剪接因子Prp6是剪接三聚体U4/U6.U5中的关键蛋白，在人类细胞和裂殖酵母中，它也是调控前体mRNA剪接的激酶Prp4的底物。前期研究发现引起小麦赤霉病的禾谷镰孢菌FgPrp6蛋白序列的自发突变（角突变）可以部分恢复Fgprp4突变体的表型。禾谷镰孢菌FgPrp4激酶调控剪接效率，其敲除突变体生长缓慢且丧失产孢、有性生殖和致病能力。为了进一步探索FgPrp6与激酶FgPrp4的关系，本研究通过对随机收集的240株Fgprp4角突变子的FgPRP6基因进行PCR产物测序，鉴定了20个角变子中的12个突变。其中3个突变位点在FgPrp6蛋白的N端结构域和HAT重复结构域的连接处，7个突变位点位于前两个HAT重复区域。对角变子的转录组数据分析结果表明FgPrp6上不同位置的角突变对Fgprp4突变体前体mRNA剪接缺陷的恢复程度不同。通过在野生型菌株中转入FgPrp6^E308K-GFP载体或在内源FgPrp6上原位引入R230H突变，同时敲除FgPRP4的方法证实FgPrp6上的E308K或R230H都可以抑制Fgprp4。本研究利用co-IP和BiFc的方法证明禾谷镰孢菌的FgPrp6和激酶FgPrp4可以在体内互作，并进一步利用磷酸化抗体检测体内FgPrp6磷酸化水平的方法实验证明FgPrp6为FgPrp4的底物。通过将FgPrp6上保守的Prp4磷酸化位点和预测的磷酸化位点突变为A的方法验证这些位点的功能，结果表明T261，T219&T221和T199&T200对FgPrp6在菌落生长和有性生殖中的功能无关紧要，但是对其在侵染植物阶段的功能至关重要。扫描电镜和共聚焦显微镜观察发现它们主要在禾谷镰孢菌侵染生长，如侵染垫的形成和在植物细胞间的扩展中发挥作用。通过对野生型禾谷镰孢菌、Fgprp6/FgPRP6^Δ199-221-GFP或Fgprp6/FgPRP6^Δ250-262-GFP侵染三天的小麦麸片的转录组数据分析禾谷镰孢菌的前体mRNA剪接缺陷发现Fgprp6/FgPRP6^Δ199-221-GFP和Fgprp6/FgPRP6^Δ250-262-GFP菌株中各有28%和35%的内含子剪接具有缺陷，推测这种剪接缺陷是突变体侵染生长缺陷的原因。该研究为将来进一步解析禾谷镰孢菌前体mRNA剪接调控及剪接与致病性的关系奠定了基础。

Plants glycerol-3-phosphate dehydrogenase (GPDH) catalyzes the formation of glycerol-3-phosphate, and plays an essential role in glycerolipid metabolism and stress responses. In the present study, the knock-out mutants of cytosolic GPDH (AtGPDHc2) and wild-type Arabidopsis plants were treated with 0, 50, 100, and 150 mmol L^–1 NaCl to reveal the effects of AtGPDHc2 deficiency on salinity stress responses. The fluctuation in redox status, reactive oxygen species (ROS) and antioxidant enzymes as well as the transcripts of genes involved in the relevant processes were measured. In the presence of 100 and 150 mmol L^–1 NaCl treatments, AtGPDHc2-deficient plants exhibited a pronounced reduction in germination rate, fresh weight, root length, and overall biomass. Furthermore, loss of AtGPDHc2 resulted in a significant perturbation in cellular redox state (NADH/NAD+ and AsA/DHA) and consequent elevation of ROS and thiobarbituric acid-reactive substances (TBARS) content. The elevated ROS level triggered substantial increases in ROS-scavenging enzymes activities, and the up-regulated transcripts of the genes (CSD1, sAPX and PER33) encoding the antioxidant enzymes were also observed. In addition, the transcript levels of COX15, AOX1A and GLDH in gpdhc2 mutants decreased in comparison to wild-type plants, which demonstrated that the deficiency of AtGPDHc2 might also has impact on mitochondrial respiration under salt stress. Together, this work provides some new evidences on illustrating the roles of AtGPDHc2 playing in response to salinity stress by regulating cellular redox homeostasis, ROS metabolism and mitochondrial respiration.

Xanthomonas oryzea pv. oryzae (Xoo) is the causal agent of bacterial blight of rice, which is a significant threat to many of rice-growing regions. The type III secretion system (T3SS) is an essential virulence factor in Xoo. Expression of the T3SS is often induced in the host environment or in hrp-inducing medium but is repressed in nutrient-rich medium. The elucidation of molecular mechanism underlying induction of T3SS genes expression is a very important step to lift the veil on global virulence regulation network in Xoo. Thus, an efficient and reliable genetic tool system is required for detection of the T3SS proteins. In this study, we constructed a protein expression vector pH3-flag based on the backbone of pHM1, a most widely used vector in Xoo strains, especially a model strain PXO99^A. This vector contains a synthesized MCS-FLAG cassette that consists of a multiple cloning site (MCS), containing a modified pUC18 polylinker, and Flag as a C-terminal tag. The cassette is flanked by transcriptional terminators to eliminate interference of external transcription enabling detection of accurate protein expression. We evaluated the potential of this expression vector as T3SS proteins detection system and demonstrated it is applicable in the study of T3SS genes expression regulation in Xoo. This improved expression system could be very effectively used as a molecular tool in understanding some virulence genes expression and regulation in Xoo and other Xanthomonas spp.

Mechanical transplanting with carpet seedlings (MC) and mechanical direct seeding (MD) are newly developed planting methods, which increase in popularity and planted area each year. Knowing the difference for yield and rice quality under different planting methods is of great importance for the development of high quality and yield cultivation techniques under mechanical conditions. Therefore, three kinds of japonica rice including hybrid japonica rice, inbreed japonica rice, and soft rice were adopted as materials. And the differences in the quality of processing, appearance, cooking and eating quality, nutrition, and the rapid viscosity analyzer (RVA) profile were studied to reveal the effects of planting methods on yield and quality of different types of japonica rice. Results showed that the milled rice and head rice rates under MC was significantly higher than those under MD, and the processing quality of inbreed japonica rice was the most stable. Compared with MC, length/width ratio of rice under MD was significantly increased, and chalkiness rate, size, and degree were significantly decreased. The protein content under MD was lower than that under MC. MC showed higher peak viscosity and breakdown value than MD. The taste value was the greatest for soft rice, followed by inbreed japonica rice, and then by japonica hybrid rice, with no significant differences resulting from planting methods. Compared with MC, MD significantly improved the appearance quality, though processing quality and nutritional quality were decreased. And there was no significant difference in cooking and eating quality between MC and MD. Under different planting methods, the appearance quality of inbreed japonica rice changed the most and the processing quality was the most stable. The nutritional, cooking and eating quality of soft rice changed the least. Therefore, according to the different planting methods and market needs, selecting the appropriate rice varieties can reduce the risks in rice production and achieve good rice quality.

L-Ascorbic acid (AsA) plays an important role in plants and animals.  In plants, GDP-D-mannose pyrophosphorylase (GMP) is essential in the AsA biosynthetic pathway.  However, little is known about the genes encoding GMP in soybean and here we report genetic and functional analysis of the GmGMP1 (Glycine max GDP-D-mannose pyrophosphorylase 1) gene in this species.  GmGMP1 encoded a GDP-mannose pyrophosphorylase and exhibited higher transcript levels in the leaf than in the root, stem, flower, and seed.  Transcript of this gene was ubiquitous in the vegetative and reproductive organs, and was induced by abiotic stress and light.  Increasing expression of GmGMP1 in Arabidopsis and soybean through an overexpressing approach caused pronounced enhancement of AsA content, and was implicated in lowering the superoxide anion radical content and lipid peroxidation levels in Arabidopsis, and conferring tolerance to osmotic and high salt stresses during seed germination.  The present study represents the first systematic determination of soybean genes encoding GDP-mannose pyrophosphorylase and provides useful evidence for the functional involvement of GmGMP1 in control of AsA content and conferring tolerance to osmotic and salt stress.

Aiming at searching for plant growth promoting rhizobacteria (PGPR), a bacterium strain coded as 7016 was isolated from soybean rhizosphere and was characterized in the present study. It was identified as Burkholderia sp. based on 16S rDNA sequence analysis, as well as phenotypic and biochemical characterizations. This bacterium presented nitrogenase activity, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity and phosphate solubilizing ability; inhibited the growth of Sclerotinia sclerotiorum, Gibberella zeae and Verticillium dahliae; and produced small quantities of indole acetic acid (IAA). In green house experiments, significant increases in shoot height and weight, root length and weight, and stem diameter were observed on tomato plants in 30 d after inoculation with strain 7016. Result of 16S rDNA PCR-DGGE showed that 7016 survived in the rhizosphere of tomato seedlings. In the field experiments, Burkholderia sp. 7016 enhanced the tomato yield and significantly promoted activities of soil urease, phosphatase, sucrase, and catalase. All these results demonstrated Burkholderia sp. 7016 as a valuable PGPR and a candidate of biofertilizer.

RNA sequencing of the sensitive GH01 variety of Brassica napus L. seedling roots under 12 h of waterlogging was compared with previously published data of the ZS9 tolerant variety to unravel genetic mechanisms of waterlogging tolerance beyond natural variation. A total of 2 977 genes with similar expression patterns and 17 genes with opposite expression patterns were identified in the transcription profiles of ZS9 and GH01. An additional 1 438 genes in ZS9 and 1 861 genes in GH01 showed strain specific regulation. Analysis of the overlapped genes between ZS9 and GH01 revealed that waterlogging tolerance is determined by ability to regulate genes with similar expression patterns. Moreover, differences in both gene expression profiles and abscisic acid (ABA) contents between the two varieties suggest that ABA may play some role in waterlogging tolerance. This study identifies a subset of candidate genes for further functional analysis.

This paper studied the effects of crop insurance on agricultural output with an economic growth model. Based on Ramsey- Cass-Koopmans (RCK) model, a basic model of agriculture economic growth was developed. Extending the basic model to incorporate uncertainty and insurance mechanism, a risk model and a risk-insurance model were built to study the influences of risk and crop insurance on agricultural output. Compared with the steady states of the three models, the following results are achieved: (i) agricultural output decreases if we introduce uncertainty into the risk-free model; (ii) crop insurance promotes agriculture economic growth if insurance mechanism is introduced into the risk model; (iii) premium subsidy constantly improves agricultural output. Our contribution is that we studied the effects of crop insurance and premium subsidy from the perspective of economic growth in a dynamic framework, and proved the output promotion of crop insurance theoretically.

The importance of zinc (Zn) as a micronutrient essential for plant growth and development is becoming increasingly apparent. Much of the world’s soil is Zn-deficient, and soil-based Zn deficiency is often accompanied by Zn deficiency in human populations. MicroRNAs (miRNAs) play important roles in the regulation of plant gene expression at the level of translation. Many miRNAs involved in the modulation of heavy metal toxicity responses in plants have been identified; however, the role of miRNAs in the plant Zn deficiency response is almost completely unknown. Using high-throughput Solexa sequencing, we identified several miRNAs that respond to Zn deficiency in Brassica juncea roots. At least 21 conserved candidate miRNA families, and 101 individual members within those families, were identified in both the control and the Zn-deficient B. juncea roots. Among this, 15 miRNAs from 9 miRNA families were differentially expressed in the control and Zn-deficient plants. Of the 15 differentially expressed miRNAs, 13 were up-regulated in the Zn-deficient B. juncea roots, and only two, miR399b and miR845a, were down-regulated. Bioinformatics analysis indicated that these miRNAs were involved in modulating phytohormone response, plant growth and development, and abiotic stress responses in B. juncea roots. These data help to lay the foundation for further understanding of miRNA function in the regulation of the plant Zn deficiency response and its impact on plant growth and development.

The whitefly Bemisia tabaci has risen to international prominence since the 1980s due to the rapid spread around the globe by the two species B and Q within this species complex. The invasion of B has often been associated with the displacement of indigenous whiteflies. As the genetic structure of B. tabaci is diverse, more case studies of the competitive relationships between B and indigenous species of the whitefly species complex will help to understand further the mechanisms underlying the invasion of B. We examined the competitive interactions between B and ZHJ2, a widely distributed indigenous whitefly in Asia, on host plants with differential levels of suitability to the two species in the laboratory, and also tested the effect of insecticide application on the competitive relationships. Three species of plants were tested including cotton, a plant showing similar levels of suitability to both species, squash, a plant showing higher suitability to B than to ZHJ2, and kidney bean, a plant showing higher suitability to ZHJ2 than to B. In the case of no insecticide application, B displaced ZHJ2 on cotton, squash, and kidney bean by the 6th, 3rd and 10th generation, respectively. With the application of imidacloprid, the displacement of ZHJ2 by B on cotton occurred by the 5th generation. As the displacement progressed, the proportion of B females increased, and the proportion of ZHJ2 females decreased on cotton and squash. In contrast, on kidney bean the proportion of B females remained unchanged while that of ZHJ2 increased. These results show the strong capacity of the invasive B to displace ZHJ2, and indicate that host plants with differential levels of suitability to the two species may affect the speed but not the trend of displacement and insecticide application may accelerate the process of displacement.