Speaker: Ming Luo

mingluo168@gmail.com

Title: Polycomb Repressive Complex 2 (PRC2) suppresses asexual embryo and autonomous endosperm formation in rice

Host: Dabing Zhang

Time：May 30, 2023, 9:00 AM (Beijing zone)

Address: Shuhua Hall, School of Life Science and Biotechnology, SJTU

Speaker biography：

Dr. Ming Luo is a senior research scientist at CSIRO Agriculture and Food. He completed his PhD at the Australian National University in 2004 and obtained a Master's degree from Sichuan Agricultural University in 1985. With a longstanding interest in plant reproductive biology, Dr. Luo has focused his research on understanding the epigenetic mechanisms that influence seed development. His contributions to the field include the groundbreaking discovery of the mechanisms responsible for maintaining the quiescent state of the central cell and egg in a female gametophyte prior to fertilization. Presently, Dr. Luo is leading two projects that explore the utilization of microorganisms as feed additives to mitigate methane emissions from livestock. Additionally, he is actively involved in engineering plant disease resistance in crops. Dr. Luo's research findings have been published in high-impact journals such as Nature Biotechnology, Proceedings of the National Academy of Sciences (PNAS), and other esteemed scientific publications.

Abstract:

Prevention of autonomous division of the egg apparatus and central cell in a female gametophyte before fertilization ensures successful reproduction in flowering plants. Here we show that rice ovules with PRC2 Osfie1 and Osfie2 double mutations exhibit asexual embryo and autonomous endosperm formation at a high frequency, while ovules with a single Osfie2 mutation display asexual pre-embryo-like structures at a lower frequency without fertilization. Confocal microscopy images indicate that the asexual embryos were mainly derived from eggs in the double mutants, while the asexual pre-embryos likely originated from eggs or synergids. Early onsetting, higher penetrance and better development of asexual embryos in the double mutants compared with those in Osfie2 suggest that autonomous endosperm facilitated the asexual embryo development. Transcriptomic analysis showed pluripotency factors such as male genome expressed OsBBM1 and OsWOX8/9 were activated in the asexual embryos. Similarly, the maternal alleles of the paternally expressed imprinted genes were activated in the autonomous endosperm. Our results suggest that the egg apparatus and central cell convergently adopt PRC2 to suppresses asexual embryo and autonomous endosperm formation possibly through silencing male genome-expressed genes.