Using a genomic clone encoding a rice lipid transfer protein, LTP1, we analysed the activity of the 5' region of the Ltp1 gene in transgenic rice (Oryza sativa L.) during plant development and under pathogen attack. The -1176/+13, -556/+13 and -284/+13 regions of the promoter were fused upstream from the uidA reporter gene and nos 3' polyadenylation signal, resulting in the pdelta1176Gus, pdelta556Gus and pdelta284Gus constructs which were transferred to rice by microprojectile bombardment. Histochemical and fluorometric GUS assays and in situ detection of uidA transcripts in transgenic homozygous lines harbouring the pdelta1176Gus construct demonstrated that the Ltp1 promoter is preferentially active in aerial vegetative and reproductive organs and that both specificity and level of expression are regulated during organ development. In leaf sheath, GUS activity which is initially strictly localized in the epidermis of growing tissue, becomes restricted to the vascular system in mature tissues. In expanded leaf blade, expression of the uidA gene was restricted to the cutting level suggesting inducibility by wounding. Strong activity was detected in lemma and palea, sterile glumes, and immature anther walls and microspores but not in female reproductive organs. No GUS activity was detected during seed embryo maturation whereas the uidA gene was strongly expressed at early stages of somatic embryogenesis in scutellum tissue. The Ltp1 transcripts were found to strongly accumulate in response to inoculation with the fungal agent of the blast disease, Magnaporthe grisea, in two rice cultivars exhibiting compatible or incompatible host-pathogen interactions. Analysis of pdelta1176Gus leaf samples inoculated with the blast fungus demonstrated that the Ltp1 promoter is induced in all cell types of tissues surrounding the lesion and notably in stomata guard cells. In plants harbouring the Ltp1 promoter deletion construct pdelta556Gus, activity was solely detected in the vascular system of mature leaves whereas no uidA gene expression was observed in pdelta284Gus plants. These observations are consistent with the proposed role of LTP1 in strenghtening of structural barriers and organ protection against mechanical disruption and pathogen attack.

中文翻译：

---

通过病原体攻击和水稻Ltp1基因的发育调控诱导。

使用编码水稻脂质转移蛋白LTP1的基因组克隆，我们分析了转基因水稻（Oryza sativa L.）在植物发育过程中和病原体侵袭下Ltp1基因5'区域的活性。启动子的-1176 / + 13，-556 / + 13和-284 / + 13区在uidA报告基因上游与nos 3'聚腺苷酸化信号融合，产生pdelta1176Gus，pdelta556Gus和pdelta284Gus构建体，并将其转移至水稻受到微粒轰击。组织化学和荧光GUS测定法以及在原位检测包含pdelta1176Gus构建体的转基因纯合株中uidA转录物的研究表明，Ltp1启动子在空中无性和生殖器官中优先活跃，并且在器官发育过程中，特异性和表达水平均受到调控。在叶鞘中，GUS活性最初严格定位在生长组织的表皮中，但已限于成熟组织的血管系统。在膨胀的叶片中，uidA基因的表达被限制在切割水平，表明伤口可诱导。在外和内脏，不育颖片，不成熟的花药壁和小孢子中检测到强活性，但在雌性生殖器官中未检测到强活性。在种子胚胎成熟过程中未检测到GUS活性，而uidA基因在盾片体细胞胚发生的早期强烈表达。Ltp1转录本发现在稻瘟病真菌Magnaporthe grisea的接种后，在两个表现出相容或不相容宿主-病原体相互作用的水稻品种中强烈积累。接种了原始真菌的pdelta1176Gus叶样品的分析表明，Ltp1启动子在病变周围组织的所有细胞类型中都有明显的诱导，尤其是在气孔保卫细胞中。在携带Ltp1启动子缺失构建体pdelta556Gus的植物中，仅在成熟叶片的血管系统中检测到活性，而在pdelta284Gus植物中未观察到uidA基因表达。这些观察结果与LTP1在加强结构性屏障以及抵抗机械破坏和病原体侵袭的器官保护中所提出的作用相一致。仅在成熟叶片的血管系统中检测到活性，而在pdelta284Gus植物中未观察到uidA基因表达。这些观察结果与LTP1在加强结构性屏障和抵抗机械破坏和病原体侵袭的器官保护中的拟议作用一致。仅在成熟叶片的血管系统中检测到活性，而在pdelta284Gus植物中未观察到uidA基因表达。这些观察结果与LTP1在加强结构性屏障和抵抗机械破坏和病原体侵袭的器官保护中的拟议作用一致。