Collin Anna, Matkowski Hubert, Sybilska Ewa, Biantari Asmarany, Król Oliwia, Daszkowska-Golec Agata
Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Jagiellońska 28, 40 - 032, Katowice, Poland.
BMC Plant Biol. 2025 Apr 8;25(1):445. doi: 10.1186/s12870-025-06485-y.
Abscisic acid (ABA) is a phytohormone that mediates plant responses to drought stress by regulating stomatal conductance, gene expression, and photosynthetic efficiency. Although ABA-induced stress priming has shown the potential to improve drought tolerance, the molecular mechanisms underlying ABA pretreatment effects remain poorly understood. This study aimed to determine how ABA pre-treatment at the booting stage influences physiological and molecular responses to drought at the heading stage in barley.
The ABA-treated plants exhibited earlier stomatal closure, increased expression of ABA-responsive genes (HvNCED1, HvBG8, and HvA22), and maintained higher chlorophyll levels under drought conditions. Photosynthetic parameters, including photosystem II activity, electron transport rate, and the number of active reaction centers, were preserved in ABA-pretreated plants compared with drought-only plants. Transcriptomic analysis revealed that ABA pre-treatment primed plants for faster activation of stress-responsive pathways, with enhanced expression of genes related to chromatin modifications, RNA metabolism, and ABA signaling during drought. Importantly, Alternative splicing (AS) and isoform switching were significantly amplified in ABA-pretreated plants, underscoring a unique molecular mechanism of ABA priming that enhances drought resilience. Post-stress recovery analysis revealed a greater number of differentially expressed genes (DEGs) and alternatively spliced transcripts (DAS) in ABA-pretreated plants, particularly those involved in chromatin organization and photosynthesis. Physiological analyses demonstrated that time- and dose-optimized ABA applications improved yield parameters, including grain weight and seed area, while mitigating spike sterility under drought conditions.
This study demonstrates that ABA pretreatment enhances drought resilience in barley by triggering early stomatal closure, preserving chlorophyll content, and maintaining photosynthetic performance under water stress. At the molecular level, ABA priming accelerates stress-response pathways, promoting alternative splicing, isoform switching, and chromatin modifications that enable transcriptome plasticity. These processes facilitate faster recovery and sustain critical yield components, such as spike number and grain weight, when ABA is applied at optimized timing and concentrations. While large-scale ABA application poses challenges, this study provides a framework for breeding and agronomic strategies to mimic ABA effects, offering a practical path to enhance drought tolerance and yield stability in barley.
脱落酸（ABA）是一种植物激素，通过调节气孔导度、基因表达和光合效率来介导植物对干旱胁迫的响应。尽管ABA诱导的胁迫引发已显示出提高耐旱性的潜力，但ABA预处理效果的分子机制仍知之甚少。本研究旨在确定孕穗期ABA预处理如何影响大麦抽穗期对干旱的生理和分子响应。
经ABA处理的植株气孔关闭更早，ABA响应基因（HvNCED1、HvBG8和HvA22）的表达增加，并且在干旱条件下保持较高的叶绿素水平。与仅受干旱处理的植株相比，ABA预处理植株的光合参数，包括光系统II活性、电子传递速率和活跃反应中心数量得以保留。转录组分析表明，ABA预处理使植株更快地激活胁迫响应途径，干旱期间与染色质修饰、RNA代谢和ABA信号传导相关的基因表达增强。重要的是，在ABA预处理植株中，可变剪接（AS）和异构体转换显著增加，突出了ABA引发增强干旱恢复力的独特分子机制。胁迫后恢复分析显示，ABA预处理植株中有更多的差异表达基因（DEG）和可变剪接转录本（DAS），特别是那些参与染色质组织和光合作用的基因。生理分析表明，经过时间和剂量优化的ABA处理提高了产量参数，包括粒重和种子面积，同时减轻了干旱条件下的穗不育。
本研究表明，ABA预处理通过触发早期气孔关闭、保持叶绿素含量以及在水分胁迫下维持光合性能来增强大麦的干旱恢复力。在分子水平上，ABA引发加速胁迫响应途径，促进可变剪接、异构体转换和染色质修饰，从而实现转录组可塑性。当以优化的时间和浓度施用ABA时，这些过程有助于更快恢复并维持关键产量构成要素，如穗数和粒重。虽然大规模施用ABA存在挑战，但本研究为模仿ABA效应的育种和农艺策略提供了框架，为提高大麦的耐旱性和产量稳定性提供了一条切实可行的途径。
