木糖对多年生黑麦草愈伤组织生长的影响

The effect of xylose on the callus growth of perennial ryegrass

木糖被认为是生物安全的选择试剂。为探讨木糖异构酶基因能否作为筛选标记在多年生黑麦草(Loliumperenne)遗传转化中运用,以成熟种子诱导的愈伤组织为外植体,研究木糖作为碳源对愈伤组织生长的影响,5周后观察结果。结果表明,在愈伤组织继代培养基(SM)中分别添加蔗糖、木糖以及不同配比蔗糖+木糖,愈伤组织生长状况不同。单糖质量浓度在0～30 g/L的条件下,愈伤组织生长量随着糖浓度的增加而增加,但在添加蔗糖的培养基中生长明显优于在木糖中;在混合糖培养中(糖总量为30 g/L),愈伤组织的生长量高于对照,但随着蔗糖量减少和木糖含量增加,愈伤组织生长量下降。本研究表明,木糖能显著影响多年生黑麦草愈伤组织的生长,使其生长受到较大程度地限制。在总糖质量浓度为30 g/L的继代培养基中,25 g/L木糖+5 g/L蔗糖和只含有30 g/L木糖的培养基中,愈伤组织生长量最低。推测可用这两种质量浓度作为多年生黑麦草愈伤组织遗传转化的木糖筛选体系的选择压。

Xylose as a selective agent is considered to be biosafe for plant genetic transformation. For investigating the possibility of xylose isomerase gene as a selective marker in genetic transformation of perennial ryegrass （Loliurn perenne）, the effect of xylose on the growth of calli which derived from mature embryos of perennial ryegrass was detected. Cultured on subultivation medium （SM） with different proportions of sucrose, xylose and sucrose＋xylose respectively,the calli were analyzed and their weight gain were determined after 5 week culture. The results of this study showed that the weight gain of calli increased with the enhancing of sugar content from 0 to 30 g/L. Calli grew much better on the media with sucrose than with xylose at the same concentration. At 30 g/L total amount of sugar in the mixed media, the weight gain of calli declined when the proportion of sucrose decreased in the meanwhile xylose increased. These results presented that xylose restricted the callus growth evidently. Moreover, on the media of SM＋5 g/L sucrose＋25 g/L xylose or SM＋30 g/L xylose, the biomassincrement was lower than others. It was suggested that xylose could be employed as a positive selective agent in perennial ryegrass genetic transformation at the selection pressure of 25 g/L xylose＋5 g/L sucrose or 30 g/L xylose.