Smith C J, Watson C F, Morris P C, Bird C R, Seymour G B, Gray J E, Arnold C, Tucker G A, Schuch W, Harding S
Department of Physiology and Environmental Science, University of Nottingham, Faculty of Agricultural and Food Sciences, Sutton Bonington, Loughborough, UK.
Plant Mol Biol. 1990 Mar;14(3):369-79. doi: 10.1007/BF00028773.
The role of the cell wall hydrolase polygalacturonase (PG) during fruit ripening was investigated using novel mutant tomato lines in which expression of the PG gene has been down regulated by antisense RNA. Tomato plants were transformed with chimaeric genes designed to express anti-PG RNA constitutively. Thirteen transformed lines were obtained of which five were analysed in detail. All contained a single PG antisense gene, the expression of which led to a reduction in PG enzyme activity in ripe fruit to between 5% and 50% that of normal. One line, GR16, showed a reduction to 10% of normal PG activity. The reduction in activity segregated with the PG antisense gene in selfed progeny of GR16. Plants homozygous for the antisense gene showed a reduction of PG enzyme expression of greater than 99%. The PG antisense gene was inherited stably through two generations. In tomato fruit with a residual 1% PG enzyme activity pectin depolymerisation was inhibited, indicating that PG is involved in pectin degradation in vivo. Other ripening parameters, such as ethylene production, lycopene accumulation, polyuronide solubilisation, and invertase activity, together with pectinesterase activity were not affected by the expression of the antisense gene.
利用新型突变番茄品系研究了细胞壁水解酶多聚半乳糖醛酸酶（PG）在果实成熟过程中的作用，在这些品系中，PG基因的表达已通过反义RNA被下调。用设计用于组成型表达抗PG RNA的嵌合基因转化番茄植株。获得了13个转化株系，其中5个进行了详细分析。所有株系都含有一个单一的PG反义基因，其表达导致成熟果实中PG酶活性降低至正常水平的5%至50%。一个株系GR16的PG活性降低至正常水平的10%。在GR16的自交后代中，活性降低与PG反义基因分离。反义基因纯合的植株PG酶表达降低超过99%。PG反义基因稳定遗传了两代。在PG酶活性残留1%的番茄果实中，果胶解聚受到抑制，这表明PG参与了体内果胶的降解。其他成熟参数，如乙烯生成、番茄红素积累、聚半乳糖醛酸溶解和转化酶活性，以及果胶酯酶活性，均不受反义基因表达的影响。
