Kohler Andrea R, Hollender Courtney A, Raines Doug, Demuth Mark, Tang Lisa, Farcuh Macarena, Dardick Chris
Department of Horticulture, Michigan State University, 1066 Bogue St, East Lansing, MI 48824 USA.
Appalachian Fruit Research Station, Agricultural Research Service, United States Department of Agriculture, 2217 Wiltshire Rd, Kearneysville, WV 25430 USA.
Hortic Res. 2025 Apr 16;12(7):uhaf106. doi: 10.1093/hr/uhaf106. eCollection 2025 Jul.
Controlling branch orientation is a central challenge in tree fruit production, as it impacts light interception, pesticide use, fruit quality, yield, and labor costs. To modify branch orientation, growers use many different management practices, including tying branches to wires or applying growth regulator sprays. However, these practices are often costly and ineffective. In contrast, altering the expression of genes that control branch angles and orientations would permanently optimize tree architecture and reduce management requirements. One gene implicated in branch angle control, , has potential for such applications as it is a key modulator of upward branch orientations in response to gravity. Here, we describe the phenotypes of transgenic plum () trees containing an antisense vector to silence . We found that silencing significantly increased branch and petiole angles. - lines also displayed 'wandering' or weeping branch trajectories. These phenotypes were not associated with decreases in branch strength or stiffness. We evaluated the utility of trees for use in two planar orchard systems by training them according to super slender axe and espalier methods. We found that the trees had more open canopies and were easier to constrain to the trellis height. This work illustrates the power of manipulating gene expression to optimize plant architecture for specific horticultural applications.
控制枝条方向是树果生产中的一项核心挑战，因为它会影响光照截获、农药使用、果实品质、产量和劳动力成本。为了改变枝条方向，种植者采用了许多不同的管理措施，包括将枝条绑在铁丝上或喷施生长调节剂。然而，这些措施往往成本高昂且效果不佳。相比之下，改变控制枝条角度和方向的基因表达将永久性地优化树体结构并减少管理需求。一个与枝条角度控制有关的基因，由于它是响应重力向上枝条方向的关键调节因子，具有此类应用的潜力。在这里，我们描述了含有反义载体以沉默该基因的转基因李树的表型。我们发现该基因沉默显著增加了枝条和叶柄角度。该基因沉默系还表现出“蜿蜒”或下垂的枝条轨迹。这些表型与枝条强度或刚度的降低无关。我们通过按照超细长纺锤形和篱壁形方法对其进行整形，评估了该基因沉默李树在两种平面果园系统中的应用价值。我们发现该基因沉默李树具有更开阔的树冠，并且更容易控制在棚架高度。这项工作说明了操纵基因表达以优化特定园艺应用的植物结构的作用。
