Pollen biotechnology of crop plants

The increasing social demand for global food security in the face of a changing climate, decreasing natural resources and increasing world population, is pushing the search for new crop varieties, with increasing yield and better adapted to new environmental conditions. Present agriculture faces significant economic pressure worldwide for more efficient and accelerated breeding of crops. In this context, breaking knowledge and efficient technologies to exploit plant cell in vitro reprogramming potential for selected plant regeneration and propagation are highly valuable and needed in plant breeding and biotechnology, as well as in applied and basic plant research.

We investigate the regulatory mechanisms of stress-induced plant cell reprogramming to embryogenesis, key biotechnological process for improvement, regeneration and selection of high quality/adapted plants for agroforestry and industrial sectors. We also analyzed plant cell responses to stress conditions. Our aim is to identify new pathways and molecular targets for chemical intervention by small bioactive compounds to improve in vitro cell response to stress, embryogenesis and plant regeneration yield for crop/forestry breeding.

When reprogramming is induced in the haploid microspore (immature pollen), the process is named stress-induced microspore embryogenesis and constitutes the fastest way to produce haploid and doubled-haploid (DHs) plants. DHs are widely used by seed and horticulture companies as a source of new genetic variability fixed in homozygous plants in only one generation, therefore saving time and costs of breeding programs. When in vitro embryogenesis is induced in other somatic cells, somatic embryogenesis is very useful for large-scale clonal propagation and cryopreservation of elite genotypes in species with long reproductive cycles or low seed set, as many forest species.

We perform our investigation in the model crop species rapeseed and barley, and analyse the transfer of results to other species of agronomic or forestry interest, like cork oak. We use a multidisciplinary and integrated approach with techniques of plant physiology, molecular and cell biology.

MAIN RESEARCH LINES

Stress-induced cell death: We investigate the role of autophagy and cell-death proteases as crucial players in the balance between death and life in the plant cell response to stress conditions required to induce reprogramming towards embryogenesis. The aim is to modulate this response to increase cell viability and embryogenesis yield.                                    

Hormonal regulation of stress-induced cell reprogramming and embryogenesis: Our studies aim to characterize the involvement of phytohormones, mainly auxins and cytokinins, in regulation of cell reprogramming, totipotency acquisition and embryogenesis initiation and progression. Their biosynthesis, intercelular transport, signalling and appropriate auxin/cytokinin balance are required for correct embryogenesis induction and progression.

Epigenetic control of cell reprogramming to embryogenesis: We analyze the role of epigenetic marks, particularly DNA methylation, histone H3-H4 acetylation and H3K9 methylation, among other modfications, in the regulation of the swicht of cell fate. We have identified genome-wide changes of these chromatin modifications that accompany cell reprogramming, and found that define epigenetic modulators can induce such changes and enhance reprogramming.

 Cell wall remodelling: Our studies have revealed that remodelling of cell wall, operated by pectin methylesterases and arabinogalactan proteins (AGPs), is induced and neccessary for cell reprogramming and embryo formation.

Small molecules to improve reprogramming of cell fate for new biotech strategies: Recent advances in chemically-controlled reprogramming of specialized cells the great potential of application of small chemical molecules to regulate cellular reprogramming. We investigate the effects of small compounds, by screening of chemical libraires and with modulators of autophagy, proteases, epigenetic marks, and other enzymes, to reduce cell death and improve embryogenesis yield. These small molecules are opening up the development of new biotechnological approaches for improving in vitro embryo production in breeding programs.