解析褪黑素诱导增强中度干旱胁迫牛至植物光系统II功能的机制

Deciphering the Mechanism of Melatonin-Induced Enhancement of Photosystem II Function in Moderate Drought-Stressed Oregano Plants.

作者信息

Moustaka Julietta, Sperdouli Ilektra, İşgören Sumrunaz, Şaş Begüm, Moustakas Michael

机构信息

Department of Botany, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.

Institute of Plant Breeding and Genetic Resources, Hellenic Agricultural Organisation-Demeter (ELGO-Demeter), 57001 Thessaloniki, Greece.

出版信息

Plants (Basel). 2024 Sep 16;13(18):2590. doi: 10.3390/plants13182590.

DOI:10.3390/plants13182590

PMID:39339565

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11434670/

Abstract

Melatonin (MT) is considered as an antistress molecule that plays a constructive role in the acclimation of plants to both biotic and abiotic stress conditions. In the present study, we assessed the impact of 10 and 100 μM MT foliar spray, on chlorophyll content, and photosystem II (PSII) function, under moderate drought stress, on oregano ( L.) plants. Our aim was to elucidate the molecular mechanism of MT action on the photosynthetic electron transport process. Foliar spray with 100 μM MT was more effective in mitigating the negative impact of moderate drought stress on PSII function, compared to 10 μM MT. MT foliar spray significantly improved the reduced efficiency of the oxygen-evolving complex (OEC), and PSII photoinhibition (F/F), which were caused by drought stress. Under moderate drought stress, foliar spray with 100 μM MT, compared with the water sprayed (WA) leaves, increased the non-photochemical quenching (NPQ) by 31%, at the growth irradiance (GI, 205 μmol photons m s), and by 13% at a high irradiance (HI, 1000 μmol photons m s). However, the lower NPQ increase at HI was demonstrated to be more effective in decreasing the singlet-excited oxygen (O) production at HI (-38%), in drought-stressed oregano plants sprayed with 100 μM MT, than the corresponding decrease in O production at the GI (-20%), both compared with the respective WA-sprayed leaves under moderate drought. The reduced O production resulted in a significant increase in the quantum yield of PSII photochemistry (Φ), and the electron transport rate (ETR), in moderate drought-stressed plants sprayed with 100 μM MT, compared with WA-sprayed plants, but only at the HI (+27%). Our results suggest that the enhancement of PSII functionality, with 100 μM MT under moderate drought stress, was initiated by the NPQ mechanism, which decreased the O production and increased the fraction of open PSII reaction centers (q), resulting in an increased ETR.

摘要

褪黑素（MT）被认为是一种抗逆分子，在植物适应生物和非生物胁迫条件中发挥着建设性作用。在本研究中，我们评估了在中度干旱胁迫下，10 μM和100 μM MT叶面喷施对牛至（Origanum vulgare L.）植物叶绿素含量和光系统II（PSII）功能的影响。我们的目的是阐明MT对光合电子传递过程作用的分子机制。与10 μM MT相比，100 μM MT叶面喷施在减轻中度干旱胁迫对PSII功能的负面影响方面更有效。MT叶面喷施显著改善了干旱胁迫导致的放氧复合体（OEC）还原效率降低和PSII光抑制（F/F）。在中度干旱胁迫下，与喷水（WA）叶片相比，100 μM MT叶面喷施在生长光照强度（GI，205 μmol光子·m⁻²·s⁻¹）下使非光化学猝灭（NPQ）增加了31%，在高光强（HI，1000 μmol光子·m⁻²·s⁻¹）下增加了13%。然而，在喷施100 μM MT的干旱胁迫牛至植物中，HI下较低的NPQ增加在降低HI下单线态激发氧（¹O₂）产生方面（-38%）比GI下¹O₂产生的相应降低（-20%）更有效，两者均与中度干旱下各自喷水的叶片相比。¹O₂产生的减少导致在喷施100 μM MT的中度干旱胁迫植物中，PSII光化学量子产率（Φ）和电子传递速率（ETR）显著增加，与喷水植物相比，但仅在HI下（+27%）。我们的结果表明，在中度干旱胁迫下，100 μM MT增强PSII功能是由NPQ机制启动的，该机制降低了¹O₂产生并增加了开放PSII反应中心的比例（q），从而导致ETR增加。