What is Barnase Barstar system? Transgenic Male Sterility in Plants. Plant Breeding and Agriculture Notes Simple and Easy. Helpful for ASRB-NET and ICAR-NET.

 Male Sterility

• The production of non-functional male gametes mean unviable pollen grains is called as male sterility.
• REASON: Environment factors and Genetic factors.
• It can be caused by a recessive gene or a dominate gene like in BARNASE BARSTAR system.

barnase barstar system

• Present in Bacillus amyloliquefaciens. (A Bacteria)
• Barnase is a dominant gene means a segment on DNA.
• Barnase gene will form RNase by gene expression.
• When this gene from bacteria isolated and transformed into a desired plant it will lead to male sterility.
• The Barnase gene can be manipulated with a promoter named TA29.
• TA29 is a promoter specifically for Tapetal cells of Anther. 
• The gene along with promoter when added in plant it led to male sterility.
• The gene specifically express in the tapetal cells and then degrade the tapetal cells due to which the microspore produced will be non-functional or unviable hence causes male sterility.

So, the steps involved are:

STEP 1: Selection of Bacteria namely Bacillus amyloliquefaciens.

STEP 2: Isolation of Barnase gene from Bacillus amyloliquefaciens.

STEP 3: Manipulation of Barnase gene means make some changes with gene like addition of promoter TA29 to it.

STEP 4: Transformation of gene with a desired plant.

STEP 5: Expression of gene Barnase and production of RNase.

STEP 6: Degradation of Tapetal cells by RNase.

STEP 7: Production of Nonfunctional Pollen grains.

• Another gene named Barstar gene.
• It is the restorer of Fertility.
• Means it restore the male sterility caused by Barnase gene.
• If the Barnase gene and Barstar gene present in same amount it leads to No male sterility.
• If Barnase gene is present more amount it will lead to male sterility.

Watch out the complete explanation Video Here