在乡村旅游蓬勃发展之际，农田作画已成为吸引游客观光和提升农民收入的关键策略。然而，在我国重要的油料作物——花生中，缺少可供花生田作画使用的紫叶品种。因此，开发紫叶花生品种势在必行。甜菜碱是一种源自氨基酸酪氨酸的植物天然色素，呈现红紫色，并且具备抗氧化功能对人体健康有益。甜菜碱的生物合成途径相对简单，仅通过三个酶反应便可将酪氨酸转化为甜菜碱。RUBY基因是由编码甜菜碱合成所需的P450 加氧酶（CYP76AD1）、二羟基苯丙氨酸双加氧酶（DODA）和糖基转移酶的三个基因组成的人工开放阅读框，可利用酪氨酸合成甜菜碱。本研究采用农杆菌介导的转化方式，在 35S 启动子的驱动下，在花生中异源表达RUBY 基因。在转基因植株的愈伤组织、再生芽以及根、叶、茎、花、豆荚和种子中均观察到了紫色组织存在。与野生型植株相比，紫色叶片中转基因植株含有显著更高量级的甜菜碱。综上所述，我们成功创制出了具备观赏植物潜力的带有紫色叶片特征的花生新种质，为培育紫叶花生品种提供了理论和材料基础。此外，RUBY在花生转化过程中展现出了作为可见报告基因的潜力，可用于高效筛选转化植株。

产酶溶杆菌（Lysobacter enzymogenes）OH11分泌的热稳定性抗真菌因子HSAF具有广谱高效的抑菌活性。目前无法利用化学合成和异源表达等方法生产HSAF。OH11菌株中HSAF原始产量低，是规模化生产的主要瓶颈。从分子层面阐明HSAF生物合成的调控网络可为提升活性代谢物产量，研发绿色高效的新型生防产品奠定理论基础。本研究发现一个编码乳清酸核苷-5'-单磷酸脱羧酶（ODCase）的基因Le0752，该基因在尿嘧啶从头合成途径中催化乳清酸核苷酸（OMP）生成尿嘧啶核苷酸（UMP）。Le0752缺失突变株的HSAF产量及其发酵粗提液对辣椒疫霉（Phytophthora capsici）的皿内抑菌活性均显著降低，而用Le0752缺失突变体发酵液处理过的辣椒疫霉对本氏烟（Nicotiana benthamiana）的毒力较野生型显著提高。Le0752突变体在1/10 TSA平板上生长减缓，但蹭行运动（twitching motility）能力不受影响。qRT-PCR结果表明，Le0752缺失突变后HSAF合成关键基因lafB及其关键调控因子clp的基因表达水平显著降低，遗传学试验证明Le0752通过转录因子Clp调控lafB的转录进而影响HSAF的生物合成。生物信息学分析显示，溶杆菌属中的ODCases归于Group III类群，而与溶杆菌属亲缘关系较近的黄单胞菌属和寡养单胞菌属的ODCases归属Group I类群。基因染色体同源替换实验中，稻黄单胞菌水稻致病变种（Xanthomonas oryzae pv. oryzae）中的ODCase（pyrF）能够完全恢复Le0752缺失突变表型。本研究阐明尿嘧啶从头合成酶ODCase对HSAF合成的关键调控作用，将为改造HSAF高产菌株提供理论支撑，并拓展对细菌ODCase功能与进化的认识。

亚油酸是一种必需的多不饱和脂肪酸，不能由人类或动物自身合成，只能从外部获得。亚油酸的含量对肉的质量和风味有影响，并间接影响消费者的偏好。然而，影响亚油酸在生物体内沉积的分子机制并不清楚。因为对于亚油酸沉积的分子机制尚不明晰，为了研究影响亚油酸含量的主要效应基因，本研究旨在通过转录组测序（RNA-Seq）和加权基因共表达网络分析（WGCNA）来筛选慢型型黄羽鸡的关键基因。我们为了筛选与慢型黄羽肉鸡中亚油酸含量相关的候选基因，在126天上市日龄时宰杀了399只天农麻鸡，测量了胸肌中的脂肪酸含量，并收集胸肌组织进行转录组测序。通过将转录组测序结果与WGCNA的表型相结合，来筛选候选基因。并对在相关度最高的模块中显著相关的基因进行了KEGG富集分析。在对399个胸肌组织进行基于RNA-Seq的质量控制后，共获得13，310个基因。使用这些基因进行了WGCNA，共得到26个模块，其中有8个与亚油酸含量高度相关的模块。根据|GS|>0.2和|MM|>0.8的标准进行筛选，得到四个关键基因，即MDH2、ATP5B、RPL7A和PDGFRA。KEGG富集后结果显示，目标模块内的基因主要富集在代谢途径中。本研究通过大样本量的转录组分析，发现代谢途径在天农麻鸡亚油酸含量的调控中起着重要作用，并筛选出MDH2、ATP5B、RPL7A和PDGFRA作为影响亚油酸含量的重要候选基因。本研究结果为选择分子标记和全面了解影响肌肉中亚油酸含量的分子机制提供了理论依据，为慢速型黄羽肉鸡的育种提供了重要参考。

Silicon can improve drought tolerance of plants, but the mechanism still remains unclear.  Previous studies have mainly concentrated on silicon-accumulating plants, whereas less work has been conducted in silicon-excluding plants, such as tomato (Solanum lycopersicum L.).  In this study, we investigated the effects of exogenous silicon (2.5 mmol L^–1) on the chlorophyll fluorescence and expression of photosynthesis-related genes in tomato seedlings (Zhongza 9) under water stress induced by 10% (w/v) polyethylene glycol (PEG-6000).  The results showed that under water stress, the growth of shoot and root was inhibited, and the chlorophyll and carotenoid concentrations were decreased, while silicon addition improved the plant growth and increased the concentrations of chlorophyll and carotenoid.  Under water sterss, chlorophyll fluorescence parameters such as PSII maximum photochemical efficiency (F_v/F_m), effective quantum efficiency, actual photochemical quantum efficiency (Ф_PSII), photosynthetic electron transport rate (ETR), and photochemical quenching coefficient (q_P) were decreased; while these changes were reversed in the presence of added silicon.  The expressions of some photosynthesis-related genes including PetE, PetF, PsbP, PsbQ, PsbW, and Psb28 were down-regulated under water stress, and exogenous Si could partially up-regulate their expressions.  These results suggest that silicon plays a role in the alleviation of water stress by modulating some photosynthesis-related genes and regulating the photochemical process, and thus promoting photosynthesis.

    A 45 d pot experiment was conducted to examine the effects of silicon fertilizer or iron fertilizer on the growth of two typical Ipomoea aquatica cultivars (Daye and Liuye) and arsenic (As) accumuation of Daye and Liuye grown in As-contaminated soils at different As dosage levels. The results showed that the application of these two fertilizers generally enhanced the growth of the plants, which may be partly attributable to the reduction in As toxicity. The addition of these two fertilizers also significantly reduced the uptake of As by the plants though the iron fertilizer was more effective, as compared to the silicon fertilizer. The accumulation of As in shoot portion was weaker for Daye than for Liuye. The research findings obtained from this study have implications for developing cost-effective management strategies to minimize human health impacts from consumption of As-containing I. aquatica.

A greenhouse experiment was carried out to determine plant growth, reactive oxygen species (ROS) metabolism in roots and functions of plasma membrane (PM) and tonoplast in cucumber seedlings (Cucumis sativus L. cv. Xintaimici) treated with 40 μmol L-1 CuSO4·5H2O, which were either ungrafted or grafted onto the rootstock (Cucurbita ficifolia). Cu treatment inhibited growth, induced significant accumulation of H2O2 and led to serious lipid peroxidation in cucumber roots, and the ROS-scavenging enzymes activities in grafted seedlings roots were significantly higher than that of ungrafted plants, thus less accumulation in grafted cucumber roots induced by Cu. As a result, lipid peroxidation in roots decreased. Furthermore, the activities of H+-ATPase, H+-PPase and Ca2+-ATPase in PM and/or tonoplast in grafted cucumber seedlings under Cu stress were obviously higher than that in ungrafted plants, resulting into higher ability in grafted plants to expulse the excess H+, promote the cytoplasm alkalinization, regulate the intracellular Ca2+ concentration and brought the cytoplasma concentration of free Ca2+ to extremely low level under Cu stress.

The β-1,3-glucan from yeast has been extensively examined for its immuno-enhancing effects in animals. However, investigation on the relationship among β-glucan, gut microbiota and immune-modulating effects remains limited particularly in pigs. Considering the critical roles of gut methanogens in the microbial fermentation, energy metabolism and disease resistance, we investigated the phylogenetic diversity of methanogens from fermented cultures of porcine colonic digesta with (G) or without (N) yeast β-glucan based on sequences of the archaeal 16S rRNA gene. A total of 145 sequences in the G library were assigned into 8 operational taxonomic units (OTUs) with the majority of sequences (114/145) related to strains Methanobrevibacter millerae or Methanobrevibacter gottschalkii with high identities ranging from 97.9 to 98.6%, followed by 23 sequences to Methanobrevibacter ruminantium, 2 sequences to Methanobrevibacter smithii and one sequence to Methanobrevibacter wolinii. The 142 sequences in the N library were assigned to 2 OTUs with most sequences (127/142) related to strains M. millerae or M. gottschalkii with sequence identities ranging from 97.9 to 98.5%, and 15 sequences related to M. gottschalkii with 97.9% identity. Shannon diversity index showed that the G library exhibited significantly higher archaeal diversity (P<0.05) and Libshuff analysis indicated the differences in the community structure between the two libraries were significant (P<0.0001). In conclusion, the current study provides evidence that addition of yeast β-glucan significantly increased the diversity of methanogens in in vitro fermented porcine colonic digesta.

Citrus Huanglongbing (HLB, yellow shoot disease) was first observed in the coastal Chaoshan Plain of Guangdong Province, China, in the late 19th century based on descriptions of yellow shoot symptoms. “Candidatus Liberibacter asiaticus” has been considered as a putative pathogen associated with HLB since 1994. Information about the curent prevalence of this bacterium is important for HLB control in Guangdong and also provides useful reference for HLB study elsewhere. In 2007, we collected HLB symptomatic citrus samples from 16 cultivars in 12 prefecture cities, mostly in the north and west regions of Guangdong, where major citrus fruits are currently produced. Among the 359 samples collected, 241 (67.1%) were positive for “Ca. L. asiaticus”, distributed in 15 out of the 16 cultivars from all 12 cities, indicating the widespread prevalence of “Ca. L. asiaticus” in Guangdong Province. The detection rates varied from 16.7 to 100% depending on location and cultivar. Lower detection rates were found in newer citrus cultivation cities among the previously less popular but now promoted cultivars. In reviewing the citrus management and pest control practice, we believe that infected nursery stocks play a key role in the current spread of “Ca. L. asiaticus”.