Vallarino José G, Yeats Trevor H, Maximova Eugenia, Rose Jocelyn K, Fernie Alisdair R, Osorio Sonia
Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", University of Malaga- Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Department of Molecular Biology and Biochemistry, Campus de Teatinos, 29071, Málaga, Spain.
Department of Plant Biology, Cornell University, Ithaca, USA.
Phytochemistry. 2017 Oct;142:11-20. doi: 10.1016/j.phytochem.2017.06.007. Epub 2017 Jun 26.
The cell wall invertase gene (LIN5) was reported to be a key enzyme influencing sugar uptake of tomato (Solanum lycopersicum) fruit. It was additionally revealed to be a key regulator of total soluble solids content in fruit as well as for reproductive development, being mainly involved in flower development, early fruit and seed development but also in ripening. Here, we demonstrate that silencing of the LIN5 gene promotes changes affecting fruit cuticle development which has a direct effect on postharvest properties. Transformants were characterized by reduced transpirational water loss in mature fruits accompanied by several other changes in the cuticle. Quantitative chemical composition, coupled with microscopy of isolated cuticle fruits revealed that the cuticle of the transformants were characterized by an increase of the thickness as well as significant increase in the content of cuticle components (cutin, phenolic compounds, and waxes). Furthermore, detailed analysis of the waxes revealed that the transformants displayed changes in waxes composition, showing higher levels of n-alkanes and triterpenoids which can shift the proportion of crystalline and amorphous waxes and change the water flux through the cuticle. Expression of the genes involved in cuticle biosynthesis indicated that LIN5 influences the biosynthesis of components of the cuticle, indicating that this process is coupled to sugar uploading via a mechanism which links carbon supply with the capacity for fruit expansion.
细胞壁转化酶基因（LIN5）据报道是影响番茄（Solanum lycopersicum）果实糖分吸收的关键酶。此外，它还被揭示为果实总可溶性固形物含量以及生殖发育的关键调节因子，主要参与花的发育、早期果实和种子发育，也参与果实成熟过程。在此，我们证明LIN5基因的沉默促进了影响果实表皮发育的变化，这对采后特性有直接影响。转基因植株的特征是成熟果实的蒸腾失水减少，同时表皮还有其他一些变化。对分离的表皮果实进行定量化学成分分析并结合显微镜观察发现，转基因植株的表皮特征是厚度增加以及表皮成分（角质、酚类化合物和蜡质）含量显著增加。此外，对蜡质的详细分析表明，转基因植株的蜡质成分发生了变化，显示出较高水平的正构烷烃和三萜类化合物，这会改变结晶蜡质和无定形蜡质的比例，并改变通过表皮的水分通量。参与表皮生物合成的基因表达表明，LIN5影响表皮成分的生物合成，这表明该过程通过一种将碳供应与果实膨大能力联系起来的机制与糖分上传相关联。
