College of Horticulture, Northwest A & F University, Yangling, 712100, Shaanxi, China.
College of Mechaincal and Electronic Engineering, Northwest A & F University, Yangling, 712100, Shaanxi, China.
Plant Mol Biol. 2019 Jan;99(1-2):45-66. doi: 10.1007/s11103-018-0801-2. Epub 2018 Dec 5.
Shoot bending, as an effective agronomic measure, has been widely used to promote flowering in 'Fuji' apple trees. Here, we examined the transcriptional responses of genes in 'Fuji' apple buds at different flowering stages under a shoot-bending treatment using RNA sequencing. A complex genetic crosstalk-regulated network, involving abscisic acid-related genes, starch metabolism and circadian rhythm-related genes, as well as stress response-related genes, was up-regulated by shoot bending, in which were contrbuted to apple flower bud formation in response to shoot-bending conditions. Flower induction plays an important role in the apple tree life cycle, but young trees produce fewer and inferior flower buds. Shoot bending, as an effective agronomic measure, has been widely used to promote flowering in 'Fuji' apple trees. However, little is known about the gene expression network patterns and molecular regulatory mechanisms caused by shoot bending during the induced flowering. Here, we examined the transcriptional responses of genes in 'Fuji' apple buds at different flowering stages under a shoot-bending treatment using RNA sequencing. A steady up-regulation of carbon metabolism-related genes led to relatively high levels of sucrose in early induced flowering stages and starch accumulation during shoot bending. Additionally, global gene expression profiling determined that cytokinin, indole-3-acetic acid, gibberellin synthesis and signalling-related genes were significantly regulated by shoot bending, contributing to cell division and differentiation, bud growth and flower induction. A complex genetic crosstalk-regulated network, involving abscisic acid-related genes, starch metabolism- and circadian rhythm-related genes, as well as stress response-related genes, was up-regulated by shoot bending. Additionally, some transcription factor family genes that were involved in sugar, abscisic acid and stress response signalling were significantly induced by shoot bending. These important flowering genes, which were mainly involved in photoperiod, age and autonomous pathways, were up-regulated by shoot bending. Thus, a complex genetic network of regulatory mechanisms involved in sugar, hormone and stress response signalling pathways may mediate the induction of apple tree flowering in response to shoot-bending conditions.
拉枝作为一种有效的农艺措施，已被广泛用于促进富士苹果树的开花。在这里，我们使用 RNA 测序研究了拉枝处理下富士苹果芽在不同开花阶段的基因转录响应。一个涉及脱落酸相关基因、淀粉代谢和昼夜节律相关基因以及应激反应相关基因的复杂遗传串扰调控网络，被拉枝上调，这有助于苹果花芽在应对拉枝条件下的形成。花诱导在苹果生命周期中起着重要作用，但幼树产生的花芽较少且质量较差。拉枝作为一种有效的农艺措施，已被广泛用于促进富士苹果树的开花。然而，对于拉枝诱导开花过程中引起的基因表达网络模式和分子调控机制知之甚少。在这里，我们使用 RNA 测序研究了拉枝处理下富士苹果芽在不同开花阶段的基因转录响应。碳代谢相关基因的稳定上调导致早期诱导开花阶段蔗糖水平相对较高，拉枝过程中淀粉积累。此外，全基因表达谱分析确定，细胞分裂素、吲哚-3-乙酸、赤霉素合成和信号相关基因受拉枝显著调控，有助于细胞分裂和分化、芽生长和花诱导。一个涉及脱落酸相关基因、淀粉代谢和昼夜节律相关基因以及应激反应相关基因的复杂遗传串扰调控网络被拉枝上调。此外，一些参与糖、脱落酸和应激反应信号的转录因子家族基因也被拉枝显著诱导。这些重要的开花基因主要参与光周期、年龄和自主途径，被拉枝上调。因此，涉及糖、激素和应激反应信号通路的复杂遗传调控网络机制可能介导了苹果树对拉枝条件下开花的诱导。
