LEADER 00000nam  2200301   4500 
001    AAI3399938 
005    20110907152244.5 
008    110907s2009    ||||||||||||||||| ||eng d 
020    9781109664904 
035    (UMI)AAI3399938 
040    UMI|cUMI 
100 1  Pudota, Bala Bhaskar 
245 10 Gene silencing based approach to study late blight 
       resistance and cold sweetening in potato 
300    139 p 
500    Source: Dissertation Abstracts International, Volume: 71-
       03, Section: B, page: 1415 
500    Adviser: Jiming Jiang 
502    Thesis (Ph.D.)--The University of Wisconsin - Madison, 
       2009 
520    RNA Interference (RNAi) is a post-transcriptional gene-
       silencing phenomenon widely used in plant biotechnology as
       a precise way to engineer specific reductions in gene 
       expression. I used gene silencing based approach to study 
       the function of several potato genes associated with late 
       blight disease resistance and cold-induced sweetening. (1)
       Late blight is the most serious potato disease and 
       currently the utilization of late blight resistant 
       varieties is the most cost-effective and environmentally 
       friendly method to control the disease. Previously, 
       transgenic potato lines containing a single  RB 
       (Resistance from bulbocastanum) gene showed broad-spectrum
       resistance to Phytophthora infestans. Several other late 
       blight resistance genes have also been cloned in recent 
       years. However, there is almost no information available 
       about the resistance pathways mediated by any of these 
       genes. In this study, an initial effort has been made to 
       functionally characterize the roles of Rar1 and Sgt1 using
       RNAi -based silencing. We found that Sgt1, but not  Rar1, 
       is essential for RB-mediated resistance. (2) Potato tubers
       must be stored under low temperatures to prevent sprouting,
       reduce respiration and minimize disease losses. 
       Unfortunately, cold storage also triggers the accumulation
       of glucose and fructose; a phenomenon recognized as cold-
       induced sweetening (CIS). Processing potato chips and 
       fries from tubers that have accumulated high levels of 
       glucose and fructose produce unacceptably brown- to black-
       pigmented products via a non-enzymatic, Maillard-type 
       reaction. In addition these may have elevated amounts of 
       acrylamide, which can be harmful to human health. There 
       are no commercially acceptable potato varieties available 
       that can be processed directly from cold storage. We have 
       used an  RNAi-based approach to control the CIS problem by
       silencing the potato Vacuolar Invertase (VInv) gene. 
       Tubers harvested from  VInv-silenced RNAi lines produced 
       light color potato chips after several months of cold 
       storage and produced chips with low levels of acrylamide 
590    School code: 0262 
650  4 Agriculture, Plant Culture 
690    0479 
710 2  The University of Wisconsin - Madison 
773 0  |tDissertation Abstracts International|g71-03B 
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