薇甘菊（Mikania micrantha）是一种快速生长的全球性入侵杂草，广泛分布在热带和亚热带地区。薇甘菊的入侵会对当地自然生态系统造成严重破坏，并对森林和作物生产造成巨大的经济损失。它在光合作用方面具有优势，其净光合速率与C₄植物相近，固碳能力较高。研究表明薇甘菊的光合能力是其快速生长和快速殖民新栖息地的重要原因之一。然而，目前尚没有研究揭示薇甘菊光合作用的进化机制和昼夜规律。本研究采用基因组学和转录组学相结合的方法，揭示了薇甘菊光合作用的进化机制和昼夜表达模式。结果显示，在薇甘菊中有16个正选择基因，主要集中于光反应和光同化物的利用两个过程中，并且叶绿素a/b结合蛋白、苹果酸脱氢酶、丙酮酸正磷酸二激酶和苹果酸酶家族的基因数量与C₄植物(高粱或玉米)相似，显著高于其他植物。在不同组织中，98.1%与光反应相关的基因在茎中具有较高表达，C₄循环相关的基因中有一半以上在茎中高于叶中的表达。气孔开闭过程中，2个碳酸酐酶基因在18:00的表达量高于8:00，SLAC1和HT1基因在18:00表达量最低。此外，与光合作用相关的基因在7:00和17:00表达量较高。因此我们推测，薇甘菊能够在茎和花器官中进行光合作用，并且叶片的一些气孔在夜间能够通过CO₂信号打开。此外，它的进化可能会减弱高光强时的光抑制，并在低光强时提高光合作用的效率。组织特异性光合类型和光合相关基因的不同昼夜模式可能有助于薇甘菊在新栖息地的快速定植。薇甘菊可能通过这些变化增加了它的种间优势和侵袭性。本文的研究结果为了解薇甘菊的光合作用机制及其控制和生物利用度提供了有价值的信息。

厘清大豆种质籽粒中的类胡萝卜素组分和含量对大豆种质营养品质评价具有重要意义。本研究针对遗传多样性丰富的中国大豆种质的类胡萝卜素和叶绿素含量进行了系统分析，并揭示了不同营养品质组分间的相关性。结果显示基因型、种植年份、种质类型、子叶色和生态区来源显著影响籽粒中类胡萝卜素和叶绿素含量，其平均类胡萝卜素总含量变化范围为8.15-14.72 µg g^-1。大豆农家种的类胡萝卜素含量是栽培种的1.2倍，特别是绿子叶种质的类胡萝卜素和叶绿素含量显著高于黄子叶种质。需要指出的是单一组分中叶黄素的含量是最高的，其变化范围为1.35-37.44 µg g^-1。类胡萝卜素和叶绿素含量与其他品质组分显著相关，这有利于育种者在强化类胡萝卜素含量同时而不影响其他品质组分。我们结果证明了大豆籽粒中的类胡萝卜素含量是丰富的，但其积累宜受遗传因素、种质类型和种质来源的显著影响。我们还鉴定了一批高类胡萝卜素含量的大豆新种质，可以为大豆育种、食品加工和化妆品行业利用。

花色苷是影响植物颜色和营养品质的重要色素。MYBs在植物花色苷的合成和积累中起着重要作用。然而，MYB转录因子在亚麻花的花色苷合成中的调节作用尚不清楚。在本研究中，从亚麻基因组中共鉴定出402个MYB转录因子，这些MYB成员在15条染色体上分布不均。其中，R2R3-LuMYB成员被分为32个亚家族。实时荧光定量（qRT-PCR）分析显示，进化树相邻亚家族中的7个R2R3-LuMYB基因具有相似的表达模式，其中LuMYB216在不同颜色的花瓣中高度表达。此外，对LuMYB216在亚麻中进行基因编辑后，观察到突变体植物的花瓣颜色、花药颜色和种皮颜色明显浅于野生型植株。测定lumyb216突变体植株的花瓣和种皮的花色苷，发现含量较野生型显著降低。相关分析表明，LuMYB216与其上游调控因子bHLH30共表达，且显著正相关。本研究系统分析了亚麻中的MYB基因家族，为研究LuMYB216在亚麻花的花色苷合成中的调控奠定了基础。

提高小麦产量是全球小麦育种者的长期目标。发掘优良遗传资源，解析小麦重要农艺性状的遗传基础，是小麦高产育种的必经之路。本研究评价了两年七个环境中由156个育成品种和77个地方品种组成的四川小麦自然群体的9个重要农艺性状表现。农艺性状调查结果表明，地方品种分蘖较多，穗粒数（KNS）较高，育成品种千粒重（TKW）和穗粒重（KWS）较高。9个农艺性状的广义遗传力（H ²）在0.74到0.95之间。利用来自小麦55K SNP芯片的43198个单核苷酸多态性（SNP）标记进行群体结构分析可以将自然群体分为三组。基于混合线性模型Q+K方法的全基因组关联分析（GWAS）共鉴定出67个数量性状位点（QTL）。本研究主要对三个重要性状的QTL进行了分析，即分别检测到的可育分蘖数（FTN）位点QFTN.sicau-7BL.1的四种单倍型、KNS位点QKNS.sicau-1AL.2的三种单倍型和TKW位点QTKW.sicau-3BS.1的四种单倍型。从2002—2013年区域试验的42个品种的产量表现来看，FTN-Hap2、KNS-Hap1和TKW-Hap2分别是每个QTL中的优良单倍型。具有三个优良单倍型的品种相比具有两个或一个优良单倍型的品种产量更高。此外，基于每穗粒数的QTL位点 QKNS.sicau-1AL.2开发了连锁的KASP-AX-108866053标记能在2018年至2021年区域试验中鉴定63个品种的三种单倍型（或等位基因）。这些遗传位点和连锁标记可用于标记辅助选择或基于图谱的基因克隆，用于小麦产量的遗传改良。

氮肥在中国的过度使用及其对农业生产的不利影响已在国内和国际引起关注。除公共机构推动的多种促进农业可持续发展的实践外，借助信息通讯技术或数字服务手段推动可持续农业实践的私人部门创新和创业正在崭露头角。本研究探讨了一个创业企业依托信息技术提供农业技术推广服务对农户采用可持续农业实践的影响。结果表明，依托信息技术的农业社会化服务并没有显著减少小麦种植中的氮肥使用量。然而，信息技术在农业社会化服务的使用却促使农民的氮肥施用趋向于可持续和精准施肥。创业企业的此种创业模式在农户参与性和财务可持续性方面面临巨大挑战。

Now, lodging is a major constraint factor contributing to yield loss of maize (Zea mays L.) under high planting density. Chemical regulation and nitrogen fertilizer could effectively coordinate the relationship between stem lodging and maize yield, which significantly reduce lodging and improve the grain yield. The purpose of this study was to explore the effects of chemical regulation and different nitrogen application rates on lodging characteristics, grain filling and yield of maize under high density. For this, we established a field study during 2017 and 2018 growing seasons, with three nitrogen levels of N100 (100 kg ha^–1), N200 (200 kg ha^–1) and N300 (300 kg ha^–1) at high planting density (90 000 plants ha^–1), and applied plant growth regulator (Yuhuangjin, the mixture of 3% DTA-6 and 27% ethephon) at the 7th leaf. The results showed that chemical control increased the activities of phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), 4-coumarate:CoA ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD), and increased the lignin, cellulose and hemicellulose contents at the bottom of the 3rd internode, which significantly reduced the lodging percentage. The lignin-related enzyme activities, lignin, cellulose and hemicellulose contents decreased with the increase of nitrogen fertilizer, which significantly increased the lodging percentage. The 200 kg ha^–1 nitrogen application and chemical control increased the number, diameter, angle, volume, and dry weight of brace roots. The 200 kg ha^–1 nitrogen application and chemical control significantly increased the activities of ADP-glucose pyrophosphorylase (AGPase), soluble starch synthase (SSS) and starch branching enzyme (SBE), which promoted the starch accumulation in grains. Additional, improved the maximum grain filling rate (V_max) and mean grain filling rate (V_m), which promoted the grain filling process, significantly increased grain weight and grain number per ear, thus increased the final yield.

 

Chinese vegetable production cooperatives supply their members, mostly smallholder farmers, with a rotation schedule for the year.  Since vegetable prices are not stable throughout the year, designing a rotation schedule that maximizes expected profits, distributes farmers’ profits more equitably, maintains the diversity of produce in the market, and reduces the risk of pests and diseases, requires adaptive, price-contingent rotation schedules (here, called “self-adaptive adjustment”).  This study uses an agent-based simulation (ABS) to design self-adaptive rotation schedules that deliver these aims.  The self-adaptive adjustment strategy was more profitable for farmers when faced with price volatility, and more equitable as well.  This work provides a decision-support tool for managers of Chinese vegetable production cooperatives to provide farmers with more profitable and equitable rotation schedules.   

Melatonin is a naturally occurring compound in plants.  Here, we tested the effect of exogenous melatonin on rapeseed (Brassica napus L.) grown under salt stress.  Application of 30 μmol L^–1 melatonin alleviated salt-induced growth inhibition, and the shoot fresh weight, the shoot dry weight, the root fresh weight, and the root dry weight of seedlings treated with exogenous melatonin increased by 128.2, 142.9, 122.2, and 124.2%, respectively, compared to those under salt stress.  In addition, several physiological parameters were evaluated.  The activities of antioxidant enzymes including peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were enhanced by 16.5, 19.3, and 14.2% compared to their activities in plants without exogenous melatonin application under salt stress, while the H₂O₂ content was decreased by 11.2% by exogenous melatonin.  Furthermore, melatonin treatment promoted solute accumulation by increasing the contents of proline (26.8%), soluble sugars (15.1%) and proteins (58.8%).  The results also suggested that higher concentrations (>50 μmol L^–1) of melatonin could attenuate or even prevent the beneficial effects on seedling development.  In conclusion, application of a low concentration of exogenous melatonin to rapeseed plants under salt stress can improve the H₂O₂-scavenging capacity by enhancing the activities of antioxidant enzymes such as POD, CAT and APX, and can also alleviate osmotic stress by promoting the accumulation of osmoregulatory substances such as soluble proteins, proline, and water soluble glucan.  Ultimately, exogenous melatonin facilitates root development and improves the biomass of rapeseed seedlings grown under salt stress, thereby effectively alleviating the damage of salt stress in rapeseed seedlings.

   Loquat (Eriobotrya japonica Lindl.) can be divided into yellow- and white-fleshed cultivars by flesh color. However, a Dongting loquat mutant, which involved bud sport and growing white-fleshed fruit in the central region of the trunk (as wild loquat bears yellow-fleshed fruits naturally), was discovered in the preliminary study. The study cloned the coding sequence (CDS) of NAD⁺-dependent sorbitol dehydrogenase (NAD⁺-SDH ) gene from the selected materials of mutant loquat, wild loquat and other nine loquat cultivars/accessions, and found that the CDS of NAD⁺-SDH gene from the mutant loquat, other than the rest two types of materials, had three single nucleotide polymorphisms (SNPs) loci; in addition, the amino acid encoded at variation loci changed accordingly. NAD⁺-SDH plays an active role in converting sorbitol into fructose in loquat cultivars. For the mutant white-fleshed loquat, the activity of NAD⁺-SDH rises first and then drops, the sorbitol content decreases steadily, and its fructose content is higher than that in wild loquat from coloration to maturation stage. As demonstrated by the real-time fluorescence quantification PCR analysis, the expression level of NAD⁺-SDH gene at maturation stage is about 5-fold lower than wild type. It may be assumed that, the three SNPs loci might lead to excessive conversion of sorbitol into fructose under the catalytic action of NAD⁺-SDH of white-fleshed mutant loquat at maturation stage, resulting in the increase of fructose content and reduced expression abundance of mRNA after transcription. Besides, NAD⁺-SDH gene may be related to flesh color and carbohydrate variation of white-fleshed mutant loquat.

Ten populations of Radopholus similis from different ornamental hosts were tested for their parasitism and pathogenicity to water spinach (Ipomoea aquatic), malabar spinach (Basella rubra), and squash (Cucurbita moschata) in pots. The results showed all three plants were new hosts of R. similis. Growth parameters of plants inoculated with nematodes were significantly lower than those of healthy control plants. All R. similis populations were pathogenic to the three plants, but pathogenicity differed among populations from different hosts. The same R. similis populations also showed different pathogenic effects in the three different plants. RadN5 population from Anthurium andraeanum had the highest pathogenicity to the three studied plants. RadN1 from A. andraeanum had the lowest pathogenicity to squash and RadN7 from Chrysalidocarpus lutesens had the lowest pathogenicity to water spinach and malabar spinach. R. similis is usually associated with root tissues, but here we report that it could be found to move and feed in the stem bases of all three studied plants. Sequence and phylogenetic analyses of DNA markers of the 18S rRNA, 28S rRNA, ITS rRNA, and mitochondrial DNA gene sequences of ten R. similis populations revealed significant genetic diversity. RadN5 and RadN6 populations from anthurium showed a close genetic relationship and could be distinguished from other populations by PCR-RFLP. At the same time, RadN5 and RadN6 populations were the most pathogenic to three studied plants. These results confirm the existence of large biological variability and molecular diversity among R. similis populations from the same or different hosts, and these characteristics are related to pathogenic variability.

Conogethes punctiferalis (Guenée) (Lepidoptera: Crambidae) was originally considered as one species with fruit-feeding type (FFT) and pinaceae-feeding type (PFT), but it has subsequently been divided into two different species of Conogethes punctiferalis and Conogethes pinicolalis. The relationship between the two species was investigated by phylogenetic reconstruction using maximum-likelihood (ML) parameter estimations. The phylogenetic tree and network were constructed based upon sequence data from concatenation of three genes of mitochondrial cytochrome c oxidase subunits I, II and cytochrome b which were derived from 118 samples of C. punctiferalis and 24 samples of C. pinicolalis. The phylogenetic tree and network showed that conspecific sequences were clustering together despite intraspecific variability. Here we report the results of a combined analysis of mitochondrial DNA sequences from three genes and morphological data representing powerful evidence that C. pinicolalis and C. punctiferalis are significantly different.

Plants reshape their transcriptomes, proteomes and metabolomes in response to insect damage. In this study, we used suppression subtractive hybridization to investigate the transcriptomes of two cotton varieties (CCRI41 and CCRI23) under Apolygus lucorum damage. From the CCRI23 libraries we obtained 92 transcripts and from the CCRI41 libraries we obtained 96 transcripts. 26 and 63 of the transcripts from CCRI23 and CCRI41, respectively, had known functions. Using reverse transcription PCR, we detected expression profile of genes with known functions. Ultimately, we identified eight significantly regulated genes, including one downregulated and four upregulated genes from the CCRI41 libraries, and one downregulated and two upregulated genes from the CCRI23 libraries. Only the gene encoding the polyphenol oxidase (PPO) is involved in plant defense against insect herbivores, and the others are related to improving tolerance to insect damage. Quantitative real-time PCR was used to study changes in expression levels during A. lucorum damage in CCRI23 and CCRI41. Significantly regulated genes from CCRI23 showed a response in CCRI23 but not response in CCRI41. Similarly, significantly regulated genes from CCRI41 showed a response in CCRI41 but not response in CCRI23. The results showed that, among transcriptomes of cotton varieties, there are different responses to A. lucorum damage.

Alfalfa (Medicago sativa L.) is an important forage crop in the world and it is of great significance for the improvement of its salt tolerance. To improve salt tolerance in alfalfa, a rice ascorbate peroxidase gene (OsAPX2) was introduced into alfalfa using Agrobacterium tumefaciens-mediated transformation with marker gene bar. The different T-DNA insertions in T1 transgenic alfalfa were identified by Southern hybridization. Three independent T2 transgenic lines were selected for stress analysis and the results showed that all of them were salt tolerant compared with wild-type plants. The transgenic plants had low levels of H2O2, malondialdehyde and relative electrical conductivity under salt and drought stresses. Moreover, the contents of chlorophyll and proline, and APX activity were high in transgenic plants under salt and drought stresses. Taken together, the overexpression of OsAPX2 enhances salt tolerance in alfalfa through scavenging reactive oxygen species.

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.

Drought is one of the major abiotic stresses that limit maize productivity. Apart from the principal transcriptional regulation, post-transcriptional regulation mediated by microRNAs appears to be the prevalent response of plants to abiotic stress. In this study, the differential expression of microRNAs in the previously evaluated drought-tolerant inbred lines R09 under drought stress was detected by microarray hybridization. The target genes of the differentially-expressed microRNAs were predicted by bioinformatics software WMD3 for plant target gene prediction. The possible regulation of the differentially-expressed microRNAs as well as their target genes in maize response to drought stress was analysed according to Gene Ontology. Sixty-eight microRNAs in 29 microRNA families were detected to be differentially expressed in the seedling of the drought-tolerant inbred line R09, accounting for 5.97% of the total number of the probes. The expression profiles were different between the two time points of the drought stress. The functions of the genes targeted by the differentially-expressed microRNAs involve multiple physiological and biochemical pathways of response to abiotic stress, such as transcription regulation, metabolism, signal transduction, hormone stimulation, and transmembrane transport. Under drought stress, the differential expression of microRNAs regulates the expression of their target genes, resulting in multiple responses of physiological and biochemical pathways relative to drought tolerance of maize. miR156, miR159 and miR319 families may play more important roles. The different members of the same family may play similar regulation effects in most cases.

The virulent strain B6 of Curvularia lunata was screened out from 65 fungus strains isolated from the diseased leaves of barnyardgrass (Echinochloa crus-galli). Greenhouse and field studies were conducted to evaluate the feasibility of the strain being exploited as a mycoherbicide for barnyardgrass control in paddy fields. The results of pathogenicity experiments showed that this strain was highly pathogenic to barnyardgrass at the 1- to 2.5-leaf stages. The fresh weight reduction increased with the increase of inoculated conidial concentrations and the prolongation of dew duration. Strain B6 provided excellent barnyardgrass control when it was applied at the concentration of 1×104-1×106 conidia mL-1 in paddy fields with water layer. This strain was very safe to rice and the most plant species except wheat, barley and corn. Findings of this study indicated that this strain could be a potential mycoherbicide for barnyardgrass control in paddy fields in the future.

Morphology and morphometry of six biotypes (B, Q, Cv, ZHJ-1, ZHJ-2 and ZHJ-3) of Bemisia tabaci (Gennadius) from China on cotton plants were studied by using microscopes. Nymphal body sizes and characters were measured and observed, especially on the 4th instar (pupal case), including the vasiform orifice, operculum, lingula, length and thickness of anterior and posterior wax margins, width of thoracic tracheal combs. Adult characters of both sexes were investigated including the body size, compound eyes, antennal segments, vasiform orifice, hind tarsi and genitals. The results indicated that differences of some morphological characters or morphometrics were significant among the six biotypes of B. tabaci in China: (1) Pupal sizes of the exotic biotypes (B and Q) were significantly larger than the indigenous biotypes with the following order as B>Q>ZHJ-1>Cv>ZHJ-3>ZHJ-2; (2) for both male and female adults, sizes of all characters investigated in the invading biotypes (B and Q), especially B, were much larger than those of the indigenous ones.

Wolbachia are maternally inherited endosymbiotic bacteria infecting a wide range of arthropods and filarial nematodes. They can induce various reproduction alterations in their hosts, including thelytokous parthenogenesis, cytoplasmic incompatibility (CI), feminization of genetic males and male killing. Here we investigated diversity and prevalence patterns of Wolbachia infection in 43 geographical populations of the Asian corn borer, Ostrinia furnacalis, in China and one population in North Korea. Based on Wolbachia surface protein gene (wsp) sequences, nine strains of Wolbachia (wFur1-wFur9), belonging to supergroups A and B, were identified in populations of O. furnacalis with an average infection rate of 10.5%. Superinfection commonly appeared in individuals of O. furnacalis and coinfection patterns were very complex. There was no specific pattern for the prevalence and distribution of the nine Wolbachia strains suggesting an intricate evolutionary history of Wolbachia infection in this species. The genetic similarity of the wFur1-wFur9 strains with those detected in two parasitoids of O. furnacalis, Macrocentrus cingulum and Lydella grisescens, strongly suggests host-parasitoid horizontal transmission.

14-3-3 proteins belong to a family of phosphoserine/threonine-binding modules and participate in a wide array of signal transduction and regulatory events. Our previous study demonstrated that Ta14-3-3 was significantly down-regulated in leaf and root tissues of hybrid wheat at the tillering stage. In this paper, three homoeologous Ta14-3-3 genes were cloned from common wheat (Triticum aestivum L., 2n=6x=42, AABBDD) and mapped on chromosomes 2A, 2B, and 2D, respectively. Transgenic Arabidopsis plants ectopically overexpressing Ta14-3-3 displayed shorter primary roots, delayed flowering and retarded growth rates, indicating that Ta14-3-3 acted as a growth inhibitor in Arabidopsis. In wheat, Ta14-3-3 was down-regulated in roots and leaves of hybrids as compared to their parental lines. We proposed that Ta14-3-3 proteins might regulate growth vigor in hybrid wheat.

Jojoba (Simmondsia chinensis) is mainly distributed in desert, and the molecular mechanisms of jojoba in response to abiotic stress still remain elusive. In this paper, we cloned and characterized a SOD gene from jojoba named as ScMnSOD, and introduced into Arabidopsis to investigate its functions of responding to drought stress. The transgenic Arabidopsis showed an improvement in drought tolerance. Moreover, under a water deficit condition, the accumulation of reactive oxygen species (ROS) was remarkably decreased in the transgenic lines compared to the WT. Furthermore, the ScMnSOD promoter was cloned to the 5´-upstream of GUS coding region in a binary vector, and introduced into Arabidopsis. And results showed that ScMnSOD expression can be induced by drought, salt, ABA, and low temperature. In conclusion, ScMnSOD plays an important role in drought tolerance which is, at least partially, attributed to its role in ROS detoxification.

2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), the dominant benzoxazinoid hydroxamic acid in maize (Zea Mays L.), serves as important factors of resistance against insects and microbial diseases, allelochemicals used in competition with other plants. In this paper, a novel and simple method for the isolation and purification of DIMBOA from maize seedlings was developed. Frozen shoots from 7-d-old maize seedlings (1 000×g) were firstly defrosted and then were directly homogenized and extracted with ethyl acetate. The macerate was allowed to stand at room temperature (25±2)°C for 1 h to allow enzymatic release of DIMBOA from DIMBOA-glucoside. Then the ethyl acetate phase was filtered, dried and evaporated to dryness. The resulting light-tan, semicrystalline residue was stored at -20°C for 24 h. Upon recrystallization from acetone-hexane, a relative higher yield (0.58 g) of pure DIMBOA crystals was obtained compared with the yield afforded by Woodward methodology (0.26 g).

This paper introduces efforts and achievements of Agriculture Ontology Service Research Group of Agricultural Information Institute of Chinese Academy of Agriculture Sciences in last 10 years. It summarizes the research on ontology construction methodology, ontology management system, ontology application and etc.