Ding Xiang-Zhen, Wang Bei-Guo, Gao Qing-Hua, Zhang Qiong, Yan Gui-Qin, Duan Ke, Huang Jian-Hua
Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Biological Technique, Shanghai Academy of Agricultural Sciences (SAAS), Beidi Road 2901, Minhang Zone, 201106 Shanghai, China.
Plant Cell Rep. 2009 Oct;28(10):1487-95. doi: 10.1007/s00299-009-0748-5. Epub 2009 Jul 25.
The maize genome remains abundant in molecular diversity, and the rich genetic diversity of maize starch-synthesis genes is crucial for controlling various grain traits. To explore the unique mechanism controlling the advantageous waxy trait and characterize the molecular feature of genes relevant to starch composition in two elite waxy inbreds, expression profiling combined with gene organization analysis was performed in them as compared to one normal inbred. Genotype-specific expression patterns were observed for most genes studied. The waxy inbreds were shown to contain mutations in multiple starch-synthesis genes, namely gbssI (wx), gbssIIb and isa2 (potentially isa3 too).The mis-splicing events directly accounted for wx loss of function. Contrarily, disruption of 5' and 3' transcript sequence may contribute to the absence of GbssIIb and Isa2 transcripts in waxy inbreds, respectively. Besides, the splicing of Sugary1 transcript was developmentally regulated in the normal inbred, and DNA polymorphisms were detected within SSIIIb-1 gene in waxy inbreds.
玉米基因组在分子多样性方面仍然十分丰富，玉米淀粉合成基因丰富的遗传多样性对于控制各种籽粒性状至关重要。为了探究控制优良糯性性状的独特机制，并表征两个优良糯性自交系中与淀粉组成相关基因的分子特征，与一个正常自交系相比，对它们进行了表达谱分析并结合基因组织分析。在所研究的大多数基因中观察到了基因型特异性表达模式。结果表明，糯性自交系在多个淀粉合成基因中存在突变，即颗粒结合型淀粉合成酶I（gbssI，wx）、颗粒结合型淀粉合成酶IIb和异淀粉酶2（可能还有异淀粉酶3）。错配剪接事件直接导致了wx功能丧失。相反，5'和3'转录本序列的破坏可能分别导致了糯性自交系中GbssIIb和Isa2转录本的缺失。此外，在正常自交系中，糖1转录本的剪接受发育调控，在糯性自交系的SSIIIb-1基因内检测到了DNA多态性。
