番茄果实成熟相关基因SlPEL和SlAPL的表达特性

分析27个代表番茄不同发育阶段和生物反应的组织特异性、含有152 635个独立EST数据库的数码表达，发现果胶裂解酶基因 (pectate lyase, SlPEL) 和番茄AP2 Like (SlAPL)的转录受果实成熟的调节。以授粉后不同发育时期的番茄(品种为美味樱桃)果实为试材, 用半定量PCR和荧光实时定量PCR分析SlPEL的表达模式，结果表明，授粉后12 d，其表达水平明显上升；授粉后16~18 d，达到第一个小高峰；28 d到最高峰；从28 d到完全成熟逐步下降到第一个小高峰的水平。SlAPL的表达模式与SlPEL类似，但其表达启动的时期迟于SlPEL。从授粉后25 d，SlAPL转录启动；授粉后28~32 d，其转录水平上升到第一个小高峰；39 d达到最高峰，以后到完全成熟略有下降。该研究也印证利用EST的数据库进行基因数码表达分析的可行性。

Isolation and Expression of Two Fruit Ripening Related Genes SlPEL and SlAPL in Tomato(Solanum lycopersicum)

During ripening, fruits undergo complicated developmental changes with varying physiological and biochemical activities that affect color, flavor, and texture. In tomato, these changes include accumulation of ethylene, the red pigment lycopene and the cell wall hydrolase, polygalacturonase (PG). Recently, genes of PG, pectin esterase (PE), ACC synthetase, ACC oxidase, and ethylene syshetase etc. from tomato, banana, carica papaya, peach and mango have been cloned. In this report, a large tomato expressed sequence tag (EST) dataset (152 635 in total) from 27 different EST libraries was analyzed to gain insights into digital gene expressions of two fruit ripening related genes SlPEL and SlAPL in tomato. Their expression profiles were detected using semi-quantitative RT-PCR assays and real-time RT-PCR assays in tomato (cv. Meiweiyingtao) during fruit development and ripening. SlPEL expression increased in the fruit at 12 days after pollination, and reached the small peak 4-6 days later and the larger peak at 28 days after pollination; then dropped to the level of the small peak until red ripening stage. As SlPEL, SlAPL expression was also induced by the fruit ripening. But SlAPL expressed two weeks later than SlPEL. SlPEL expression achieved the small peak at 28-32 days after pollination and the large peak at 39 days after pollination; and kept the higher levels until red ripening stage. The results confirmed that the digital gene expression using different EST libraries is an effective way to check the research value genes.