Moine Amedeo, Chitarra Walter, Nerva Luca, Agliassa Chiara, Gambino Giorgio, Secchi Francesca, Pagliarani Chiara, Boccacci Paolo
Institute for Sustainable Plant Protection - National Research Council (CNR-IPSP), Torino, Italy.
Research Centre for Viticulture and Enology - Council for Agricultural Research and Economics (CREA-VE), Conegliano (TV), Italy.
Physiol Plant. 2024 Nov-Dec;176(6):e70003. doi: 10.1111/ppl.70003.
Physiological and molecular mechanisms underpinning plant water stress responses still need deeper investigation. Particularly, the analysis of rootstock-mediated signals represents a complex research field, offering potential applicative perspectives for improving the adaptation of fruit crops to environmental stresses. Nonetheless, fundamental knowledge on this subject needs to be widened, especially in some woody species, including European hazelnut (Corylus avellana L). To fill these gaps, we inspected dynamic changes in gas exchanges and stem water potential of two hazelnut genotypes, the 'San Giovanni' cultivar (SG), the non-suckering rootstock 'Dundee' (D), and their heterograft (SG/D), during a drought stress treatment followed by recovery. Biometric and anatomical traits were measured at the beginning and end of water stress imposition. Additionally, differences in abscisic acid and proline contents were analysed in leaves and roots taken from well-irrigated, stressed and recovered plants, in combination with expression profiles of candidate genes. Grafting with 'Dundee' rootstock positively affected the ability of 'San Giovanni' plants to endure drought by increasing their intrinsic water use efficiency and facilitating post-rehydration recovery. Although anatomical adjustments occurred, we showed that the improved stress adaptation of grafted plants rather depended on biochemical modifications, resulting in increased root proline concentrations and leaf ABA accumulation both during water stress and recovery. We also proved that those metabolic changes were controlled by a differential reprogramming of genes involved in hormone metabolism and stress defence. Grafting with non-suckering rootstocks could therefore represent a promising and environmentally-friendly strategy for improving the adaptability of hazelnut to water deficit.
支撑植物水分胁迫响应的生理和分子机制仍需深入研究。特别是，对砧木介导信号的分析是一个复杂的研究领域，为提高果树作物对环境胁迫的适应性提供了潜在的应用前景。然而，关于这一主题的基础知识仍需拓宽，尤其是在一些木本物种中，包括欧洲榛子（Corylus avellana L）。为了填补这些空白，我们在干旱胁迫处理及恢复过程中，检测了两种榛子基因型（‘圣乔瓦尼’品种（SG）、非萌蘖砧木‘邓迪’（D）及其异源嫁接体（SG/D））的气体交换和茎水势的动态变化。在水分胁迫施加的开始和结束时测量了生物特征和解剖学特征。此外，结合候选基因的表达谱，分析了从充分灌溉、胁迫和恢复的植株上采集的叶片和根系中脱落酸和脯氨酸含量的差异。用‘邓迪’砧木嫁接通过提高‘圣乔瓦尼’植株的内在水分利用效率并促进复水后的恢复，对其耐旱能力产生了积极影响。尽管发生了解剖学调整，但我们表明，嫁接植株对胁迫适应性的提高更多地依赖于生化修饰，导致在水分胁迫和恢复过程中根系脯氨酸浓度增加以及叶片脱落酸积累。我们还证明，这些代谢变化是由参与激素代谢和胁迫防御的基因的差异重编程所控制的。因此，用非萌蘖砧木嫁接可能是提高榛子对水分亏缺适应性的一种有前景且环保的策略。
