Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, NO. 120, Dongling Road, Shenhe District, Shenyang, China.
Tree Physiol. 2023 Jul 9;43(7):1187-1200. doi: 10.1093/treephys/tpad040.
Lycium ruthenicum is an important ecoeconomic thorny shrub. In this study, the L. ruthenicum plants of a clone showed two types of 'fewer leaves without thorn' and 'more leaves with thorns' under the same condition after transplanting. Microscopic observation revealed that the apical buds of the thornless (Thless) and thorny (Thorny) branches should be selected as materials for further study. RNA-Seq analysis showed that the KEGG pathway of starch and sucrose metabolism and differentially expressed genes of sugar transport protein 13 (SUT13), sucrose synthase (SUS), trehalose-phosphate phosphatase (TPP) and trehalose-phosphate synthase (TPS) were significantly up-regulated in Thorny. The results of qRT-PCR confirmed the accuracy and credibility of the RNA-Seq. The content of sucrose in Thorny was significantly higher than that in Thless, but the content of trehalose-6-phosphate (T6P) was opposite. Leaf-clipping treatments reduced sucrose content and inhibited the occurrence/development of branch-thorns; exogenous sucrose of 16 g l-1 significantly promoted the occurrence and growth of branch-thorns, and the promotion effects were significantly higher than those treated with non-metabolizable sucrose analogs (isomaltolose and melitose). These findings suggested that sucrose might play a dual role of energy and signal in the occurrence of branch-thorns. Higher sucrose supply in apical buds from more leaves promoted the occurrence of branch-thorns via a lower content of T6P and higher expression levels of SUS, TPP and TPS, whereas fewer leaves inhibited the occurrence. The molecular hypothesis model of the leaf number/sucrose supply regulating the occurrence of branch-thorns in L. ruthenicum was established in the study, which provides foundation for breeding both Thless L. ruthenicum and Thless types of other species.
黑果枸杞是一种重要的生态经济型多刺灌木。在本研究中，同一无性系的黑果枸杞植株在移栽后表现出两种类型：少叶无刺型（Thless）和多叶有刺型（Thorny）。微观观察表明，无刺（Thless）和有刺（Thorny）枝条的顶芽应作为进一步研究的材料。RNA-Seq 分析表明，在 Thorny 中，淀粉和蔗糖代谢的 KEGG 途径以及糖转运蛋白 13（SUT13）、蔗糖合酶（SUS）、海藻糖-6-磷酸磷酸酶（TPP）和海藻糖-6-磷酸合酶（TPS）的差异表达基因显著上调。qRT-PCR 的结果证实了 RNA-Seq 的准确性和可信度。Thorny 中的蔗糖含量显著高于 Thless，但海藻糖-6-磷酸（T6P）的含量则相反。叶片剪取处理降低了蔗糖含量并抑制了枝条刺的发生/发育；16 g l-1 的外源蔗糖显著促进了枝条刺的发生和生长，其促进效果明显高于非代谢性蔗糖类似物（异麦芽糖和蜜二糖）处理。这些发现表明，蔗糖可能在枝条刺的发生中发挥能量和信号的双重作用。更多叶片的顶芽中较高的蔗糖供应通过降低 T6P 含量和提高 SUS、TPP 和 TPS 的表达水平来促进枝条刺的发生，而叶片数量较少则抑制了枝条刺的发生。本研究建立了黑果枸杞叶片数量/蔗糖供应调节枝条刺发生的分子假说模型，为培育少叶型黑果枸杞和其他物种的少叶型类型提供了基础。
