小麦迟熟α-淀粉酶的研究进展

Progress of Study on Late Maturity α-Amylase in Wheat

本文讨论了迟熟 α-淀粉酶 (L ate m atureα- amylase,L MA)的概念及其与小麦发芽籽粒中其它 α-淀粉酶同工酶的区别 ,综述了其遗传特性、表达的差异性、影响因素和鉴定方法。认为迟熟α-淀粉酶 (L MA)是某些品种在籽粒发育后期在没有发生穗发芽的环境下所合成的一系列 α-淀粉酶同工酶 ,其种类与发芽期间合成的高 p I的 α-淀粉酶同属受 Amy- 1基因控制的α-淀粉酶同工酶。 L MA的表达在一定程度上具有倾母遗传特性。α-淀粉酶活性测定和FN值测定的结果表明 ,在不同小区、不同植株、不同穗子以及不同籽粒中 ,其表达都存在显著差异。同时 ,温度、矮秆基因、钼营养等因素对 L MA的表达也都有不同程度的影响。矮秆基因 (尤其是 Rht3)能够降低 L MA的表达效果。低温对于某些品种在籽粒发育中期 L MA的表达具有诱导作用 ,但机理至今仍不清楚。土壤中钼元素的存在对于 L MA的表达有时具有正调控作用 ,有时却有负调控作用。对于 L MA基因的定位和分子标记仍在研究中 ,目前已初步将其定位在小麦 6 B染色体的长臂上。

The definition of late mature α amylase (LMA)and its difference from the α amylase isozyme synthesized in germinating grains were discussed in the paper. The inheritance, expression variation , screening and influence factors in expression of LMA were reviewed. LMA was referred to the α amylase isozymes during the later stages of grain development in the absence of pre harvest sprouting. LMA and the α amylase isozymes with high pI synthesized in germination grain were controlled by the Amy 1 genes located on the group 6 chromosomes . The genetics of LMA was affected by a maternal effect. Furthermore, there were obvious variations between trial plots, individual plants, spikes and grains. Dwarfing or gibberellic acid (GA) insensitivity could reduce the expression of LMA. Synthesis of LMA in some genotypes only appeared to occur if grains experienced a period of cool temperature during the middle stage of grain development . But the mechanism involved in the triggering effect of cool temperature was also unclear. Molybdenum application reduced α amylase activity in some cultivars, but increased it in others. Preliminary evidence suggested that the LMA gene was located on the long arm of chromosome 6B. LMA gene location and developing molecular markers were still underway.