Scientists have made a significant discovery in plant biology by identifying a new gene, HMGB15, which is essential for the formation of stamens, the male reproductive structures involved in pollen and seed formation. This research, conducted on Arabidopsis plants (closely related to mustard and cabbage), reveals critical insights into plant reproduction and opens up avenues for improving crop fertility and seed production.
Pollen formation is a vital phase in a plant's life cycle, representing the male gametophyte responsible for delivering genetic material to the embryo sac. Successful fertilization depends on the production of healthy pollen grains, their transfer to the stigma, germination, and rapid pollen tube growth through the style to the ovary. These processes are essential for seed formation and are directly influenced by the genetic mechanisms controlling pollen development. Understanding the process of pollen development not only sheds light on the fundamental mechanisms of sexual reproduction in flowering plants but also provides critical insights for potential advancements in crop production.
A team led by Prof. Shubho Chaudhuri at the Bose Institute, Kolkata, has identified the HMGB15 gene, a non-histone protein that restructures chromatin, as critical for stamen development and pollen viability. Mutation in this gene results in partial male sterility in Arabidopsis plants. The mutant plants show significant reproductive abnormalities, including low pollen grain viability, defective pollen wall patterning, reduced pollen tube germination rates, and shorter filaments incapable of reaching the stigma. These defects lead to reduced seed production, highlighting the gene’s importance in reproductive success.
Molecular analysis of the mutants showed disruptions in important developmental pathways, including the biosynthesis of the phytohormone jasmonic acid (JA), the apoptosis of tapetal cells (which support pollen development), and the dynamics of actin polymerization that are crucial for pollen tube growth. This comprehensive study determines the intricate gene regulatory networks that are essential for the formation and maturation of viable pollen grains.
The research, published in prestigious journals Plant Physiology and Plant Reproduction, provides valuable insights into the sexual reproduction of flowering plants. It also highlights the potential for manipulating these molecular mechanisms to enhance crop yields.
Supported by SERB, India, this discovery not only deepens our understanding of plant biology but also offers promising strategies for addressing challenges in agricultural productivity.
