An unusual polymorphic locus useful for tagging Rps1 resistance alleles in soybean.

Area of Science:

• Plant genetics
• Molecular biology
• Agricultural science

Background:

• Phytophthora root and stem rot is a significant soybean disease.
• The resistance locus Rps1 is crucial for managing this disease.
• Understanding Rps1 allele variations is key for breeding resistant soybean varieties.

Purpose of the Study:

• To investigate polymorphisms at locus A071-1 for tagging Phytophthora resistance alleles.
• To determine if A071-1 can differentiate soybean germplasm with Rps1 alleles.
• To assess the utility of A071-1 polymorphisms in soybean breeding programs.

Main Methods:

• Screening soybean germplasm with seven Rps1 alleles using eight restriction enzymes.
• Restriction fragment length polymorphism (RFLP) mapping.
• Comparison with an EMBL3 clone and Southern hybridization.

Main Results:

• Six enzymes revealed polymorphisms at locus A071-1.
• A071-1 exhibited three polymorphisms per enzyme, indicating multiple mutation events.
• While not distinguishing Rps1- and Rps1-containing genotypes, polymorphisms allowed grouping into five distinct soybean germplasm sets.
• Polymorphisms were detected in Rps1 donors and U.S. soybean varieties.

Conclusions:

• Locus A071-1 displays significant and unusual polymorphism.
• These polymorphisms are valuable for tracking Rps1 inheritance in soybean breeding.
• A071-1 serves as a useful marker for soybean genetic diversity related to Phytophthora resistance.