School of Plant Sciences Seminar Series
Jianwei Zhang
Jianwei Zhang
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Abstract: The transfer of chloroplast or mitochondrial DNA into the nuclear genome is a common phenomenon across many species, representing a significant source of genetic variation in the nuclear genome and playing a crucial role in cellular evolution. However, the evolutionary fate and mechanisms of organelle DNA transfer in higher plants remain poorly understood. To explore the landscape and evolutionary dynamics of nuclear organelle DNA (NORG), this study identified and analyzed NORG sequences at the pan-genome level in the genus Oryza. Analysis of 22 genome assemblies from seven Oryza species revealed abundant organelle DNA insertions, categorized into 3,406 orthologous NORG groups (ONGs). Our findings indicate that NORGs are continuously integrated into the nuclear genome via organelle DNA, bypassing mRNA/cDNA intermediates, and are facilitated by double-strand break repair pathways and replication-based mechanisms. Furthermore, complex NORGs were also observed to form via single mutational events during or prior to insertion through the ligation of multiple plastid and/or mitochondrial DNA fragments. The dynamic processes of ongoing NORG insertion and loss, coupled with transposable element (TE)-induced fragmentation, appear to play critical roles in adaptive evolution and domestication. These findings offer novel insights into the systematic understanding of crop biology through a pan-genome perspective.
Bio: Dr. Jianwei Zhang has been a dual-appointed professor at the College of Life Science and Technology and the College of Informatics at Huazhong Agricultural University (HZAU) since 2019. He is also a member of the National Key Laboratory of Crop Genetic Improvement. Dr. Zhang earned his Ph.D. in Biochemistry and Molecular Biology (specializing in Bioinformatics) from HZAU in 2006. From 2006 to 2019, he worked at the Arizona Genomics Institute, University of Arizona, where he successively held positions as a Research Associate, Assistant Research Scientist, and Research Assistant Professor before returning to HZAU.
Dr. Zhang’s research focuses on genomics and bioinformatics, particularly in complete genome assembly, bioinformatics analysis, and the development of integrated data platforms. His contributions include the development of sequence assembly and editing tools, the generation of gap-free reference genome sequences for key crops such as rice and soybean, the establishment of the Rice Gene Index platform for comparative genomics, and the application of high-quality pan-genomes to study the genetic diversity and evolutionary dynamics of Asian rice.