Plant growth promoting rhizobacteria: a sustainable way towards improving the quality of saffron

Saffron (Fam. Iridaceae) is worldly known for the most precious spice. The plant is sterile and reproduction is only vegetative through clonal corms. Therefore, horticultural practices are essential for the improvement of this crop. The interest in the use of bioinoculants, such as plant growth promoting rhizobacteria (PGPR), has recently increased as they are considered a sustainable agricultural solution to enhance plant quality and productivity, cope with the effects of climate change, and reduce environmental costs. In this study saffron was soilless grown in a protected cultivation system with the PGPR Bacillus megaterium CB97032 and Paenibacillus durus CB1806. The influence exerted by the PGPR during flowering and the vegetative-reproductive phases was investigated. The PGPR resulted to improve the saffron spice quality increasing the content of safranal, i.e., the principal aroma compound of saffron, and the total phenolic content (TPC).