Firstly, we analyzed the cytomorphological features of starchy endosperm cell death. We showed that a different cell death processes from the one happening in the center of the starchy endosperm takes place in the endosperm adjacent to the embryo, leading to cell elimination. The execution of these two cell death processes proved to be entirely different, suggesting the involvement of different regulators.
To analyze the differences in gene networks activated during these two starchy endosperm cell death processes, we subsequently conducted a novel transcriptomic approach. This allowed us to generate an atlas of endosperm single nucleus RNA-seq during the filling stage when both cell death processes are active. Interestingly, we observed that the classical regulators of plant cell death were expressed in the endosperm adjacent to the embryo but not in the central starchy endosperm.
Following a screening of numerous potential candidates for starchy endosperm cell death regulation, we ultimately identified two candidates capable of inducing ectopic cell death when overexpressed. Upon inhibiting them in the starchy endosperm, we observed impaired endosperm elimination around the embryo, resulting in smaller embryos. Importantly, this effect was not observed in central starchy endosperm cell death, indicating the involvement of potentially distinct regulators.
In summary, our study reveals the occurrence of two distinct cell death processes in the starchy endosperm of maize: the conservative cell death of the central starchy endosperm and cell elimination in the starchy endosperm adjacent to the embryo. These processes are likely regulated by different gene networks, and for the latter, we have already identified two regulators.
Currently, we are in the process of writing an article summarizing the obtained results, with the intention of publishing it within next months in a high-quality, peer-reviewed journal. We also plan to disseminate the results through conferences such as the Cell Biology of Plants, and beyond from the SCBF. Additionally, the results will be shared on my X account @NicolasMDoll after publication. In parallel, we are currently writing a review on endosperm cell death in angiosperms that will be submitted to the Journal of Experimental Botany next week.
