Zhang Chao, Zhang Lin, Zhang Sheng, Zhu Shuang, Wu Pingzhi, Chen Yaping, Li Meiru, Jiang Huawu, Wu Guojiang
Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
BMC Plant Biol. 2015 Jan 21;15:17. doi: 10.1186/s12870-014-0397-x.
Physic nut (Jatropha curcas L.) is a small perennial tree or large shrub, which is well-adapted to semi-arid regions and is considered to have potential as a crop for biofuel production. It is now regarded as an excellent model for studying biofuel plants. However, our knowledge about the molecular responses of this species to drought stress is currently limited.
In this study, genome-wide transcriptional profiles of roots and leaves of 8-week old physic nut seedlings were analyzed 1, 4 and 7 days after withholding irrigation. We observed a total of 1533 and 2900 differentially expressed genes (DEGs) in roots and leaves, respectively. Gene Ontology analysis showed that the biological processes enriched in droughted plants relative to unstressed plants were related to biosynthesis, transport, nucleobase-containing compounds, and cellular protein modification. The genes found to be up-regulated in roots were related to abscisic acid (ABA) synthesis and ABA signal transduction, and to the synthesis of raffinose. Genes related to ABA signal transduction, and to trehalose and raffinose synthesis, were up-regulated in leaves. Endoplasmic reticulum (ER) stress response genes were significantly up-regulated in leaves under drought stress, while a number of genes related to wax biosynthesis were also up-regulated in leaves. Genes related to unsaturated fatty acid biosynthesis were down-regulated and polyunsaturated fatty acids were significantly reduced in leaves 7 days after withholding irrigation. As drought stress increased, genes related to ethylene synthesis, ethylene signal transduction and chlorophyll degradation were up-regulated, and the chlorophyll content of leaves was significantly reduced by 7 days after withholding irrigation.
This study provides us with new insights to increase our understanding of the response mechanisms deployed by physic nut seedlings under drought stress. The genes and pathways identified in this study also provide much information of potential value for germplasm improvement and breeding for drought resistance.
麻疯树(Jatropha curcas L.)是一种小型多年生乔木或大型灌木,非常适应半干旱地区,被认为具有作为生物燃料生产作物的潜力。它现在被视为研究生物燃料植物的优秀模式植物。然而,目前我们对该物种对干旱胁迫的分子反应的了解有限。
在本研究中,对8周龄麻疯树幼苗在停止灌溉1、4和7天后的根和叶进行了全基因组转录谱分析。我们分别在根和叶中观察到总共1533个和2900个差异表达基因(DEG)。基因本体分析表明,与未受胁迫植物相比,干旱植物中富集的生物学过程与生物合成、运输、含核碱基化合物和细胞蛋白质修饰有关。在根中上调的基因与脱落酸(ABA)合成和ABA信号转导以及棉子糖合成有关。与ABA信号转导以及海藻糖和棉子糖合成相关的基因在叶中上调。内质网(ER)应激反应基因在干旱胁迫下的叶中显著上调,而一些与蜡生物合成相关的基因在叶中也上调。与不饱和脂肪酸生物合成相关的基因下调,停止灌溉7天后叶中的多不饱和脂肪酸显著减少。随着干旱胁迫加剧,与乙烯合成、乙烯信号转导和叶绿素降解相关的基因上调,停止灌溉7天后叶中的叶绿素含量显著降低。
本研究为我们增进对麻疯树幼苗在干旱胁迫下所采用的反应机制的理解提供了新的见解。本研究中鉴定的基因和途径也为种质改良和抗旱育种提供了许多潜在有价值的信息。