Schematic diagram of autophagy pathways during pollen tube growth. Courtesy of the research team
The study by Hao Wang, a professor at the College of Life Sciences of South China Agricultural University, revealed that autophagy plays an important regulatory biological role in mediating mitochondrial quality control during arabidopsis pollen tube growth and male reproduction. The study was recently published in Autophagy.
Autophagy is one of the main catabolic pathways of eukaryotes, involved in regulating processes such as plant growth, development, and aging. Recent studies have found that autophagy is also involved in regulating plant reproduction and fertility, including male gametophyte formation and plant incompatibility. Fast and polar growth pollen tubes mediate and transport two sperm cells to the ovary and release, playing a key function in the plant’s sexual reproduction process.
The rapid growth of pollen tubes requires consuming a lot of substance and energy. By degrading substances such as starch, lipids and proteins stored intracellularly, pollen tubes can sustainably obtain the substances and energy needed for cell growth. However, whether autophagy is involved in and regulates pollen tube growth and what biological functions it plays during plant fertilization have not yet been studied and revealed.
This study found that autophagy plays an important biological role in Arabidopsis pollen tube growth and male fertility. By studying and tracking the subcellular localization and motility trajectories of the autophagy reporter protein SH3P2 and the core ATG protein, the biogenesis process and spatiotemporal distribution of autophagy in the pollen tube were revealed. Further studies have found that inhibition of autophagy significantly inhibits Arabidopsis pollen germination, pollen tube growth and plant fertilization.
In growing pollen tubes, real-time tracking imaging of ATG8e-labeled autophagosomes and depolarized mitochondria found that they could combine and interact in space-time to induce the occurrence of mitochondrial autophagy, and further found that this interaction was specifically mediated by the ATG8-family interacting motif (AIM) identification site.
The study found that in the pollen tube, mitochondrial autophagy coexists with various forms of autophagy and maintains the rapid growth of the pollen tube, playing an important regulatory function in the fertilization process of Arabidopsis male gametogenes. This study lays an important theoretical foundation for in-depth elucidation of the molecular mechanism and biological function of autophagy in regulating the polar growth and fertility of pollen tubes.
Dr. Yan He, College of Life Sciences, South China Agricultural University, is the first author of the paper, and Professor Wang Hao is the corresponding author. Professors Wu Hong and Huang Wei of South China Agricultural University and Professor Xie Yucong of Southern University of Science and Technology provided valuable technical support for this research. The relevant research has been funded by the Major Research Program and Surface Project of the National Natural Science Foundation of China and the Natural Science Foundation of Guangdong Province. (Source: China Science Daily Zhu Hanbin)
Related paper information:https://doi.org/10.1080/15548627.2022.2095838