蔗糖磷酸合成酶（SPS）是蔗糖合成途径中的限速酶，与磷酸蔗糖磷酸酶（SPP）形成复合体共同催化合成蔗糖，在植物生长发育过程中提供能量并在果实品质提升方面发挥着重要作用。目前，关于苹果SPS基因家族的进化模式及系统性分析的研究较少。本研究从苹果基因组GDDH13 v1.1中鉴定了7个MdSPS基因和4个MdSPP基因，并分析了其基因结构、基因启动子顺式元件、蛋白保守基序、亚细胞定位和生理生化特性。染色体定位和基因组复制分析表明，全基因组复制（WGD）和片段复制是MdSPS基因家族进化的主要方式，MdSPS基因对的Ka/Ks比值分析指出该家族成员在驯化过程中经历了较强的纯化选择。根据系统发育关系将SPS基因划分为3个亚家族，并观察到基因亚家族间古老的基因复制事件和差异显著的进化速率。此外，根据‘金冠’、‘富士’、‘秦冠’和‘蜜脆’四个苹果品种果实发育过程中可溶性糖含量与SPS家族基因表达水平的相关性，鉴定了一个蔗糖积累相关的关键基因MdSPSA2.3。随后通过病毒诱导MdSPSA2.3基因沉默证实了该基因在苹果果实蔗糖积累中的重要功能。本研究为更好地阐明MdSPS基因在苹果果实发育过程中的生物学功能奠定了理论基础。

腐烂茎线虫（Ditylenchus destructor）是一种重要的检疫性病原线虫，严重危害甘薯、马铃薯和中药材等根茎类作物。该线虫的种内分化明显，根据ITS-rDNA序列差异，国外的研究将其分为A-G 7个单倍型，但主要集中于马铃薯和甘薯的线虫群体。本研究对腐烂茎线虫中药材群体ITS-rDNA序列及其RNA二级结构进行分析，以明确其单倍型分化，并通过ITS-rDNA与28S D2-D3系统发育关系、ITS-RFLR和ITS特异性引物PCR扩增进一步验证不同群体单倍型的分化。在甘肃、青海、陕西、内蒙和黑龙江等5个省，共采集当归、党参、马铃薯和甘薯的腐烂茎线虫群体43个，其中中药材群体37个。线虫群体的ITS-rDNA序列长度为727 bp-969 bp，长度差异主要表现在ITS1区串联重复序列的数量不同，且串联重复序列在ITS1二级结构中形成了稳定的茎环，即H9螺旋。依据H9螺旋结构的有无及其差异，43个群体的ITS-rDNA序列可划分为10个单倍型。与已知单倍型（A-G）对比分析，发现其中3个单倍型分别与A、B和C单倍型一致，而另外7个单倍型与已知单倍型不同，将其依次命名为H、I、J、K、L、M和N单倍型，这7个新单倍型均来源于中药材。综合本研究和已知单倍型分类体系，腐烂茎线虫中发现A-N 14个单倍型。ITS和28S系统发育分析显示，所有单倍型群体分化为两支：A单倍型为一支，B-N单倍型为另一支。对比ITS和28S系统发育树，发现A单倍型均单独聚为一支，但B-N分支不太一致，且不同单倍型系统发育关系较为混乱。ITS-RFLP和特异性引物PCR结果显示，H和A单倍型酶切图谱和特异性片段长度相同， B和C单倍型特异性片段长度相同，但其它单倍型间存在明显差异。除K单倍型不同群体间有差异外，其它单倍型的群体间无明显差异。本研究发现了腐烂茎线虫中药材群体中存在新的单倍型，并明确了不同单倍型的差异，该结果将推动茎线虫生物学的研究进展，且对中药材腐烂茎线虫病的识别和防治具有指导意义。

小伞山羊草二倍体 (Ae. umbellulata, 2n=2x=14, UU) 是对普通小麦遗传改良具有潜在利用价值的小麦近缘植物。本研究报道了46份小伞山羊草的条锈病抗性、抽穗期、微量元素铁、锌含量以及“面筋蛋白”含量的调查结果。在四个环境下，42份小伞山羊草表现抗小麦条锈病，4份感条锈病。小伞山羊草的平均抽穗期 (180.9天) 显著晚于3个普通小麦对照 (137.0天)，但1份材料PI226500除外，为138.9天。小伞山羊草材料间的铁、锌含量有广泛的变异，变幅分别为69.74–348.09 mg/Kg和49.83–101.65 mg/Kg。PI 542362, PI 542363和PI 5543993份这3份材料的铁、锌含量高于其他小伞山羊草，分别为230.96–348.09 mg/Kg和92.46–101.65 mg/Kg。小伞山羊草的铁含量与顶芒山羊草 (Ae. comosa, 2n = 2x =14, MM) 和尾状山羊草 (Ae. markgrafii, 2n = 2x =14, CC) 的相当，但高于节节麦 (Ae. tauschii, 2n = 2x =14, DD) 和普通小麦对照。小伞山羊草的锌含量高于节节麦、顶芒山羊草和普通小麦对照，但低于尾状山羊草。用高效液相色谱分析了小伞山羊草以及作为对照的其他山羊草二倍体的面筋蛋白含量。与其他物种相比较，小伞山羊草具有独特的洗脱峰，如41-42分钟的低分子量谷蛋白以及大约57分钟时的γ-醇溶蛋白。在所研究的物种中，小伞山羊草的γ-醇溶蛋白含量是最高的 (小伞山羊草vs. 其他物种，平均含量: 72.11%% vs. 49.37%，变异幅度 55.33–86.99% vs. 29.60–67.91%)。这些研究结果表明，小山羊草在这些性状上有很大遗传变异，是可供用于普通小麦相关性状遗传改良利用的潜在基因库。

B-box（BBX）基因家族编码的蛋白是由包含锌指结构的转录因子组成，其N端有一个或两个高度保守的B-box基序。BBX蛋白在植物生长发育的各个方面起着至关重要的作用，包括幼苗的光形态发生、避荫、开花时间以及生物和非生物胁迫响应。目前,各国的研究者已经从几种植物中鉴定了BBX的家族成员，然而玉米中的BBX家族成员还知之甚少。通过对玉米BBX家族基因的全基因组鉴定、表达和互作的综合分析，可为了解其功能提供有用信息。本研究共鉴定出36个玉米BBX家族成员，进化分析显示其分布于三个主要分支。在每个主分支中ZmBBXs都具有相似的结构域、基序和基因组结构。基因重复分析表明，玉米BBX蛋白家族的扩张主要是通过片段重复来完成的。利用实时荧光定量PCR技术，本研究分析了ZmBBXs在不同器官组织和不同非生物胁迫条件下的表达。利用生物信息学工具，本研究建立了ZmBBXs蛋白的相互作用网络，并通过双分子荧光互补（BiFC）试验进行了验证。本研究的发现有助于理解ZmBBX家族的复杂性，并为揭示ZmBBX蛋白的生物学功能提供新的线索。

利用渤海湾和黄土高原地区545名苹果种植户的微观数据，运用Double-hurdle模型，本文实证分析影响农户精准农药技术的采纳意愿和支付意愿的因素。结果表明，78.72%的农户表示，愿意采纳由合作社、专业企业等服务机构提供精准农药技术服务；69.72%的农户表示愿意购买精准农药技术设备。同时，农户感知、农场规模、是否加入合作社、数字信息获取和金融服务可获得性对农户精准农药技术的采纳意愿具有显著的正向影响。而合作成员、技术培训和环境法规则显影响农户精确农药技术的支付意愿，年龄、农业经验与农户精准农药技术服务的采纳意愿和支付意愿之间存在非线性关系。

小麦的高产主要通过增施氮肥和增加灌水实现，但过量的氮肥和灌水投入增加了倒伏的风险。本研究的主要目的是明确高产小麦抗倒伏能力对氮肥和灌水的响应以及探索提高小麦抗倒伏性的有效途径。试验于2015-2016和2016-2017生长季在山东农业大学农学实验站进行，供试品种为济麦22，设置3个施氮量和4个灌水处理，主要研究结果如下：随施氮量增加，倒伏指数和倒伏率增加，倒伏风险上升。增加氮肥用量，与倒伏指数呈正相关的株高、基部节间长度和重心高度显著增加，与倒伏指数呈负相关的基部第二节间（茎秆和叶鞘）充实度及其细胞壁组分含量显著降低。适度增加灌水可增加基部第二节间壁厚、茎秆抗折力和叶鞘的充实度，增加了茎秆强度。在本实验条件下，施氮量240 kg hm^-2 并配合在拔节期和开花期各灌水600 m³ hm^-2在获得最高产量的同时茎秆强度最大。结果表明，适宜的株高保证高产所需的足够的生物量，较厚的壁厚、较高的茎秆和叶鞘充实度以及细胞壁组分含量保证了较大的茎秆强度，以上特征可作为创建小麦高产抗倒群体的参考指标。

尽管目前的研究极大地促进了我们对于植物适应低氮胁迫的认知，但是关于不同作物基因型适应低氮胁迫能力不同的机制仍需要进一步探讨。本文中，我们根据田间条件下304份玉米自交系对低氮胁迫的耐受性，从中选择了Ye478（低氮胁迫敏感材料）和Qi319（耐受低氮胁迫材料）进行进一步的研究。首先我们对Ye478和Qi319正常氮水培和低氮水培的地上部和根部构建了16个转录组文库，并进行高通量测序。结果分析发现Qi319根系中特异上调表达的基因主要富集在代谢能相关途径，包括三羧酸代谢过程和烟酰胺代谢过程。在低氮胁迫处理5天后，仅在Ye478中观察到老叶变黄的表型；与Qi319相比，在Ye478地上部特异下调表达的基因主要与类囊体、叶绿体、光合膜和叶绿体基质等有关。对转录因子进行分析，共有216个转录因子在Ye478和Qi319之间差异表达，表明氮胁迫响应路径中的转录调控在不同作物基因型适应低氮胁迫中起重要作用。此外，在Ye478和Qi319中还发现了15个差异表达的miRNAs。综上所述，我们的研究有助于了解玉米耐受低氮胁迫的遗传变异和分子基础。

杂交水稻为世界粮食的供应做出了重大贡献，而骨干亲本在杂交水稻品种选育中发挥着重要作用。为明确水稻骨干亲本蜀恢527（SH527，Oryza sativa）在育种过程中所利用的关键基因组区域，本研究对其进行了基于系谱的全基因组分析。利用高密度单核苷酸多态性（SNP）阵列对包括SH527、6个亲本品种及17个衍生恢复系在内的24个品种进行了扫描，分析了上游亲本对SH527基因组的独特贡献，确定了SH527及其衍生品种中保守的关键基因组区域。同时，利用多年的产量性状数据和SNP 芯片结果进行全基因组关联分析，发现了一些可能的已知或新的产量性状的关联位点。这项研究初步揭示了SH527育种的关键区域，将为后续育种提供参考。杂交水稻为世界粮食的供应做出了重大贡献，而骨干亲本在杂交水稻品种选育中发挥着重要作用。为明确水稻骨干亲本蜀恢527（SH527，Oryza sativa）在育种过程中所利用的关键基因组区域，本研究对其进行了基于系谱的全基因组分析。利用高密度单核苷酸多态性（SNP）阵列对包括SH527、6个亲本品种及17个衍生恢复系在内的24个品种进行了扫描，分析了上游亲本对SH527基因组的独特贡献，确定了SH527及其衍生品种中保守的关键基因组区域。同时，利用多年的产量性状数据和SNP 芯片结果进行全基因组关联分析，发现了一些可能的已知或新的产量性状的关联位点。这项研究初步揭示了SH527育种的关键区域，将为后续育种提供参考。

Auxin regulates cell division and elongation of the primordial cells through its concentration and then shaped the plant architecture.  Cell division and elongation form the internode of soybean and result in different plant heights and lodging resistance.  Yet the mechanisms behind are unclear in soybean.  To elucidate the mechanism of the concentration difference of auxin related to stem development in soybean, samples of apical shoot, elongation zone, and mature zone from the developing stems of soybean seedlings, Charleston, were harvested and measured for auxin concentration distributions and metabolites to identify the common underlying mechanisms responsible for concentration difference of auxin.  Distribution of indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and methylindole-3-acetic acid (Me-IAA) were determined and auxin concentration distributions were found to have a complex regulation mechanism.  The concentrations of IAA and Me-IAA in apical shoot were significantly different between elongation zone and mature zone resulting in an IAA gradient.  Tryptophan dependent pathway from tryptamine directly to IAA or through indole-3-acetonitrile to IAA and from indole-3-propionic acid (IPA) to IAA were three primary IAA synthesis pathways.  Moreover, some plant metabolites from flavonoid and phenylpropanoid synthesis pathways showed similar or reverse gradient and should involve in auxin homeostasis and concentration difference.  All the data give the first insight in the concentration difference and homeostasis of auxin in soybean seedlings and facilitate a deeper understanding of the molecular mechanism of stem development and growth.  The gathered information also helps to elucidate how plant height is formed in soybean and what strategy should be adopted to regulate the lodging resistance in soybean.

Received  21 December, 2017    Accepted  14 March, 2018

© 2018 CAAS. Publishing services by Elsevier B.V.  All rights reserved.
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   RING is a really interesting new gene which plays important regulatory roles in many developmental processes as well as in plant-environment interactions. In the present report, the ZmRHCP1 gene encoding a putative RING-HC protein was isolated from maize and characterized. The ZmRHCP1 protein contained 310 amino acid residues with a conserved RING-HC zinc-finger motif and two transmembrane (TM) domains. ZmRHCP1 was expressed ubiquitously in various organs (root, stem, leaf, seedling, immature ear, and tassel), but its transcript levels were higher in vegetative organs than in reproductive organs. Moreover, the expression pattern of ZmRHCP1 in brace roots indicated that ZmRHCP1 functions in brace root initiation. In addition, ZmRHCP1 expression was regulated by abiotic stresses. The expression results suggested that ZmRHCP1 plays important roles in brace root development and abiotic stress responses. The findings of the present study provide important information to help us understand the function of ZmRHCP1 in maize.

Streptomyces rubrogriseus HDZ-9-47, isolated from eggs of Meloidogyne spp., was evaluated as a potential biocontrol agent of Meloidogyne incognita under in vitro and protective field.  Microscopic observations showed that HDZ-9-47 parasitized eggs of M. incognita within 7 days.  In vitro, the culture filtrate of HDZ-9-47 caused 97.0% mortality of second-stage juveniles (J2s) of M. incognita and inhibited more than 50% egg hatching.  In the field, compared with the control, the root-knot index and J2s density in the treatment of drench the broth contained 10¹² HDZ-9-47 spores were respectively reduced by 51.1 and 80.7% at 90 days post transplantation, which were better than that in other application doses and methods.  In addition, reduction rates of root-knot index and J2s density of the treatment of combined application of HDZ-9-47 with biofumigation was 87.1 and 91.0%, respectively, better than either of HDZ-9-47 or biofumigation used alone or fosthiazate treatment.  And tomato yield also increased by 16.1%.  Together, our results suggest that HDZ-9-47 could be an effective biocontrol agent of M. incognita, and that application of HDZ-9-47 combined with cabbage residue biofumigation was a promising and sustainable option for M. incognita control.

To dissect the genetic control of the sensory and textural quality traits of Chinese white noodles, a population of recombinant inbred lines (RILs), derived from the cross of waxy wheat Nuomai 1 (NM1) and Gaocheng 8901 (Gc8901), was used.  The RILs were tested in three different environments to determine the role of environmental effects on quantitative trait loci (QTL) analysis.  A total of 45 QTLs with additive effects for 17 noodle sensory and textural properties under three environments were mapped on 15 chromosomes.  These QTLs showed 4.23–42.68% of the phenotypic variance explained (PVE).  Nineteen major QTLs were distributed on chromosomes 1B, 1D, 2A, 3B, 3D, 4A, and 6A, explaining more than 10% of the phenotypic variance (PV).  Clusters were detected on chromosomes 2B (3 QTLs), 3B (11 QTLs) and 4A (5 QTLs).  The cluster detected on chromosome 4A was close to the Wx-B1 marker.  Five co-located QTLs with additive effects were identified on chromosomes 2B, 3D, 4A, 6A, and 7B.  The two major QTLs, Qadh.sdau-3B.1 and Qspr.sdau-3B.1, in cluster wPt666008–wPt5870 on chromosome 3B were detected in three different environments, which perhaps can be directly applied to improve the textural properties of noodles.  These findings could offer evidence for the selection or development of new wheat varieties with noodle quality using molecular marker-assisted selection (MAS).

Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis (phz) genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato (Pst) DC3000 and Xanthomonas oryzae pv. oryzae (Xoo) PXO99^A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99^A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-1-carboxylic acid (PCA) of Pst DC3000 accumulated to 13.4 μg L^–1, while that of Xoo PXO99^A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL^–1 PCA, while Xoo PXO99^A was sensitive to 50 μg mL^–1 PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.

An experiment was carried out to investigate the relative bioavailability of tribasic zinc (Zn) sulfate relative to Zn sulfate for broilers fed a conventional corn-soybean meal diet. A total of 504 1-d-old Arbor Acres commercial male chicks were randomly assigned by body weight of birds to one of seven treatments involving a 2×3 factorial arrangement with three levels of added Zn (30, 60, or 90 mg of Zn kg–1) and two Zn sources (tribasic Zn sulfate and Zn sulfate) plus a control with no added Zn for an experimental phase of 14 d. Plasma Zn, tibia ash Zn, pancreas Zn, and pancreas metallothionein (MT) messenger RNA (mRNA) were analyzed at 6 or 14 d of age post-hatching. The results showed that plasma Zn, tibia ash Zn, pancreas Zn, and pancreas MT mRNA increased linearly (P<0.002) as dietary Zn concentration increased at 6 or 14 d of age. The R2 for a linear model was greater on d 6 than on d 14 for the above 4 responsive criteria, and among these indices, the fitting of the tibia ash Zn concentration was the best (R2=0.99). Therefore, based on slope ratios from the multiple linear regressions of the above 4 indices of the birds at 6 d of age on daily intake of dietary Zn, the bioavailabilities of tribasic Zn sulfate relative to Zn sulfate (100%) were 95.6% (P=0.18), 83.5% (P=0.01), 87.9% (P=0.53), and 75.9% (P=0.38) for the tibia ash Zn, pancreas Zn, plasma Zn, and pancreas MT mRNA, respectively. The results indicated that generally, Zn from tribasic Zn sulfate was as available as Zn from Zn sulfate for broilers.

In the study, an improved approach was proposed to identify the contribution shares of three group factors that are climate, technology and input, social economic factors by which the grain production is shaped. In order to calibrate the method, Jiangxi Province, one of the main paddy rice producers in China was taken as an example. Based on 50 years (1961-2010) meteorological and statistic data, using GIS and statistical analysis tools, the three group factors that in certain extent impact China’s paddy rice production have been analyzed quantitatively. The individual and interactive contribution shares of each factor group have been identified via eta square (η2). In the paper, two group ordinary leasr square (OLS) models, paddy models and climate models, have been constructed for further analysis. Each model group consists of seven models, one full model and six partial models. The results of paddy models show that climate factors individually and interactively contribute 11.42-15.25% explanatory power to the variation of paddy rice production in the studied province. Technology and input factors contribute 16.17% individually and another 8.46% interactively together with climate factors, totally contributing about 25%. Social economic factors contribute about 7% of which 4.65% is individual contribution and 2.49% is interactive contribution together with climate factors. The three factor groups individually contribute about 23% and interactively contribute additional 41% to paddy rice production. In addition every two of the three factor groups also function interactively and contribute about 22%. Among the three factor groups, technology and input are the most important factors to paddy rice production. The results of climate models support the results of paddy models, and display that solar radiation (indicated by sunshine hour variable) is the dominate climate factor for paddy rice production.

GmPHR1 from soybean (Glycine max) was isolated and characterized. This novel homolog of the AtPHR1 transcription factor confers tolerance to inorganic phosphate (Pi)-starvation. The gene is 2751 bp long, with an 819-bp open reading frame and five introns. Analysis of transcription activity in yeast revealed that the full-length GmPHR1 and its C-terminal activate the reporter genes for His, Ade and Ura, suggesting that the C-terminal peptide functions as a transcriptional activator. Quantitative real-time PCR indicated that patterns of GmPHR1 expression differed. For example, under low-Pi stress, this gene was quickly induced in the tolerant JD11 after 0.5 h, with expression then decreasing slowly before peaking at 12-24 h. By contrast, induction in the sensitive Niumaohuang (NMH) was slow, peaking at 6 h before decreasing quickly at 9 h. GmPHR1 showed sub-cellular localization in the nuclei of onion epidermal cells and Arabidopsis roots. Growth parameters in wild-type (WT) Arabidopsis plants as well as in overexpression (OE) transgenic lines were examined. Under low-Pi conditions, values for shoot, root and whole-plant dry weights, root to shoot ratios, and lengths of primary roots were significantly greater in OE lines than in the WT. These data demonstrate that GmPHR1 has an important role in conferring tolerance to phosphate starvation.

The importance of microRNA (miRNA) at the post-transcriptional regulation level has recently been recognized in both animals and plants. In recent years, many studies focused on miRNA target identification and functional analysis. However, little is known about the transcription and regulation of miRNAs themselves. In this study, the transcription start sites (TSSs) for 11 miRNA primary transcripts of soybean from 11 miRNA loci (of 50 loci tested) were cloned by a 5´ rapid amplification of cDNA ends (5´ RACE) procedure using total RNA from 30-d-old seedlings. The features consistent with a RNA polymerase II mechanism of transcription were found among these miRNA loci. A position weight matrix algorithm was used to identify conserved motifs in miRNA core promoter regions. A canonical TATA box motif was identified upstream of the major start site at 8 (76%) of the mapped miRNA loci. Several cis-acting elements were predicted in the 2 kb 5´ to the TSSs. Potential spatial and temporal expression patterns of the miRNAs were found. The target genes for these miRNAs were also predicted and further elucidated for the potential function of the miRNAs. This research provides a molecular basis to explore regulatory mechanisms of miRNA expression, and a way to understand miRNAmediated regulatory pathways and networks in soybean.

Although water and energy resources are well-recognized concerns regarding economic and social development sustainability, little specific research has focused on both water and energy problems at the same time. This study analyzed the water and electricity-use patterns in Shenzhen, South China during 2001-2009. A curve regression method was used to examine the relationship between water and electricity use per gross domestic product (GDP) in Shenzhen and its three sectors, i.e., agriculture, industry & construction, and residential life & services. Results showed that agriculture only covered less than 10% of water and electricity use in Shenzhen, while industry & construction and residential life & services accounted for more than 90% of water and electricity use in Shenzhen, which coincided with the city’s industrial structure. The water and electricity use per GDP in agriculture was the biggest among three sectors in Shenzhen during 2001-2009, which means inefficiency of water and electricity use in agriculture. Due to transitioning to advanced materials and manufacturing, both water and electricity use per GDP in industry & construction decreased during 2001-2009 and their utilization efficiencies gradually increased over time. The same held true for those in residential life & services transformed toward modern business, creative culture, finance services, etc. Derived from the survival of the fittest in competing for limited water and electricity resources, agriculture in Shenzhen has been gradually substituted by industry & construction and residential life & services, with much higher efficiencies of water and electricity use. And traditional agriculture will not be sustainable in the process of urbanization and industrialization, except high-tech intensive agriculture with low water and energy cost. Furthermore, by means of curve regression, we found that there was a significant quadratic relationship between water use per GDP and electricity use per GDP in the entire city and its three sectors. Suitable industrial transformation and advancement was a very effective way to save water and energy for modern cities. This can provide some reference for systematic planning and design of water and electricity allocation and use in agriculture, industry & construction and residential life & services in a city.

To study the relationships between C4 enzyme activities and yield, C4 enzyme activities (phosphoenolpyruvate carboxylase (PEPCase), NADP-malate dehydrogenase (NADP-MDH), NADP-malic enzyme (NADP-ME), and pyruvate phosphate dikinase (PPDK)) in different organs of ten soybean cultivars with different yields were measured at different growth stages in China. The result showed that four enzyme activities in C4 pathway were obviously different among cultivars, especially PPDK activity was not detected in the leaves of Dongnong 1567 and Dongnong 1068 and the young leaves of Gongjiao 9107-1 and Dongnong 97-172, but there were weak activities in pod coats. The order of C4 enzyme activities is young leaves < old leaves < pod coats. The correlation coefficients between PEPCase activity and yield and between NADP-MDH activity at blooming stage and yield were 0.6979 and 0.6565, respectively, and both reached the significant level (5%), and PEPCase activity kept significant positive correlation with plant photosynthetic rate. There was a negative correlation between NADP-ME activity and yield, and no correlation was found between PPDK activity and yield.

1 Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P.R.China 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, P.R.China 3 Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P.R.China Carotenoid biosynthetic pathway produces not only pigments that protect photosynthetic system against photo-oxidative damage, but also precursors of abscisic acid, the major hormone regulates stress responses. To understand the response of carotenoid biosynthetic pathway to salt stress, the expression of the genes involved in carotenoid and ABA biosynthesis were compared in cultivated tomato Solanum lycopersicon cv. Moneymaker and its relative wild genotype S. pimpinellifolium (PI365967) together with the contents of carotenoids and ABA. The results showed that 11 of the 15 genes investigated were up-regulated and four unaltered in Moneymaker after 5 h of salt stress; whereas only four genes were up-regulated, four unaltered, and seven down-regulated in PI365967 after stress. Further comparison revealed that 11 salinity-induced genes were expressed significantly lower in Moneymaker than in PI365967 under normal condition, and 8 of them were induced to similar levels after salt stress. In consistence, ABA level was doubled in Moneymaker but kept consistent in PI365967 after salt stress, though the contents of neoxanthin, violaxanthin, β-carotene, lutein, and total carotenoids were kept unchanged in both species. Since it is known that PI365967 is more tolerant to salt stress than Moneymaker, we proposed that the constitutive high level of carotenoid and ABA biosynthetic pathway under normal growth condition could be benefit to PI365967 for establishing the early response to salt stress. In addition, CrtR-b1 and CrtR-b2 that encode β-carotenoid hydroxylases were the only genes in carotenoid biosynthetic pathway that were up-regulated by salt stress in both species. The CrtR-b2 gene was cloned from both species and no essential difference was found in the encoded amino acid sequences. Transformation of CrtR-b2 to tobacco improved the seed germination under salt stress condition, indicating that the hydrolysis of β-carotenoid is the target of transcriptional regulation of the carotenoid biosynthesis in both tomato cultivar and wild relative.

EST-derived SSR marker has been developed in many species, but few methods of high efficiency have been reported for the exploitation of EST-SSR markers. Thus, a high efficiency method for mining millions of redundant EST data is needed. A modified method for the EST-SSR development with high efficiency was established based on the redundant EST data of soybean in this study. The method achieved its function through classifying ESTs according to the same SSR motif and detected candidate loci with redundant sequences. In this study, a total of 80 polymorphic EST-SSR markers of soybean were developed, 50 of them were exploited by this modified method which proved the higher speed and efficiency of this method. All the 80 polymorphic EST-SSRs were mapped on soybean physical map through in silico mapping and 15 markers were integrated on a genetic map constructed in previous study. A software named hpSSR (high polymorphic SSR) was programmed based on the concept of the up-built method for EST-SSR development. This method is not only pragmatic for EST-SSR exploitation in soybean, but also effective for the development of the marker in other species if the redundancy EST data is available.

Soyasaponins are valuable compounds in certain drugs, industry, food additives and surfactants. Selecting cultivars with higher-soyasaponin content along with agronomic traits is a main goal for many soybean breeders. The aim of the present study was to identify the quantitative trait loci (QTLs) associated with total soyasaponin content through a F2 population, which was derived from a cross between Ha 91016 (higher soyasaponin content cultivar, 16.8 mg g-1) and N98-9445A (lower soyasaponin content, only 5.7 mg g-1). A genetic linkage map including a total of 162 simple sequence repeat markers was constructed, which covered the total length 2 735.5 cM, and the average distance between markers was 16.96 cM. Two QTLs associated with total soyasaponin content were identified. One, qSAP_1 (located in sat_044-satt102 of linkage group (LG) K), could explain 12.6% of phenotypic variance. The other, qSAP_2, was located between satt368 and sat_413 of LG D1a, which could explain 15.8% of phenotypic variance. It was concluded that the two QTLs would have some potential value for marker-assisted selection for high-soyasaponin content breeding in soybeans.

A mutant was isolated from the M2 of 60Co-g ray mutagenized male-fertility restorer line Zao-R974 in rice. The mutant showed pleiotropic phenotypes including dwarfism, delayed heading time, short and partially enclosed panicles, short uppermost internode, decreased grain and secondary branch numbers per panicle, and partially degenerated spikelets. The mutant was named as esp1 (enclosed shorter panicle 1). Genetic analysis indicated that the mutant phenotype was controlled by a recessive locus. Spraying exogenous GA3 did not rescue the panicle enclosure. Using an F2 and a BC1 population of the cross between esp1 and a japonica cultivar Nipponbare, we mapped the ESP1 locus to a region of ~260 kb on chromosome 11. This result provides a basis for further map-based cloning of the ESP1 locus.

Crop models can be useful tools for optimizing fertilizer management for a targeted crop yield while minimizing nutrient losses. In this paper, the parameters of the decision support system for agrotechnology transfer (DSSAT)-CERES-Maize were optimized using a new method to provide a better simulation of maize (Zea mays L.) growth and N uptake in response to different nitrogen application rates. Field data were collected from a 5 yr field experiment (2006-2010) on a Black soil (Typic hapludoll) in Gongzhuling, Jilin Province, Northeast China. After cultivar calibration, the CERES-Maize model was able to simulate aboveground biomass and crop yield of in the evaluation data set (n-RMSE=5.0-14.6%), but the model still over-estimated aboveground N uptake (i.e., with E values from -4.4 to -21.3 kg N ha-1). By analyzing DSSAT equation, N stress coefficient for changes in concentration with growth stage (CTCNP2) is related to N uptake. Further sensitivity analysis of the CTCNP2 showed that the DSSAT model simulated maize nitrogen uptake more precisely after the CTCNP2 coefficient was adjusted to the field site condition. The results indicated that in addition to calibrating 6 coefficients of maize cultivars, radiation use efficiency (RUE), growing degree days for emergence (GDDE), N stress coefficient, CTCNP2, and soil fertility factor (SLPF) also need to be calibrated in order to simulate aboveground biomass, yield and N uptake correctly. Independent validation was conducted using 2008-2010 experiments and the good agreement between the simulated and the measured results indicates that the DSSAT CERES-Maize model could be a useful tool for predicting maize production in Northeast China.

The importance of microRNAs (miRNAs) at the post-transcriptional regulation level has recently been recognized in bothanimals and plants. In this study, the simple and most effective method of comparative genomic approach was used. Firstknown plants miRNAs BLAST against the soybean genome, and then the located candidates were searched for novelmiRNAs by RNA folding method in the vicinity (±400 nt) of the candidates. The results showed that a total of 521 novelsoybean miRNA genes, including 236 mature miRNAs, were identified. All these mature miRNAs were grouped into 58families, of which 21 of them were novel family in soybean. The upstream 2 000 nt of potential pre-miRNAs was used forpromoter prediction, in order to investigate prediction of miRNAs and detect transcript unit and clustering. In this study,miRNA genes less tend to be present as clusters in soybean. Only 9 clusters, containing 21 miRNA genes (accounted for4.0% of the total), were observed as part of polycistronic transcripts. Detailed analysis of sequence characteristics ofnovel miRNAs in soybean and all previous known plants miRNAs, were carried out. These results of this study providea reference point for further study on miRNAs identification in plants, and improve the understanding of genome insoybean.

Actin and myosin were found to be associated with the cytoplasmic sleeve of plasmodesmata. As cytoskeletal proteins, actin and myosin are believed to regulate the conductivity of plasmodesmata (PDs) in higher plants. Using immunocytochemical methods, we found the two proteins to be co-localized - and closely linked to each other - in plasmodesmata and ectodesmata-like structure in ageing parenchymatous cells of Allium sativum L. We suggest that intercellular communication is affected by the interaction between actin and myosin.