Zhu Yanmin, Shao Jonathan, Zhou Zhe, Davis Robert E
USDA-ARS, Tree Fruit Research Laboratory, Wenatchee, WA 98801, USA.
USDA-ARS, Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA.
Int J Plant Genomics. 2017;2017:8950746. doi: 10.1155/2017/8950746. Epub 2017 Mar 30.
Two apple rootstock genotypes G.935 and B.9 were recently demonstrated to exhibit distinct resistance responses following infection by As part of an effort to elucidate the genetic regulation of apple root resistance to soilborne pathogens, preinoculation transcriptome variations in roots of these two apple rootstock genotypes are hypothesized to contribute to the observed disease resistance phenotypes. Results from current comparative transcriptome analysis demonstrated elevated transcript abundance for many genes which function in a system-wide defense response in the root tissue of the resistant genotype of G.935 in comparison with susceptible B.9. Based on the functional annotation, these differentially expressed genes encode proteins that function in several tiers of defense responses, such as pattern recognition receptors for pathogen detection and subsequent signal transduction, defense hormone biosynthesis and signaling, transcription factors with known roles in defense activation, enzymes of secondary metabolism, and various classes of resistance proteins. The data set suggested a more poised status, which is ready to defend pathogen infection, in the root tissues of resistant genotype of G.935, compared to the susceptible B.9. The significance of preformed defense in the absence of a pathogen toward overall resistance phenotypes in apple root and the potential fitness cost due to the overactivated defense system were discussed.
最近有研究表明，两种苹果砧木基因型G.935和B.9在受到[病原体名称未给出]感染后表现出不同的抗性反应。作为阐明苹果根系对土传病原体抗性遗传调控研究的一部分，推测这两种苹果砧木基因型根系接种前的转录组变化有助于解释观察到的抗病表型。目前的比较转录组分析结果表明，与易感的B.9相比，抗性基因型G.935根系中许多参与全系统防御反应的基因转录丰度升高。基于功能注释，这些差异表达基因编码的蛋白质在多层防御反应中发挥作用，如用于病原体检测和后续信号转导的模式识别受体、防御激素生物合成和信号传导、在防御激活中具有已知作用的转录因子、次生代谢酶以及各类抗性蛋白。数据集表明，与易感的B.9相比，抗性基因型G.935的根系处于更易于防御病原体感染的状态。文中还讨论了在无病原体情况下预先形成的防御对苹果根系整体抗性表型的意义，以及过度激活的防御系统可能带来的潜在适合度代价。
