Melatonin regulates the functional components of photosynthesis, antioxidant system, gene expression, and metabolic pathways to induce drought resistance in grafted Carya cathayensis plants
Melatonin regulates the functional components of photosynthesis, antioxidant system, gene expression, and metabolic pathways to induce drought resistance in grafted Carya cathayensis plants
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褪黑素调节光合作用、抗氧化系统、基因表达和代谢途径的功能成分，诱导嫁接山核桃植物的抗旱性
DOI：
10.1016/j.scitotenv.2020.136675
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发表时间：
2020-04-15
影响因子：
9.8
通讯作者：
Zheng, Bingsong
中科院分区：
文献类型：
--
作者：
Sharma, Anket;Wang, Junfeng;Zheng, Bingsong
中国山核桃（Carya cathayensis）是一种重要的经济树种，其坚果广受欢迎。然而，这棵树需要很长时间才能达到结出坚果的阶段。为了克服这个问题，嫁接被广泛用于缩短从营养阶段到生殖阶段的时间。由于气候变化，这种树种也面临许多环境挑战；干旱是影响山核桃生长发育的重要因素，本研究设计了褪黑素对干旱胁迫下嫁接山核桃植株的保护作用。结果表明，外源褪黑素能有效恢复嫁接山核桃植株的生长，提高其光合效率。外源褪黑激素还可以增强干旱胁迫下植物的抗氧化防御系统，从而增强活性氧（ROS）的清除能力。褪黑素也会引发相容溶质（如总可溶性糖和脯氨酸）的积累。此外，代谢组学分析显示，褪黑激素处理的干旱胁迫植物调节了苯丙素、叶绿素和类胡萝卜素的生物合成、碳固定和糖代谢等关键代谢途径。为了进一步验证叶绿素代谢（叶绿素酶，CHLASE）、抗氧化防御（超氧化物歧化酶，SOD：过氧化氢酶，CAT；抗坏血酸过氧化物酶，APX；过氧化物酶，POD）和苯丙氨酸解氨酶（PAL）等关键基因的表达，研究了其分子机制。外源性褪黑激素显著调节了上述生物过程中关键基因的转录水平。褪黑素还与其他激素（玉米素、赤霉素A14、24-表油菜素内酯、茉莉酸和脱落酸）相互作用，调节生理过程。本研究结果表明，褪黑激素在代谢和分子水平上调节生物过程以抵抗干旱胁迫。(C) 2020年Elsevier B.V.出版
The Chinese hickory (Carya cathayensis) is an economically important tree species popular for its nuts. However, the tree requires a long time to reach the nut-producing phase. To overcome this problem, grafting is widely used to reduce the time from the vegetative to the reproductive phase. This tree species also faces many environmental challenges due to climate change; drought is an important factor affecting growth and development Here, we designed an experiment to assess the protective efficiency of melatonin in grafted Chinese hickory plants under drought stress. The results revealed that exogenously applied melatonin successfully recovered the growth of grafted Chinese hickory plants and improved photosynthetic efficiency. Exogenously applied melatonin also boosted the antioxidative defense system of the plants under drought stress, resulting in enhanced reactive oxygen species (ROS) scavenging.The accumulation of compatible solutes such as total soluble sugars and proline was also triggered by melatonin. Moreover, the analyses using metabolomics revealed that drought-stressed plants treated with melatonin regulated key metabolic pathways such as phenylpropanoid, chlorophyll and carotenoid biosynthesis, carbon fixation, and sugar metabolism. To further validate the physiological, biochemical, and metabolomic factors, we studied the molecular mechanisms by analyzing the expression of key genes involved in chlorophyll metabolism (chlorophyllase, CHLASE), antioxidative defense (superoxide dismutase, SOD: catalase, CAT; ascorbate peroxidase, APX; peroxidase, POD), and phenylalanine ammonia-lyase (PAL). Exogenously applied melatonin significantly regulated the transcript levels of key genes involved in the biological processes mentioned above. Melatonin also showed crosstalk with other hormones (zeatin, gibberellin A14, 24-epibrassinolide, jasmonic acid, and abscisic acid) to regulate the physiological processes. The results of this study show that melatonin regulates biological processes at the metabolic and molecular levels to resist drought stress. (C) 2020 Published by Elsevier B.V.