Transformation studies for increasing salt tolerance and nitrogen fixation in Azospirillum halopraeferens

Transformation studies for increasing salt tolerance and nitrogen fixation in Azospirillum halopraeferens

SP. Sundaram*, S. Kannaiyan and S. Muthukumarasamy

Center of Advanced studies in Agricultural Microbiology,

Tamil Nadu Agricultural University,

Coimbatore 641003, India.

* corresponding author

ABSTRACT

Azospirillum halopraeferens strains APK-16 and APK-1 previously identified by the authors were used in the present study. APK-16 was found to be tolerant to 9% NaCl and less nitrogen fixation. Whereas APK-1 a high nitrogen fixer was found to be tolerant only to 3% NaCl hence an attempt was made to transform the salt tolerant phenotype of A. halopraeferens APK-16 into APK-1. Two transformants namely APK-T2 and APK-T1 were selected based on high nitrogen fixation phenotype in terms of protein accumulation and acetylene reduction activity with 9% tolerance to NaCl. The transformants also retained the antibiotic resistant characters and nitrogen fixation phenotype of APK-1.