植物的单性花可以有效促进异交，研究单性花的形成和调控机制对于理解植物性别决定过程有重要意义，也为研究者和农业生产者利用杂种优势提供便利。在黄瓜杂交制种过程中，将只开雌花的株系种植于只开雄花的株系周围，可以显著降低制种成本。筛选更多不同基因背景的只开雄花的材料，将增加可用于育种的种质资源。我们基于前期构建的EMS诱变自交系材料“406”的突变体库，发现了一个新的只开雄花的突变体。遗传分析、全基因组重测序和分子标记辅助验证表明，ACS11基因上发生的异义突变第301位丝氨酸（Ser）变为苯丙氨酸（Phe）导致全雄株的产生。体外酶活性测定表明，此突变导致酶活性完全丧失。本研究为黄瓜雄性亲本选育提供了新的种质资源，并为 ACS 酶的催化机理提供了新的认识。

Aerated irrigation has been proven to increase crop production and quality, but studies on its environmental impacts are sparse.  The effects of aeration and irrigation regimes on soil CO₂ and N₂O emissions in two consecutive greenhouse tomato rotation cycles in Northwest China were studied via the static closed chamber and gas chromatography technique.  Four treatments, aerated deficit irrigation (AI1), non-aerated deficit irrigation (CK1), aerated full irrigation (AI2) and non-aerated full irrigation (CK2), were performed.  The results showed that the tomato yield under aeration of each irrigation regime increased by 18.8% on average compared to non-aeration, and the difference was significant under full irrigation (P<0.05).  Full irrigation significantly increased the tomato yield by 23.9% on average in comparison to deficit irrigation.  Moreover, aeration increased the cumulative CO₂ emissions compared to non-aeration, and treatment effects were significant in the autumn-winter season (P<0.05).  A slight increase of CO₂ emissions in the two seasons was observed under full irrigation (P>0.05).  There was no significant difference between aeration and non-aeration in soil N₂O emissions in the spring-summer season, whereas aeration enhanced N₂O emissions significantly in the autumn-winter season.  Furthermore, full irrigation over the two seasons greatly increased soil N₂O emissions compared to the deficit irrigation treatment (P<0.05).  Correlation analysis indicated that soil temperature was the primary factor influencing CO₂ fluxes.  Soil temperature, soil moisture and NO₃^– were the primary factors influencing N₂O fluxes.  Irrigation coupled with particular soil aeration practices may allow for a balance between crop production yield and greenhouse gas mitigation in greenhouse vegetable fields.

Spermidine (Spd) is known to be involved in the regulation of plant responses to chilling stress and counteract the adverse effect of stress conditions. Antioxidant activities, endogenous hormones and ultrastructure change under chilling stress were investigated in indica-japonica hybrid rice seedlings. 12-d-old seedlings were subjected to exogenous Spd (1 mmol L–1) and then a chilling stress (6°C, 4 d) was induced, followed by a subsequent recovery (25°C, 4 d). Results showed that malondialdehyde (MDA) and proline content were enhanced significantly, whereas shoot fresh and dry weights decreased during chilling stress and after recovery; chlorophyll content of chilling-stressed seedlings increased slightly but declined after recovery; additionally, total soluble sugar, sucrose, fructose and starch contents increased significantly during chilling stress, and only soluble sugar and fructose contents were observed in increase after recovery; chilling stress-induced increases in superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities, but declined after recovery, and the level of ascorbate peroxidase was lower during chilling stress and after recovery; however, endogenous indole-3-acetic acid (IAA), zeatin riboside (ZR), gibberellic acid (GA3), and abscisic acid (ABA) levels were induced decreased compared with Spd pretreatment. The microscopic analysis revealed that chilling stress-induced destruction of the chloroplast envelope during chilling stress and increased the number of plastoglobuli along with aberrations in thylakoid membranes after recovery. In contrast, exogenous Spd protected rice seedlings from chilling-induced injuries in terms of lower malondialdehyde, proline and carbohydrates accumulation coupled with increased endogenous hormones metabolism. After recovery, Spd pretreatment chilling-exposed seedlings showed higher activities of antioxidant enzymes and normal physiological function of chloroplasts. These results suggest that Spd could promote effectively chilling tolerance which might be largely attributable to the integrity of cell structure and normal metabolism of endogenous hormones in indica-japonica hybrid rice seedlings.

Bordetella bronchiseptica is a Gram-negative pathogen that causes acute and chronic respiratory infection in a variety of animals. To identify useful antigen candidates for diagnosis and subunit vaccine of B. bronchiseptica, immunoproteomic analysis was adopted to analyse outer membrane proteins of it. The outer membrane proteins extracted from B. bronchiseptica were separated by two-dimensional gel electrophoresis and analyzed by Western blotting for their reactivity with the convalescent serum against two strains. Immunogenic proteins were identified by matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS), a total of 14 proteins are common immunoreactive proteins, of which 1 was known antigen and 13 were novel immunogenic proteins for B. bronchiseptica. Putative lipoprotein gene was cloned and recombinantly expressed. The recombinant protein induced high titer antibody, but showed low protective indices against challenges with HB (B. bronchiseptica strain isolated from a infected rabbit). The mortality of mice was 80% compared to 100% of positive controls. The identification of these novel antigenic proteins is an important resource for further development of a new diagnostic test and vaccine for B. bronchiseptica.

Our previous studies demonstrated that the region around markers BMS470 and BMS1242 on BTA6 showed a linkage to 305-d milk yield and composition traits in the Chinese Holstein population. We herein focused on such narrow region to fine map milk production QTLs with 15 SNPs across 25 Mb with each SNP in 1 Mb within most regions in a Chinese Holstein population with daughter design. 1 449 Holstein cows and 11 sires were genotyped for such SNPs by using TaqMan probe and RFLP assays. Multipoint linkage analysis across family revealed a QTL affecting milk yield between PPARGC1A C4075T and SLC34A2 T1713C. Meanwhile, within family analysis found three milk yield QTLs (two in CR T60984131G-CEP135 C501T and one in PDLIM5 A106C-OPN T3907, a fat yield QTL in UGDH T1670C-CR T60984131G region, and two protein yield QTLs in TBC1D1 G501C-UGDH T1670C and PPARGC1A C4075T-SLC34A2 T1713C, respectively. Associations between aforementioned significant SNP markers and milk production traits were further implemented. We found significant associations of PPARGC1A C4075T, SLC34A2 T1713C with milk yield (P<0.05, P<0.01, P<0.01), UGDH T1670C, and CR T60984131G with fat yield (P<0.01, P<0.01), and PPARGC1A C4075T, SLC34A2 T1713C, UGDH T1670C and OPN T3907 with protein yield (P<0.01, P<0.01, P<0.01, P<0.01). Our findings implied that QTLs affecting milk production traits on BTA6 were pleictropism or multigenic effect and PPARGC1A and OPN may be the causal mutations behind milk production QTLs on BTA6 in the Chinese Holstein population.

The symbiotic matching for nodulation of Bradyrhizobium japonicum strains is a synergy of multi-proteins and plays a key role in symbiotic nitrogen fixation in nature. Studies on mechanism of symbiotic matching are significant in both theory and practice. In this paper, B. japonicum USDA110-A with high symbiotic matching with high-oil content soybean cultivar Suinong 20 and B. japonicum 2178 with low symbiotic matching were selected for proteomic to reveal mechanism of different symbiotic nodulation. The results showed that the amount and categories of proteins identified in this test were different when the two strains were treated by symbiotic nodulation. There were 10 up-regulated proteins and 5 down-regulated proteins with significant difference for B. japonicum USDA110-A. Proteins associated with nodulation and metabolism of energy and material, which were propitious to symbiotic nodulation, were all up-regulated, such as PHDPS synthase, metal-dependent phosphohydrolase, glycosyl transferase family. In contrast, only 5 up-regulated and 7 down-regulated differential proteins were detected in B. japonicum 2178. Molecular chaperones and defensive proteins, which influence the folding of nascent polypeptide chains and the active of azotase were down-regulated. To a certain extent, the different responses of B. japonicum to daidzein were one of the most important reasons that cause varieties in symbiotic matching ability.

Nonhost resistance is a phenomenon that enables plants to protect themselves against the majority of potential pathogens, and thus has a great potential for application in plant protection. We recently found that CfHNNI1 (for Cladosporium fulvum host and nonhost plant necrosis inducer 1) is an inducer of plant hypersensitive response (HR) and nonhost resistance. In this study, its functional mechanism was analyzed. CfHNNI1 was a single copy gene in C. fulvum genome. The functional ORF of the CfHNNI1 cDNA was ATG3-TAG780, which showed homology with genes encoding bZIP transcription factors. The functional ORF included in frame an inner one ATG273-TAG780, which was sufficient to induce HR in plants. CfHNNI1 induced plant HR in a dose-dependent manner. CfHNNI1-induced necrosis in NahG transgenic tomato plants was significantly stronger than that in their wild type controls. However, the necrosis in Nr and def1 tomato mutants was similar to that in their corresponding wild type plants. These data demonstrate that induction of HR and nonhost resistance by CfHNNI1 is negatively regulated by salicylic acid signalling pathway but independent of ethylene and jasmonic acid signalling pathways.

Continuous monoculture problems, or replanting diseases, are one of the key factors affecting productivity and quality ofChinese medicinal plants. The underlying mechanism is still being explored. Most of the studies on continuous monocultureof Rehmannia glutinosa L. are focused on plant nutritional physiology, root exudate, and its autotoxicity. However, thechanges in the diversity of microflora in the rhizosphere mediated by the continuous monoculture pattern have beenremained unknown. In this study, terminal restriction fragment length polymorphism (T-RFLP) technique was used forfingerprinting fungal diversity in the rhizosphere soil sampled from the fields of R. glutinosa monocultured for 1 and 2 yr. Theresults showed that the structure of fungal community in consecutively moncultured rhizosphere soil was different fromthat in control soil (no cropping soil), and varied with the consecutive monoculture years (1 and 2 yr). The comprehensiveevaluation index (D) of fungal community estimated by principal component analysis of fragment number, peak area,Shannon-Weiner index, and Margalef index was higher in 1 yr monoculture soil than that in 2 yr monoculture soil,suggesting that consecutive monoculture of R. glutinosa could be a causative agent to decrease the diversity of fungalcommunity in the rhizosphere soil.

Competitiveness for nodulation of Bradyrhizobium japonicum strains plays a key role in symbiotic nitrogen fixation. Inorder to reveal the difference in competitiveness, B. japonicum 4534 with high competitiveness and B. japonicum 4222with low competitiveness for nodulation were analyzed by proteomic technique. The results showed that differentialproteins were fewer when two strains were treated with just daidzein. Only 24 and 10 differential proteins were detectedwith an up-regulated rate of 58 and 40% in B. japonicum 4534 and B. japonicum 4222, respectively. However, moredifferential proteins were detected upon treatment with daidzein and mutual extracellular materials simultaneously. Therewere 78 differential proteins detected in B. japonicum 4534 with 43 being up-regulated and 35 being down-regulated.These differential proteins, such as metabolism-related proteins, transporters, transcription-related proteins, translationrelatedproteins, and flagellin, were found to be associated with nodulation process. 25 up-regulated and 22 down-regulatedproteins were detected in B. japonicum 4222. Some of these proteins were not related to nodulation. More differentialproteins associated with nodulation in B. japonicum 4534 may be the reason for its high competitiveness. The results canprovide a guide to the selection and inoculation of effective strains and are significant to biological nitrogen fixation.

Two rice maintaining lines with different drought tolerances, viz., Jin 23B (tolerant) and Zhenshan 97B (sensitive), wereused to study the oxidative stress and soluble sugar in rice anthers and pollen viability under drought stress duringflowering stage. Higher antioxidant enzyme activities and lower malonaldehyde (MDA) content in rice anthers wereobserved in Jin 23B than in Zhenshan 97B under drought stress. Further, a great increase in the content of soluble sugarin rice anthers of Jin 23B was observed across the whole drought exposure, while Zhenshan 97B showed significantdecrease in soluble sugar during 9-12 d after drought stress (DADS). Accordingly, a marked decline of pollen fertility andactivity, pollen numbers in an anther and pollen numbers on a stigma was observed in Zhenshan 97B, whereas littledifference was found in Jin 23B. Thus, we suggest that pollen abortion caused by drought stress may be related with thereciprocity between oxidative stress and soluble sugar content in rice anthers.