Cramer Grant R, Ghan Ryan, Schlauch Karen A, Tillett Richard L, Heymann Hildegarde, Ferrarini Alberto, Delledonne Massimo, Zenoni Sara, Fasoli Marianna, Pezzotti Mario
Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, 89557, USA.
Center for Bioinformatics, University of Nevada, Reno, NV, 89557, USA.
BMC Plant Biol. 2014 Dec 19;14:370. doi: 10.1186/s12870-014-0370-8.
Grapevine berry, a nonclimacteric fruit, has three developmental stages; the last one is when berry color and sugar increase. Flavors derived from terpenoid and fatty acid metabolism develop at the very end of this ripening stage. The transcriptomic response of pulp and skin of Cabernet Sauvignon berries in the late stages of ripening between 22 and 37 °Brix was assessed using whole-genome micorarrays.
The transcript abundance of approximately 18,000 genes changed with °Brix and tissue type. There were a large number of changes in many gene ontology (GO) categories involving metabolism, signaling and abiotic stress. GO categories reflecting tissue differences were overrepresented in photosynthesis, isoprenoid metabolism and pigment biosynthesis. Detailed analysis of the interaction of the skin and pulp with °Brix revealed that there were statistically significantly higher abundances of transcripts changing with °Brix in the skin that were involved in ethylene signaling, isoprenoid and fatty acid metabolism. Many transcripts were peaking around known optimal fruit stages for flavor production. The transcript abundance of approximately two-thirds of the AP2/ERF superfamily of transcription factors changed during these developmental stages. The transcript abundance of a unique clade of ERF6-type transcription factors had the largest changes in the skin and clustered with genes involved in ethylene, senescence, and fruit flavor production including ACC oxidase, terpene synthases, and lipoxygenases. The transcript abundance of important transcription factors involved in fruit ripening was also higher in the skin.
A detailed analysis of the transcriptome dynamics during late stages of ripening of grapevine berries revealed that these berries went through massive transcriptional changes in gene ontology categories involving chemical signaling and metabolism in both the pulp and skin, particularly in the skin. Changes in the transcript abundance of genes involved in the ethylene signaling pathway of this nonclimacteric fruit were statistically significant in the late stages of ripening when the production of transcripts for important flavor and aroma compounds were at their highest. Ethylene transcription factors known to play a role in leaf senescence also appear to play a role in fruit senescence. Ethylene may play a bigger role than previously thought in this non-climacteric fruit.
葡萄浆果属于非跃变型果实，有三个发育阶段；最后一个阶段是浆果颜色加深且糖分增加。在这个成熟阶段末期，源自萜类化合物和脂肪酸代谢的风味物质开始形成。利用全基因组微阵列评估了赤霞珠葡萄浆果在成熟后期（22至37°Brix）果肉和果皮的转录组反应。
约18000个基因的转录丰度随°Brix和组织类型而变化。在许多涉及代谢、信号传导和非生物胁迫的基因本体（GO）类别中发生了大量变化。反映组织差异的GO类别在光合作用、类异戊二烯代谢和色素生物合成中占比过高。对果皮和果肉与°Brix相互作用的详细分析表明，在果皮中，参与乙烯信号传导、类异戊二烯和脂肪酸代谢且转录本丰度随°Brix变化的基因在统计学上显著更多。许多转录本在已知的风味产生最佳果实阶段左右达到峰值。在这些发育阶段，约三分之二的AP2/ERF转录因子超家族的转录本丰度发生了变化。ERF6型转录因子的一个独特分支的转录本丰度在果皮中变化最大，并与参与乙烯、衰老和果实风味产生的基因聚集在一起，包括ACC氧化酶、萜烯合酶和脂氧合酶。参与果实成熟的重要转录因子的转录本丰度在果皮中也更高。
对葡萄浆果成熟后期转录组动态的详细分析表明，这些浆果在果肉和果皮中，尤其是在果皮中，经历了涉及化学信号传导和代谢的基因本体类别中的大量转录变化。在这个非跃变型果实成熟后期，当重要风味和香气化合物的转录本产量最高时，参与乙烯信号通路的基因转录本丰度变化在统计学上显著。已知在叶片衰老中起作用的乙烯转录因子似乎也在果实衰老中起作用。乙烯在这种非跃变型果实中可能发挥比以前认为的更大的作用。
