| 摘要: |
| 为筛选出更实用的小麦籽粒多酚氧化酶（PPO）活性分子标记，试验根据PPO基因的EST序列设计引物，以PPO活性差异较大的2组材料基因组DNA为模版进行PCR扩增，对小麦籽粒PPO活性分子标记进行了研究。结果表明，引物PPO18扩增产物的电泳带型在2组材料间存在明显差异，其在高PPO活性的材料中均扩增出685bp片段，在低PPO活性的材料中均扩增出876bp片段，相差191 bp。在所扩增的PPO基因序列中存在两个内含子（内含子Ⅰ和内含子Ⅱ），其中内含子Ⅰ符合内含子的GT-AG法则，在不同PPO活性材料间存在191bp的DNA序列差异，与扩增片段的长度差异相吻合；内含子Ⅱ为‘GC-AG’型内含子，没有内含子的‘GT-AG’典型特征。在所扩增的PPO基因序列外显子区段，不同PPO活性材料之间存在两个单核苷酸多态性位点（SNP）。PPO18及其所标记的PPO基因定位于2AL染色体上。结果表明，PPO18标记是共显性、可靠、简便、实用的功能标记，可用于小麦种质资源评价和育种后代标记的辅助选择。 |
| 关键词: 普通小麦 面制品颜色 籽粒PPO活性 STS分子标记 |
| DOI： |
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| 基金项目:国家自然科学基金项目(30270822);国家“973”项目(2002CB111300)；国家“863”项目(2002AA207003);西北农林科技大学博士科研启动基金项目 |
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| Development of molecular marker for grain PPO activity in bread wheat |
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| Abstract: |
| To screen out more practicable PPO activity molecular marker,which could greatly improve selection efficiency in breeding programs,were studied.Based on the sequences of PPO genes (EST) conditioning PPO activity during kernel development,28 pairs of primers were designed.One of the markers designated as PPO18 can amplify a 685 bp and a 876 bp fragment in the cultivars with high and low PPO activity respectively.The STS marker PPO18 was mapped to chromosome 2AL using a DH population derived from a cross Zhongyou 9507×CA9632,and a set of nulli-tetrasomic lines and ditelosomic line 2AS of Chinese Spring.QTL analysis indicated that the PPO gene co-segregated with the STS marker PPO18 and is closely linked to Xgwm312 and Xgwm294 on chromosome 2AL.A total of 233 Chinese wheat cultivars and advanced lines were used to validate the correlation between the polymorphic fragments of PPO18 and grain PPO activity.The results showed that PPO18 is a co-dominant,efficient and reliable molecular marker for PPO activity and can be used in wheat breeding programs targeted for noodle quality improvement.The sequence alignments revealed that at the position of intron Ⅰ,in accordance with “GT-AG” law,the PPO gene in cultivars with low PPO activity has 191 bases more than that in cultivars with high PPO activity where PPO gene is expressed intron Ⅱa intron with ‘GC-AG’ characteristics,doesn’t have typical “GT-AG” characteristics.The additional 191 bp insertion sequence might influence the splicing of premature mRNA,which could cause the PPO gene unable to express.Results show that PPO18 marker is reliable,simple and practicable and can be used as a supplement in the quality evaluation of wheat seed and breeding marking. |
| Key words: bread wheat noodle color grain PPO activity molecular marker |
