Wang Xiaoli, Li Xiaodong, Zhang Sheng, Korpelainen Helena, Li Chunyang
Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China Guizhou Institute of Prataculture, Guizhou Academy of Agriculture Science, Guiyang 550006, Guizhou, China.
Guizhou Institute of Prataculture, Guizhou Academy of Agriculture Science, Guiyang 550006, Guizhou, China.
Tree Physiol. 2016 May;36(5):628-42. doi: 10.1093/treephys/tpw019. Epub 2016 Apr 19.
The aim of this study was to reveal mechanisms responsible for nitrogen (N) stress in two contrasting Populus clones. Leaves of Nanlin 1388 (N stress-insensitive clone hybrids of Populus deltoides Bart.CV. × Populus euramericana (Dode) Guineir CV) and Nanlin 895 (N stress-sensitive clone hybrids of Populus deltoides Bart.CV. × Populus euramericana (Dode) Guineir CV) were harvested and analyzed. Different responses visible in photosynthesis, N and carbon contents, physiological traits, and chlorophyll were observed. The Solexa/Illumina's digital gene expression system was used to investigate differentially expressed miRNAs and mRNAs under N stress. Target profiling, and biological network and function analyses were also performed. Randomly selected mRNAs and miRNAs were validated by quantitative reverse transcription polymerase chain reaction. In all, 110 Nanlin 1388 and 122 Nanlin 895 miRNAs were differentially expressed, among which 34 and 23 miRNAs were newly found in the two clones, respectively. Under N stress, a total of 329 and 98 mRNAs were regulated in N stress-insensitive and -sensitive clones, respectively. Notably, the miR396 family and its regulated mRNAs were altered in both clones under N stress, while miR646 was regulated only in the N stress-insensitive clone (Nanlin 1388), and miR156, miR319 and miR393 in the N stress-sensitive clone (Nanlin 895). Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses also proved several clone-specific functions and pathways. These findings may be significant for understanding the genetic responses of Populus to N stress.
本研究的目的是揭示两个对比杨树无性系中氮（N）胁迫的作用机制。采集并分析了南林1388（美洲黑杨×欧美杨杂种无性系，对N胁迫不敏感）和南林895（美洲黑杨×欧美杨杂种无性系，对N胁迫敏感）的叶片。观察到光合作用、N和碳含量、生理特性及叶绿素方面存在不同反应。利用Solexa/Illumina数字基因表达系统研究N胁迫下差异表达的miRNA和mRNA。还进行了靶标分析以及生物网络和功能分析。通过定量逆转录聚合酶链反应对随机选择的mRNA和miRNA进行验证。总共分别有110个南林1388和122个南林895的miRNA差异表达，其中两个无性系分别新发现了34个和23个miRNA。在N胁迫下，对N胁迫不敏感和敏感的无性系分别有329个和98个mRNA受到调控。值得注意的是，N胁迫下两个无性系中miR396家族及其调控的mRNA均发生改变，而miR646仅在对N胁迫不敏感的无性系（南林1388）中受到调控，miR156、miR319和miR393在对N胁迫敏感的无性系（南林895）中受到调控。基因本体论和京都基因与基因组百科全书分析也证实了一些无性系特异性的功能和途径。这些发现可能对理解杨树对N胁迫的遗传反应具有重要意义。
