Tea [Camellia sinensis (L) O. Kuntze], worldwide known source of popular non-alcoholic beverage, is severely affected by various biotic and abiotic stresses. Among these, blister blight (BB) disease caused by the obligate biotrophic fungus Exobasidium vexan is responsible for significant depletion of its yield and quality. Our comparative NGS transcriptomic analysis although elucidated global gene expression pattern of BB defense transitions, yet left with 12,022 transcripts categorized as ‘hypothetical proteins (HPs)’. In this study, efforts were made for assigning functions to HPs derived from RNA-Seq data and successfully identified novel putative candidates involved in BB defense in tea. Domain and family-based characterization identified 9390 HPs representing 2867 protein families and 953 super families. Of these, 213 HPs were assigned with novel putative defense related functional categories (LRR, WRKY, NAC, chitinases and peroxidases). Further, sub-cellular localization (cytosolic,133 HPs; transmembranic, 80 HPs) with abundance of HPs exhibiting of acidic (133) and basic (80) nature suggests their wider functional range. 36 HPs upregulated in tolerant genotype having significant interactions with defense responsive candidates in Protein–Protein Interaction Network analysis, possibly suggests their key regulatory role in BB defense. Interestingly, 12 stereo-dynamically stable structures [LRR (5), NAC (4), WRKY, Chitinase & Peroxidase (1 each)] of HP’s were successfully modelled based on their conserved signature sequences and empirically validated using qRT-PCR analysis, therefore, can be potential novel candidates possibly involved in signal transduction and pathogen recognition during BB defense in tea. Futuristically, novel genes identified in this study can be potentially utilized to expedite genetic improvement efforts in tea. The approach successfully employed in tea can also be adopted for assigning molecular function to the HPs in other plant species.

中文翻译：

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茶中水疱病抗性相关的假设蛋白的功能注释和表征

茶[茶花（L）O. Kuntze]是世界公认的流行非酒精饮料来源，受到各种生物和非生物胁迫的严重影响。其中，专性生物营养真菌Exobasidium v​​exan引起的水疱枯萎病（BB）导致其产量和质量显着下降。我们的比较性NGS转录组学分析虽然阐明了BB防御转换的整体基因表达模式，但仍留下了12,022个被分类为“假设蛋白（HPs）”的转录本。在这项研究中，努力为从RNA-Seq数据衍生的HP分配功能，并成功鉴定了参与茶中BB防御的新型假定候选物。基于域和家族的表征鉴定出9390个HP，代表2867个蛋白家族和953个超家族。在这些人中，有213个HP被分配了新的与防御相关的功能类别（LRR，WRKY，NAC，几丁质酶和过氧化物酶）。此外，亚细胞定位（胞质，133 HP；跨膜，80个HP）具有丰富的HP表现出酸性（133）和碱性（80）性质，表明它们的功能范围更广。在蛋白质-蛋白质相互作用网络分析中，耐受基因型上调的36个HP与防御反应候选物有显着相互作用，这可能表明它们在BB防御中的关键调控作用。有趣的是，HP的12种立体动力学稳定结构[LRR（5），NAC（4），WRKY，几丁质酶和过氧化物酶（各1个）]已基于其保守的签名序列成功建模，并通过qRT-PCR分析进行了经验验证。可能是茶中BB防御过程中可能涉及信号转导和病原体识别的潜在新候选物。从未来的角度来看，本研究中鉴定出的新基因可潜在地用于加速茶的遗传改良工作。