Contents lists available at ScienceDirect Plant Physiology and Biochemistry journal homepage: www.elsevier.com/locate/plaphy Research article Grapevine immune signaling network in response to drought stress as revealed by transcriptomic analysis Muhammad S. Haider 1 , Mahantesh M. Kurjogi 1 , M. Khalil-Ur-Rehman, Muhammad Fiaz, Tariq Pervaiz, Songtao Jiu, Jia Haifeng, Wang Chen, Jinggui Fang * Key Laboratory of Genetics and Fruit Development, College of Horticulture, Nanjing Agricultural University, Tongwei Road 6, Nanjing 210095, PR China ARTICLE INFO Keywords: Calcium signaling MAPK-Signaling WRKY CDPK Grapevine Pathogen-related proteins ABSTRACT Drought is a ubiquitous abiotic factor that severely impedes growth and development of horticulture crops. The challenge postured by global climate change is the evolution of drought-tolerant cultivars that could cope with concurrent stress. Hence, in this study, biochemical, physiological and transcriptome analysis were investigated in drought-treated grapevine leaves. The results revealed that photosynthetic activity and reducing sugars were significantly diminished which were positively correlated with low stomatal conductance and CO 2 exchange in drought-stressed leaves. Further, the activities of superoxide dismutase, peroxidase, and catalase were sig- nificantly actuated in the drought-responsive grapevine leaves. Similarly, the levels of abscisic acid and jasmonic acid were also significantly increased in the drought-stressed leaves. In transcriptome analysis, 12,451 differ- entially-expressed genes (DEGs) were annotated, out of which 8021 DEGs were up-regulated and 4430 DEGs were down-regulated in response to drought stress. In addition, the genes encoding pathogen-associated mo- lecular pattern (PAMP) triggered immunity (PTI), including calcium signals, protein phosphatase 2C, calcineurin B-like proteins, MAPKs, and phosphorylation (FLS2 and MEKK1) cascades were up-regulated in response to drought stress. Several genes related to plant-pathogen interaction pathway (RPM1, PBS1, RPS5, RIN4, MIN7, PR1, and WRKYs) were also found up-regulated in response to drought stress. Overall the results of present study showed the dynamic interaction of DEG in grapevine physiology which provides the premise for selection of defense-related genes against drought stress for subsequent grapevine breeding programs. 1. Introduction Grapevine (Vitis vinifera L.) is widely distributed fruit crop, with the cultivation area of about 7.8 million hectares and the annual produce of about 67.6 million tons globally (Griesser et al., 2015; Pervaiz et al., 2016). The grape berries are primarily classified into table grapes (fresh) and wine grapes, along with numerous value-added products (Khalil-ur-Rehman et al., 2017). China is the leading producer, con- tributing nearly 14% in the world grape production (Fasoli et al., 2012). The severity of drought mainly affects the morphological and physio- logical traits, which include hindered plant growth, wilting, reduction in total water potential and turgor, and decrease in cell enlargement (Khan, 2011; Lovisolo et al., 2010). Moreover, the diffusion and mass flow of water-soluble nutrients are also diminished by the drought stress as it confines the accessibility and transport of soil nutrients from roots (Osakabe et al., 2014). The plant response and defense me- chanism to drought are likely to involve in the growth inhibition, osmotic homeostasis/regulation, and detoxification, or stress repair mechanism; all these are often associated with signal transduction (Zhu, 2002). Due to constant exposure to drought stress, plants become suscep- tible to different pathogens, insects, and diseases (Wu et al., 2014). In response to pathogen susceptibility, plants can develop sensing me- chanism mediated by signaling cascades, and transcription networks (Jones and Dangl, 2006), which regulate the expression of certain proteins in response to abiotic stresses. These signaling networks and transcription factors are powerful targets for genetic engineering in stress tolerance plants. In addition, these targets can induce or repress the activity of stress-responsive genes along with several changes in the physiological and biochemical factors like, modifications of proteins by phosphorylation, cytosolic calcium (Ca 2+ cyt ) elevation, activation of mi- togen-activated protein kinases (MAPKs) cascades and production of reactive oxygen species (ROS) in the oxidative burst that can initiate defense responses (Boller and Felix, 2009; Ren et al., 2008; https://doi.org/10.1016/j.plaphy.2017.10.026 Received 6 July 2017; Received in revised form 26 October 2017; Accepted 26 October 2017 * Corresponding author. 1 Both authors have contributed equally. E-mail address: fanggg@njau.edu.cn (J. Fang). Plant Physiology and Biochemistry 121 (2017) 187–195 Available online 31 October 2017 0981-9428/ © 2017 Elsevier Masson SAS. All rights reserved. MARK