ADPglucose pyrophosphorylase activity and starch accumulation in immature tomato fruit:: the effect of a Lycopersicon hirsutum-derived introgression encoding for the large subunit
ADPglucose pyrophosphorylase activity and starch accumulation in immature tomato fruit:: the effect of a Lycopersicon hirsutum-derived introgression encoding for the large subunit
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DOI：
10.1016/s0168-9452(99)00224-1
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发表时间：
2000-03-21
期刊：
影响因子：
5.2
通讯作者：
Bar, M
中科院分区：
文献类型：
--
作者：
Schaffer, AA;Levin, I;Bar, M
通过与多毛番茄（Lycopersicon hirsutum）的种间杂交，获得了一种未成熟果实淀粉含量增加、成熟果实可溶性糖含量增加的番茄选育品系。蔗糖-淀粉代谢途径酶的体外活性比较表明，与番茄品种M-82相比，高淀粉品系只有ADPglucose焦磷酸化酶活性显著升高。利用聚合酶链反应（PCR）技术对番茄adp葡萄糖焦磷酸化酶的4个已知基因（LS1、LS2、LS3、SS）中的每一个等位基因进行区分。对高淀粉系的分析表明，该系携带L. hirsutum （LS1(H)）的LS1等位基因。在高淀粉系与M-82杂交的分离群体中，LS1H等位基因与未成熟果实中adp葡萄糖焦磷酸化酶活性和淀粉水平的增加以及成熟果实中可溶性固形物含量的增加有关。对LS1(H)等位基因进行克隆和测序，与L等位基因的一致序列比较，esculentum LS1(E)等位基因在n端附近出现了3个氨基酸的Glu-Lys-Lys重复，另外3个氨基酸发生了变化。利用番茄的基因渗入系将这4个基因定位到不同的染色体片段上，进一步证明了这4个基因是不同的adp葡萄糖焦磷酸化酶基因。这些结果表明，ADPglucose焦磷酸化酶活性限制了发育果实中淀粉的合成；此外;番茄属中存在自然遗传变异，可用于提高栽培果实中的酶活性和淀粉积累。此外，我们提出了一个可能的基因功能，迄今为止描述的QTL果实白利度水平。(C) 2000爱思唯尔科学爱尔兰有限公司版权所有。
A breeding line of tomato with an increased level of starch in the immature fruit, and a concomitantly increased soluble sugar level in the mature fruit, was developed from an interspecific cross with Lycopersicon hirsutum. A comparison of in vitro activities of enzymes of the sucrose-to-starch metabolic pathway indicated that only the activity of ADPglucose pyrophosphorylase was significantly increased in the high starch line, compared to the Lycopersicon esculentum cultivar, M-82. Polymerase chain reaction (PCR) markers were developed to distinguish between the L. esculentum and L. hirsutum alleles for each of the four known genes of ADPglucose pyrophosphorylase in tomato (LS1, LS2, LS3, SS). Analysis of the high starch line showed that it carries the LS1 allele from L. hirsutum (LS1(H)). In segregating populations from the cross between the high starch line and M-82 the LS1H allele was correlated with increases in ADPglucose pyrophosphorylase activity and starch level in the immature fruit and soluble solids content in the mature fruit. The LS1(H) allele was cloned and sequenced and a comparison with the consensus sequence of the L, esculentum LS1(E) allele shows a three amino acid duplication of Glu-Lys-Lys near the N-terminal, and three additional amino acid changes. The four genes were mapped to different chromosomal segments, using Lycopersicon pennellii introgression lines, which is further evidence that these are distinct ADPglucose pyrophosphorylase genes in tomato. These results suggest that ADPglucose pyrophosphorylase activity is limiting to starch synthesis in developing fruits; furthermore; there exists natural genetic variability within the Lycopersicon genus that may be utilized to increase enzyme activity and starch accumulation in the cultivated fruit. Furthermore, we proposes a possible gene function for a hitherto described QTL for fruit Brix levels. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.