Bonnin Marie, Soriano Alexandre, Favreau Bénédicte, Lourkisti Radia, Miranda Maëva, Ollitrault Patrick, Oustric Julie, Berti Liliane, Santini Jérémie, Morillon Raphaël
Projet Ressources Naturelles Axe Adaptation des végé taux aux changements globaux, Unité Mixte de Recherche Centre National de la Recherche Scientifique (UMR CNRS) 6134 Science Pour l'Environment (SPE), Universitéde Corse, Corsica, France.
Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales (UMR AGAP) Institut, Univ. Montpellier, Centre de coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Institut Agro, Montpellier, France.
Front Plant Sci. 2024 Oct 30;15:1469115. doi: 10.3389/fpls.2024.1469115. eCollection 2024.
Citrus is an important fruit crop for human health. The sensitivity of citrus trees to a wide range of abiotic stresses is a major challenge for their overall growth and productivity. Among these abiotic stresses, salinity results in a significant loss of global citrus yield. In order to find straightforward and sustainable solutions for the future and to ensure citrus productivity, it is of paramount importance to decipher the mechanisms responsible for salinity stress tolerance. Thisstudy aimed to investigate how ploidy levels influence salt stress tolerance in citrus by comparing the transcriptomic responses of diploid and tetraploid genotypes. In a previous article we investigated the physiological and biochemical response of four genotypes with different ploidy levels: diploid trifoliate orange (Poncirus trifoliata [L.] Raf.) (PO2x) and Cleopatra mandarin (Citrus reshni Hort. Ex Tan.) (CL2x) and their respective tetraploids (PO4x, CL4x).
In this study, we useda multifactorial gene selection and gene clustering approach to finely dissect the influence of ploidy level on the salt stress response of each genotype. Following transcriptome sequencing, differentially expressed genes (DEGs) were identified in response to salt stress in leaves and roots of the different citrus genotypes.
Gene expression profiles and functional characterization of genes involved in the response to salt stress, as a function of ploidy level and the interaction between stress response and ploidy level, have enabled us to highlight the mechanisms involved in the varieties tested. Saltstress induced overexpression of carbohydrate biosynthesis and cell wall remodelling- related genes specifically in CL4x Ploidy level enhanced oxidative stress response in PO and ion management capacity in both genotypes. Results further highlighted that under stress conditions, only the CL4x genotype up- regulated genes involved in sugar biosynthesis, transport management, cell wall remodelling, hormone signalling, enzyme regulation and antioxidant metabolism. These findings provide crucial insights that could inform breeding strategies for developing salt-tolerant citrus varieties.
柑橘是对人类健康至关重要的水果作物。柑橘树对多种非生物胁迫的敏感性是其整体生长和生产力面临的主要挑战。在这些非生物胁迫中，盐胁迫导致全球柑橘产量大幅损失。为了找到未来直接且可持续的解决方案并确保柑橘生产力，解读负责盐胁迫耐受性的机制至关重要。本研究旨在通过比较二倍体和四倍体基因型的转录组反应，研究倍性水平如何影响柑橘的盐胁迫耐受性。在之前的一篇文章中，我们研究了四种不同倍性水平基因型的生理和生化反应：二倍体枳壳（Poncirus trifoliata [L.] Raf.）（PO2x）和埃及酸橙（Citrus reshni Hort. Ex Tan.）（CL2x）及其各自的四倍体（PO4x，CL4x）。
在本研究中，我们使用多因素基因选择和基因聚类方法来精细剖析倍性水平对每种基因型盐胁迫反应的影响。转录组测序后，在不同柑橘基因型的叶片和根系中鉴定出响应盐胁迫的差异表达基因（DEGs）。
作为倍性水平以及胁迫反应与倍性水平之间相互作用的函数，参与盐胁迫反应的基因的表达谱和功能表征使我们能够突出所测试品种中涉及的机制。盐胁迫诱导碳水化合物生物合成和细胞壁重塑相关基因的过表达，特别是在CL4x中。倍性水平增强了PO中的氧化应激反应以及两种基因型中的离子管理能力。结果进一步强调，在胁迫条件下，只有CL4x基因型上调了参与糖生物合成、运输管理、细胞壁重塑、激素信号传导、酶调节和抗氧化代谢的基因。这些发现提供了关键见解，可为培育耐盐柑橘品种的育种策略提供参考。
