Institute of Plant Sciences, Volcani Research Center, Derech Hamacabim, Rishon Lezion, Israel.
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Rehovot, Israel.
J Exp Bot. 2019 Feb 5;70(3):1017-1031. doi: 10.1093/jxb/ery405.
Deciduous trees require sufficient chilling during winter dormancy to grow. To decipher the dormancy-regulating mechanism, we carried out RNA sequencing (RNA-Seq) analysis and metabolic profiling of European pear (Pyrus communis L.) vegetative buds during the dormancy phases. Samples were collected from two cultivars that differed greatly in their chilling requirements: 'Spadona' (SPD), a low chilling requirement cultivar; and Harrow Sweet (HS), a high chilling requirement cultivar. Comparative transcriptome analysis revealed >8500 differentially expressed transcripts; most were related to metabolic pathways. Out of 174 metabolites, 44 displayed differential levels in both cultivars, 38 were significantly changed only in SPD, and 15 only in HS. Phospholipids were mostly accumulated at the beginning of dormancy, sugars between before dormancy and mid-dormancy, and fatty acids, including α-linolenic acid, at dormancy break. Differentially expressed genes underlying previously identified major quantitative trait loci (QTLs) in linkage group 8 included genes related to the α-linolenic acid pathway, 12-oxophytodienoate reductase 2-like, and the DORMANCY-ASSOCIATED MADS-BOX (DAM) genes, PcDAM1 and PcDAM2, putative orthologs of PpDAM1 and PpDAM2, confirming their role for the first time in European pear. Additional new putative dormancy-related uncharacterized genes and genes related to metabolic pathways are suggested. These results suggest the crucial role of α-linolenic acid and DAM genes in pear bud dormancy phase transitions.
落叶树在冬季休眠期间需要充足的低温来生长。为了解休眠调节机制，我们对欧洲梨（Pyrus communis L.）营养芽在休眠阶段进行了 RNA 测序（RNA-Seq）分析和代谢物分析。我们从两个品种中采集了样本，这两个品种在低温需求方面差异很大：‘Spadona'（SPD），一种低温需求品种；和 Harrow Sweet（HS），一种高低温需求品种。比较转录组分析显示，有>8500 个差异表达的转录本；大多数与代谢途径有关。在 174 种代谢物中，有 44 种在两个品种中显示出不同的水平，38 种仅在 SPD 中显著变化，15 种仅在 HS 中变化。磷脂在休眠开始时积累最多，糖在休眠前和休眠中期之间积累，脂肪酸（包括α-亚麻酸）在休眠解除时积累。在第 8 连锁群中先前确定的主要数量性状位点（QTLs）的差异表达基因中，包括与α-亚麻酸途径、12-氧代-植物二烯酸还原酶 2 样和休眠相关的 MADS-BOX（DAM）基因相关的基因，PcDAM1 和 PcDAM2，PpDAM1 和 PpDAM2 的假定同源基因，首次证实了它们在欧洲梨中的作用。还提出了其他新的休眠相关的未描述基因和与代谢途径相关的基因。这些结果表明，α-亚麻酸和 DAM 基因在梨芽休眠阶段的转变中起着关键作用。
