Frouin Julien, Languillaume Antoine, Mas Justine, Mieulet Delphine, Boisnard Arnaud, Labeyrie Axel, Bettembourg Mathilde, Bureau Charlotte, Lorenzini Eve, Portefaix Muriel, Turquay Patricia, Vernet Aurore, Périn Christophe, Ahmadi Nourollah, Courtois Brigitte
Centre de coopération internationale en recherche agronomique pour le développement, Unité mixte de recherche Amélioration génétique et adaptation des plantes méditerranéennes et tropicales, Montpellier, France.
Centre Français du Riz, Arles, France.
PLoS One. 2018 Jan 17;13(1):e0190964. doi: 10.1371/journal.pone.0190964. eCollection 2018.
Salinity tolerance is an important quality for European rice grown in river deltas. We evaluated the salinity tolerance of a panel of 235 temperate japonica rice accessions genotyped with 30,000 SNP markers. The panel was exposed to mild salt stress (50 mM NaCl; conductivity of 6 dS m-1) at the seedling stage. Eight different root and shoot growth parameters were measured for both the control and stressed treatments. The Na+ and K+ mass fractions of the stressed plants were measured using atomic absorption spectroscopy. The salt treatment affected plant growth, particularly the shoot parameters. The panel showed a wide range of Na+/K+ ratio and the temperate accessions were distributed over an increasing axis, from the most resistant to the most susceptible checks. We conducted a genome-wide association study on indices of stress response and ion mass fractions in the leaves using a classical mixed model controlling structure and kinship. A total of 27 QTLs validated by sub-sampling were identified. For indices of stress responses, we also used another model that focused on marker × treatment interactions and detected 50 QTLs, three of which were also identified using the classical method. We compared the positions of the significant QTLs to those of approximately 300 genes that play a role in rice salt tolerance. The positions of several QTLs were close to those of genes involved in calcium signaling and metabolism, while other QTLs were close to those of kinases. These results reveal the salinity tolerance of accessions with a temperate japonica background. Although the detected QTLs must be confirmed by other approaches, the number of associations linked to candidate genes involved in calcium-mediated ion homeostasis highlights pathways to explore in priority to understand the salinity tolerance of temperate rice.
耐盐性是欧洲在三角洲地区种植水稻的一项重要品质。我们评估了一组235份温带粳稻种质的耐盐性，这些种质通过30000个单核苷酸多态性（SNP）标记进行了基因分型。该组种质在幼苗期受到轻度盐胁迫（50 mM NaCl；电导率6 dS m-1）。对对照和胁迫处理下的植株测量了8种不同的根和地上部生长参数。使用原子吸收光谱法测量胁迫处理植株的Na+和K+质量分数。盐处理影响了植株生长，尤其是地上部参数。该组种质显示出广泛的Na+/K+比率范围，温带种质分布在一个递增轴上，从最耐受到最敏感的对照品种。我们使用控制结构和亲缘关系的经典混合模型，对叶片中胁迫响应指标和离子质量分数进行了全基因组关联研究。通过子抽样验证共鉴定出27个数量性状基因座（QTL）。对于胁迫响应指标，我们还使用了另一个侧重于标记×处理相互作用的模型，并检测到50个QTL，其中3个也通过经典方法鉴定出来。我们将显著QTL的位置与大约300个在水稻耐盐性中起作用的基因的位置进行了比较。几个QTL的位置与参与钙信号传导和代谢的基因位置相近，而其他QTL则与激酶的位置相近。这些结果揭示了温带粳稻背景种质的耐盐性。尽管检测到的QTL必须通过其他方法进行确认，但与参与钙介导的离子稳态的候选基因相关的关联数量突出了优先探索的途径，以了解温带水稻的耐盐性。
