Phenology-specific molecular characterization of polyamine genes in Parthenium hysterophorus for strategic herbicide interventions

Parthenium hysterophorus is a highly invasive weed that poses a serious threat to biodiversity due to its adaptability. This case study examines its vegetative and reproductive phases, focusing on phenological growth stages using the universal BBCH coding system, and the role of polyamines (PAs) in these stages. Our research identified significant polymorphisms in key enzymes involved in PAs biosynthesis, including spermidine synthase (SPDS), spermine synthase (SPMS), arginine decarboxylase (ADC), and caffeic acid O-methyltransferase (COMT), during specific growth stages. SPDS polymorphisms were more pronounced during stem elongation and flowering, while SPMS showed heightened variability primarily during flowering. Conversely, ADC and COMT exhibited increased polymorphisms during leaf development and flowering stages. These findings underscore the dynamic regulation of PA metabolism across different growth stages in P. hysterophorus . Drawing from these findings, we can develop targeted weed management strategies that correspond to the polymorphism patterns of vital PA biosynthetic genes. Specifically, we propose the use of broad-spectrum non-selective herbicides such as Paraquat before stem elongation, transitioning to post-stem elongation application of selective herbicides like Bromoxynil, and utilizing foliar-active translocated herbicides like glyphosate during leaf formation. These innovative strategies aim to optimize effectiveness while reducing herbicide usage by tailoring interventions to the plant's metabolic state.