CAJ | 학술논문

淀粉是玉米种子的主要组成成分,它包括直链淀粉和支链淀粉.支链淀粉的合成需要淀粉合成酶、分支酶和脱支酶的共同作用,而直链淀粉的合成则是在颗粒结合型淀粉合成酶的作用下进行的.颗粒结合型淀粉合成酶基因的突变造成玉米种子的腊质(糯性)表型.与支链淀粉合成的分子机制的研究相比,目前对玉米种子中直链淀粉合成的分子机制了解相对较少.以野生型黄早4玉米自交系和突变体糯玉米为实验材料,研究了种子不同发育时期直链淀粉的积累规律.通过碘染色的方法,观察了玉米种子发育过程中淀粉积累的形态变化.定量分析表明,从授粉后10d至25d,黄早4种子中直链淀粉的含量逐渐增加,同时颗粒结合型淀粉合成酶(GBSS)的活性逐渐提高;而在糯玉米中,直链淀粉和GBSS活性均未检测到.进而,通过RT-PCR方法,从黄早4种子中分离出编码GBSSI的cDNA片段.在授粉后10d至25d的玉米胚乳中均可检测到GBSSI的表达,而在胚中直到授粉后25d才检测到该基因表达的微弱信号.在糯玉米种子中没有检测到该基因的表达.研究结果表明,在玉米种子发育过程中,GBSSI基因的表达通过控制GBSS的合成,最终控制直链淀粉的合成.研究工作为理解玉米种子中直链淀粉合成的分子机制提供了重要信息.
정분시옥미충자적주요조성성분,타포괄직련정분화지련정분.지련정분적합성수요정분합성매、분지매화탈지매적공동작용,이직련정분적합성칙시재과립결합형정분합성매적작용하진행적.과립결합형정분합성매기인적돌변조성옥미충자적석질(나성)표형.여지련정분합성적분자궤제적연구상비,목전대옥미충자중직련정분합성적분자궤제료해상대교소.이야생형황조4옥미자교계화돌변체나옥미위실험재료,연구료충자불동발육시기직련정분적적루규률.통과전염색적방법,관찰료옥미충자발육과정중정분적루적형태변화.정량분석표명,종수분후10d지25d,황조4충자중직련정분적함량축점증가,동시과립결합형정분합성매(GBSS)적활성축점제고;이재나옥미중,직련정분화GBSS활성균미검측도.진이,통과RT-PCR방법,종황조4충자중분리출편마GBSSI적cDNA편단.재수분후10d지25d적옥미배유중균가검측도GBSSI적표체,이재배중직도수분후25d재검측도해기인표체적미약신호.재나옥미충자중몰유검측도해기인적표체.연구결과표명,재옥미충자발육과정중,GBSSI기인적표체통과공제GBSS적합성,최종공제직련정분적합성.연구공작위리해옥미충자중직련정분합성적분자궤제제공료중요신식.
Starch, which includes amylose and amylopectin, is the most important component in maize (Zea mays L.) seeds. The accumulation of amylose in maize seeds was examined in this study. The percentage of arnylose content gradually increased in seeds from day 10 to day 25 after pollination, which is consistent with the changes of GBSS activity. The transcripts of GBSSI were detected in both the endosperm and embryo of wild-type maize. However, its transcripts, GBSS activity, and amylose were not detected in either the endosperm or embryo of waxy maize. These results indicate that the accumulation of amylose is controlled by GBSSI expression in the seeds of maize.