Tea (Camellia sinensis (L). O. Kuntze) is known as the oldest, mild stimulating caffeine containing non-alcoholic beverage. One of the major threats in south Asian tea industry is the blister blight leaf disease (BB), caused by the fungus Exobasidium vexans Masse. SSR DNA marker EST SSR 073 is used as a molecular marker to tag blister blight disease resistance trait of tea. The amino acid sequences were derived from cDNA sequences related to EST SSR 073 of BB susceptible (TRI 2023) and BB resistant (TRI 2043) cultivars. An attempt has been made to understand the structural characteristics and variations of EST SSR 073 locus that may reveal the factors influencing the BB resistance of tea with multiple bioinformatics tools such as ORF finder, ExPasy ProtParam tools, modeler V 9.17, Rampage server, UCSF-Chimera, and HADDOCK docking server. The primary, secondary, and tertiary structures of EST SSR 073 coding protein were analyzed using the amino acid sequences of both BB resistant TRI 2043 and BB susceptible TRI 2023 tea cultivars. The coding amino acid sequences of both the cultivars were homologous to photosystem I subunit protein (PsaD I) of Pisum sativum. The predicted 3D structures of proteins were validated and considered as an acceptable overall stereochemical quality. The BB resistant protein showed CT repeat extension and did not involve in topology of the PsaD I subunit. The C terminal truncation of BB resistance caused the formation of hydrogen bonds interacting with PsaD I and other subunits of photosystem I in the modeled three-dimensional protein structure. Camellia sinensis EST 073 SSR motif coding protein was identified as the PsaD I subunit of photosystem I. The exact mechanism of PsaD I conferring the resistance for blister blight in tea needs to be further investigated.

中文翻译：

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茶树（L）EST073基序编码蛋白的计算机结构同源性建模。

茶 (Camellia sinensis (L). O. Kuntze) 被称为最古老的、温和刺激的含咖啡因的非酒精饮料。南亚茶业的主要威胁之一是由真菌 Exobasidium v​​exans Masse 引起的水疱叶疫病 (BB)。SSR DNA 标记 EST SSR 073 被用作分子标记来标记茶的水疱疫病抗病性状。氨基酸序列来源于与 BB 敏感 (TRI 2023) 和 BB 抗性 (TRI 2043) 品种的 EST SSR 073 相关的 cDNA 序列。已经尝试使用多种生物信息学工具（例如 ORF finder、ExPasy ProtParam 工具、modeler V 9.17、Rampage server、UCSF- Chimera 和 HADDOCK 对接服务器。使用 BB 抗性 TRI 2043 和 BB 敏感 TRI 2023 茶品种的氨基酸序列分析了 EST SSR 073 编码蛋白的一级、二级和三级结构。两种栽培品种的编码氨基酸序列均与豌豆光系统I亚基蛋白（PsaD I）同源。预测的蛋白质 3D 结构经过验证并被认为是可接受的整体立体化学质量。BB抗性蛋白显示CT重复延伸并且不涉及PsaD I亚基的拓扑结构。BB 抗性的 C 末端截断导致在建模的三维蛋白质结构中形成与 PsaD I 和光系统 I 的其他亚基相互作用的氢键。Camellia sinensis EST 073 SSR 基序编码蛋白被鉴定为光系统 I 的 PsaD I 亚基。