Rabello Aline R, Guimarães Cléber M, Rangel Paulo H N, da Silva Felipe R, Seixas Daniela, de Souza Emanuel, Brasileiro Ana C M, Spehar Carlos R, Ferreira Márcio E, Mehta Angela
Embrapa Recursos Genéticos e Biotecnologia, PqEB Av W5 Norte Final, CEP 70770-900, Brasília, DF, Brazil.
BMC Genomics. 2008 Oct 15;9:485. doi: 10.1186/1471-2164-9-485.
Rice (Oryza sativa L.) germplasm represents an extraordinary source of genes that control traits of agronomic importance such as drought tolerance. This diversity is the basis for the development of new cultivars better adapted to water restriction conditions, in particular for upland rice, which is grown under rainfall. The analyses of subtractive cDNA libraries and differential protein expression of drought tolerant and susceptible genotypes can contribute to the understanding of the genetic control of water use efficiency in rice.
Two subtractive libraries were constructed using cDNA of drought susceptible and tolerant genotypes submitted to stress against cDNA of well-watered plants. In silico analysis revealed 463 reads, which were grouped into 282 clusters. Several genes expressed exclusively in the tolerant or susceptible genotypes were identified. Additionally, proteome analysis of roots from stressed plants was performed and 22 proteins putatively associated to drought tolerance were identified by mass spectrometry.
Several genes and proteins involved in drought-response, as well as genes with no described homologs were identified. Genes exclusively expressed in the tolerant genotype were, in general, related to maintenance of turgor and cell integrity. In contrast, in the susceptible genotype, expression of genes involved in protection against cell damage was not detected. Several protein families identified in the proteomic analysis were not detected in the cDNA analysis. There is an indication that the mechanisms of susceptibility to drought in upland rice are similar to those of lowland varieties.
水稻（Oryza sativa L.）种质是控制诸如耐旱性等重要农艺性状基因的非凡来源。这种多样性是培育更适应水分限制条件新品种的基础，特别是对于在降雨条件下种植的旱稻而言。对耐旱和敏感基因型的消减cDNA文库及差异蛋白质表达进行分析，有助于理解水稻水分利用效率的遗传控制。
利用遭受胁迫的耐旱和敏感基因型的cDNA与水分充足植株的cDNA构建了两个消减文库。电子分析揭示了463条读数，这些读数被归为282个簇。鉴定出了几个仅在耐旱或敏感基因型中表达的基因。此外，对受胁迫植株的根进行了蛋白质组分析，通过质谱鉴定出22种可能与耐旱性相关的蛋白质。
鉴定出了几个参与干旱响应的基因和蛋白质，以及一些没有已知同源物的基因。通常，仅在耐旱基因型中表达的基因与膨压维持和细胞完整性有关。相反，在敏感基因型中，未检测到参与防止细胞损伤的基因表达。在蛋白质组分析中鉴定出的几个蛋白质家族在cDNA分析中未被检测到。有迹象表明，旱稻对干旱的敏感机制与低地品种相似。
