Are pectolytic bacteria isolated from cutAcaciastems responsible for reduced vase life?

Abstract

Bacteria have long been known to cause vascular blockages in cut stems and have been implicated in reduced vase life. Soft-rot bacteria can be both latent and opportunistic pathogens that are able to invade many plant species, causing internal destruction as their pectolytic enzymes degrade the middle lamellae of cell walls. They are well-known to cause soft rots, but their presence in cut flower stems is unclear. The basal 0-5 and 5-10 cm stem segments of Acacia amoena were destructively harvested and aseptically ground every 24 h for 5 d. The resultant slurries were then spread onto selective (Crystal Violet Pectate, CVP) media and grown for 48 h at 30°C. Slurries were also spread onto sterilised potato slices to determine rotting, also indicative of pectolytic bacteria. Representative bacterial colonies from CVP media were purified and then identified using 16S rRNA sequencing. Several isolates of pectolytic bacteria such as Bacillus licheniformis, B. subtilis, Paenibacillus lautus and Pseudomonas syringae pv. tomato, were found, suggesting that pectolytic bacteria are on or in cut stems and so may be involved in reducing the water uptake and vase life of cut flower stems.