| Potato tuber development is the most important step in potato cultivation andproductivity. In vitro culture condition, potato tubers have consistent maturation anduniformity, and it is easy to accurately judge its development period. Potato tuberdevelopment is regulated and controlled by a variety of endogenous hormones, whichultimately showed related genes translated into the corresponding protein. Changes ofprotein expression can reflect the changes of potato tuber gene expression andmetabolic regulation. It is necessary to investigate the level of protein expression intuber development. The comparative proteomic analysis of potato tuber can reveal thedifference of protein expression in tuber development, which has an importantsignificance to study the tuber development mechanism.Potato tuber development in vitro condition was established. Endogenoushormones content of four tuber development stages were detected with HPLCmethods. Potato tuber proteins of the four development stages were extracted withtwo-step precipitation method, and separated by two-dimensional electrophoresis(2-DE). The2-DE images were analyzed by PDQuest8.0software to obtain thenumber and intensity of the protein spots. The change of the protein spots number infour development stages and the differentially expressed protein spots wereinvestigated. Further, the differentially expressed protein spots were identified byMALDI-TOF-MS (Matrix assisted laser desorption ionization time of flight massspectrometry). Their roles in tuber development were discussed. The expression ontranscripitional level of nine differentially expressed protein spots were detecectedwith RT-PCR method. The results were as following:1. The content of GA3was highest at the stolon induction and differentiationstage, and then decreased with the tuber development. The result indicated that GA3has no obvious effect on tuber formation. The contents of ABA and MeJA wereincreased gradually with tuber development and up to the highest content at tuberenlargement stage. The result indicated that ABA and MeJA have promoting effect ontuber fomation. 2. There was no significant difference in the number of protein spots among thestage of stolon initiation (1020±27), stolon elongation growth (1210±35) and stolondiageotropic growth (1183±76).3. There fourty-six differentially expressed protein spots were detected in fourtuber developmental stages. In these spots, sixteen spots were up-regulated, nineteenspots were down-regulated after up-regulated, seven spots were down-regulated, andfour spots up-regulated after down-regulated.4. Fourty-six differentially expressed protein spots were identified withLC-ES-MS/MS analyses. Those differentially expressed proteins involved in differentpathways, including bioenergy and metabolism, cell defense and rescue, storage, celltransportation, signal transduction and transcription.5. Patatin proteins with phospholipase activity rapidly accumulated from thestage of stolon diageotropic growth, which promoted the tuber fomation. The changein the expression of sucrose synthase, fructokinase, indicated that the starch synthesiswas promoted from the stage of stolon elongation growth. The tuber development wasfurther stimulated by starch synthesis, which played a role of positive regulation in thetuber morphogenesis.6. Nine genes were detected with RT-PCR. Four genes showed same expressiontendency compared with protein level, such as Patatin and Catalase gene. Five genesshowed different expression tendency compared with protein level. |
