Effects Of The Transconjugant Pseudomonas Fluorescens Carrying 1-Aminocyclopropane-1-Carboxylate Deaminase Gene On Drought Tolerance Of Wheat

Abstract

To increase drought tolerance of efficient plant growth promoting Pseudomonas fluorescens isolated
from Iraq- Erbil Kurdistan soils, ACC-deaminase genes were transferred from Pseudomonas putida to P.
fluorescens. ACC deaminase containing plant growth promoting rhizobacteria are capable to decrease
ethylene inhibition of plant growth following a wide range of abiotic and biotic stresses. For P.
fluorescens and P. putida isolations, different Soil samples were collected in Erbil Governorate.
According to microscopical, morphological, biochemical and molecular examinations 75 P. fluorescens
isolates and 65 P. putida isolates were identified from 110 Soil samples. Most P. fluorescens isolates
illustrated efficiency in phosphate solubilization, hydrogen cyanide, siderophores and indol acidic acid
production. According to results the most efficient P. fluorescens (Mpf16) was selected for conjugation
process. Potential transferring of ACC - deaminase genes were considered in this research. ACCdeaminase genes were moved completely from P. putida into P. fluorescens by conjugation technique
after confirming via molecular techniques using selected primers. The effective of transferred ACCdeaminase genes from transconjugant P. fluorescens was confirmed in pot experiments under unirrigation condition by evaluating growth rate and chemical analysis of wheat crops. The highest growth
rate of root length(cm), plant height(cm), spike number/crops, root dry weight (gm/crops), total seed
weight (gm/crop) and shoot dry weight (gm/crop) were 25.90, 54.10, 32.62, 18.15, 14.55 and 28.15
respectively, and they were recorded by inoculated transconjugant P. fluorescens treatments and
significantly differed from control treatment. The new mutated P. fluorescens (transconjugant P.
fluorescens) can be proposed as an efficient bio-fertilizer agent for increasing plant growth and drought
tolerance of crops.