Max Planck Institute of Molecular Plant Physiology, Potsdam, Brandenburg, Germany.
PLoS One. 2013 May 22;8(5):e63637. doi: 10.1371/journal.pone.0063637. Print 2013.
Rice provides about half of the calories consumed in Asian countries, but its productivity is often reduced by drought, especially when grown under rain-fed conditions. Cultivars with increased drought tolerance have been bred over centuries. Slow selection for drought tolerance on the basis of phenotypic traits may be accelerated by using molecular markers identified through expression and metabolic profiling. Previously, we identified 46 candidate genes with significant genotype × environment interaction in an expression profiling study on four cultivars with contrasting drought tolerance. These potential markers and in addition GC-MS quantified metabolites were tested in 21 cultivars from both indica and japonica background that varied in drought tolerance. Leaf blades were sampled from this population of cultivars grown under control or long-term drought condition and subjected to expression analysis by qRT-PCR and metabolite profiling. Under drought stress, metabolite levels correlated mainly negatively with performance parameters, but eight metabolites correlated positively. For 28 genes, a significant correlation between expression level and performance under drought was confirmed. Negative correlations were predominant. Among those with significant positive correlation was the gene coding for a cytosolic fructose-1,6-bisphosphatase. This enzyme catalyzes a highly regulated step in C-metabolism. The metabolic and transcript marker candidates for drought tolerance were identified in a highly diverse population of cultivars. Thus, these markers may be used to select for tolerance in a wide range of rice germplasms.
水稻提供了亚洲国家所消耗卡路里的一半，但它的生产力经常受到干旱的影响，特别是在雨养条件下。几个世纪以来，人们一直在培育具有更高耐旱性的品种。通过利用表达和代谢分析鉴定的分子标记，可以加速基于表型性状的耐旱性的缓慢选择。之前，我们在对四个耐旱性不同的品种进行的表达谱研究中，鉴定出了 46 个候选基因，这些基因与基因型与环境互作有关。这些潜在的标记物和 GC-MS 定量代谢物在来自籼稻和粳稻背景的 21 个具有不同耐旱性的品种中进行了测试。从这个品种群体中，在对照或长期干旱条件下生长的叶片被取样，并通过 qRT-PCR 和代谢谱进行表达分析。在干旱胁迫下，代谢物水平主要与性能参数呈负相关，但有八种代谢物呈正相关。对于 28 个基因，在干旱条件下，其表达水平与性能之间的显著相关性得到了确认。负相关占主导地位。其中与正相关显著的是编码细胞质果糖-1,6-二磷酸酶的基因。该酶催化 C 代谢中高度调控的步骤。在高度多样化的品种群体中鉴定出了耐旱性的代谢和转录标记候选物。因此，这些标记物可以用于选择广泛的水稻种质的耐受性。
