To achieve the dual goals of high yield and good quality with low environmental costs, slow-release fertilizer (SRF) has been widely used in lotus cultivation as new type of fertilizer instead of traditional nitrogen fertilizer.  However, the optimal amount of SRF and how it would promote lotus rhizome quality remain unclear.  This study was designed to investigate the photosynthetic characteristics and the synthesis, accumulation, and physicochemical properties of lotus rhizome starches under six SRF levels (CK, S1, S2, S3, S4, and S5).  Compared with CK (0 kg ha^–1), the net photosynthetic rate (P_n) and SPAD values of leaves remained at higher levels under SRF treatment.  Further research showed that SRF increased the lotus rhizome yield, the contents of amylose, amylopectin, and total starch, and the number of starch granules.  Among the six SRF levels, S3 (1 035 kg ha^–1) showed the greatest difference from CK and produced the highest levels.  With the increasing SRF levels, the peak, hot and final viscosities decreased at first and then increased, but the setback viscosity and pasting temperature increased.  In order to interpret these changes at the molecular level, the activities of key enzymes and relative expression levels of starch accumulation related genes were analyzed.  Each of these parameters also increased under SRF treatment, especially under the S3 treatment.  The results of this study show that SRF, especially S3 (1 035 kg ha^–1), is a suitable fertilizer option for lotus planting which can improve lotus rhizome quality by affecting starch accumulations related enzymes and genes.  These results will be useful for SRF application to high-quality lotus rhizome production with low environmental costs.

Phosphomannose isomerase (PMI) encoding gene manA is a desirable selective marker in transgenic research. Understanding of its expression patterns in transgenic plant and establishing highly sensitive detection method based on immunoassay have great impacts on the application of PMI. In this study, PMI-specific monoclonal antibodies were generated using recombinant protein as immunogen, and could be used in Western blot to detect as little as 0.5 ng His-tagged PMI protein or rice expressed PMI protein in sample accounted for 0.4% of single rice grain (about 0.08 mg). PMI protein driven by CaMV-35S promoter was detected in dozens of tested tissues, including root, stem, leaf, panicle, and seed at all developmental stages during rice growing, and PMI protein accounted for about 0.036% of total protein in the leaves at seedling stage. The established method potentially can be used to monitor PMI protein in rice grains.

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.