plant surface microbiology.pdf

Contents IX
5 Diversity and Functions of Soil Microflora
in Development of Plants . . . . . . . . . . . . . . . . . . . . 71
Ramesh Chander Kuhad, David Manohar Kothamasi,
K.K. Tripathi and Ajay Singh
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
2 Functional Diversity of Soil Microflora . . . . . . . . . . . . 72
3 Role of Soil Microflora in Plant Development . . . . . . . . 76
3.1 Mycorrhiza . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
3.2 Actinorhiza . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
3.3 Plant Growth-Promoting Rhizobacteria . . . . . . . . . . . 82
3.4 Phosphate-Solubilizing Microorganisms . . . . . . . . . . . 84
3.5 Lignocellulolytic Microorganisms . . . . . . . . . . . . . . . 85
4 Plant Growth Promoting Substances Produced
by Soil Microbes . . . . . . . . . . . . . . . . . . . . . . . . . 88
5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
References and Selected Reading . . . . . . . . . . . . . . . . . . . . . 91
6 Signalling in the Rhizobia–Legumes Symbiosis . . . . . . . 99
Dietrich Werner
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
2 The Signals from the Host Plants . . . . . . . . . . . . . . . 101
2.1 Phenylpropanoids: Simple Phenolics, Flavonoids
and Isoflavonoids . . . . . . . . . . . . . . . . . . . . . . . . 102
2.2 Metabolization of Flavonoids and Isoflavonoids . . . . . . . 104
2.3 Vitamins as Growth Factors and Signal Molecules . . . . . . 106
3 Signals from the Microsymbionts . . . . . . . . . . . . . . . 107
3.1 Nod Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
3.2 Cyclic Glucans . . . . . . . . . . . . . . . . . . . . . . . . . . 109
3.3 Lipopolysaccharides . . . . . . . . . . . . . . . . . . . . . . 110
3.4 Exopolysaccharides . . . . . . . . . . . . . . . . . . . . . . . 110
4 Signal Perception and Molecular Biology
of Nodule Initiation . . . . . . . . . . . . . . . . . . . . . . . 111
References and Selected Reading . . . . . . . . . . . . . . . . . . . . . 114