Loss of starch branching enzyme IIb (BEIIb) leads to altered starch structure and increased amylose content. The changes in starch fine structure and function during seed development were investigated as a result from differentially expressed genes between wildtype (WT) and be2b rice. The expression patterns of all starch synthesis related genes except the AGPS1 were altered in be2b. From five to 15 days after flowering (DAF), the amylose content and proportion of A chains of amylopectin increased, while those of B2, B3 chains and average chain length declined in both WT and be2b. The mutant had a C-type crystalline pattern and a higher relative crystallinity (RC) at five and 10 DAF, which was transferred to a B-type and a lower RC at 15 DAF in be2b, while the WT had A-type starch at all developmental stages. A possible model for amylose and amylopectin structure in WT and be2b was proposed.

淀粉支化酶 IIb (BEIIb) 的损失导致淀粉结构改变和直链淀粉含量增加。由于野生型（WT）和be2b水稻之间的差异表达基因，研究了种子发育过程中淀粉精细结构和功能的变化。除AGPS1外，所有淀粉合成相关基因的表达模式在be2b中都发生了改变。开花后5～15天（DAF），WT和be2b的支链淀粉A链直链淀粉含量和比例增加，而B2、B3链和平均链长均下降. 突变体在 5 天和 10 天时具有 C 型结晶模式和较高的相对结晶度 (RC)，在be2b中其在 15 天时转移到 B 型和较低的 RC ，而 WT 在 15 天时具有 A 型淀粉所有发展阶段。提出了 WT 和be2b中直链淀粉和支链淀粉结构的可能模型。