SJTU Prof. Wenhui LIN’s research group recently published a paper titled Asynchrony of ovule primordia initiation in Arabidopsis in high-impact journal Development, elucidating the asynchrony and regulation mechanism of  ovule initiation, which is important in understanding the bigger picture of plant developmental process.

The first author is doctoral student Shixia YU from School of Life Sciences and Biotechnology, SJTU, and the corresponding author is Prof. Wenhui LIN from School of Life Sciences and Biotechnology, SJTU. This project was collaborated with Dr. Lvwen ZHOU and Dr. Shiliang FENG from Ningbo University, Prof. Yuling JIAO from Institute of Genetics and Developmental Biology, and Prof. Lin XU from CAS Center for Excellence in Molecular Plant Sciences.

Plant ovule initiation determines the maximum of ovule number and has a great impact on the seed number per fruit. Understanding the regulation mechanism of ovule initiation not only advances the development of science, but also enjoys a promising application prospect. However, currently little research has been carried out in this respect.

This research revealed the asynchrony of ovule initiation, indicating the asynchronicity in the growth of different groups of ovule primordia on the same placentae, and made further exploration of the regulation mechanism of ovule initiation. That ovule primordia initiate asynchronously is of great biological importance, because plants could determine whether there is enough nutrition and a sound environment for a new group of primordia initiation by monitoring the current distance among ovules, and further control the number of its filial generation. 

Their research was sponsored by the National Natural Science Foundation of China, the Open Project of State Key Laboratory of Plant Molecular Genetics, Foundation of Agri-X and Bio-X Institute of SJTU, as well as SJTU Science Innovation Foundation.

ABSTRACT:

Plant ovule initiation determines the maximum of ovule number and has a great impact on the seed number per fruit. The detailed processes of ovule initiation have not been accurately described, although two connected processes, gynoecium and ovule development, have been investigated. Here, we report that ovules initiate asynchronously. The first group of ovule primordia grows out, the placenta elongates, the boundaries of existing ovules enlarge and a new group of primordia initiates from the boundaries. The expression pattern of different marker genes during ovule development illustrates that this asynchronicity continues throughout whole ovule development. PIN-FORMED1 polar distribution and auxin response maxima correlate with ovule primordia asynchronous initiation. We have established computational modeling to show how auxin dynamics influence ovule primordia initiation. Brassinosteroid signaling positively regulates ovule number by promoting placentae size and ovule primordia initiation through strengthening auxin response. Transcriptomic analysis demonstrates numerous known regulators of ovule development and hormone signaling, and many new genes are identified that are involved in ovule development. Taken together, our results illustrate that the ovule primordia initiate asynchronously and the hormone signals are involved in the asynchrony.