Doctor Nijat Imin

• Plant development and molecular biology

• Plant peptide signalling and gene regulation

• Root system architecture, nutrient uptake and use

• Legume rhizobium symbiosis and biological nitrogen fixation

1. Discovering molecular mechanisms regulating nitrogen demand signalling and nitrogen use efficiency in plants

Nitrogen (N) is a key determinant of crop productivity. In agriculture, the demand for nitrogen (N) fertilisers to produce food, fibre, and feed from crops and pastures is increasing dramatically. The adverse environmental effects of using N-fertilisers in their current form, however, make their use unsustainable. A major challenge in agriculture is to reduce our reliance on environmentally devastating and expensive N-fertilisers. Breeds that boost nutrient-capture and have efficient N usage are highly-desired. Plants coordinate the distribution and allocation of nutrients from the source to support growth. How this is achieved remains unanswered. We have shown that plant-specific small secreted peptides and their receptors act between the roots and the shoots to coordinate root deployment, N-uptake, and, in legumes, nodule formation and N-fixation. This project aims to decipher the output of peptide hormone systems that control nitrogen demand signalling, N-uptake and -utilisation. It will identify key components of these peptide/receptor circuits and investigate how these peptide/receptor circuits operate and how they coordinate growth, maintain homeostasis and respond to nutritional cues. This project will help to identify and nominate key gene candidates for breeding programs for improving plant’s N economy, biological N-fixation and yield, all of which will ultimately aid for sustainable agriculture where N eco-efficiency of intensification of farming and grazing is highly-desired.

2. Uncovering regulatory networks that control symbiotic nitrogen fixation

Legume plants enables atmospheric N fixation in root nodules through symbiotic N-fixation (SNF), delivers substantial amounts of N to agriculture in a sustainable manner and it is an attractive solution for reducing the need for N-fertiliser. However, lack of understanding how SNF is regulated limits its impact. Signalling molecules are known to regulate N-demand signalling, nodule development and SNF. However, it is unclear how they target nodule development and SNF. We recently have identified a ‘regulatory hub’ that is downstream of peptide signalling and directly controls nodulation and SNF. This proposal aims to uncover how this ‘hub’ works to control SNF. In particular, we will investigate how newly discovered transcription factors regulate nodulation and SNF using reverse genetics, gene expression and phenotypic analyses. The overall significance of this work is that it will revolutionise our understanding of how SNF are regulated, providing a unified conceptual framework. It will help to identify key candidate genes for improving the efficiency of SNF. The ultimate goal of this research is to sustain global food security by sustainable N-use in Agriculture. Further, this proposal addresses fundamental questions in plant biology - how plant cells communicate through intercellular peptide signalling, to coordinate growth and respond to their environment.

This information has been contributed by Doctor Imin.