Department of Horticulture, Auburn University, AL 36849, USA.
J Exp Bot. 2010 Jun;61(6):1635-42. doi: 10.1093/jxb/erq031. Epub 2010 Feb 24.
A full-length drought-responsive gene Ccrboh, encoding the respiratory burst oxidase homologue (rboh), was cloned in Citrullus colocynthis, a very drought-tolerant cucurbit species. The robh protein, also named NADPH oxidase, is conserved in plants and animals, and functions in the production of reactive oxygen species (ROS). The Ccrboh gene accumulated in a tissue-specific pattern when C. colocynthis was treated with PEG, abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), or NaCl, while the homologous rboh gene did not show any change in C. lanatus var. lanatus, cultivated watermelon, during drought. Grafting experiments were conducted using C. colocynthis or C. lanatus as the rootstock or scion. Results showed that the rootstock significantly affects gene expression in the scion, and some signals might be transported from the root to the shoot. Ccrboh in C. colocynthis was found to function early during plant development, reaching high mRNA transcript levels 3 d after germination. The subcellular location of Ccrboh was investigated by transient expression of the 35S::Ccrboh::GFP fusion construct in protoplasts. The result confirmed that Ccrboh is a transmembrane protein. Our data suggest that Ccrboh might be functionally important during the acclimation of plants to stress and also in plant development. It holds great promise for improving drought tolerance of other cucurbit species.
克隆了一个全长抗旱基因 Ccrboh，该基因编码呼吸爆发氧化酶同源物（rboh），在一种非常耐旱的葫芦科植物苦瓜中。robh 蛋白，也称为 NADPH 氧化酶，在植物和动物中保守，其功能是产生活性氧物种（ROS）。PEG、脱落酸（ABA）、水杨酸（SA）、茉莉酸（JA）或 NaCl 处理苦瓜时，Ccrboh 基因在组织中特异性积累，而同源 rboh 基因在栽培西瓜苦瓜中没有任何变化。使用苦瓜或西瓜作为砧木或接穗进行嫁接实验。结果表明，砧木显著影响接穗中的基因表达，一些信号可能从根部传递到茎部。苦瓜中的 Ccrboh 在植物发育早期发挥作用，在萌发后 3 天达到高水平的 mRNA 转录水平。通过在原生质体中瞬时表达 35S::Ccrboh::GFP 融合构建体研究了 Ccrboh 的亚细胞定位。结果证实 Ccrboh 是一种跨膜蛋白。我们的数据表明，Ccrboh 在植物适应胁迫和发育过程中可能具有重要的功能。它有望提高其他葫芦科植物的耐旱性。
