Page 2 Plant-Bacteria Interactions Edited by Iqbal Ahmad, John ...

102j 5 Diversity and Potential of Nonsymbiotic Diazotrophic Bacteria in Promoting Plant Growth
(ii) The PGP traits exhibited by inoculant strains and their expression under plant
rhizosphere influence need to be examined.
(iii) Physiological and molecular mechanisms in regulating PGP traits of the
inoculant strain should be investigated.
(iv) The role of QS in bacteria–bacteria and plant–bacteria interactions and its
influence need to be understood.
Acknowledgments
The authors are grateful to Professor Pichtel (USA) for his critical input and
valuable suggestions in the preparation of this manuscript. We are also thankful
to Mr Arshad, Ikram Ansari, Mohd Imran and Ms Maryam Zahin for their
cooperation.
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