Unit of Plant Physiology, Department of Plant Biology, Faculty of Biology, University of Barcelona, Barcelona, 08028, Spain.
Department of Plant Biochemistry and Molecular Biology, Faculty of Chemistry, University of Seville, Sevilla, 41012, Spain.
J Integr Plant Biol. 2016 Jan;58(1):48-66. doi: 10.1111/jipb.12359. Epub 2015 Sep 8.
Elucidating the relationships between gene expression and the physiological mechanisms remains a bottleneck in breeding for resistance to salinity and drought. This study related the expression of key target genes with the physiological performance of durum wheat under different combinations of salinity and irrigation. The candidate genes assayed included two encoding for the DREB (dehydration responsive element binding) transcription factors TaDREB1A and TaDREB2B, another two for the cytosolic and plastidic glutamine synthetase (TaGS1 and TaGS2), and one for the specific Na(+) /H(+) vacuolar antiporter (TaNHX1). Expression of these genes was related to growth and different trait indicators of nitrogen metabolism (nitrogen content, stable nitrogen isotope composition, and glutamine synthetase and nitrate reductase activities), photosynthetic carbon metabolism (stable carbon isotope composition and different gas exchange traits) and ion accumulation. Significant interaction between genotype and growing conditions occurred for growth, nitrogen content, and the expression of most genes. In general terms, higher expression of TaGS1, TaGS2, TaDREB2B, and to a lesser extent of TaNHX1 were associated with a better genotypic performance in growth, nitrogen, and carbon photosynthetic metabolism under salinity and water stress. However, TaDREB1A was increased in expression under stress compared with control conditions, with tolerant genotypes exhibiting lower expression than susceptible ones.
阐明基因表达与生理机制之间的关系仍然是耐盐和耐旱性育种的一个瓶颈。本研究将关键靶基因的表达与不同盐度和灌溉组合下硬粒小麦的生理性能相关联。测定的候选基因包括两个编码 DREB（脱水响应元件结合）转录因子的 TaDREB1A 和 TaDREB2B，另外两个编码细胞质和质体谷氨酰胺合成酶的 TaGS1 和 TaGS2，以及一个编码特异 Na(+) /H(+)液泡反向转运蛋白的 TaNHX1。这些基因的表达与生长和氮代谢的不同性状指标（氮含量、稳定氮同位素组成、谷氨酰胺合成酶和硝酸还原酶活性）、光合作用碳代谢（稳定碳同位素组成和不同的气体交换特性）和离子积累有关。基因型和生长条件之间存在显著的互作，影响生长、氮含量和大多数基因的表达。总的来说，在盐度和水分胁迫下，TaGS1、TaGS2、TaDREB2B 的表达水平较高，与生长、氮和碳光合作用代谢的基因型表现较好有关，而 TaNHX1 的表达水平较低。然而，与对照条件相比，TaDREB1A 在胁迫下的表达增加，而耐盐基因型的表达低于敏感基因型。
