|Storey, Kathleen - UNIVERSITY OF MINNESOTA|
|Jung, Hans Joachim|
|Somers, David - UNIVERSITY OF MINNESOTA|
Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 2006
Publication Date: July 1, 2006
Citation: Schnurr, J.A., Storey, K.K., Jung, H.G., Somers, D.A., Gronwald, J.W. 2006. UDP-sugar pyrophosphorylase is essential for pollen development in Arabidopsis [abstract]. American Society of Plant Biologists Annual Meeting, August 5-9, 2006, Boston, Massachusetts. Abstract No. P31023. Technical Abstract: Arabidopsis UDP-sugar pyrophosphorylase (AtUSP) is a broad substrate enzyme that catalyzes the synthesis of UDP-sugars. We identified two knockout lines (usp-1 and usp-2) with T-DNA insertional events within the AtUSP coding region. From selfed heterozygous individuals, only wild-type and heterozygous plants were obtained in a ratio of 1:1. Although heterozygous plants had no obvious phenotype, both AtUSP transcript level and USP activity were reduced. To determine the cause of segregation distortion, reciprocal testcrosses were performed. The usp allele had no effect on transmission through the female gametophyte, but completely blocked transmission through the male gametophyte. Analysis of pollen from usp-1, which is in the quartet background, indicated a ratio of 2:2 for normal:shrunken pollen confirming that the mutation affected the male gametophyte. Shrunken pollen grains were not viable as demonstrated by germination tests and staining with DAPI and Alexander’s stain. The usp-1 pollen phenotype was complemented by transformation with the AtUSP cDNA sequence. Ultrastructural analyses on wild-type and mutant pollen revealed that the mutation had no effect on the outer pollen wall (exine) but blocked the synthesis of the pectocellulosic inner wall (intine).