Proteomeanalysis Of Potato (Solanum Tuberosum L.) Tuber In Vitro With Tuberization Of Regulated By Gibberellin

Potato (Solanum tuberosum L.) tubers are vegetative propagation and storageorgans. Therefore, research into the process of potato tuber initiation and development,which can help us to improve the yield and quality of potato harvests. The control oftuber formation is a complex biological process, is often influenced by environmentfactors and phytohormone. However, as a kind of plant growth regulator, gibberellinshave an important regulatory role in potato tuber initiation and development, whichultimately showed related proteins changed in expression level.In this study, the potato stolon cuttings were used as experimental material, andthe effect of GA3on morphology, physiology and the proteome levels during potatotuberization were investigated. The mechanism of potato tuber development under thecontrol of gibberellins in vitro clarified by physiological and proteomics methods. Bystudying, we obtained a number of research achievements, the detailed results were asfollowing:1. Potato tubers were inhibited obviously under GA3treatments. In1.0μMtreatment，tuberization was delayed or completely inhibited，the reducing sugarscontents were increased significantly and had a maximum value in this treatment;With the increase of GA3concentration from0.01to1.0μM, the α-amylase activitywere markedly increased compared with control, however, the contents of starch andsucrose were declined markedly during tuberization under GA3treatments. Theresults indicate a negative role for GA3in regulating carbohydrate accumulationduring tuberization.2. The endogenous GA3and IAA levels were detected by HCLP. Theendogenous GA3levels were significantly declined, and inversely, the endogenousIAA levels were raised in control before the stolon begain to swelling; Theendogenous GA3and IAA levels in GA3-treated was significantly higher than controland had a maximum value in1.0μM treatment. These results suggested thatexogenous GA3intensively promoted the endogenous GA3and IAA levels andinhibited the potato tuber formation and development in vitro. 3. In present study, we applied comparative proteomic approaches to identify anumber of differentially expressed proteins that are putatively involved in theGA3-induced of potato tuber initiation and development in vitro. The analysis showsthat the Patatin protein, protease inhibitors, and other storage proteins, polysaccharideand jasmonic acid synthesis related enzymes were down-regulated; Conversely, thereare a few proteins were up-regulated which were involved with starch metabolism,polysaccharide metabolism and amino acid metabolism, fatty acid metabolism andterpenoids synthesis, protein folding and signal transduction etc.4. These findings demonstrated that gibberellins have a important role, and as ainhibitor in the accumulation of storage proteins (such as Patatin and proteaseinhibitors), which inhibited the tuber fomation during tuberization; The change in theexpression of ADP-glucose pyrophosphorylase, Cytosolic phosphoglucomutase,NAD-dependent malate dehydrogenase, indicated that the carbohydrates catabolismwere promoted and the starch accumulation were inhibited during tuberization, itindicated that gibberellins have changed the transport direction of nutrient andinhibited the tuber formation and development.