The Analysis Of Base On The GBSS I-RNAi Transgenic Enotypes Differentially Expressed Proteome In Cassava

Cassava (Manihot esculenta Crantz) has attracted extensive interests as a food and bioenergy crop, the content and composition of tuberous roots exhibit a great influence to the processing and utilization. In addition, due to the low protein content and amylopectin ratio, cassava starch is very popular in the processing and applications.However, as a result of restriction in traditional breeding, it is difficult to get plant having expected traits in a short term. Therefore, the genetic engineering technology has become a promising method to solve this problem. However, because of many uncertainties in transgenic technology, some limitations in terms of evaluation and selection of transgenic plants using agronomic traits and starch quality still exist. In order to understand the impact of transgene on agronomic traits and starch quality of cassava, proteomics was used in this study to compare with the whole protein profiles between C3and4transgenic genotypes based on GBSSI-RNAi. The main results are as follow:1. There is no significant difference in yield between C3and transgenic cassava, but it shows impact on stem and height in transgenic.2. The result of nutrient between C3and transgenic roots shows that dry matter is no significance between C3and transgenic; But the starch content in4transgenic genotypes has decreased particularly SSA8and SSA17, which reach the significant levels. However, amylase content in transgenic plants generally increased, and SSA8and SSA17show the fastest increase and reach significant levels.3. The analysis of other nutrient indicates that RNA interference GBSS I gene expression have some impact on the content of β-carotene, soluble sugar and crude fiber.4. Compare with C3, the number of differentially expressed proteins was19,22,20,16in SSA8, SSA10, SSA11and SSA17, respectively. The differential proteins was identified by MALDI-TOF-TOF-MS/MS, which shows that the number of down-regulated protein spots is more than up-regulated spots in SSA8and SSA10, while the number of up-regulated spots is more than3times compared with down-regulated spots in SSA11and SSA17.5. The proteins associated with starch synthesis mainly participate in carbon and energy metabolic pathways including Starch phosphorylase L, Enolase, pyruvate dehydrogenase, triosephosphate isomerase, ATP synthase, NADH-ubiquinone oxidoreductase, dihydrolipoamide dehydrogenase precursor-Bruguiera gymnorhiza, V-type proton ATPase catalytic subunit A.6. The study reveals that carbon and energy metabolism pathways is changed after GBSSI gene expression is disturbed in cassava root, such as the high expression level of low affinity starch phosphorylase associated with starch promoting starch degradation and leading to the decrease of starch content and increase of amylose content. The results are consistent with agronomic traits and nutrition. Consequently, this study provides a good reference for creating special cassava germplasm through molecular breeding.