Chervin Christian, Tira-Umphon Arak, Terrier Nancy, Zouine Mohamed, Severac Dany, Roustan Jean-Paul
UMR 990, Génomique et Biotechnologie des Fruits, INRA-INP/ENSAT, Université de Toulouse, BP 32607, 31326 Castanet-Tolosan, Cedex, France.
Physiol Plant. 2008 Nov;134(3):534-46. doi: 10.1111/j.1399-3054.2008.01158.x. Epub 2008 Jul 31.
Grape is considered as a non-climacteric fruit, the maturation of which is independent of ethylene. However, previous work had shown that ethylene is capable of affecting the physiological processes during maturation of grape berries. Experiments were designed to screen the gene pool affected by ethylene at the ripening inception in Cabernet Sauvignon berries. The results showed that only 73 of 14 562 genes of microarray slides were significantly modulated by a 24-h ethylene treatment (4 microl l(-1)), performed 8 weeks after flowering. The study then focused on accumulation of several mRNAs affected by ethylene in relation to the berry size. Indeed, we observed that ethylene application at véraison led to a berry diameter increase. This increase is mainly because of sap intake and cell wall modifications, enabling cell elongation. This was related to changes in the expression pattern of many genes, classified in two groups: (1) 'water exchange' genes: various aquaporins (AQUA) and (2) 'cell wall structure' genes: polygalacturonases, xyloglucan endotransglucosylases (XTH), pectin methyl esterases, cellulose synthases and expansins. The expression patterns were followed either along berry development or in three berry tissues (peel, pulp and seeds). Ethylene stimulates the accumulation of most gene transcripts in 1 h, and in several parts of the berry, this stimulation may last for 24 h in some cases. One XTH and one AQUA seem to be good candidates to explain the ethylene-induced berry expansion. This work brings more clues about the ethylene involvement in the development and ripening of grape berries.
葡萄被认为是一种非跃变型果实，其成熟过程不依赖乙烯。然而，先前的研究表明乙烯能够影响葡萄浆果成熟期间的生理过程。本实验旨在筛选赤霞珠浆果成熟初期受乙烯影响的基因库。结果显示，在开花后8周进行24小时乙烯处理（4 μl l(-1)）后，微阵列载玻片上14562个基因中只有73个受到显著调控。该研究随后聚焦于几种受乙烯影响的mRNA积累与浆果大小的关系。事实上，我们观察到在转色期施用乙烯会导致浆果直径增加。这种增加主要是由于汁液吸收和细胞壁修饰，从而使细胞伸长。这与许多基因表达模式的变化有关，这些基因分为两组：（1）“水分交换”基因：各种水通道蛋白（AQUA）；（2）“细胞壁结构”基因：多聚半乳糖醛酸酶、木葡聚糖内转糖基酶（XTH）、果胶甲酯酶、纤维素合酶和扩张蛋白。我们沿着浆果发育过程或在浆果的三个组织（果皮、果肉和种子）中追踪这些基因的表达模式。乙烯在1小时内刺激大多数基因转录本的积累，在浆果的几个部位，这种刺激在某些情况下可能持续24小时。一种XTH和一种AQUA似乎是解释乙烯诱导浆果膨大现象的良好候选基因。这项工作为乙烯参与葡萄浆果发育和成熟过程提供了更多线索。
