Two Genes Involved In The Starch Synthase Were Introduced Into Rice By Agrobacterium-mediated Transformation

Starch makes up about 90% of the dry matter content of milled rice, which is divided into amylose and amylopectin. It proved that their molecular structure and compositional proportion have influenced cooking and eating of rice quality. At present quality of most of rice cultivars is very poor, it is mainly induced by high amylose. So, it is increasing tendency to decrease amylose content. But it is very difficult to improve Starch Quality by routinely genetic improvement because of endosperm characteristic of amylose.With quick development of molecular and gene engineering of starch, It is possible to improve rice starch quality by gene engineering. Soluble starch synthase enzyme gene SSS and starch branching enzyme gene RBE1 have been introduced into rice restoring line Hang 1 hao ( Indica Sativa L. ) and Minhui81 ( Indica Sativa L. ) by Agrobacterium-mediated transformation and try to find out the possibility of manipulation of Indica Rice Starch Quality via Genetic Engineering. Now, this report was summarized as following:1. Forward expression soluble starch synthase gene SSS and forward or reverse expression starch branching enzyme gene RBEl was introduced into rice restoring line Hang 1 hao and Minhui81 by Agrobacterium-medlated transformation. We have totally obtained 45 Hang 1 hao and 71 MinhuiSl independent transgenic plants. X 2 detecting showed that the majority of TO generation transgenic plants accorded with Mendelian segregation (3:1).2. PCR and Southern blot showed that soluble starch synthase gene and starch branching enzyme gene have been integrated into rice genome and expressed.3. Amylose content of To generation seeds analysis showed: The quantity of amylose of forward expression starch branching enzyme gene had reduced compared to the original species, the biggest decreasing rate arrived 34.68%, the quantity of amylose had decreased to 9.6% in Hang 1 hao. The quantity of amylose of forward expression soluble starch synthase gene of Minhui81 had reduced markedly compared to the original species, the biggest decreasing rate arrived 21.45%, and the quantity of amylose had decreased to 9.91% in Minhui81. The quantity of amylose of forward expression starch branching enzyme gene had also reduced compared to the original species, the biggest decreasing rate arrived 21.87%, and the quantity of amylase had decreased to 9.91% in Minhui81. While the quantity of amylose of reverse expression starch branching enzyme gene, biggest increasing rate arrived 16.95% compared to the original species in Mihhui81. So, it is possible to improve rice starchquality by gene engineering.