Periodic Reporting for period 4 - PLANTGROWTH (Exploiting genome replication to design improved plant growth strategies)
Periodo di rendicontazione: 2023-12-01 al 2025-05-31
Plants are exposed to enormous challenges derived from their sessile nature and the changes in environmental conditions, such as temperature, drought, salinity, among others. These tend to reduce plant performance. As a consequence, there is an increasing pressure to improve plant yield to feed the growing world population, since plants constitute more than 50% of all calories taken by the human population worldwide. Plants respond to their environment with striking plasticity since they have developed complex signaling pathways based on the modulation of growth and cell proliferation. In the PLANTGROWTH project we have explored unconventional ways to modulate plant development under stress conditions with a focus on how cells divide to produce new cells in the growing organs and how they duplicate their genetic material. The final aim of our project is to identify mechanisms that may serve as targets to rationally improve plant growth and environmental adaptation to a changing climate and eventually increase plant productivity.
Although at the beginning of the Project the COVID19 pandemic affected some of the activities, we managed to organize activities and personnel to maximize the group performance. During the Project we have generated transgenic plants specifically tailored for each objective, among others plants expressing markers for cell cycle analysis, chromatin modifying enzymes targeted to specific genomic locations, and testing a collection of mutants for phenotypic characteristics towards resistance to abiotic stress using molecular, cellular, genetic and genomic strategies. The main results achieved so far and their dissemination are:
- Generation of the PlaCCI reporter line (Nat Plants 2020), a useful tool used now in ~200 laboratories worldwide, and recognized by the community (Roeder A & Clark F: Faculty Opinions Recommendation, In Faculty Opinions, 16 Nov 2020; 10.3410/f.738749588. 793579825), instrumental for several other publications and parts of the project.
- The EMBO J review (2020) defined the key patwhays of the cell cycle controlled by the retinoblastoma protein.
- Evolutionary features of ORC proteins, protein domains and their relevance in DNA replication (Genome Biol Evol 2020).
- We defined the distinct roles of ORC1a and ORC1b, two DNA replication initiation proteins in heterochromatin maintenance and DNA replication, respectively (Nat Comm 2023).
- We found a diurnal control of deposition of the histone mark H3K27me1 relevant for controlling the expression of DNA damage response genes (Pkant J 2024).
- We identified the role of the histone variant H3.14 expressed in endoreplicating cells and required for the early response to abiotic stress to repress cell division and stimulate the expression of stress reposnse genes (Dev Cell 2025).
- We defined a novel regulatory step of cell proliferation during root growth and established that stem cell derivatives have a long G1 compared to cells developing their last cell cycle before entering differentiation by a mechanism involved a direct relationship between stem cell regualtors and the retinoblastoma pathway (Nat Plants 2025, still in press).
- Generation of the PlaCCI reporter line (Nat Plants 2020), a useful tool used now in ~200 laboratories worldwide, and recognized by the community (Roeder A & Clark F: Faculty Opinions Recommendation, In Faculty Opinions, 16 Nov 2020; 10.3410/f.738749588. 793579825), instrumental for several other publications and parts of the project.
- The EMBO J review (2020) defined the key patwhays of the cell cycle controlled by the retinoblastoma protein.
- Evolutionary features of ORC proteins, protein domains and their relevance in DNA replication (Genome Biol Evol 2020).
- We defined the distinct roles of ORC1a and ORC1b, two DNA replication initiation proteins in heterochromatin maintenance and DNA replication, respectively (Nat Comm 2023).
- We found a diurnal control of deposition of the histone mark H3K27me1 relevant for controlling the expression of DNA damage response genes (Pkant J 2024).
- We identified the role of the histone variant H3.14 expressed in endoreplicating cells and required for the early response to abiotic stress to repress cell division and stimulate the expression of stress reposnse genes (Dev Cell 2025).
- We defined a novel regulatory step of cell proliferation during root growth and established that stem cell derivatives have a long G1 compared to cells developing their last cell cycle before entering differentiation by a mechanism involved a direct relationship between stem cell regualtors and the retinoblastoma pathway (Nat Plants 2025, still in press).
As originally proposed we expected to reach the main objectives by the end of the Project, which has been now extended until May 2025, due to the COVID19 pandemic.
We expected to have delivered several tools, invaluable not only for this project but also for the plant community. Some have been already generated, such a plant line that allows the possibility to determine the cell cycle parameters, useful to correlate with organ growth. Others are in progress. In addition, experiments have identified a series of mutants in DNA replication proteins that appear to have a better performance and growth under conditions of abiotic stress, such high salinity or drought. These are being now evaluated in more detail to identify the mechanisms involved and what kind of information obtained in the model plant Arabidopsis could be transferred to crop plants of economic interest.
We expected to have delivered several tools, invaluable not only for this project but also for the plant community. Some have been already generated, such a plant line that allows the possibility to determine the cell cycle parameters, useful to correlate with organ growth. Others are in progress. In addition, experiments have identified a series of mutants in DNA replication proteins that appear to have a better performance and growth under conditions of abiotic stress, such high salinity or drought. These are being now evaluated in more detail to identify the mechanisms involved and what kind of information obtained in the model plant Arabidopsis could be transferred to crop plants of economic interest.