Data Sheet 1_Abscisic acid metabolism to dehydrovomifoliol by Candidatus Liberibacter asiaticus and CLas-associated Flavobacterium strains CGRL1 and CGRL2.pdf

Although alterations in plant hormone homeostasis, including salicylic acid and abscisic acid (ABA), are hallmarks of HLB, the contribution of plant-associated microbiota to these hormonal changes remains poorly understood. Here, we investigated whether ABA depletion in HLB-affected citrus is associated with microbial metabolism.</p>Methods<p>ABA and its metabolites were quantified in HLB-affected citrus tissues by liquid chromatography–mass spectrometry.

The capacity of CLas strain Ishi-1 and Flavobacterium spp. strains CGRL1 and CGRL2 to metabolize ABA was assessed using in vitro culture assays. The effects of exogenous ABA on bacterial growth were also evaluated.</p>Results<p>ABA concentrations were significantly decreased in symptomatic HLB-affected tissues, concomitant with the accumulation of the ABA catabolite dehydrovomifoliol. Furthermore, CLas strain Ishi-1 and Flavobacterium strains CGRL1 and CGRL2 degraded ABA and produced dehydrovomifoliol, whereas no such activity was detected in non-inoculated controls.