Researchers at Iowa State University may have overcome a long-standing problem connected with the rapid production of pure genetic lines.
The use of “doubled haploid” (DH) genetics has evolved into one of the fundamental technologies underlying current maize breeding. Yet, DH technology offers both benefits and disadvantages. Then, “haploid” plants with just a single mother genome must be created. The single genome of the haploid plant is then doubled by a chemical technique that speeds up the creation of genetically pure inbred strains.
One of the greatest limitations in DH technology is that haploid male flowers are frequently sterile. This condition necessitates exposing the seedlings to the poisonous chemical colchicine, which promotes genome doubling and restores male flower fertility. The procedure is time-consuming and expensive.
A recent study published in Nature Plants reports on a mutation found by the authors that restores male fertility in haploids without the application of colchicine. The study was undertaken by Siddique I. Aboobucker, research scientist in agronomy, alongside Thomas Lübberstedt, Frey Chair in Agronomy and head of the Raymond F. Baker Center for Plant Breeding, and former agronomy graduate student Liming Zhou .
They proved that haploid plants may be restored to male fertility by using mutations that change the location of the spindle mechanism during the plant reproductive phase known as meiosis.
The spindle mechanism aids in the regulation of cell division. During normal meiosis, spindles in standard “diploid” plants with two sets of chromosomes are organised in perpendicular pairs that readily line up. The chromosomes in haploid plants are unequally distributed during cell division, resulting in high rates of sterility throughout the subsequent stages of reproduction.
To solve this issue, Aboobucker had an idea that the team believed was worth looking into. They anticipated that a group of genetic plant anomalies known as parallel spindle mutants, or “ps mutants,” which alter the spindles during meiosis to a parallel rather than perpendicular orientation, may boost male fertility in haploids. They tested the hypothesis using Arabidopsis thaliana, a model study plant that is often employed as a prelude to work on maize and other crop species.
It worked: the haploid mutant plants flourished, and the majority of them were fertile. The findings confirm their hypothesis that the uneven development of spindle fibres at a key period of meiosis in haploid males may be addressed by taking advantage of the mutants’ predisposition to promote more horizontal spindle formation.
“Using this mutation to address the male fertility issue in haploid plants has enormous potential,” Lübberstedt stated.
He attributes the majority of the credit to Aboobucker, who lead the initiative to solve the long-standing mystery of male haploid infertility.
“I’m seeing this is a significant thing,” Aboobucker remarked. “The reaction from colleagues all across the globe has been a touch overwhelming since our story was published last month.”
Lübberstedt and Aboobucker think the advantageous mutations they discovered may be applied to maize and other crops with modest changes. Investigating this possibility is one of their next endeavours.
You might also be interested in reading, A novel elastic polymer dielectric to produce wafer-scale stretchable electronics
