Synthesis and modifications of plant growth regulators

In 2004, germination promotor of many plant species worldwide has been isolated from the smoke of burning vegetation. This remarkable potent germination stimulant, with effective germination promotion observed at nanomolar concentrations (10-9M) was identified independently by Flematti and Van Staden as compound 1. Later, other derivatives have been identified in the smoke and this class of bioactive compounds is referred to as karrikins. In 2010, Van Staden discovered in the smoke also 3,4,5-trimethylfuran-2(5H)-one (TMB), the compound that inhibits germination of seeds and significantly reduces effect of karrikins.

This multidisciplinary project involving chemists, plant physiologists and molecular biologists, is focused on the study of mode of action of the above mentioned compounds, their effect to germination of seeds and grow of young plants (Annals of Botany 111: 489-497, 2013) as well as to the study of mutual effect of karrikins and TMB when applied simultaneously (New Phytologist 196: 1060-1073, 2012).

The main objective of the chemical part of this project is the synthesis of analogues of germination inhibitor for the purposes of structure-activity relationship (SAR) study. Modifications are carried out mainly in position C-5 (Journal of Plant Physiology 170: 1235-1242, 2013). Additionally, synthesis of halogen-, alkoxy-, aryloxyderivatives and esters is underway. Structure-activity relationship study of analogues differing in electronic and steric properties identifies the most active candidates that will be used for the synthesis of molecular probes for mode of action investigations.

Other publications: South African Journal of Botany 88: 107, 2013; Australian Journal of Botany 62: 347, 2014; South African Journal of Botany 91: 53, 2014; Plant Biology 17: 825, 2015; Seed Science Research 25: 286, 2015; Weed Science 63: 312, 2015; Tetrahedron 72: 3809, 2016; Plant Biology 18: 289, 2016; Plant Growth Regulation 82: 47, 2017; South African Journal of Botany 115: 256, 2018; Monatshefte für Chemie – Chemical Monthly 149: 1475, 2018; Phytochemistry 163: 187, 2019.