Increase of secondary metabolite content in marigold by inoculation with plant growth-promoting rhizobacteria

CAPPELLARI, L., SANTORO, M.V., NIEVAS, F., GIORDANO, W. AND BANCHIO, E.

APPLIED SOIL ECOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 70 p. 16 - 22

0929-1393

The effects of single inoculation and co-inoculation of two plant growth-promoting rhizobacteria (PGPR)(Pseudomonas fluorescens, Azospirillum brasilense) on growth and essential oil (EO) composition and phe-nolic content were evaluated in marigold (Tagetes minuta). Plant growth parameters (shoot fresh weight,root dry weight, leaf number, node number) were measured. EO yield increased 70% in P. fluorescens-inoculated and co-inoculated plants in comparison with control (non-inoculated) plants, without alteringEO composition. The biosynthesis of the major EO components was increased in the inoculated plants.Shoot fresh weight and EO yield were significantly higher in P. fluorescens-inoculated and in co-inoculatedplants than in control plants. The total phenolic content was 2-fold higher in singly-inoculated orco-inoculated treatments than in controls. In view of the economic importance of monoterpenes andphenolic compounds for a variety of applications in the food and cosmetic industries, P. fluorescens andother PGPR have clear potential for improving the productivity of cultivated aromatic plants. Better under-standing of the processes that affect the accumulation of secondary metabolites will lead to increasedyields of these commercially valuable natural products.