Locating a site on the maize B chromosome that controls preferential fertilization

Area of Science:

• Genetics
• Plant breeding
• Molecular biology

Background:

• The B chromosome in maize exhibits nondisjunction during pollen development, resulting in sperm cells with either two B chromosomes or none.
• Preferential fertilization describes the phenomenon where sperm carrying two B chromosomes are preferentially transmitted to the embryo.
• The TB-9Sb translocation, involving the B chromosome and chromosome 9, shares these properties and serves as a model for studying preferential fertilization.

Purpose of the Study:

• To investigate the role of centric heterochromatin and adjacent euchromatin in the B-9 chromosome's ability to induce preferential fertilization.
• To determine if deletion derivatives of the B-9 chromosome, lacking specific regions, retain the capacity for preferential fertilization.

Main Methods:

• Generation of deletion derivatives of the B-9 chromosome, specifically those lacking centric heterochromatin.
• Testing the ability of these deletion derivatives to induce preferential fertilization in maize.

Main Results:

• Deletion derivatives of the B-9 chromosome, which are deficient in centric heterochromatin and potentially adjacent euchromatin, were found to lack the capacity for preferential fertilization.
• This suggests that the centric heterochromatin and/or adjacent euchromatin are essential for the induction of preferential fertilization by the B-9 chromosome.

Conclusions:

• The centric heterochromatin and possibly adjacent euchromatin on the B-9 chromosome are critical for its ability to induce preferential fertilization.
• The findings contribute to understanding the mechanisms underlying B chromosome behavior and transmission in maize.