Pollen maturation and germination are essential for successful fertilization and generation alteration in plant. However, the molecular mechanism of these processes is still unclear. Peroxisome is a single-membrane organelle involved in multiple metabolic and signaling pathways. Up to now, a series of peroxisome-localized proteins have been identified, but the molecular function is still unrevealed.
Colleagues in Weicai Yang’s lab, a lab of the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, isolated a mutant named dayu which is specifically defective in pollen maturation and germination. Genetics and molecular complementation analysis showed that DAYU encodes APEM9 which has been shown to be involved in peroxisomal matrix protein import. By fluorescence marker and transmission electron microscopy analysis, they found that dayu pollen lack integral peroxisomes. This data first showed that DAYU/APEM9 is directly involved in peroxisome biogenesis. They also investigated other peroxisomal membrane proteins which have been shown to be involved in peroxisomal matrix protein import. Their results found new function of some of these proteins in early peroxisome biogenesis. In dayu pollen, the content of hormone JA is substantially reduced which is synthesized in peroxisomes, and application of JA manually on the plant can partially rescue the pollen defect. Biochemical experiments showed that DAYU interaction with PEX13 and PEX16, two peroxisomal membrane proteins, in plant. This research first revealed the function of peroxisome in pollen maturation and sheds light on the assembly of membrane proteins during the peroxisome biogenesis.
This work has been published online on The Plant Cell (doi:10.1105/tpc.113.121087) with Xinran Li, Hongju Li and Li Yuan as the co-authors. This research was supported by grants from Ministry of Science and Technology and National Natural Science Foundation of China.
AUTHOR CONTACT:
Weicai Yang, Ph.D.
Institute of Genetics and Developmetnal Biology, Chinese Academy of Sciences, Beijing, China.
