Laboratório de Genoma Funcional, Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil.
PLoS One. 2012;7(9):e44697. doi: 10.1371/journal.pone.0044697. Epub 2012 Sep 11.
Drought is a major abiotic stress that affects crop productivity worldwide. Sugarcane can withstand periods of water scarcity during the final stage of culm maturation, during which sucrose accumulation occurs. Meanwhile, prolonged periods of drought can cause severe plant losses.
METHODOLOGY/PRINCIPAL FINDINGS: In a previous study, we evaluated the transcriptome of drought-stressed plants to better understand sugarcane responses to drought. Among the up-regulated genes was Scdr1 (sugarcane drought-responsive 1). The aim of the research reported here was to characterize this gene. Scdr1 encodes a putative protein containing 248 amino acids with a large number of proline (19%) and cysteine (13%) residues. Phylogenetic analysis showed that ScDR1is in a clade with homologs from other monocotyledonous plants, separate from those of dicotyledonous plants. The expression of Scdr1 in different varieties of sugarcane plants has not shown a clear association with drought tolerance.
CONCLUSIONS/SIGNIFICANCE: The overexpression of Scdr1 in transgenic tobacco plants increased their tolerance to drought, salinity and oxidative stress, as demonstrated by increased photosynthesis, water content, biomass, germination rate, chlorophyll content and reduced accumulation of ROS. Physiological parameters, such as transpiration rate (E), net photosynthesis (A), stomatal conductance (gs) and internal leaf CO(2) concentration, were less affected by abiotic stresses in transgenic Scdr1 plants compared with wild-type plants. Overall, our results indicated that Scdr1 conferred tolerance to multiple abiotic stresses, highlighting the potential of this gene for biotechnological applications.
干旱是一种主要的非生物胁迫，影响着全球作物的生产力。甘蔗在茎成熟的最后阶段能够耐受水分短缺时期，在此期间会发生蔗糖积累。然而，长时间的干旱会导致严重的植物损失。
方法/主要发现：在之前的研究中，我们评估了干旱胁迫下植物的转录组，以更好地了解甘蔗对干旱的反应。上调基因之一是 Scdr1（甘蔗干旱响应 1）。本研究旨在对该基因进行特征描述。Scdr1 编码一个含有 248 个氨基酸的假定蛋白，脯氨酸（19%）和半胱氨酸（13%）残基数量较多。系统发育分析表明，ScDR1 与其他单子叶植物的同源物在一个分支中，与双子叶植物的同源物分开。Scdr1 在不同甘蔗品种中的表达与耐旱性没有明显的关联。
结论/意义：Scdr1 在转基因烟草植物中的过表达增加了它们对干旱、盐和氧化应激的耐受性，表现为光合作用、水分含量、生物量、发芽率、叶绿素含量增加，ROS 积累减少。与野生型植物相比，转 Scdr1 植物的生理参数，如蒸腾速率（E）、净光合速率（A）、气孔导度（gs）和叶片内 CO2 浓度，受非生物胁迫的影响较小。总的来说，我们的结果表明 Scdr1 赋予了植物对多种非生物胁迫的耐受性，突出了该基因在生物技术应用中的潜力。
