Question

In general, the cytoplasmic male sterility (CMS) causing genes are transcribed in which plant cell organelle?

• A. Nucleus
• B. Peroxisome
• C. Mitochondria
• D. Chloroplast

Hint:

Remember that CMS is {C}ytoplasmic, so the genes are not in the nucleus. Between the two cytoplasmic organelles with DNA (mitochondria and chloroplast), associate CMS with the {M}itochondria ({M}ale sterility \(\rightarrow\) {M}itochondria).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Cytoplasmic male sterility (CMS) is a maternally inherited trait where a plant is unable to produce functional pollen. The term "cytoplasmic" indicates that the genes controlling this trait are located in the cytoplasm, not the nucleus.
Step 2: Detailed Explanation:
The cytoplasm of a plant cell contains organelles that have their own genomes, separate from the nuclear genome. These are the mitochondria and the chloroplasts.
Research has shown that in the vast majority of cases across different plant species, the genes responsible for causing CMS are located in the mitochondrial genome. These CMS-associated genes are often novel, chimeric open reading frames that arise from rearrangements in the mitochondrial DNA. Their expression, typically in the anther tapetum, disrupts pollen development, leading to male sterility. While chloroplast genes can sometimes influence CMS expression, the primary causative genes are almost always mitochondrial.
Step 3: Final Answer:
The genes causing cytoplasmic male sterility are generally transcribed in the mitochondria.