Petunias Preventing Self-Fertilization

By Celine Qi


Summary:
The Institute of Evolutionary Biology and Environmental Studies at the University of Zurich have discovered evidence that many plant species are able to recognize self and non-self pollen. These plants also have the ability to reject pollen. This ability of the plants allows them to avoid inbreeding, which may result in genetic defects appearing in their offspring. Plants are able to recognize pollen made by themselves because of a molecular mechanism called "self-incompatibility", or "SI". The one-to-one self-recognition evolved from plants and animals and is when a single male protein is able to identify a single female protein; this can prompt a pollen rejection response to occur. Petunias do not use one male and one female protein for the one-to-one recognition but instead involve multiple proteins; eighteen male proteins identify forty female proteins. 

S-genes, proteins which are coded by self-incompatibility genes, are a part of the self-recognition process. The direct interaction between the male SLF proteins (S-locus F-box) and the female S-RNases (S-ribonucleases) is extremely complicated in petunias. This mechanism in the flowers exhibits evolutionary patterns that are similar to the immune defense systems in animals, including humans. Studying this procedure enables the understanding of how such a complex system evolved and how it is managed at the cellular level. This information also benefits plant breeders.

Relevance:
This article relates to the curriculum's study of Heredity. In this unit, breeding between plants, specifically Mendel's pea plants, were studied. Gregor Mendel allowed his plants to self-pollinate, producing identical offspring. Pea plants are self-fertilizing plants, where the pollen of one plant, the male sex cells fertilize the eggs, the female sex cells, of the same plant. However, for petunias, these flowers did not allow themselves to inbreed. This is because its forty female proteins were toxic to the plants own pollen. As a result, the plants could not fertilize themselves. In the unit of Molecular Genetics, disorders were studied and relate to the genetic defects that can show up in the petunias' offspring through inbreeding. This would have resulted in weaker, more sickly plants because they would have had an increased risk of being affected by harmful traits.


Source: http://www.sciencedaily.com/releases/2015/01/150108084447.htm
Date of Publication: January 8th, 2015