Samuela Palombieri , Arianna Frittelli , Maria Dolores Garcia Molina , Romina Beleggia , Valentina Giovanniello , Enrica Alicandri , Agostino Sorgonà , Pasquale De Vita , Stefania Masci , Francesco Sestili
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引用次数: 0
Abstract
Carotenoids are essential pigments in plants, playing critical roles in photosynthesis, photoprotection, and stress tolerance, particularly under environmental conditions such as high light intensity and drought. To enhance β-carotene content in durum wheat (Triticum durum Desf.), a TILLING approach was used to generate null mutants for the lycopene ε-cyclase (LCYE) and β-hydroxylases 1 (HYD1) genes, which are key players in carotenoid biosynthesis. Homozygous mutants for both genes were obtained by crossing single homeoallelic mutant lines, resulting in three distinct mutant lines (LxH_1, LxH_2, LxH_3). Carotenoid metabolism and antioxidant-related genes expression were analyzed during seed ripening, revealing significantly reduced expression of LCYE and HYD1, while violaxanthin de-epoxidase (VDE) gene was upregulated at later stages. The mutant lines also showed significantly higher β-carotene accumulation in seeds, with an increase of up to 245 % compared to the control, while lutein content was reduced by over 99 %. In leaves, β-carotene levels remained unchanged, but zeaxanthin and violaxanthin accumulated at significantly higher levels compared to the control plants. Chlorophyll content was reduced in the mutant leaves, leading to altered chlorophyll a/b ratios and an overall decrease in total carotenoid levels. Although photosynthetic efficiency was lower in the mutants, gas exchange parameters remained unaffected, suggesting that primary carbon assimilation was not severely compromised. Phenotypic analysis revealed a reduction in plant height, spike length, and spikelet number; however, key yield traits were largely preserved. Notably, the mutant lines exhibited albinism under cold acclimation conditions, a phenotype absent in the control plants, likely due to the crucial role of lutein in photoprotection at low temperatures.
These findings demonstrate that the pyramiding of mutations in LCYE and HYD1 effectively alters carotenoid composition, impacts photosynthesis-related traits, and influences plant responses to environmental stresses. This study provides valuable insights for breeding programs aimed at enhancing carotenoid content in wheat, with potential applications in improving both nutritional quality and stress resilience in cereal crops.
类胡萝卜素是植物必需的色素,在光合作用、光保护和抗逆性等方面发挥着关键作用,特别是在强光和干旱等环境条件下。为了提高硬粒小麦(Triticum durum Desf.)中β-胡萝卜素的含量,采用TILLING方法获得了类胡萝卜素合成关键基因——番茄红素ε-环化酶(LCYE)和β-羟化酶1 (HYD1)基因的零突变体。通过杂交获得两个基因的纯合突变体,得到LxH_1、LxH_2、LxH_3三个不同的突变体。分析了种子成熟过程中类胡萝卜素代谢和抗氧化相关基因的表达,发现LCYE和HYD1的表达显著降低,而紫黄质去环氧酶(VDE)基因在种子成熟后期表达上调。突变系种子中β-胡萝卜素的积累量也显著增加,与对照相比增加了245%,而叶黄素含量减少了99%以上。叶片中β-胡萝卜素含量保持不变,但玉米黄质和紫黄质积累量显著高于对照植株。突变体叶片叶绿素含量降低,导致叶绿素a/b比改变,总类胡萝卜素水平总体下降。虽然突变体的光合效率较低,但气体交换参数未受影响,表明初级碳同化并未受到严重损害。表型分析显示株高、穗长和小穗数减少;然而,关键的产量性状在很大程度上保留了下来。值得注意的是,突变系在冷驯化条件下表现出白化,这是对照植株所没有的表型,可能是由于叶黄素在低温光保护中的关键作用。这些发现表明,LCYE和HYD1突变的金字塔化有效地改变了类胡萝卜素的组成,影响了光合作用相关性状,并影响了植物对环境胁迫的反应。该研究为提高小麦类胡萝卜素含量的育种计划提供了有价值的见解,在提高谷类作物的营养品质和抗逆性方面具有潜在的应用价值。
期刊介绍:
Plant Physiology and Biochemistry publishes original theoretical, experimental and technical contributions in the various fields of plant physiology (biochemistry, physiology, structure, genetics, plant-microbe interactions, etc.) at diverse levels of integration (molecular, subcellular, cellular, organ, whole plant, environmental). Opinions expressed in the journal are the sole responsibility of the authors and publication does not imply the editors'' agreement.
Manuscripts describing molecular-genetic and/or gene expression data that are not integrated with biochemical analysis and/or actual measurements of plant physiological processes are not suitable for PPB. Also "Omics" studies (transcriptomics, proteomics, metabolomics, etc.) reporting descriptive analysis without an element of functional validation assays, will not be considered. Similarly, applied agronomic or phytochemical studies that generate no new, fundamental insights in plant physiological and/or biochemical processes are not suitable for publication in PPB.
Plant Physiology and Biochemistry publishes several types of articles: Reviews, Papers and Short Papers. Articles for Reviews are either invited by the editor or proposed by the authors for the editor''s prior agreement. Reviews should not exceed 40 typewritten pages and Short Papers no more than approximately 8 typewritten pages. The fundamental character of Plant Physiology and Biochemistry remains that of a journal for original results.