Investigation On The Effects Of Allelic Variation Of Starch Synthesis-related Genes By Using Near-isogenic Lines

Rice is an important crop cereal in the world;Rice quality will directly affect the value of their goods.Starch is the major component of rice endosperm and is composed of amylose and amylopectin.The previous studies had showed that the fine structure of amylopectin,amylose and amylopectin content have a large impact on the quality of the rice.Starch synthesis is involved by the four major categories of enzymes,including granule-bound starch synthase(GBSS),soluble starch synthase(SS),starch branching enzyme(SBE),and starch debranching enzyme(DBE).In this study,in order to investigate of the effect of the genes responsible for starch synthesis(SSRGs)on cooking quality in rice,near isogenic lines(NILs)were developed which used jiaponica Nipponbare or indica Longtefu as the recurrent parents,and other three indica cultivars Longtefu,9311,9308,and one japonica waxy cultivar Suyunuo(SYN)as the donor parents.The main results were shown as followings:(1)There was no significant difference on most agronomic traits between the NILs and the recurrent parent,which indicated that the backgrounds of the NILs were nearly the same to Nipponbare as the recurrent parent.(2)Through determining and comparison of the physiochemical properties of rice grains and the fine structure of starches between the NILs and their recurrent parents,the results showed that there have a certain impact of the allelic variations on rice grain quality.(3)In the japonica background of Nippobare,the physical and chemical properties of grains from selected NILs and their recurrent parents were carefully measured and compared.The results showed that the variations of Wx,wx,SS?-3,ISA genes have a significant effect on amylose content,gel consistency,rapid viscosity properties,and DSC and the fine structure of starch.(4)The NILs in the indica background were developed which used indica cultivars Longtefu(LTF)and Zhenshan97B(ZS97B)as the recurrent parents,and another indica cultivar 9311 as the donor parent.The results showed that the variation of Wx gene has a significant effect on amylose content,gel consistency,rapid viscosity properties and DSC.On the genetic background with the same Wx gene,the variation of SSI from 9311 has a significant effect on amylose content,gel consistency and DSC.Besides,on the background of ZS97B with Anti-Wx gene,when the SSIa allele was substituted by the SSIi,the amylose content and setback value increased significantly,but the gel consistency,breakdown value and enthalpy decreased significantly.