Terpene Production by Bacteria and its Involvement in Plant Growth Promotion, Stress Alleviation, and Yield Increase

Plant growth-promoting bacteria (PGPB) is the name coined for microorganisms that inhabit the rhizosphere and the plant tissues at the apoplastic level with no visible deleterious effects on the host but rather with a positive influence on plant growth and development. Diverse PGPB have been tested in a wide range of agricultural species to enhance seed emergence, plant mass, and crop yields, and/or to accomplish disease tolerance (Kloepper and Schroth, 1978; Kloepper et al., 1991; Okon and Labandera-Gonzalez, 1994). The interaction between plants and associated bacteria has a variable effect on a plant’s growth, development and health, and on soil quality (Bashan and Holguin, 1998; Compant et al., 2005; Aslantas et al., 2007). These microorganisms can trigger plant cell metabolism, so that on exposure to stress primed plants are able to respond more quickly and more efficiently than nonprimed ones (Compant et al., 2005). Ever since PGPB were characterized as beneficial for plants, different genera such as Azospirillum, Bacillus, Bulkholderia, Gluconoacetobacter, Herbaspirillum, Pseudomonas, and others have been tested to improve yield and production of different crops (Egamberdiyeva and