Title : Barley strigolactone-signalling mutant hvd14.d presents highly-tillered phenotype due to hormonal network alterations
Abstract:
Plants architecture is continuously adjusted to environmental changes to optimize their growth and development. The regulation of plant branching, influenced by environmental conditions impacting hormone balance and gene expression, is crucial for agronomic purposes due to its direct correlation with yield. A well-branched crop typically produces more flowers, fruits, or grains, resulting in higher yields at harvest time. Therefore, research on branching has become a popular topic worldwide.
Strigolactones (SLs), the youngest class of phytohormones, primarily shape the architecture of plants. Barley plants harbouring the mutation in the HvDWARF14 (D14) gene, which encodes the SL-specific receptor, produce almost twice as many tillers as wild-type (WT) plants Sebastian. Here, through hormone profiling and comparison of transcriptomic and proteomic changes between two-week-old and four-week-old tested genotypes, we elucidate the regulatory mechanism that might affect the tillering of SL-insensitive plants.
The analysis showed statistically significant increased cytokinin content and decreased auxin and abscisic acid content in our ‘bushy’ hvd14.d compared to WT, which aligns with the commonly known actions of these hormones regarding branching regulation. The hormone profiling also indicates altered content of jasmonic acid and salicylic acid. The transcriptomic and proteomic analysis revealed in total 181 and 1127 differentially expressed genes (DEG) and differentially abundant proteins (DAP) in hvd14.d two- and four-week-old plants when compared to the WT. Functional annotation of these dataset showed that 11,6% for younger plants (21/181) and 14,6% for older plants (165/1127) of transcriptomic and proteomic changes are associated with phytohormone-related processes. However, some of the identified genes/proteins were annotated to more than one term linked to phytohormones. Most of DEG and DAP are linked to ABA and JA, which aligns with results obtained after phytohormone content measurement. Next, bioinformatics analyses allowed identifying strigolactone-dependent transcription factors (TFs) that may control the differences observed in the hvd14.d transcriptome and proteome. Moreover, comparison with data available for Arabidopsis thaliana allowed us to select TFs that may be involved in the transduction of strigolactone signal in both monocotyledonous and dicotyledonous plants.
Audience Takeaway:
- The role of strigolactone in plant growth and development.
- The bioinformatic approach of analyzing genes with the open access tools.
- The set of TF which might regulate SL-dependent genes.
- Interactions of SL with other phytohormones in shoot branching.
