The key difference between genetic male sterility and cytoplasmic male sterility is that genetic male sterility occurs due to genome mutations, while cytoplasmic male sterility occurs due to cytoplasmic and nuclear factors.
Male sterility in plants refers to a condition where the male reproductive part of the plant is sterile. The plants will produce non-functional pollen grains. Male sterility can take place at the stage of pollen development. It prevents autogamy and leads to heterozygosity. The classification of male sterility in plants is mainly of two types. They are genetic male sterility and cytoplasmic male sterility.
CONTENTS
1. Overview and Key Difference
2. What is Genetic Male Sterility
3. What is Cytoplasmic Male Sterility
4. Similarities – Genetic Male Sterility and Cytoplasmic Male Sterility
5. Genetic Male Sterility vs Cytoplasmic Male Sterility in Tabular Form
6. Summary – Genetic Male Sterility vs Cytoplasmic Male Sterility
What is Genetic Male Sterility?
Genetic male sterility refers to male sterility in plants that is controlled by the genome of the plant. This can lead to total or partial sterility. It is also referred to as nuclear male sterility. Genetic male sterility is of three types: temperature-sensitive genetic male sterility, photoperiod-sensitive genetic male sterility, and transgenic genetic male sterility. The genetic male sterility can occur either prior to meiosis, during meiosis, or at the end of meiosis. The mutagens that enhance the occurrence of genetic male sterility are gamma rays, colchicine, ethyl methane sulphonate, ethidium bromide, and acetone. The occurrence of mutations could be either spontaneous or artificial.
Figure 01: Functional Anthers
What is Cytoplasmic Male Sterility?
Cytoplasmic male sterility refers to total or partial male sterility present in plants due to specific mitochondrial and nuclear interactions mediated by cytoplasmic factors. Here, plants fail to produce functional pollens, anthers, or male gametes. With the development of technology, biologists have identified more than 150 species of plants that show cytoplasmic male sterility.
Cytoplasmic male sterility is more common than cytoplasmic female sterility. The main reason for this is that the external environment provides more protection to the female ovule and embryo sac when compared to the male sporophyte and gametophyte. The development of cytoplasmic male sterility solely depends on cytoplasmic factors. It may also depend on interactions that take place between cytoplasmic factors and nuclear factors.
What are the Similarities Between Genetic Male Sterility and Cytoplasmic Male Sterility?
- Genetic male sterility and cytoplasmic male sterility occur in plants.
- They lead to male sterility.
- Moreover, they lead to the production of non-viable pollen grains.
- Genetic and cytoplasmic male sterility can arise at any stage of the development of pollen grain.
- Both methods act as an outbreeding device that prevents autogamy and leads to heterozygosity.
What is the Difference Between Genetic Male Sterility and Cytoplasmic Male Sterility?
Genetic male sterility occurs due to genome mutations, while cytoplasmic male sterility occurs due to cytoplasmic and nuclear factors. Thus, this is the key difference between genetic male sterility and cytoplasmic male sterility. DNA is the major biomolecule involved in genetic male sterility, while protein is the main biomolecule involved in cytoplasmic male sterility. There are three types of genetic male sterility mechanisms, but there is only one type of cytoplasmic male sterility.
The following table summarizes the difference between genetic male sterility and cytoplasmic male sterility.
Summary – Genetic Male Sterility vs Cytoplasmic Male Sterility
Male sterility in plants refers to a condition where the male reproductive part of the plant is sterile and produces non-functional pollen grains. The significance of male sterility is that it can arise at any stage of the development of pollen grains. There are two types of male sterility in plants as genetic male sterility and cytoplasmic male sterility. Genetic male sterility occurs due to genome mutations, while cytoplasmic male sterility occurs due to cytoplasmic and nuclear factors. So, this summarizes the difference between genetic male sterility and cytoplasmic male sterility. Both processes help to prevent autogamy and lead to heterozygosity.
Reference:
1. Abbas A; Yu P; Sun L; Yang Z; Chen D; Cheng S; Cao L; “Exploiting Genic Male Sterility in Rice: From Molecular Dissection to Breeding Applications.” Frontiers in Plant Science, U.S. National Library of Medicine.
2. Xu, Fengyuan, et al. “Exploiting Sterility and Fertility Variation in Cytoplasmic Male Sterile Vegetable Crops.” Horticulture Research, Oxford University Press.
Image Courtesy:
1. “Amaryllis stamens aka” By André Karwath aka Aka – Own work (CC BY-SA 2.5) via Commons Wikimedia