MutL homolog 1 participates in interference-sensitive meiotic crossover formation in soybean

Area of Science:

• Plant genetics
• Molecular biology
• Reproductive biology

Background:

• MutL homolog 1 (MLH1) is vital for recombination in many species.
• The function of MLH1 in soybean (Glycine max) reproduction was previously unknown.

Purpose of the Study:

• To investigate the role of MLH1 in soybean fertility.
• To characterize the genetic basis of the Glycine max female and male sterility 1 (Gmfms1) mutation.

Main Methods:

• Map-based cloning to identify the causal gene of Gmfms1.
• CRISPR/Cas9 gene editing to validate the function of Glycine max MutL homolog 1 (GmMLH1).
• Meiotic analysis to assess chromosome behavior and crossover frequency.

Main Results:

• The Gmfms1 mutation was attributed to the GmMLH1 gene.
• GmMLH1 knockout resulted in reduced pollen viability and embryo sac abortion, causing female-male sterility.
• Loss of GmMLH1 function led to disrupted bivalent formation, univalent mis-segregation, and a significant decrease in meiotic crossover frequency.
• Interaction between GmMLH1 and GmMLH3A/GmMLH3B was observed.

Conclusions:

• GmMLH1 is essential for interference-sensitive crossover formation during soybean meiosis.
• This study elucidates the conserved role of MLH1 in plant reproductive processes.
• The findings provide insights into the genetic control of fertility in soybean.