Moon David H, Salvatierra Guillermo R, Caldas Danielle G G, Gallo de Carvalho Mayra C C, Carneiro Raphael T, Franceschini Lívia M, Oda Shinitiro, Labate Carlos A
Laboratório Max Feffer de Genética de Plantas, Departamento de Genética, Escola Superior de Agricultura 'Luiz de Queiroz', Universidade de São Paulo, Piracicaba-SP, Brasil.
Suzano Papel e Celulose, Av. Brigadeiro Faria Lima n° 1355, 8° andar, CEP 01452-919, São Paulo-SP, Brasil.
Funct Plant Biol. 2007 Dec;34(11):1010-1018. doi: 10.1071/FP07094.
Eucalyptus grandis Hill ex Maiden and its hybrids are commonly planted by the Brazilian pulp and paper industry, but they are the most susceptible to the neotropical rust disease caused by Puccinia psidii Winter. In an initial attempt to understand the mechanisms of resistance, we constructed two contrasting Serial Analysis of Gene Expression (SAGE) libraries using susceptible and resistant individuals from a segregating half-sibling E. grandis population. Using the Z-test we identified tags differentially expressed between the libraries, preferentially 239 in the susceptible and 232 in the resistant type individuals. Using public (Expressed Sequence Tags) EST databases, 40 of the susceptible and 70 of the resistant tags matched ESTs and were annotated. By comparing the type of genes and their expression levels, distinct differences between the libraries were observed. Susceptible plants showed gene expression linked to leaf senescence, generalised stress responses and detoxification, and are apparently incapable of inducing a competent host defence response. On the other hand, resistant plants showed genes upregulated for cellular polarisation, cytoskeleton restructuring, vesicle transport, and cellulose and lignin biosynthesis. In the resistant individuals, evidence for systemic resistance, anti-oxidative responses and a hypersensitive response was also observed, although no R gene was identified.
巨桉（Eucalyptus grandis Hill ex Maiden）及其杂交种是巴西制浆造纸工业常用的种植树种，但它们对由冬孢锈菌（Puccinia psidii Winter）引起的新热带锈病最为敏感。在初步尝试了解其抗性机制时，我们利用一个分离的半同胞巨桉群体中的感病和抗病个体构建了两个对比的基因表达序列分析（SAGE）文库。使用Z检验，我们鉴定了文库之间差异表达的标签，其中感病类型个体中优先鉴定出239个，抗病类型个体中优先鉴定出232个。利用公共的（表达序列标签）EST数据库，感病标签中有40个与EST匹配并得到注释，抗病标签中有70个与EST匹配并得到注释。通过比较基因类型及其表达水平，观察到文库之间存在明显差异。感病植株表现出与叶片衰老、普遍胁迫反应和解毒相关的基因表达，显然无法诱导有效的宿主防御反应。另一方面，抗病植株表现出细胞极化、细胞骨架重组、囊泡运输以及纤维素和木质素生物合成相关基因上调。在抗病个体中，也观察到系统抗性、抗氧化反应和过敏反应的证据，尽管未鉴定到R基因。
