Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Apdo Correos 164, 30100 Espinardo (Murcia), Spain.
Adv Virus Res. 2009;75:119-59. doi: 10.1016/S0065-3527(09)07504-6. Epub 2010 Jan 13.
About half of the approximately 200 known virus resistance genes in plants are recessively inherited, suggesting that this form of resistance is more common for viruses than for other plant pathogens. The use of such genes is therefore a very important tool in breeding programs to control plant diseases caused by pathogenic viruses. Over the last few years, the detailed analysis of many host/virus combinations has substantially advanced basic research on recessive resistance mechanisms in crop species. This type of resistance is preferentially expressed in protoplasts and inoculated leaves, influencing virus multiplication at the single-cell level as well as cell-to-cell movement. Importantly, a growing number of recessive resistance genes have been cloned from crop species, and further analysis has shown them all to encode translation initiation factors of the 4E (eIF4E) and 4G (eIF4G) families. However, not all of the loss-of-susceptibility mutants identified in collections of mutagenized hosts correspond to mutations in eIF4E and eIF4G. This, together with other supporting data, suggests that more extensive characterization of the natural variability of resistance genes may identify new host factors conferring recessive resistance. In this chapter, we discuss the recent work carried out to characterize loss-of-susceptibility and recessive resistance genes in crop and model species. We review actual and probable recessive resistance mechanisms, and bring the chapter to a close by summarizing the current state-of-the-art and offering perspectives on potential future developments.
大约 200 种已知的植物病毒抗性基因中，约有一半是隐性遗传的，这表明这种形式的抗性在病毒中比在其他植物病原体中更为常见。因此，利用这些基因是控制由致病病毒引起的植物病害的育种计划中的一个非常重要的工具。在过去的几年中，对许多宿主/病毒组合的详细分析极大地推动了作物物种隐性抗性机制的基础研究。这种类型的抗性优先在原生质体和接种的叶片中表达，影响病毒在单细胞水平以及细胞间运动中的增殖。重要的是，越来越多的隐性抗性基因已从作物物种中克隆出来，进一步的分析表明，它们都编码 4E（eIF4E）和 4G（eIF4G）家族的翻译起始因子。然而，在诱变宿主的突变体收集物中鉴定的敏感性丧失突变体并非都对应于 eIF4E 和 eIF4G 的突变。这一点，以及其他支持性数据，表明对抗性基因自然变异性的更广泛特征描述可能会识别出赋予隐性抗性的新的宿主因子。在本章中，我们讨论了在作物和模式物种中表征易感性丧失和隐性抗性基因的最新工作。我们回顾了实际和可能的隐性抗性机制，并通过总结当前的最新技术状况并提供对潜在未来发展的展望来结束本章。
