昆虫的气味受体（Odorant receprot，OR）是它们探测和识别与其生存密切相关的外部化学线索的关键。昆虫识别配体的特异性受体与一个广泛存在的气味受体共受体（Odorant receptor coreceptor，Orco）构成了异聚体复合体。本研究运用CRISPR/Cas9基因敲除技术对我国重大入侵害虫草地贪夜蛾的Orco基因进行了敲除，并揭示了该基因在气味受体调控的嗅觉行为中的重要作用。触角电位结果表明，Orco基因敲除之后，雌雄成虫对8种测试的植物挥发物和两种性信息素的电生理反应均丧失。然而，Orco基因对雌雄成虫交配行为的影响却存在明显的差异：雄虫Orco突变体的交配行为完全被干扰而雌虫Orco突变体的交配行为却不受影响。产卵实验结果表明，Orco突变体雌虫的产卵量比野生型雌虫的产卵量减少了24.1%。总之，这些结果表明了Orco是一个干扰草地贪夜蛾正常行为的优良靶标，并为害虫的防治提供了一种可行的方法。

为明确不同生育时期受灾对棉花恢复生长及产量的影响，本研究于2018-2019年，以鲁棉研24号为供试材料，采用自制工具拍打法从棉花五叶期至吐絮期每隔约15天（同一地块只进行一次损害处理）进行4种程度（0%、30%、60%和90%），共计六次（Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ）的雹灾模拟试验，获取受灾后植株叶面积指数、光合势、干物质积累与分配、产量及吐絮铃空间分布图。研究结果表明，棉花籽棉产量随受灾程度的增加而下降，降幅随受灾时期的推迟而增大，其中在花后（第Ⅳ、Ⅴ、Ⅵ时期），30%、60%和90%受灾程度的产量比0%受灾程度分别减少9%-17%、22%-37%和48%-71%。这是由于棉花受雹灾损害后植株叶面积指数和光合势下降，导致干物质积累量减少，但由于棉花的无限生长习性，花前（第Ⅰ、Ⅱ、Ⅲ时期）受灾后营养器官产生较强的补偿能力进而促使蕾铃发育，仅植株中上部及外围果节的吐絮铃受到影响，造成较少的产量损失；花后受灾后营养器官补偿能力下降、恢复时间短，不足以促进新生铃发育、成熟，导致有效果枝数及各果节吐絮铃数下降，造成较大的产量损失。因此，花前受灾后补救措施应以促蕾铃发育为主，促叶片发育为辅；花后受灾后补救应以保铃、促叶片发育为主。本文从灾后植株叶面积指数、光合势、地上生物量积累与分配等方面研究棉花受雹灾损害后的恢复生长及其对最终产量的影响，该研究结果可为减灾、制定灾后管理方案及产量预测提供理论依据。

深播是包括玉米在内的作物躲避干旱的一种重要策略，候选基因的克隆是进行玉米耐深播分子机理研究的基础工作。本研究中，我们利用包含386份玉米自交系的关联分析群体对10厘米和20厘米播种深度条件下的四个性状进行鉴定。利用50万SNP标记进行关联分析发现了273个耐深播性状显著关联的SNP。对两组不同的处理进行RNA测序分析分别发现1944和2098个差异基因，其中包含281个共同的差异基因。通过比较273个SNP和281个差异基因的位置发现了7个可能与耐深播相关的候选基因，其中GRMZM2G119769编码一个SNF1激酶互作的蛋白。由于GRMZM2G119769在其他植物中的同源基因跟器官伸长、生长素和光响应有关。同时，候选基因关联分析表明GRMZM2G119769基因的自然变异与玉米的中胚轴长度有关。另外，基因表达分析表明GRMZM2G119769在耐深播材料中表达量高。这些研究结果都支持GRMZM2G119769是玉米耐深播性状的候选基因。本研究不但评价了玉米资源的耐深播特性，还鉴定出一些可能对未来玉米耐深播研究有参考价值的候选基因。

二花脸猪、梅山猪和米猪是我国太湖流域优良的地方猪品种，为商品猪的遗传改良做出了巨大贡献。分析这3个猪种的遗传结构和近交水平，对地方猪遗传多样性的保护以及商品猪的持续改良具有重要意义。长纯合片段（Runs of homozygosity，ROH）的长度、数量以及在基因组中的分布模式可以作为评价群体近交水平和物种起源的指标。本研究利用SLAF-seq数据对4个不同品种（二花脸猪、梅山猪、米猪和长白猪）的猪群体进行全基因组ROH 检测，并根据ROH信息计算了各个猪群体的近交系数（F_ROH）。此外，研究还在高频ROH区域筛选与母猪繁殖性状相关的候选基因。在4个猪种的116个个体中共检测到10,568个ROH。PCA分析表明，太湖流域3个猪种的遗传结构与长白猪存在显著差异，而二花脸猪和米猪的遗传结构较为相似。在4个猪群体中，长白猪短ROH（<5 Mb）的频率最高，而梅山猪长ROH（>5 Mb）的频率最高，明显高于二花脸猪和米猪。梅山猪个体ROH覆盖总基因组的长度和ROH总数接近于长白猪，也明显高于二花脸猪和米猪。同时，梅山猪的平均F_ROH最高与长白猪相近，二花脸猪的平均F_ROH最低与米猪相近。以上结果表明梅山猪和长白猪一样表现出较高的近交水平，梅山猪较高的近交水平主要来源于近代的近亲繁殖，而二花脸猪和米猪的近交水平相对较低。此外，大量与母猪繁殖性状相关的候选基因在高频ROH区被鉴定到，这些基因有望作为标记辅助选择(MAS)育种的候选基因。本研究的结果为太湖流域3个猪种的遗传多样性保护、防止近交衰退和遗传改良提供了理论依据。

试验采用温室水培的方式，以豫麦49（高铵迟钝型）和鲁麦15（高铵敏感型）为材料，设置了5.0 mM NH₄⁺-N（EAC）和NO₃^--N（CON）两个处理，研究了小麦幼苗根系氧化代谢对高铵胁迫的响应机制。结果表明，高铵胁迫下，两个小麦品种根系生长显著降低，其中鲁麦15降低程度高于豫麦49。高铵胁迫增加了两个小麦品种根系单脱氢抗坏血酸还原酶活性和脱氢抗坏血酸还原酶活性，但降低了处理12天后的根系抗坏血酸（ASA）含量和GDP-甘露糖焦磷酸酶（GMPase）活性，其中鲁麦15根系ASA含量和GMPase活性分别降低了62.0和71.4%，豫麦49根系ASA含量和GMPase活性分别降低了38.8和62.2%，说明高铵胁迫提高了ASA再生，但减少了ASA合成。此外，EAC增加了两个小麦品种根系DHA/ASA，活性氧（ROS）含量，丙二醛含量和抗氧化物酶活性。与豫麦49相比，鲁麦15根系中ROS含量和可溶性糖含量相对增加较多，而抗氧化物酶活性增加较少，说明鲁麦15根系氧化代谢紊乱更严重。结果表明，高铵胁迫下，GMPase活性降低导致ASA生物合成的减少可能是ROS过量积累和氧化还原失衡的原因之一，进而抑制小麦幼苗根系生长。与高铵敏感型品种鲁麦15相比，豫麦49具有较强的氧化胁迫保护能力，维持较低水平DHA/ASA，进而保持较好的氧化还原平衡状态，因此更耐高铵。

Available irrigation resources are becoming increasingly scarce in the North China Plain (NCP), and nitrogen-use efficiency of crop production is also relatively low. Thus, it is imperative to improve the water-use efficiency (WUE) and nitrogen fertilizer productivity on the NCP. Here, we conducted a two-year field experiment to explore the effects of different irrigation amounts (S60, 60 mm; S90, 90 mm; S120, 120 mm; S150, 150 mm) and nitrogen application rates (150, 195 and 240 kg ha^–1; denoted as N1, N2 and N3, respectively) under micro-sprinkling with water and nitrogen combined on the grain yield (GY), yield components, leaf area index (LAI), flag leaf chlorophyll content, dry matter accumulation (DM), WUE, and nitrogen partial factor productivity (NPFP). The results indicated that the GY and NPFP increased significantly with increasing irrigation amount, but there was no significant difference between S120 and S150; WUE significantly increased first but then decreased with increasing irrigation and S120 achieved the highest WUE. The increase in nitrogen was beneficial to improving the GY and WUE in S60 and S90, while the excessive nitrogen application (N3) significantly reduced the GY and WUE in S120 and S150 compared with those in the N2 treatment. The NPFP significantly decreased with increasing nitrogen rate under the same irrigation treatments. The synchronous increase in spike number (SN) and 1 000-grain weight (TWG) was the main reason for the large increase in GY by micro-sprinkling with increasing irrigation, and the differences in SN and TGW between S120 and S150 were small. Under S60 and S90, the TGW increased with increasing nitrogen application, which enhanced the GY, while N2 achieved the highest TWG in S120 and S150. At the filling stage, the LAI increased with increasing irrigation, and greater amounts of irrigation significantly increased the chlorophyll content in the flag leaf, which was instrumental in increasing DM after anthesis and increasing the TGW. Micro-sprinkling with increased amounts of irrigation or excessive nitrogen application decreased the WUE mainly due to the increase in total water consumption (ET) and the small increase or decrease in GY. Moreover, the increase in irrigation increased the total nitrogen accumulation or contents (TNC) of plants at maturity and reduced the residual nitrate-nitrogen in the soil (SNC), which was conducive to the increase in NPFP, but there was no significant difference in TNC between S120 and S150. Under the same irrigation treatments, an increase in nitrogen application significantly increased the residual SNC and decreased the NPFP. Overall, micro-sprinkling with 120 mm of irrigation and a total nitrogen application of 195 kg ha–1 can lead to increases in GY, WUE and NPFP on the NCP.

In past 30 years, the wheat yield per unit area of China has increased by 79%. The super-high-yield (SH) cultivation played an important role in improving the wheat photosynthesis and yield. In order to find the ecophysiological mechanism underneath the high photosynthesis of SH cultivation, in situ diurnal changes in the photosynthetic gas exchange and chlorophyll (Chl) a fluorescence of field-grown wheat plants during the grain-filling stage and environmental factors were investigated. During the late grain-filling stage at 24 days after anthesis (DAA), the diurnal changes in net CO₂ assimilation rate were higher under SH treatment than under high-yield (H) treatment. From 8 to 24 DAA, the actual quantum yield of photosystem II (PSII) electron transport in the light-adapted state (ΦPSII) in the flag leaves at noon under SH treatment were significantly higher than those under H treatment. The leaf temperature, soil temperature and soil moisture were better suited for higher rates of leaf photosynthesis under SH treatment than those under H treatment at noon. Such diurnal changes in environmental factors in wheat fields could be one of the mechanisms for the higher biomass and yield under SH cultivation than those under H cultivation. ΦPSII and CO₂ exchange rate in wheat flag leaves under SH and H treatments had a linear correlation which could provide new insight to evaluate the wheat photosynthesis performance under different conditions.

Understanding the characteristics of rice productivity is of great importance for achieving high yield formation.  However, such traits have not yet been studied for different ages of hydroponically grown long-mat rice seedlings (HLMS), which constitutes a new method of seedling cultivation.  Field experiments were conducted to evaluate the effects of seedling age on the growth stage, photosynthesis characteristics, dry matter production, and yield of HLMS.  A conventional japonica rice cultivar (Wuyunjing 24) and an indica hybrid rice cultivar (6 Liangyou 9368) were used as test materials.  The results showed that the whole phase was shortened by 13–15 days for young seedlings (13-day-old) compared with old seedlings (27-day-old), which occurred because the growth process accelerated with the transplantation of young seedlings.  As seedling age increased, the dry matter weight of stems of individual plants and of the population increased at the transplanting stage but decreased at the maturity stage (MS).  Compared with that of 27-day-old seedlings, the average ratio of panicle weight to total plant dry weight of 13-day-old seedlings during a 2-year period increased by 3.71% for Wuyunjing 24 and by 3.78% for 6 Liangyou 9368 at the MS.  Moreover, as seedling age increased, the leaf area index and photosynthetic potential decreased for both cultivars, and the photosynthetic rate markedly decreased at the heading stage (HS).  With the exception of that of Wuyunjing 24 from the jointing stage to the HS in 2014, the crop growth rate was higher for young seedlings than for old seedlings.  Grain yield significantly decreased with seedling age, but no significant difference was detected between the 13- and 20-day-old seedlings for either cultivar.  Therefore, equilibrious and high biological yield formation, vigorous growth in the late stages, and high photosynthetic production capacity are important characteristics and causes of the efficient and sustainable output of photosynthetic systems and for achieving high yield formation in young transplanted seedlings (13–20-day-old).

Drip-irrigation is increasingly applied in maize (Zea mays L.) production in sub-humid region.  It is critical to quantify irrigation requirements during different growth stages under diverse climatic conditions.  In this study, the Hybrid-Maize model was calibrated and applied in a sub-humid Heilongjiang Province in Northeast China to estimate irrigation requirements for drip-irrigated maize during different crop physiological development stages and under diverse agro-climatic conditions.  Using dimensionless scales, the whole growing season of maize was divided into diverse development stages from planting to maturity.  Drip-irrigation dates and irrigation amounts in each irrigation event were simulated and summarized in 30-year simulation from 1981 to 2010.  The maize harvest area of Heilongjiang Province was divided into 10 agro-climatic zones  based on growing degree days, arid index, and temperature seasonality.  The simulated results indicated that seasonal irrigation requirements and water stress during different growth stages were highly related to initial soil water content and distribution of seasonal precipitation.  In the experimental site, the average irrigation amounts and times ranged from 48 to 150 mm with initial soil water content decreasing from 100 to 20% of the maximum soil available water.  Additionally, the earliest drip-irrigation event might occur during 3- to 8-leaf stage.  The water stress could occur at any growth stages of maize, even in wet years with abundant total seasonal rainfall but poor distribution.  And over 50% of grain yield loss could be caused by extended water stress during the kernel setting window and grain filling period.  It is estimated that more than 94% of the maize harvested area in Heilongjiang Province needs to be irrigated although the yield increase varied (0 to 109%) in diverse agro-climatic zones.  Consequently, at least 14% of more maize production could be achieved through drip-irrigation systems in Heilongjiang Province compared to rainfed conditions.

Patatin-like phospholipase domain containing 5 (PNPLA5) is a neotype neutral lipase with dual activity of anabolism and catabolism in vitro and in vivo, which has a low mRNA expression level in humans and mice.  PNPLA5, which is localized to lipid droplets and required for efficient autophagy by optimal initiation, has been speculated to possess triglyceride hydrolase activity, and has been associated with low density lipoprotein cholesterol (LDL-C).  Above all, PNPLA5 is a relatively new gene, which is reported less about its biological function research, especially the function research in the rats is still blank.  In this study, we examined the spatiotemporal expression profile of PNPLA5 and found that it was expressed at low levels in most organs of Sprague Dawley (SD) rats, but was present at very high levels in the skin and testes.  To further determine the biological function of PNPLA5 in mammals, we generated PNPLA5-knockout SD rats using the clustered regularly-interspaced short palindromic repeats (CRISPR)/Cas9 system.  PNPLA5-null rats were viable, but showed a variety of phenotypic abnormalities, such as abnormal bleeding, and varied hematobiochemical parameters including increased serum total cholesterol (TC), triglycerides and high density lipoprotein cholesterol (HDL-C) level, and reduced LDL-C level, compared with wild-type control rats.  These data are consistent with an important role for PNPLA5 in lipid metabolism, providing a new target gene and animal model for treatment of cardiovascular diseases in the future.

Strategies for insect population control are currently targeting chemical communication at the molecular level. The diamondback moth Plutella xylostella represents one of the most serious pests in agriculture, however detailed information on the proteins mediating olfaction in this species is still poor. This species is endowed with a repertoire of a large number of olfactory receptors and odorant binding proteins (OBPs). As a contribution to map the specificities of these chemical sensors in the moth and eventually unravel the complexity of chemodetection, we have measured the affinities of three selected OBPs to a series of potential odorants. Three proteins are highly divergent in their amino acid sequences and show markedly different expression profiles. In fact, PxylOBP3 is exclusively expressed in the antennae of both sexes, PxylOBP9 is male specific and present only in antennae and reproductive organs, while PxylOBP19, an unusual OBP with nine cysteines, is ubiquitously present in all the organs examined. Such expression pattern suggests that the last two proteins may be involved in non-chemosensory functions. Despite such differences, the three OBPs exhibit similar binding spectra, together with high selectivity. Among the 26 natural compounds tested, only two proved to be good ligands, retinol and coniferyl aldehyde. This second compound is particularly interesting being part of the chemical pathway leading to regeneration of lignin, one of the defense strategies of the plant against insect attack, and might find applications as a repellent for P. xylostella and other pests.

    Drought is a multifaceted stress condition that inhibits crop growth. Seed germination is one of the critical and sensitive stages of plants, and its process is inhibited or even entirely prevented by drought. Polyamines (PAs) are closely associated with plant resistance to drought stress and seed germination. However, little is known about the effect of PA on the seed germination of wheat under drought stress. This study investigated the involvement of PAs in regulating wheat seed germination under drought stress. Six wheat genotypes differing in drought resistance were used, and endogenous PA levels were measured during seed germination under different water treatments. In addition, external PA was used for seed soaking and the variation of hormones, total soluble sugar and starch were measured during the seed germination under different water treatments. These results indicated that the free spermidine (Spd) accumulation in seeds during the seed germination period favored wheat seed germination under drought stress; however, the free putrescine (Put) accumulation in seeds during the seed germination period may work against wheat seed germination under drought stress. In addition, seed soaking in Spd and spermine (Spm) significantly relieved the inhibition of seed germination by drought stress; however, soaking seeds in Put had no significant effect on seed germination under drought. External Spd and Spm significantly increased the endogenous indole-3-acetic acid (IAA), zeatin (Z)+zeatin riboside (ZR), abscisic acid (ABA), and gibberellins (GA) contents in seeds and accelerated the seed starch degradation and increased the concentration of soluble sugars in seeds during seed germination. This may promote wheat seed germination under drought stress. In conclusion, free Spd and Put are key factors for regulating wheat seed germination under drought stress and the effects of Spd and Put on seed germination under drought notably related to hormones and starch metabolism.

    The experiments were conducted for three consecutive years across 14 locations using 9 non-waxy proso millet genotypes and 16 locations using 7 waxy proso millet genotypes in China. The objectives of this study were to analyze yield stability and adaptability of proso millets and to evaluate the discrimination and representativeness of locations by analysis of variance (ANOVA) and genotype and genotype by environment interaction (GGE) biplot methods. Grain yields of proso millet genotypes were significantly influenced by environment (E), genotype (G) and their interaction (G×E) (P<0.1%). G×E interaction effect was six times higher than G effect in non-waxy group and seven times in waxy group. N04-339 in non-waxy and Neimi 6 (NM6) in waxy showed higher grain yields and stability compared with other genotypes. Also, Neimi 9 (NM9, a non-waxy cultivar) and 90322-2-33 (a waxy cultivar) showed higher adaptability in 7 and in 11 locations, respectively. For non-waxy, Dalat, Inner Mongolia (E2) and Wuzhai, Shanxi (E5) were the best sites among all the locations for maximizing the variance among candidate cultivars, and Yanchi, Ningxia (E10) had the best representativeness. Wuzhai, Shanxi (e9) and Yanchi, Ningxia (e14) were the best representative locations, and Baicheng, Jilin (e2) was better discriminating location than others for waxy genotypes. Based on our results, E10 and e14 have enhanced efficiency and accuracy for non-waxy genotypes and waxy genotypes selection, respectively in national regional test of proso millet varieties.

Mycotoxin contamination in agro-food systems has been a serious concern globally during the last few decades. Mycotoxins are toxic secondary metabolites produced by fungi when they grow in agro-food products and feedstuff. Several detection techniques have been developed in recent years to detect mycotoxins in the food and feed effectively. HPLC based techniques are very common in usage in the laboratories for the testing of mycotoxins. In recent years, immuno-based assays is widely used and have been reported at large due to its sensitivity and limited detection time. Immuno assay-based kits were developed effectively to be used in the fields and in storage systems to detect the mycotoxin levels. Microarray-based immunoassays developed in the recent years could simultaneously detect aflatoxin, ochratoxin, and zearalenone with the higher sensitivity. Aptamer-based assays could target the detection of ochratoxin and aflatoxins and fumonisins at high specificity in food products. In recent years, several assays reported for the simultaneous multiple detection of different mycotoxin was based on HPLC and LC-MS/MS. There is a need for the use of these advanced technologies in the commercial scale.

Eight compounds were isolated from the fermentation cultures of rice sheath blight pathogen Rhizoctonia solani Kühn. They were identified as ergosterol (1), 6β-hydroxysitostenone (2), sitostenone (3), m-hydroxyphenylacetic acid (4), methyl m-hydroxyphenylacetate (5), m-hydroxymethylphenyl pentanoate (6), (Z)-3-methylpent-2-en-1,5-dioic acid (7) and 3-methoxyfuran-2-carboxylic acid (8) by means of physicochemical and spectroscopic analysis. Among them, 2, 3, 5–8 were isolated from R. solani for the first time. All the compounds were evaluated for their biological activities. 4–6 and 8 showed their inhibitory activities on the radical and germ elongation of rice seeds. 1, 4 and 7 showed moderate antibacterial activity to some bacteria. 4, 7 and 8 exhibited weak inhibitory activities on spore germination of Magnaporthe oryzae. 8 showed moderate antioxidant activity with the 1,1-diphenyl-2-picryhydrazyl (DPPH) and β-carotene-linoleic acid assays. This is the first time to reveal compounds 5, 6 and 8 from rice sheath blight pathogen R. solani to have in vitro phytotoxic activity.

To determine the potential effects of climate change on crop phenological development and productivity, an integrated analysis was conducted based on the observed climatic and phenological records of Northeast China from 1992 to 2012. A set of quality assurance procedures, including repeated record checks, agro-meteorological station selection, internal consistency checks, temporal outlier checks, spatial outlier checks, and interpolation of missing data, were designed and applied to the phenology datasets of spring maize and paddy rice. Our results indicated that almost all phenological dates of spring maize and paddy rice became increasingly delayed from 1992 to 2012. The duration of the growing season was prolonged, particularly for the grain-filling stage (GS3). The prolonged growing season was beneficial to productivity. For spring maize, the average precipitation during GS3 decreased at a rate of 27.46 mm/decade, and the annual accumulated temperature over 10°C increased at a rate of 31.07°C/ decade. Farmers initiatively adjusted crop cultivars and selected drought-resistant crops to cope with the challenges of drought.

Segregation analysis of the mixed genetic model of major gene plus polygene was used to identify the major genes for cotton yield-related traits using six generations P1, P2, F1, B1, B2, and F2 generated from the cross of Baimian 1 × TM-1. In addition to boll size and seed index, the major genes for the other five traits were detected: one each for seed yield, lint percentage, boll number, lint index; and two for lint yield. Quantitative trait locus/loci (QTL) mapping was performed in the F2 and F2:3 populations of above cross through molecular marker technology, and a total of 50 QTL (26 suggestive and 24 significant) for yield-related traits were detected. Four common QTL were discovered: qLP-3b(F2)/qLP-3(F2:3) and qLP-19b (F2)/qLP-19(F2:3) for lint percentage, qBN-17(F2)/qBN-17(F2:3) for boll number, and qBS-26b(F2)/qBS-26(F2:3) for boll size. Especially, qLP- 3b(F2)/qLP-3(F2:3), not only had LOD scores >3 but also exceeded the permutation threshold (5.13 and 5.29, respectively), correspondingly explaining 23.47 and 29.55% of phenotypic variation. This QTL should be considered preferentially in marker assisted selection (MAS). Segregation analysis and QTL mapping could mutually complement and verify, which provides a theoretical basis for genetic improvement of cotton yield-related traits by using major genes (QTL).

The nicotinic acetylcholine receptors (nAchRs) are cholinergic receptors that form ligand-gated ion channels by five subunits in insect and vertebrate nervous systems. The insect nAChR is the molecular target of a class of insecticides, neonicotinoids. Here, we identified and cloned 11 candidate nAChR subunit genes in Acyrthosiphon pisum using genome-based bioinformatics combined modern molecular techniques. Most A. pisum nAChRs including α1, α2, α3, α4, α6, α8, and β1 show highly sequence identities with the counterparts of other insects examined. Expression profiles analysis showed that all subunit genes were expressed in adult head. At least two subunits have alternative splicing that obviously increase A. pisum nicotinic receptor diversity. This study will be invaluable for exploring the molecular mechanisms of neonicotinoid-like insecticides in sucking pests, and for ultimately establishing the screening platform of novel insecticides.

Although plastic-covered ridge and furrow planting (RF) has been reported to produce substantial increases in the grain weight of winter wheat, the underlying mechanism is not yet understood. The present study used two cultivars, Xinong 538 and Zhoumai 18, and RF and traditional flatten planting (TF, control) with the objective of investigating the effect of RF on wheat grain filling and the possible relationship of hormonal changes in the wheat grains under RF to grain filling. The results indicated that RF significantly increased the grain weight, although the effects on grain filling were different: RF significantly increased the grain-filling rate and grain weight of inferior grains, whereas RF had no significant effect on grainfilling rate and grain weight of superior grains. The ?nal grain weight of inferior grains under RF was 39.1 and 50.7 mg for Xinong 538 and Zhoumai 18, respectively, 3.6 and 3.4 mg higher than the values under TF. However, the final grain weight of superior grains under RF was only 0.6 and 0.8 mg higher than under TF for Xinong 538 and Zhoumai 18, respectively. RF significantly decreased the ethylene and gibberellic acid content in the inferior grains and increased the indole-3-acetic acid, abscisic acid and zeatin + zeatin riboside content in the inferior grains; however, no significant difference between RF and TF was observed for the hormonal content in the superior grains. Based on these results, we concluded that RF significantly modulated hormonal changes in the inferior grains and, thus, affected the grain filling and grain weight of the inferior grains; in contrast, RF had no significant effect on grain filling, grain weight and hormonal changes in the superior wheat grains.

In plants, basic leucine zipper (bZIP) transcription factors play important roles in regulatory processes, including stress response, pathogenic defense and light response as well as organ and tissue differentiation. Chinese wheat landrace Pingyaoxiaobaimai (PYXBM), an original parent of drought tolerant wheat varieties grown in northern China, is significantly tolerant to abiotic stresses such as drought, cold and nutrient deficiencies. In order to isolate key stress-responsive genes and then improve stress tolerances of conventional varieties, a bZIP transcription factor gene was isolated from a cDNA library of drought-treated PYXBM using the in situ plaque hybridization method, and was designated as Triticum aestivum L. abscisic acid (ABA)-responsive element binding protein 1 (TaABP1). It encodes 372 amino acids, and contains three conserved domains (C1-C3) in the N terminal and a bZIP domain in the C terminal which is a typical protein structure for the group member of bZIP family. Transcriptional activation analysis showed that TaABP1 activated the expression of downstream reporter genes in yeast without ABA application. TaABP1 protein fused with green fluorescent protein (GFP) demonstrated that the localization of TaABP1 protein is in the nucleus. Expression pattern assays indicated that TaABP1 was strongly induced by ABA, high salt, low temperature and drought, and its expression was stronger in stems and leaves than in the roots of wheat. Furthermore, overexpression of TaABP1 in tobacco showed significant improvement of drought tolerance. Data suggested that TaABP1 may be a good candidate gene for improving stress tolerance of wheat by genetic transformation and elucidation of the role of this gene will be useful for understanding the mechanism underlying drought tolerance of Chinese wheat landrace PYXBM.