STUDY THE EFFECT OF BACTERIAL 1-AMINOCYCLOPROPANE-1-CARBOXYLATE DEAMINASE (ACC deaminase) ON RESISTANCE TO SALT STRESS IN TOMATO PLANT.

1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase) produced by rhizobacteria could be remove the ethylene precursor and stimulate plant growth. Aim of the work was investigation on effect of rhizosphere bacteria Pseudomonas mendocina containing plasmid carrying gene encoding ACC deaminase on resistance of tomato plant to salinity. Amplification of acds gene in selected Pseudomonas was performed; the gene was cloned in Escherichia coli and was cloned subsequently in P. mendocina. Enzyme activity was determined in cloned Escherichia coli and cloned P. mendocina for confirmation of gene expression. Effect of bacterial ACC deaminase on resistance of tomato plants to NaCl was studied in Pot and Greenhouse. In pot experiment, tomato plant treated by cloned P. mendocina was compared with plants treated by P. mendocina (without plasmid) and control group. Salinity were established by adding 172 and 207 mM of NaCl to irrigated water. Greenhouse experiments were conducted in similar groups of bacteria in 207 mM of NaCl. Results obtained from pot experiment revealed that plants treated by cloned P. mendocina in 172 mM of NaCl was showed increasing content of growth than ones treated by P. mendocina and control as 11%, 18.4% growth for the shoot, 16.6%, 3.7% for roots and 9.6%, 27.5% for wet weight after five weeks, respectively. In 207 mM of NaCl, the results were as 14.9 %, 9.7% for shoot, 94.3%, 15.7% for roots and 96.4%, 50.6% for wet weight, respectively. In greenhouse experiment, results in same parameter in 207 mM of NaCl were revealed as 63.7%, 7 times for shoot, 2.8, 14 times for roots and 66.1%, 154 times for wet weight, respectively. We concluded that recombinant P. mendocina producing ACC deaminase by reduction of ethylene content of tomato plant in high salt concentrations could result in improvement of plant resistance to salinity. [ABSTRACT FROM AUTHOR]