Drought stress significantly impedes apple growth, development, and yield, leading to substantial economic losses within the global apple industry. Malus prunifolia (Mp), a commonly utilized apple rootstock, has shown promise in augmenting cultivated apple resistance to abiotic stress. Although Alfin-like (ALs) proteins have demonstrated pivotal roles in dicotyledonous plants' response to abiotic stresses, knowledge about AL genes in apple rootstocks is limited, and their functions remain largely elusive. In this study, we identified and characterized 10 MpAL gene members in the apple rootstock genome, confirming their localization within the nucleus. Our investigation revealed the significant regulation of MpALs' expression under drought and abscisic acid (ABA) stresses in M. prunifolia. In this study, one of the members, MpAL1, was selected for further exploration in Arabidopsis and apple to explore its potential function in response to drought and ABA stresses. The results showed that overexpression-MpAL1 transgenic apple calli grew significantly better than WT and MpAL1-RNAi lines, which regulates the accumulation of H2O2 and O2- levels. Additionally, transgenic Arabidopsis plants overexpressing MpAL1 exhibited positively regulating anti-oxidant enzymes activities under stress treatments. Further study showed that silencing MpAL1 in apple plants showed obvious chlorosis in leaves, and accumulation of reactive oxygen species under drought stress. Moreover, our detailed analysis established that MpAL1 regulates several drought and ABA-responsive genes, exerting an influence on their expression in transgenic apple. Collectively, our findings identify MpAL1 as a positive regulator that increases drought stress in apple, shedding light on its potential significance in bolstering drought resistance in this fruit crop.

中文翻译：

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研究 MpAL1 在华氏苹果干旱胁迫反应中的作用：深入了解 AL 基因家族功能


干旱胁迫严重阻碍了苹果的生长、发育和产量，导致全球苹果行业遭受重大经济损失。Malus prunifolia （Mp） 是一种常用的苹果砧木，在增强栽培苹果对非生物胁迫的抵抗力方面显示出前景。尽管 Alfin 样 （ALs） 蛋白已被证明在双子叶植物对非生物胁迫的反应中起关键作用，但对苹果砧木中 AL 基因的了解有限，其功能在很大程度上仍然难以捉摸。在这项研究中，我们在苹果砧木基因组中鉴定并表征了 10 个 MpAL 基因成员，证实了它们在细胞核内的定位。我们的调查揭示了在干旱和脱落酸 （ABA） 胁迫下 MpALs 表达的显着调控 M. prunifolia。在这项研究中，选择其中一个成员 MpAL1 在拟南芥和苹果中进一步探索，以探索其响应干旱和 ABA 胁迫的潜在功能。结果表明，过表达 MpAL1 转基因苹果愈伤组织生长显著优于 WT 和 MpAL1-RNAi 品系，WT 和 MpAL1-RNAi 品系调节 H2O2 和 O2- 水平的积累。此外，过表达 MpAL1 的转基因拟南芥植株在胁迫处理下表现出对抗氧化酶活性的正向调节作用。进一步研究表明，沉默苹果植株中的 MpAL1 表现出明显的叶片萎黄，以及干旱胁迫下活性氧的积累。此外，我们的详细分析确定 MpAL1 调节几个干旱和 ABA 反应基因，对它们在转基因苹果中的表达产生影响。 总的来说，我们的研究结果将 MpAL1 确定为增加苹果干旱胁迫的正调节因子，阐明了它在增强这种水果作物抗旱性方面的潜在意义。