摘要
稻米直链淀粉是在由蜡质基因Wx编码的颗粒结合淀粉合成酶（GBSS）的催化下合成的。最近，在Wx基因的区段内发现了一段多态性微卫星序列（CT）n。对74个非糯籼稻和粳稻材料的（CT）n多态性进行了分析，并探讨了其与直链淀粉含量之间的关系。在74个品种（系）中共发现7种（CT）n片段（Wx等位基因），即（CT）8，（CF）10，（CT）11，（CT）16，（CT）17，（CT）18，（Ch）19。在籼粳亚种间，不同（CT）n的分布存在差异较大：在籼稻中，以（CT）11和（CT）18为主，占92．6％，另有（CT）10和（CT）8各2份，（CT）17型1份；在粳稻中，以（CT）16、（CT）17为主，共占20份材料中的90．0％。在上述74个品种（系）中，以（CT）n表示的Wx基因型对稻米直链淀粉含量的决定系数R2达0．912，也即Wx基因型差异可解释这些材料直链淀粉含量变异的91．2％。还发现6份籼稻材料Wx座位上为杂合的（CT）18／（CT）11，其中2份为推广早籼优质品种浙9248和舟优903，并对其在遗传和育种研究中的意义作了探讨。
Amylose is synthesized under the catalysis of granule--bound starch synthases (GBSS) encoded by the wary gene in rice. A polymorphic (CT)n microsatellite sequence was reported within the Wx gene recently. The polymorphism of this sequence and its relationship to amylose content was explored using 74 non-waxy indica and japonica rice varieties or breeding lines. Seven Wx microsatellite alleles,namely (CD)8, (CD)10, (CT)11, (CT)16, (CD)17, (CT) 18, and (CT) 19 were identified. The distribution difference of these alleles were obvious between indica and japonica subspecies. In indica rice, 92.6% materials were either with (CT)11 or (CT)18,, or both of them (heterozygous material); remaining ones included 2 with (CT)10, 2 with (CT)8, and 1 with (CT)17. In japonica rice, 18 varieties (lines) were with (CT)16 and (CT)17, which occupied 90.0% of the total, remaining ones were 1 with (CT)18 and 1with (CT)19. The determinant coefficient [the R squared (R2 ) value] of (CT)n to amylose content was as high as 0.912, which means 91.2% of amylose content variation could be resulted from waxy gene allele difference. In the experiment, we also found that 6 indica rice materials, 2 of which were commercial varieties, were still heterozygous on the Wx locus with alleles (CT)11 and (CT)18, the implications of this finding to plant genetic study and breeding application were discussed.
基金
浙江省自然科学基金!397284
浙江省"9410"工程和国际原子能机构资助!CPR95033P
