本研究深入分析了在不同氮依赖黄瓜品种的叶片中CsGS1相对表达模式，并对CsGS1蛋白进行亚细胞定位。结果表明，低氮依赖品种D0328在叶片中特异性地高表达CsGS1，而高氮依赖品种D0422的叶片、茎和根中CsGS1的表达量没有明显差异。GS1蛋白定位于细胞质上，为细胞质蛋白。进一步将CsGS1转化到两个黄瓜品种D0328和D0422中，过量表达CsGS1可显著提高黄瓜植株的光合参数、植株鲜重、株高、根长、叶绿素b含量、植株总氮量以及GS活性等指标，反义表达CsGS1使这些指标水平显著降低。黄瓜CsGS1能够响应低氮胁迫，提高黄瓜植株对低氮的耐受性，因此CsGS1的高效表达可以作为提高黄瓜氮素利用效率的潜在育种目标。

Propamocarb is an agricultural chemical that has been widely used to protect cucumber plants from downy mildew. To understand the mechanisms of cucumber defense responses to propamocarb, we investigated the physiological and proteomic responses of the cucumber line D0351 with propamocarb application. We found that after treatment with propamocarb, the activities of detoxifying enzymes (glutathione reductase, GR; glutathione S-tramsferase, GST) and soluble sugar content of cucumber fruit were significantly increased, but malonaldehyde (MDA) content was significantly reduced. To identify components of propamocarb responsive signaling, we compared the high resolution two-dimensional gel electrophoresis (2-DE) protein profiles of control and propamocarb-treated fruits, and identified 18 differentially expressed (13 up-regulated and 5 down-regulated) proteins induced by propamocarb which were determined by matrix-assisted laser desorption/ionization timeof- flight mass spectrometry (MALDI-TOF-MS). The majority of the proteins had functions related to detoxication, energy and transport, protein biosynthesis, regulating reactions and defending against stresses. A real-time quantitative reverse transcriptional-polymerase chain reaction (qRT-PCR) was used to compare transcript and protein accumulation patterns for 18 candidate proteins, and the expression of 14 was consistent at both transcript and protein levels. The responses of cucumber proteome to propamocarb seemed complex; the identified proteins may play an important role in regulating adaptation activities following exposure to propamocarb. Data presented herein may shed light on understanding cucumber fruit defense responses under propamocarb treatment.