防御素在植物的生长发育和抵御病原菌侵染过程中发挥重要的作用，然而苹果中防御素对苹果树腐烂病菌抗性的作用尚不清楚。本研究中，共鉴定出29个苹果防御素蛋白，它们具有保守的序列特征。基于表达分析，发现苹果防御素在苹果各组织中均有分布，5个防御素基因的表达受到苹果壳囊孢的显著诱导。构建5个防御素的转基因愈伤，过表达防御素基因均能增强对苹果壳囊孢的抗性。其中，MdDEF30表达受苹果壳囊孢菌强烈诱导并显著提高愈伤抗性。进一步的体外活性实验证实MdDEF30能抑制壳囊孢的生长。MdDEF30能够促进活性氧积累和激活防卫相关基因PR4，PR10，CML13及MPK3的表达。通过构建MdDEF30共表达网络，发现转录因子MdWRKY75可能调控MdDEF30的表达。利用酵母单杂、荧光酶素报告基因和染色质免疫共沉淀荧光定量实验证实MdWRKY75能够与MdDEF30启动子直接结合。接种实验表明MdWRKY75正调控对苹果树腐烂病抗性，并且激活MdDEF30的表达。这些结果阐明苹果树通过MdWRKY75正向调控具抗菌活性和诱导抗性的MdDEF30表达抵御壳囊孢菌侵染的分子机理。

内生微生物可以帮助植物获得营养物质，抑制病原菌等生物和非生物胁迫，是影响植物生长、营养和健康的关键因素之一；然而，对于田间条件下存在于大豆不同组织中的细菌和真菌微生物群落的组成及影响因素，仍缺乏足够的了解。本研究以大豆为研究对象，对16S rRNA和ITS特定区段的PCR扩增子进行高通量测序，探究不同组织（根、茎、叶和荚）、不同品种（安豆203、荷豆12、山宁16和中黄13）以及不同地理位置（济宁、宿州和徐州）对大豆内生细菌和真菌群落组成及多样性的影响。结果表明，不同组织之间的内生微生物群落差异明显，根部内生细菌和真菌群落的组成及多样性显著区分于地上部的茎、叶和荚；供试品种间茎部的细菌群落和叶部的真菌群落组成差异最大；试验地点显著影响各个器官中的细菌群落组成，其中对根茎部的影响比叶荚部更强，而对于真菌群落组成，茎叶部所受影响比根荚部更明显。此外，与大豆病害相关的微生物丰度在不同组织和品种间存在差异（如：镰刀菌在根部丰度更高，而链格孢菌在叶部丰度更高），可能与这些微生物在寄主中的生态位以及寄主的抗感性有关。微生物群落组成与多样性的系统分析将有助于植物保护技术的发展，从而有益于大豆健康。

茄科劳尔氏菌，简称青枯菌(Ralstonia solanacearum)，是一种分布广泛的土传细菌病原菌，该病原菌从根部侵染植物，最终引发青枯病(Bacterial wilt disease)。青枯菌寄主范围广泛，可在200多种植物包括马铃薯、番茄、辣椒、烟草、花生等重要作物上引起毁灭性的植物病害，被列为世界上第二大细菌性植物病原菌，给全世界的农作物生产带来巨大威胁。研究并解析青枯菌与植物互作的分子机制可为青枯病防控策略的建立奠定基础。然而，目前科研中主要采用的青枯菌土壤灌根法接种方法存在实验周期长、所需植物培养空间大、且条件不容易控制等问题，限制了青枯菌与植物互作研究的开展。因此，亟需一种快速、操作简易、且结果稳定的青枯菌接种方法。为此，本文建立了一种培养皿内青枯菌接种方法(Petri-dish inoculation method)，该方法具备接种后发病稳定、操作简易和实验周期短等特点，可广泛用于青枯菌与植物互作研究。为了证明该方法在青枯菌与植物互作研究中的有效性，本文利用引发植物防御作用的分子模式Pep1，拟南芥感病突变体npr1，以及具有不同毒力水平的青枯菌突变体ΔhrcV和ΔRipAC，研究了青枯菌皿内接种方法在评估植物抗病性和青枯菌致病性中的适用性和高效性。同时，我们利用皿内接种方法再现了前人对4个烟草品种的抗性评估结果，表明该方法可用于不同植物种质材料的抗性评估和筛选。鉴于此方法具有快速、操作简单、节省空间，人力和财力，以及所需接种量少的优点，该方法可用于快速大规模青枯菌突变体致病性分析以及植物对青枯菌抗性种质材料的筛选和鉴定。青枯菌皿内接种方法也可为其他土传病原菌的接种提供参考。

本研究利用Cre/loxP重组系统构建了辣椒轻型斑驳病毒 (Pepper mild mottle virus, PMMoV)的嵌合体病毒载体。然而，在验证本氏烟中Cre重组酶瞬时表达量的研究中发现Cre重组酶可诱导本氏烟叶片坏死。为了缓解Cre重组酶引起的坏死表型，对本氏烟中瞬时表达Cre重组酶的表达系统进行了优化，构建了Cre表达后自敲除的瞬时表达载体 (ploxP-Cre)，有效缓解了Cre重组酶在本氏烟叶片上引起的坏死，可用于介导Cre/loxP重组系统侵染性克隆的重组。为了构建Cre/loxP重组系统的PMMoV侵染性克隆，将PMMoV基因组分段分别构建到独立的载体上获得了包含病毒基因组的载体pJM23 (1-5628 nt)，pJG1024 (5629-6356 nt)通过手足口病毒 (foot-and-mouth disease virus, FMDV)2A蛋白在PMMoV外壳蛋白(coat protein, CP)氮端 (N)融合了一个绿色荧光蛋白(modified green fluorescent protein, mGFP)，并分别在病毒基因组的重组区段插入2个同向的loxP位点和一半的内含子序列，在农杆菌介导下将pJM23、pJG1024和ploxP-Cre共转染本氏烟，转染8天后病毒发生了系统侵染，在系统侵染叶片中存在大小为300 nm×18 nm的杆状病毒粒子，实现了PMMoV病毒基因组在植物体内重组为功能性的病毒载体。进一步证实了Cre/loxP重组系统的PMMoV侵染性克隆与全长侵染性克隆的在转染4天后均可系统侵染，其系统叶病毒量无差别。同时该系统可用于研究不同病毒蛋白功能，通过构建番茄环纹斑点病毒 (Tomato zonate spot virus, TZSV)核壳体蛋白 (nucleocapsid, N) 基因的嵌合体病毒载体 (pJGTZSV)，在本氏烟中表达了N蛋白，并实现了系统侵染。我们的研究提供了一个新的方法用于嵌合体病毒和较大基因组的病毒侵染性克隆的构建。

本研究从二倍体森林草莓基因组中鉴定出14个LOX基因。系统发育树将FvLOX基因分为9-LOX和13-LOX两个亚家族。基因重复事件分析表明，全基因组复制/片段复制和分散复制有效地促进了草莓LOX家族的扩展。QRT-PCR分析表明，FvLOX基因在不同组织中均有不同程度的表达。表达谱分析表明，FvLOX1和FvLOX8在低温胁迫下表达上调，FvLOX3和FvLOX7在干旱胁迫下表达上调，FvLOX6和FvLOX9在盐胁迫下表达上调，FvLOX2、FvLOX3和FvLOX6在SA处理下表达上调，FvLOX3、FvLOX11和FvLOX14在MeJA处理下表达上调，FvLOX4和FvLOX14在ABA处理下表达上调。启动子分析表明，FvLOX基因参与植物生长发育和胁迫响应。我们对草莓FvLOX家族进行了全基因组分析和鉴定，表征了多种参与非生物胁迫响应的FvLOX候选基因，该研究为草莓在非生物胁迫中的响应机制奠定了理论和经验基础。

籽粒灌浆速率（GFR）在小麦产量形成过程中起着关键作用，但由于表型调查困难等原因，对其遗传解析研究甚少。本研究测定了1个重组自交系群体和1个自然群体籽粒灌浆性状，基于高密度图谱进行相关性状的连锁分析和全基因组关联分析。在染色体 1B、4B和5A上鉴定到17个稳定的QTLs。 其中IWB19555-IWB56078 连锁区间对性状 GFR₁、GFR_max、KL、KW、KT 和TKW具有多效性，表型变异解释率（PVE）为13.38%（KW）- 33.69%（TKW）。检测到198个显著性状关联位点（MTAs）分布在除了3D和4D之外的染色体上。GFR的主要关联位点包括 IWB44469（11.27%）、IWB8156（12.56%）和IWB24812（14.46%）。检测到IWB41019是籽粒大小相关的重要多效性位点。通过GWAS鉴定到的IWB35850与连锁分析获得的QGFR_max2B.3-11位于同一区域，该区域包含两个高置信候选基因。检测到两个重要的粒重相关 QTL与灌浆速率 QTL定位到同一区间。这些发现有助于解析 GFR 的遗传基础，为小麦产量性状 QTL候选基因预测提供理论依据。

DnaJ蛋白最初是在大肠杆菌中鉴定的一种大小约为41kDa的热休克蛋白，其蛋白家族是分子伴侣中最多样化的家族，在蛋白质折叠和各种生理活动的调节中扮演了重要角色，且在植物发育和胁迫应答中发挥重要作用。DnaJ家族蛋白已在许多物种中广泛研究，例如人类，果蝇，蘑菇，西红柿和拟南芥等，但其在小麦中的作用以及其与植物病毒之间的相互作用机制却鲜少有研究。在这篇文章中，我们鉴定了236个TaDnaJs，并对其保守结构域，基因结构、蛋白质基序、蛋白质结构、染色体定位和共线性以及顺式作用元件进行了全基因组分析。根据分析结果，我们将这些TaDnaJs按其结构域分成DJA、DJB和DJC三组，并从分组中随机选择了6个基因进行组织特异性分析和激素胁迫下的基因表达谱分析，结果表明TaDnaJ基因在不同组中存在组织差异表达，DJA组的基因表达集中在顶部叶片，对ABA和GA更为敏感；DJB组的基因表达水平在根和种子中最高，对ABA更为敏感；DJC组中的基因表达在小麦叶片中最高，其次是根和种子，对SA和GA最敏感。另外我们随机选择了17个基因分析植物病毒侵染后基因表达水平的变化，结果显示，在测试的17个TaDnaJ基因中，有16个基因在小麦黄花叶病毒（WYMV）侵染后呈现上调表达，这表明TaDnaJ家族可能参与了植物防御反应。随后我们通过酵母两杂交实验验证了WYMV NIa、NIb和7KD蛋白与WYMV侵染后表达水平变化最显著的TraesCS7A02G506000相互作用。在这篇文章中，我们探究了DnaJ蛋白介导的胁迫耐受性和敏感性的分子机制，DnaJ基因可能参与了植物对非生物和生物胁迫的抗性。本研究提高了对TaDnaJ基因表达谱的认识，并且为TaDnaJ家族与植物防御机制之间的研究提供了一定的研究基础。

据报道，兔戊型肝炎病毒 (HEV) 为潜在人畜共患性传染病。报道显示HEV 3型是造成兔HEV流行的主要原因。为调查戊型肝炎在肉兔中的流行情况，本研究从中国河北省的一个屠宰场收集了176份肝脏样本。RNA检测结果显示3份样本HEV-ORF2检测阳性，占样本量的1.7%。序列分析表明，3株分离株具有较高的同源性 (94.08%~98.85%)，为HEV基因3型。此外，免疫组化 (IHC) 检测HEV ORF2蛋白显示，131份肝脏样本阳性，占样本量的74.4%。肝脏组织病理学观察结果显示，H.E染色的组织病理学变化主要有肝细胞变性、坏死、淋巴细胞浸润、胆管上皮细胞增生、含铁血黄素沉着等。这些结果表明，在家兔中存在戊型肝炎病毒，但兔戊肝病毒 (rHEV) 的传染性及人兔跨种传播的潜在风险有待进一步研究。

    Dissecting the genetic relationships among gluten-related traits is important for high quality wheat breeding. Quantitative trait loci (QTLs) analysis for gluten strength, as measured by sedimentation volume (SV) and gluten index (GI), was performed using the QTLNetwork 2.0 software. Recombinant inbred lines (RILs) derived from the winter wheat varieties Shannong 01-35×Gaocheng 9411 were used for the study. A total of seven additive QTLs for gluten strength were identified using an unconditional analysis. QGi1D-13 and QSv1D-14 were detected through unconditional and conditional QTLs mapping, which explained 9.15–45.08% of the phenotypic variation. QTLs only identified under conditional QTL mapping were located in three marker intervals: WPT-3743–GLU-D1 (1D), WPT-7001–WMC258 (1B), and WPT-8682–WPT-5562 (1B). Six pairs of epistatic QTLs distributed nine chromosomes were identified. Of these, two main effect QTLs (QGi1D-13 and QSv1D-14) and 12 pairs of epistatic QTLs were involved in interactions with the environment. The results indicated that chromosomes 1B and 1D are important for the improvement of gluten strength in common wheat. The combination of conditional and unconditional QTLs mapping could be useful for a better understanding of the interdependence of different traits at the QTL molecular level.

Pre-harvest sprouting (PHS) occurs frequently in most of the wheat cultivation area worldwide, which severely reduces yield and end-use quality, resulting in substantial economic loss.  In this study, quantitative trait loci (QTL) for PHS resistance were mapped using an available high-density single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) genetic linkage map developed from a 269 recombinant inbred lines (RILs) population of Yanda 1817×Beinong 6.  Using phenotypic data on two locations (Beijing and Shijiazhuang, China) in two years (2012 and 2013 harvesting seasons), five QTLs, designated as QPhs.cau-3A.1, QPhs.cau-3A.2, QPhs.cau-5B, QPhs.cau-4A, and QPhs.cau-6A, for PHS (GP) were detected by inclusive composite interval mapping (ICIM) (LOD≥2.5).  Two major QTLs, QPhs.cau-3A.2 and QPhs.cau-5B, were mapped on 3AL and 5BS chromosome arms, explaining 6.29–21.65% and 4.36–5.94% of the phenotypic variance, respectively.  Precise mapping and comparative genomic analysis revealed that the TaVp-1A flanking region on 3AL is responsible for QPhs.cau-3A.2.  SNP markers flanking QPhs.cau-3A.2 genomic region were developed and could be used for introgression of PHS tolerance into high yielding wheat varieties through marker-assisted selection (MAS).

    Soil drying may induce a number of stresses on crops. This paper investigated maize (Zea mays L.) root growth as affected by drought and soil penetration resistance (PR), which was caused by soil drying and tillage in a clayey red soil. Compared with conventional tillage (C) and deep tillage (D), soil compaction (P) and no-till (N) significantly increased soil PR in the 0–15 cm layer. The PR increased dramatically as the soil drying increased, particularly in soil with a high bulk density. Increased soil PR reduced the maize root mass density distribution not only in the vertical profile (0–20 cm) but also in the horizontal layer at the same distance (0–5, 5–10, 10–15 cm) from the maize plant. With an increase in soil PR in pots, the maize root length, root surface area and root volume significantly decreased. Specifically, the maize root length declined exponentially from 309 to 64 cm per plant with an increase in soil PR from 491 to 3 370 kPa; the roots almost stopped elongating when the soil PR was larger than 2 200 kPa. It appeared that fine roots (<2.5 mm in diameter) thickened when the soil PR increased, resulting in a larger average root diameter. The average root diameter increased linearly with soil PR, regardless of soil irrigation or drought. The results suggest that differences in soil PR caused by soil drying is most likely responsible for inconsistent root responses to water stress in different soils.

In order to understand the yield performance and nitrogen (N) response of hybrid rice under different ecological conditions in southern China, field experiments were conducted in Huaiji County of Guangdong Province, Binyang of Guangxi Zhuang Autonomous Region and Changsha City of Hunan Province, southern China in 2011 and 2012. Two hybrid (Liangyoupeijiu and Y-liangyou 1) and two inbred rice cultivars (Yuxiangyouzhan and Huanghuazhan) were grown under three N treatments (N1, 225 kg ha–1; N2, 112.5–176 kg ha–1; N3, 0 kg ha–1) in each location. Results showed that grain yield was higher in Changsha than in Huaiji and Binyang for both hybrid and inbred cultivars. The higher grain yield in Changsha was attributed to larger panicle size (spikelets per panicle) and higher biomass production. Consistently higher grain yield in hybrid than in inbred cultivars was observed in Changsha but not in Huaiji and Binyang. Higher grain weight and higher biomass production were responsible for the higher grain yield in hybrid than in inbred cultivars in Changsha. The better crop performance of rice (especially hybrid cultivars) in Changsha was associated with its temperature conditions and indigenous soil N. N2 had higher internal N use efficiency, recovery efficiency of applied N, agronomic N use efficiency, and partial factor productivity of applied N than N1 for both hybrid and inbred cultivars, while the difference in grain yield between N1 and N2 was relatively small. Our study suggests that whether hybrid rice can outyield inbred rice to some extent depends on the ecological conditions, and N use efficiency can be increased by using improved nitrogen management such as site-specific N management in both hybrid and inbred rice production.

Two miniature inverted-repeat transposable elements (MITEs), MCLas-A and MCLas-B, were recently identified from ‘Candidatus Liberibacter asiaticus’ known to be associated with citrus Huanglongbing (HLB, yellow shoot disease). MCLas-A was suggested as an active MITE because of its mobility. The immediate upstream gene of the two MITEs was predicted to be a putative transposase. The goal of this study is to analyze the sequence variation in the upstream putative transposase of MITEs and explore the possible correlation between sequence variation of transposase gene and MITE activity. PCR and sequence analysis showed that 12 sequence types were found in six major amplicon types from 43 representative ‘Ca. L. asiaticus’ isolates from China, the United States and Brazil. Out of the 12 sequence types, three (T4, T5-2, T6) were reported for the first time. Recombination events were found in the two unique sequence types (T5-2 and T6) which were detected in all Brazilian isolates. Notably, no sequence variation or recombination events were detected in the upstream putative transposase gene of MCLas-A, suggesting the conservation of the transposase gene might be closely related with the MITE activity. Phylogenetic analysis demonstrated two well supported clades including five subclades were identified, clearly reflecting the geographical origins of isolates, especially that of Ruili isolates, São Paulo isolates and a few Florida isolates.

Salinity is one of the most important abiotic stresses that adversely affects crop growth and productivity. A subtractive suppression hybridization (SSH) library were constructed from the roots of salt-sensitive Yulu cultivar melon seedlings under salt stress; 557 high-quality expressed sequence tags (ESTs) were randomly sequenced, with an average size of 428 bp, which assembled into 68 contigs and 315 singletons. Compared with our previous SSH library generated from the salt-tolerant Bingxuecui cultivar, the proportion of transcripts involved in metabolism, protein fate, cellular communication/signal transduction mechanisms, and cell rescue/defense were 4, 1.46, 0.94, and 0.4% higher, respectively, in the salt-tolerant cultivar than the in salt-sensitive cultivar. Quantitative real-time PCR analysis of eleven transcripts revealed temporal variations in their expression in the two cultivars under salt stress. One NAC gene (JZ477011) was heterologously expressed in yeast for functional characterization, and enhanced the sensitivity of yeast cells to high-salinity to salt stress and inhibited their growth. Information regards to their functions would aid in the understanding of response mechanisms to saline stress and in the development of molecular markers for selecting salt-tolerant melon cultivars.

Sublethal effects of chlorantraniliprole to Helicoverpa armigera (Hübner) larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed on the insecticide-containing diet for 7 d, the LC10, LC20, LC40, and LC50 values were 3.790, 7.977, 21.577, and 33.121 μg active ingredient L-1, respectively. Chlorantraniliprole at sublethal concentrations significantly reduced the larval body mass, emergence ratio, adult longevity and egg hatching rate in both the parental and offspring generations. The pupation and copulation rate in the parental generation and the pupal mass in the offspring also strongly decreased. Reproduction was seriously disturbed in both the parental and offspring groups even when only one of the partners was exposed to chlorantraniliprole at larval stages. However, at the lowest concentration of exposure (LC10), offspring fecundity was strongly reduced only when both partners were exposed. The net reproductive rate (R0), intrinsic rate of increase (rm), and gross reproduction rate (GRR) at LC20, LC40 concentrations were significantly lower than that of the control. Post-exposure effects also included an extended larval developmental time and increased male proportion in both generations. The doubling time (Dt) at LC20, LC40 concentrations as well as gross reproduction rate (GRR) at LC10 concentration were also significantly increased. Chlorantraniliprole might have significant effects on H. armigera population dynamics even at sublethal concentrations on both parental and offspring generations.

To evaluate the possible genetic interrelationships between flour components and the sedimentation volume (SD), a doubled haploid (DH) population comprising 168 lines were used to identify the conditional quantitative trait loci (QTLs) for SD in three environments. Ten additive QTLs and 15 pairs of epistatic QTLs were detected for SD through unconditional and conditional QTL mapping. Three major additive QTLs were detected for SD conditioned on the seven quality traits. Two additive QTLs were found to be independent of these traits. Three additive QTLs were suppressed by three of the seven traits because of non-detection in unconditional mapping. Three pairs of epistatic QTLs were completely affected by the seven traits because of detection in unconditional mapping but no-detection in conditional mapping. Twelve pairs of epistatic QTLs were detected in conditional mapping. Our results indicated that conditional mapping could contribute to a better understanding of the interdependence of different and closely correlated traits at the QTL molecular level, especially some minor QTLs were found. The conditional mapping approach provides new insights that will make it possible to avoid the disadvantages of different traits by breeding through molecular design.

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”.

As one of the most effective enzymatic modification methods of protein, papain hydrolysis is applied widely in food production, accompanying starch pasting frequently in order to improve industrial quality. Effects of the papain hydrolysis on flour pasting properties were investigated in five papain/flour concentrations and five time-treatments. The structure of starch and protein networks in slurry was investigated under microscope before and after pasting. Results showed that papain hydrolysis influenced the pasting properties of wheat flour significantly through affecting structural characteristics, amylase activity and exothermic transition, especially during the early stage of hydrolysis. Peak viscosity, trough, final, integral area, and setback significantly decreased along with the increasing concentration of papain. Both hydrolysis time and concentration of papain had obviously effect on the breakdown. Pasting temperature and pasting time increased significantly with the enhancement of papain concentration. Hydrolysis time exerted minor effect on the pasting temperature and pasting time. The average peak time was slightly prolonged by lower concentration of papain, otherwise slightly shortened by higher concentration.

Calcium-dependent protein kinases (CDPKs, EC 2.7.1.37) comprise a large family of Ser/Thr kinases in plants and play an important role in plant Ca2+ signal transduction. A full-length CDPK gene, NtCDPK12 (GenBank accession number GQ337420), was isolated from common tobacco (Nicotiana tabacum) leaves by rapid amplification of cDNA ends (RACE). The NtCDPK12 cDNA is 1 816 bp length and contains an open reading frame (ORF) of 1 461 bp encoding 486 amino acids. Sequence alignments indicated that NtCDPK12 contains all conserved regions found in CDPKs and shows a high level of sequence similarity to many other plant CDPKs. The results of real-time quantitative reverse transcription-PCR (qRTPCR) showed that NtCDPK12 was highly expressed in stems and increased in roots treated with high-salt or subjected to drought stress, which indicates that NtCDPK12 was induced by high-salt and drought stresses.