昆虫中肠液在食物消化与解毒过程中发挥重要作用，为了明确稻纵卷叶螟中肠液对Bt蛋白潜在降解能力，本文利用蛋白酶抑制剂处理研究了稻纵卷叶螟中肠液酶活特性和中肠液对Bt蛋白（Cry2A，Cry1C，Cry1Aa和Cry1Ac）的降解能力。PMSF、TLCK、Pepstatin A和Leupeptin显著抑制稻纵卷叶螟中肠总蛋白酶活性；PMSF对胰凝乳蛋白酶活性有较强的抑制作用；EDTA、PMSF、TPCK、TLCK和E-64对胰蛋白酶活性有较强的抑制作用。EDTA对稻纵卷叶螟降解Cry2A的能力具有明显的抑制作用；稻纵卷叶螟对Cry1C和Cry1Aa的降解能力不同程度地受EDTA、PMSF、TPCK、TLCK抑制；稻纵卷叶螟对Cry1Ac降解能力不同程度地受EDTA、PMSF、TPCK、TLCK、E64抑制。研究结果表明，一些蛋白酶抑制剂可以抑制稻纵卷叶螟中肠蛋白酶活性，降低昆虫降解Bt蛋白的能力。本文研究结果有助于今后开发基于蛋白酶抑制剂的害虫防控新技术。

Received  29 September, 2017    Accepted  11 February, 2018

Dwarf mutants are the crucial resources for molecular biology research and rice breeding.  Here, a rice mutant, dwarf and deformed flower3 (ddf3), was identified in tissue culture of Oryza sativa cv. Dongjin.  Compared with wild type, the ddf3mutant exhibited severe dwarfism, a greater number of tillers and significantly decreased fertility.  In addition, leaf length, panicle length, and grain length, were significantly shorter.  All internodes of ddf3were shorter than those of wild type, and histological analysis revealed that internode cell elongation was significantly inhibited in ddf3.  In the ddf3mutant, pollen activity was significantly decreased, and the development of most stigmas was abnormal.  Genetic analysis indicated that the ddf3mutant phenotypes are controlled by a single or tightly linked nuclear genes.  Using an F₂ mapping population generated from a cross between ddf3and Yangdao 6 (9311), the DDF3 gene was mapped to a 45.21-kb region between insertion-deletion (InDel) markers M15 and M16 on the long arm of chromosome 7.  Sequencing revealed a 13.98-kb-deletion in this region in the ddf3 mutant genome that resulted in the complete or partial deletion of ZF (DHHC type zinc finger protein), EP (expressed protein), and FH2 (actin-binding FH2 domain-containing protein) genes.  Quantitative RT-PCR analyses revealed that in wild type, the transcript levels of FH2 were almost the same in all organs, while ZF was mainly expressed in the panicle, and no expression of EP was detected in any organ.  Based on these results, ZF and FH2 could be potential DDF3 candidate genes involved in the regulation of rice morphology and flower organ development.  Our work has laid the foundation for future functional analysis of these candidate genes and has provided a profitable gene resource for rice breeding for increased fertility in the future. 

    Reference genes, stably expressing in different tissues and cells, are commonly used as the references in expression analysis. Selecting the optimum reference gene is crucial to the success of experiments. In this study, the expression stabilities of nine common reference genes, including ACT2, 18S rRNA, APRT, EF-1α, RNA POL II, TUBα, TUBβ, GAPDH and TLF of Agropyron mongolicum, were studied under drought condition. Among them, 18S rRNA was found to be the most optimum reference gene under drought stress by the analyzing of geNorm and NormFinder software. Quantitative expression levels of P5CS using 18S rRNA as the reference gene, and proline contents under drought stress in A. mongolicum were further operated, and we found the expression level of P5CS gene and proline content had a significantly positive relationship (R2=0.7763, P<0.05). This study established and validated 18S rRNA as the reference genes in A. mongolicum under drought stress, providing a powerful tool for the quantitative expression analysis of drought genes in A. mongolicum.

Skin grafting has been used as one of the most reliable tests to determine the genetic stability of laboratory animal such as mice and rats inbred line, but no identification of swine inbred lines by skin grafting has been reported. At present, Wuzhishan miniature pig (WZSP) inbred line has acquired the F24 individuals in China. In order to verify whether WZSP inbred line had been cultivated successfully, allogeneic skin grafts and related research were performed on F20 individuals of WZSP inbreeding population, compared with a control group of autologous transplantation. We observed the transplant recipients’ wounds, detected peripheral blood-related indicators interleukin-2, 4 and 10, CD4+ and CD8+ lymphocytes, and conducted hematoxylin-eosin (HE) and Masson’s staining of skin to judge whether the immune rejection reactions occurred within 28 days after transplantation. Chr. 7 genomic heterozygosity of 48 WZSP individuals from F20 to F22 was analyzed by high-density single nucleotide polymorphism (SNP) chips (60 000 SNPs). The result showed that there were no significant differences in graft skin, the plasma interleukin-2, 4, 10, CD4+ and CD8+, HE and Masson’s staining results between the allograft and autograft groups, and no immune rejection occurred on the allograft group. We found that 11 genes in Chr. 7 of major histocompatibility complex (MHC) I and MHC II were homozygous which confirmed that immune antibody of the allograft and autograft groups were highly identical and also provided a theoretical basis to no immune rejection occurred on the allograft in the inbred WZSP. The result proved that the WZSP inbred line had been cultivated successfully for the first time in the world. The test methods also provide a scientific basis for the identification of swine and mammal inbred lines.

Drought stress is one of the major factors affecting in wheat yield and grain quality. In order to investigate how drought stress might influence wheat quality during grain filling, three wheat cultivars Gaocheng 8901, Jagger and Nongda 3406 were subjected to drought stress during the grain filling stage. Neither globulin and glutenin, nor the relative percentage of amylose significantly changed following drought treatments, whereas albumin and gliadin concentrations did. The SDS-sedimentation, which has a strong linear correlation with wheat baking quality was markedly decreased following drought stress. These results indicated that drought had an adverse effect on wheat quality. In order to investigate the protein complexes in the wheat flour, the data from native PAGE and SDS-PAGE were combined and a total of 14 spots were successfully identified, and of these eight protein types were determined to be potential complex forming proteins.

This paper estimates a stochastic frontier function using a panel data set that includes 4 961 farmer households for the period of 2005-2009 to decompose the growth of grain production and the total factor productivity (TFP) growth at the farmer level. The empirical results show that the major contributor to the grain output growth for farmers is input growth and that its average contribution accounts for 60.92% of farmer’s grain production growth in the period of 2006-2009, whereas the average contributions sourced from TFP growth and residuals are only 17.30 and 21.78%, respectively. The growth of intermediate inputs is a top contributor with an average contribution of 44.46%, followed by the planted area (18.16%), investment in fixed assets (1.05%), and labor input (-2.75%), indicating that the contribution from the farmer’s input growth is mainly due to the growth of intermediate inputs and that the decline in labor inputs has become an obstacle for farmers in seeking grain output growth. Among the elements consisting of TFP growth, the contribution of technical progress is the largest (32.04%), followed by grain subsidies (8.55%), the average monthly temperature (4.26%), the average monthly precipitation (-0.88%), the adjusted scale effect (-5.66%), and growth in technical efficiency (-21.01%). In general, the contribution of climate factors and agricultural policy factor are positive and significant.

Cuscuta campestris, a dodder, can parasitize and suppress a scrambling herbaceous to semi-woody perennial vine, Mikania micrantha, one of the most destructive weeds in the world. To assess the effects of the mixed residue of C. campestris and M. micrantha on the subsequent plant community, we conducted a one-year experiment on the germination and seedling growth of subsequent plant community after the application of C. campestris. Seven treatments of varying proportions of C. campestris and M. micrantha residue on 21 subject trees and shrubs, which were commonly found in South China, resulted in a germination rate of 35.3% for all 8715 seeds from 18 species, ranging from 5.7 to 81.9%; the remaining 3 species failed to germinate. ANOVA analysis showed that the residue did not affect the germination, growth, or mortality of the trees and shrubs. The germinated C. campestris seeds from the residue coiled the seedlings of most of the species, but less than 4% host death caused by C. campestris. In addition, the residue did not affect the germination of the herbaceous seedlings originating from the loam, and the similarity coefficients of the germinated seedlings between the treatments were very high. These results suggested that the residue had no negative impact on the germination and early seedling stages of the tree, shrub and grass species of the subsequent plant community. The use of C. campestris residue had a positive effect on the growth of M. micrantha, but it did not change the trend of M. micrantha being suppressed because re-parasitization occurred soon after the growth restarted. No negative effect was detected on the other species as a result of the parasitization of C. campestris or by the use of the mixed residue. This suggests that C. campestris is likely to be an effective and promising ecologically safe native herbaceous agent for controlling M. micrantha.