The production of cereals, vegetables, fruits, and nuts depends entirely on pollination. However, since many flowers are hermaphrodite, having the male pollen located close to the female stigma, there is a constant risk of self-fertilization, which often results in unhealthy plants. Thus, the ability to control whether or not a plant is “self-compatible” is essential for ensuring healthier and more resilient crops.
A recent study published in the journal Current Biology has identified a new gene that controls self-fertilization in an engineered version of the plant Arabidopsis thaliana – an inconspicuous small weed related to crops such as cabbage and oilseed rape that is often used by plant scientists to better understand how plants function.
The researchers performed genetic screening to identify a new gene that is critical for regulating self-incompatibility. By using an engineered self-incompatible Arabidopsis plant line, the scientists isolated a gene that, when removed, abolished self-incompatibility, allowing the plant to self-fertilize. This gene – named “Highlander” after the 1986 film with an immortal warrior – encodes a protein called PGAP1 which is found in all complex organisms, from yeast to humans.
The genetically modified Arabidopsis plants showed no evidence of developmental defects, while its self-incompatibility was completely abolished and high levels of self-seed set were observed.
“This is a major breakthrough, as it not only identifies a new mechanism that is critical for achieving self-rejection of incompatible pollen, but it also implicates a role for specific proteins, called GPI-APs in this process for the first time,” said study senior author Veronica Franklin-Tong, a former professor of Plant Cell Biology at the University of Birmingham.
The GPI-APS family of proteins plays a crucial role in other systems too, such as enhancing innate immunity by increasing the levels of interactions between certain proteins. By showing that these proteins have a fundamental role in regulating self-fertilization, Professor Franklin-Tong and her colleagues may also have found evidence that such processes could have evolved from other systems, such as those providing immunity from pathogens.
“We are very excited by the unexpected and novel findings of this study, as it opens up new avenues, leading research into completely new areas, such as the involvement of GPI-APs and possibly accessory proteins, that help cell-cell interactions, in interactions between pollen and pistil in self-incompatibility,” Professor Franklin-Tong concluded.