. It has long been used in the treatment of bacterial diseases in humans, animals, and fish.Aim: Isolate and identify some endogenous bacteria in Houttuynia cordata Thunb which have antibacterial activity against human pathogenic bacteria as well as have the ability of protein fixation and IAA synthesis to stimulate the plant growth.

Object and Method: Houttuynia cordata Thunb collected in three places of Soc Trang province. Houttuynia cordata Thunb is separated by leaf, stem, and root, and is isolated on the PDA medium to obtain the endophytic bacteria of Houttuynia cordata Thunb

Results: Twenty-eight endogenous bacteria strains have been isolated from Houttuynia cordata Thunb sample grown in Soc Trang province. The TS7 strain is capable of synthesizing the highest amount of ammonium (3.30 µg/mL). The maximum IAA production was 8.51 µg/mL (due to the synthesis of RS10). Twenty bacterial strains have the ability to dissolve the unpasteurized phosphate. The result of

antibacterial activity test on Escherichia coli and Aeromonas hydrophila has shown that there are 13 strains against Escherichia coli, 05 strains against Aeromonas hydrophila, and 04 strains against Escherichia coli and Aeromonas hydrophila.Conclusion: Three bacterial strains are identified at the species level by 16S-rRNA sequence solving. The RS4 strain is identified as Bacillus subtilis (98%), the TS7 strain has a 98% of homology with Bacillus cereus and the TS9 strain is 91% homologous to Bacillus megaterium.

Keywords: Bacillus cereus, Bacillus megaterium, Bacillus subtilis, Houttuynia cordata Thunb, antibacterial, Endophytic bacteria.