核质杂种小麦Rubisco大亚基的基因结构与功能的关系

RELATIONSHIP BETWEEN THE SEQUENCE AND FUNCTION OF RUBISCO rbcL IN NUCLEO CYTOPLASMIC HYBRID WHEAT

NC4号小麦是一高产、抗逆的核质杂种 ,它是由山羊草 (Aegilops squarrosa,♀ )与小麦 (Triticumaestivum, )杂交 ,并多次回交和筛选而获得。测定了 NC4号及其父本的 Rubisco rbc L序列 ,证明 NC4号的 rbc L是由山羊草基因编码。对核质杂种及其亲本 Rubisco的羧化和加氧活性测定表明 ,杂种的羧化 /加氧活性比低于母本山羊草 ,高于父本小麦。rbc L序列测定表明 ,NC4号与父本小麦的 rbc L 有 3个核苷酸的差异 ,即在其氨基酸序列上第 14、86和 95位有 3个残基不同。

Nucleo cytoplasmic hybrid wheat NC4 is resistent to a number of stresses and produces high yield. It was obtained by crossing Aegilops squarrosa(♀) with Triticum aestivum(), and several back crossings. The rbcLs(the gene of large subunit of Rubisco ( ribulose 1,5 bisphosphate carboxylase/oxygenase )) cloned from NC4 and T.aestivum have been sequenced, and the result showed that the rbcL of NC4 was originated from Ae. squarrosa. The ratio of carboxylase activity to oxygenase activity, V CO 2/V O 2, of hybrid NC4 was lower than that of Ae. squarrosa, but higher than that of T. aestivum. This difference may be accounted for the higher yield of NC4 than that of T. aestivum. Sequence analysis showed that three nucleotides in the rbcL of NC4 which were different from those of T. aestivum, corresponded to the No 14, 86 and 95 amino acid residues of rbcL.