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2019 Vol. 18 No. 9 Previous Issue    Next Issue

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Review
Crop Science
Horticulture
Plant Protection
Animal Science · Veterinary Medicine
Agro-ecosystem & Environment
Food Science


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Root-knot nematode (Meloidogyne spp., RKN) resistance to nematicides has become both a local and global threat to producing crops economically in protected agriculture. The combination of a fumigant such as dazomet (DZ) or chloropicrin (CP) and non-fumigating nematicide fosthiazate (FOS) showed a synergistic effect on the control of RKN. This effect main due to FOS combined with DZ or CP increased the diffusion rate of FOS across the RKN cuticle. The increase in diffusion rate shortens the time for these pesticides to cause cellular lesions in RKN ultimately leading to increased RKN mortality. Secondly, the fumigant prolongs the half-life of the nematicide FOS in the soil making more of it available for a longer period of time to control RKN. The photo is provided by the team of Prof. Cao Aocheng from Institute of Plant Protection, Chinese Academy of Agricultural Sciences. See pages 2093–2106 for details.


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Review

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Crop diversity and pest management in sustainable agriculture HE Han-ming, LIU Li-na, Shahzad Munir, Nawaz Haider Bashir, WANG Yi, YANG Jing, LI Cheng-yun 2019, 18(9): 1945-1952.  DOI: 10.1016/S2095-3119(19)62689-4 Abstract ( )   PDF in ScienceDirect   Large-scale crop monocultures facilitate the proliferation and increasing prevalence of diseases and pest insects.  Many studies highlight the impacts of plant diversification upon pathogens, and the population dynamics of insects and beneficial organism in agricultural ecosystems.  These studies provide evidence that habitat manipulation techniques such as intercropping, relay, and rotation can significantly improve disease and pest management.  This review introduces the concept of crop diversity, considers recent insights and mechanisms underlying crop diversity, and discusses its potential for improving sustainable agricultural practices.  Recently, the phytobiomes resulting from increased crop diversity are increasingly recognized for their contribution to disease and pest control.  Further, understanding the interactions between pathogens or pests with their host phytobiome may lead to novel options for the prevention of pests.  Recent advances in the agricultural systems include: (i) a better understanding of the mechanisms of interactions between crop species and genotypes; (ii) ecological progress including a better understanding of the context-dependency of those interactions; and (iii) the role of microtopographic variation in agricultural systems for priming basal resistance to multiple pests and pathogens by intercropped crops.  We also highlight recent progress in China and the potential options for habitat management and design that enhance the ecological role of biodiversity in agroecosystems.

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Degradation mechanisms of oxytetracycline in the environment LI Zhao-jun, QI Wei-ning, FENG Yao, LIU Yuan-wang, Ebrahim Shehata, LONG Jian 2019, 18(9): 1953-1960.  DOI: 10.1016/S2095-3119(18)62121-5 Abstract ( )   PDF in ScienceDirect   Over the past few decades, the usage of oxytetracycline (OTC), a kind of antibiotic, has increased with the development of aquaculture and livestock breeding.  However, about 30–90% of the applied antibiotics are excreted as the parent compounds into the environment, especially with the application of animal manure to agricultural fields.  This large influx of antibiotics may lead to the destruction of the natural microbial ecological community and pose great threats to human beings through the food chain.  Therefore, the fate and toxicity of OTC in the environment are issues of great concern.  Degradation of OTC, including the non-biodegradation and biodegradation, and the biological toxicity of its degradation products or metabolites, are reviewed in this paper.  The non-biodegradation pathways include hydroxylation, quinonization, demethylation, decarbonylation, dehydration and secondary alcohol oxidation.  Light (particularly UV light), pH and oxidizing substances play important roles in non-biodegradation.  Biodegradation products include 4-epi-OTC (EOTC), 2-acetyl-2-decarboxy-amido-OTC (ADOTC), α-apo-OTC and β-apo-OTC.  EOTC is an epimer and identied except for the configuration of the C4 dimethylamino group of OTC.  Temperature and pH are the main factors affecting biodegradation pathways of OTC.  In addition, this review discusses concerns over the biological toxicity of OTC degradation products.

Crop Science

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Reactive oxygen species are involved in cell death in wheat roots against powdery mildew LI Cheng-yang, ZHANG Nan, GUAN Bin, ZHOU Zhu-qing, MEI Fang-zhu 2019, 18(9): 1961-1970.  DOI: 10.1016/S2095-3119(18)62092-1 Abstract ( )   PDF in ScienceDirect   Inoculation of wheat (Triticum aestivum L.) leaves with wheat powdery mildew fungus (Blumeria graminis f. sp. tritici) induces the cell death in adventitious roots.  Reactive oxygen species (ROS) play a key role in respond to biotic stress in plants.  To study the involvement of ROS and the degree of cell death in the wheat roots following inoculation, ROS levels and microstructure of root cells were analyzed in two wheat cultivars that are susceptible (Huamai 8) and resistant (Shenmai 8) to powdery mildew fungus.  At 18 d after powdery mildew fungus inoculation, only Huamai 8 displayed the leaf lesions, while root cell death occurred in both varieties.  Huamai 8 had a high level of ROS accumulation, which is associated with increased root cell degradation, while in Shenmai 8, there was little ROS accumulation correlating with slight root cell degradation.  The molecular study about the expression levels of ROS scavenging genes (MnSOD and CAT) in wheat roots showed that these genes expression decreased after the leaves of wheat was inoculated.  The difference between Huamai 8 and Shenmai 8 on subcellular localization of H2O2 and O2–· was corresponded with the different down-regulation of the genes encoding for superoxide dismutase and catalase in two wheat cultivars.  These results suggested that ROS were involved in the process by which powdery mildew fungus induced cell death in wheat roots.

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Genetic effects and plant architecture influences on outcrossing rate in soybean YAN Hao, ZHANG Jing-yong, ZHANG Chun-bao, PENG Bao, ZHANG Wei-long, WANG Peng-nian, DING Xiao-yang, LIU Bao-hui, FENG Xian-zhong, ZHAO Li-mei 2019, 18(9): 1971-1979.  DOI: 10.1016/S2095-3119(18)62054-4 Abstract ( )   PDF in ScienceDirect   Outcrossing rate is an important determinant of cytoplasmic male sterile (CMS) breeding and hybrid seed production for heterosis in soybean.  Parental lines with a high outcrossing rate were screened for backcross breeding to obtain the high outcrossing rate maintenance B-lines and sterile A-lines.  Application in production practices will help to increase hybrid soybean production.  In this study, JLCMS82B and JLCMS89B were selected as parents for the construction of outcrossing rate segregation populations, and the progeny-array approach (PAA) and glyphosate resistant gene markers were used to determine outcrossing rates.  We found that: (1) The outcrossing rate between JLCMS82B and JLCMS89B was significantly different; (2) the outcrossing rate of the F2 segregating populations was a quantitative trait, though whether an additive or epistatic effect exists required analysis with a triple test intersection analysis; (3) agronomic traits correlated with outcrossing rate; outcrossing rate was the highest with plant height of about 84 cm, lower number of plant branches, earlier flowering time, larger angle between the branches and the main stem, and with more divergent plant morphology.  Correlation analysis between agronomic traits and outcrossing rate can effectively guide the screening of parents with a high outcrossing rate.

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Transcriptomic profiling of sorghum leaves and roots responsive to drought stress at the seedling stage ZHANG Deng-feng, ZENG Ting-ru, LIU Xu-yang, GAO Chen-xi, LI Yong-xiang, LI Chun-hui, SONG Yan-chun, SHI Yun-su, WANG Tian-yu, LI Yu 2019, 18(9): 1980-1995.  DOI: 10.1016/S2095-3119(18)62119-7 Abstract ( )   PDF in ScienceDirect   Drought stress affects the growth and productivity of crop plants including sorghum.  To study the molecular basis of drought tolerance in sorghum, we conducted the transcriptomic profiling of sorghum leaves and roots under drought stress using RNA-Seq method.  A total of 510, 559, and 3 687 differentially expressed genes (DEGs) in leaves, 3 368, 5 093, and 4 635 DEGs in roots responding to mild drought, severe drought, and re-watering treatments were identified, respectively.  Among them, 190 common DEGs in leaves and 1 644 common DEGs in roots were responsive to mild drought, severe drought, and re-watering environment.  Gene Ontology (GO) enrichment analysis revealed that the GO categories related to drought tolerance include terms related to response to stimulus especially response to water deprivation, abscisic acid stimulus, and reactive oxygen species.  The major transcription factor genes responsive to drought stress include heat stress transcription factor (HSF), ethylene-responsive transcription factor (ERF), Petunia NAM, Arabidopsis ATAF1/2 and CUC2 (NAC), WRKY transcription factor (WRKY), homeodomain leucine zipper transcription factor (HD-ZIP), basic helix-loop-helix transcription factor (bHLH),  and V-myb myeloblastosis viral oncogene homolog transcription facotr (MYB).  Functional protein genes for heat shock protein (HSPs), late-embryogenesis-abundant protein (LEAs), chaperones, aquaporins, and expansins might play important roles in sorghum drought tolerance.  Moreover, the genomic regions enriched with HSP, expansin, and aquaporin genes responsive to drought stress could be used as powerful targets for improvement of drought tolerance in sorghum and other cereals.  Overall, our results provide a genome-wide analysis of DEGs in sorghum leaves and roots under mild drought, severe drought, and re-watering environments.  This study contributes to a better understanding of the molecular basis of drought tolerance of sorghum and can be useful for crop improvement.

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Investigating seed mineral composition in Korean landrace maize (Zea mays L.) and its kernel texture specificity Sooyeon Lim, Gibum Yi 2019, 18(9): 1996-2005.  DOI: 10.1016/S2095-3119(18)62055-6 Abstract ( )   PDF in ScienceDirect   Mineral malnutrition affects billions of people all over the world and biofortification of staple crops provides a potential way to alleviate dietary mineral deficiencies.  For example, nutritional quality is an important breeding target for fresh waxy maize (Zea mays L.), which is widely consumed in Asian countries.  Successful improvement of mineral composition will require comprehensive profiling of the mineral composition of maize varieties and an understanding of the capacity for maize grains to accumulate minerals.  Here, using inductively coupled plasma absorption emission spectrometry, we quantified 12 minerals from the seeds of 47 maize varieties, including 25 Korean landraces.  We also compared the mineral contents in varieties with different seed starch profiles: waxy maize (which contains 100% amylopectin), dent maize (roughly 75% amylopectin and 25% amylose), and flint maize (similar to dent maize).  The amounts of potassium, phosphorus, and sulfur were correlated with seed texture, waxy maize having higher amounts of phosphorus and potassium than dent maize and lower amounts of sulfur than flint maize or dent maize.  In addition, a positive relationship was detected between the amount of phosphorus and that of potassium, magnesium, and manganese.  These results provide information on maize seed mineral composition and indicate that it could be affected by starch composition.  Furthermore, the landraces that exhibit high mineral contents could be used as germplasm materials for breeding programs aimed at producing biofortified maize cultivars.

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Effects of maize-soybean relay intercropping on crop nutrient uptake and soil bacterial community FU Zhi-dan, ZHOU Li, CHEN Ping, DU Qing, PANG Ting, SONG Chun, WANG Xiao-chun, LIU Wei-guo, YANG Wen-yu, YONG Tai-wen 2019, 18(9): 2006-2018.  DOI: 10.1016/S2095-3119(18)62114-8 Abstract ( )   PDF in ScienceDirect   Maize-soybean relay intercropping is an effective approach to improve the crop yield and nutrient use efficiency, which is widely practiced by farmers in southwest of China.  To elucidate the characteristics of different planting patterns on crop nutrient uptake, soil chemical properties, and soil bacteria community in maize-soybean relay intercropping systems, we conducted a field experiment in 2015–2016 with single factor treatments, including monoculture maize (MM), monoculture soybean (MS), maize-soybean relay intercropping (IMS), and fallow (CK).  The results showed that the N uptake of maize grain increased in IMS compared with MM.  Compared with MS, the yield and uptake of N, P, and K of soybean grain were increased by 25.5, 24.4, 9.6, and 22.4% in IMS, respectively, while the N and K uptakes in soybean straw were decreased in IMS.  The soil total nitrogen, available phosphorus, and soil organic matter contents were significantly higher in IMS than those of the corresponding monocultures and CK.  Moreover, the soil protease, soil urease, and soil nitrate reductase activities in IMS were higher than those of the corresponding monocultures and CK.  The phyla Proteobacteria, Acidobacteria, Chloroflexi, and Actinobacteria dominated in all treatments.  Shannon’s index in IMS was higher than that of the corresponding monocultures and CK.  The phylum Proteobacteria proportion was positively correlated with maize soil organic matter and soybean soil total nitrogen content, respectively.  These results indicated that the belowground interactions increased the crop nutrient (N and P) uptake and soil bacterial community diversity, both of which contributed to improved soil nutrient management for legume-cereal relay intercropping systems.

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Effects of planting patterns on yield, quality, and defoliation in machine-harvested cotton WANG Fang-yong, HAN Huan-yong, LIN Hai, CHEN Bing, KONG Xian-hui, NING Xin-zhu, WANG Xu-wen, YU Yu, LIU Jing-de 2019, 18(9): 2019-2028.  DOI: 10.1016/S2095-3119(19)62604-3 Abstract ( )   PDF in ScienceDirect   The aim of this study was to elucidate the effects of different machine-harvested cotton-planting patterns on defoliation, yield, and fiber quality in cotton and to provide support for improving the quality of machine-harvested cotton.  In the 2015 and 2016 growing seasons, the Xinluzao 45 (XLZ45) and Xinluzao 62 (XLZ62) cultivars, which are primarily cultivated in northern Xinjiang, were used as study materials.  Conventional wide-narrow row (WNR), wide and ultra-narrow row (UNR), wide-row spacing with high density (HWR), and wide-row spacing with low density (LWR) planting patterns were used to assess the effects of planting patterns on defoliation, yield, and fiber quality.  Compared with WNR, the seed cotton yields were significantly decreased by 2.06–5.48% for UNR and by 2.50–6.99% for LWR, respectively.  The main cause of reduced yield was a reduction in bolls per unit area.  The variation in HWR yield was –1.07–1.07% with reduced bolls per unit area and increased boll weight, thus demonstrating stable production.  In terms of fiber quality indicators, the planting patterns only showed significant effects on the micronaire value, with wide-row spacing patterns showing an increase in the micronaire values.  The defoliation and boll-opening results showed that the number of leaves and dried leaves in HWR was the lowest among the four planting patterns.  Prior to the application of defoliating agent and before machine-harvesting, the numbers of leaves per individual plant in HWR were decreased by 14.45 and 25.00% on average, respectively, compared with WNR, while the number of leaves per unit area was decreased by 27.44 and 36.21% on average, respectively.  The rates of boll-opening and defoliation in HWR were the highest.  Specifically, the boll-opening rate before defoliation and machine-harvesting in HWR was 44.54 and 5.94% higher on average than in WNR, while the defoliation rate prior to machine-harvesting was 3.45% higher on average than in WNR.  The numbers of ineffective defoliated leaves and leaf trash in HWR were the lowest, decreased by 33.40 and 32.43%, respectively, compared with WNR.  In conclusion, the HWR planting pattern is associated with a high and stable yield, does not affect fiber quality, promotes early maturation, and can effectively decrease the amount of leaf trash in machine-picked seed cotton, and thus its use is able to improve the quality of machine-harvested cotton.

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iTRAQ protein profile analysis of soybean stems reveals new aspects critical for lodging in intercropping systems LIU Wei-guo, WEN Bing-xiao, ZHOU Tao, WANG Li, GAO Yang, LI Shu-xian, QIN Si-si, LIU Jiang, YANG Wen-yu 2019, 18(9): 2029-2040.  DOI: 10.1016/S2095-3119(18)62123-9 Abstract ( )   PDF in ScienceDirect   Soybean is often intercropped with maize, sugarcane, and sorghum.  Because of the shade coming from the latter, the soybean stem lodging is often a very serious problem in intercropping systems.  The aim of this study is to characterize the possible mechanisms in the stem of shade-induced promotion of seedling soybean lodging in intercropping systems at the proteome level.  We found that the soybean stem became slender and prone to lodging when it was planted with maize in an intercropping system.  The inhibition of lignin biosynthesis and lack of photosynthate (soluble sugar) for the biosynthesis of the cell wall led to the lower internode breaking strength.  A total of 317 proteins were found to be affected in the soybean stem in response to shade.  Under the shade stress, the down-expression of key enzymes involving the phenylpropanoid metabolic pathway inhibited lignin biosynthesis.  The up-regulation of expansin and XTHs protein expression relaxed the cell wall and promoted the elongation of internodes.  Although the expression of the enzymes involving sucrose synthesis increased in the soybean stem, the lack of a carbon source prevented rapid stem growth.  This metabolic deficit is the principal cause of the lower cellulose content in the stem of intercropped soybean, which leads to weakened stems and a propensity for lodging.

Horticulture

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MdSWEET17, a sugar transporter in apple, enhances drought tolerance in tomato LU Jing, Sun Mei-hong, MA Qi-jun, KANG Hui, LIU Ya-jing, HAO Yu-jin, YOU Chun-xiang 2019, 18(9): 2041-2051.  DOI: 10.1016/S2095-3119(19)62695-X Abstract ( )   PDF in ScienceDirect   Sugars are important energy source and signaling molecule in plant, and sugar transporters such as SWEET (sugars will eventually be exported transporters) play important roles in plant growth and development as well as biotic and abiotic stresses.  In this study, a gene named MdSWEET17 was isolated from apple (Malus×domestic).  Expression analysis suggested that MdSWEET17 expressed in all tested tissues (root, stem, leaf, flower and fruit) and the transcript levels were different.  Furthermore, MdSWEET17 transgenic tomatoes and wild type were treated with drought.  The results showed transgenic lines had higher drought tolerance and accumulated more fructose.  Taken together, these findings indicated that MdSWEET17 take part in drought stress response and the regulation of fructose.

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Effects of the severity and timing of basal leaf removal on the amino acids profiles of Sauvignon Blanc grapes and wines YUE Xiao-feng, JU Yan-lun, TANG Zi-zhu, ZHAO Ya-meng, JIAO Xu-liang, ZHANG Zhen-wen 2019, 18(9): 2052-2062.  DOI: 10.1016/S2095-3119(19)62666-3 Abstract ( )   PDF in ScienceDirect   The effects of the severity and timing of leaf removal (LR) on the amino acids of Sauvignon Blanc grapes and wines were studied during the 2017 growing season.  High-performance liquid chromatography (HPLC) was used to analyze the amino acids profiles of grape berries and wines.  The basal leaves were removed at three time points (40, 56 and 72 days after flowering, named LR40, LR56 and LR72, respectively) at two severity levels (one at which the first, third, and fifth basal leaves of each shoot were removed (50% level); and another at which the first six basal leaves were removed (100% level)).  The results showed that leaf removal had little impact on total soluble solids (°Brix), titratable acidity, pH or berry weight.  The LR72-50% treated grapes had higher berry weight, titratable acidity and °Brix than those of the other treatments.  The highest concentrations of total amino acids and of total amino acids except proline were detected in LR72-50% treated grapes (2 952.58 and 2 764.36 mg L–1, respectively); the lowest were detected in LR72-100% treated grapes (2 172.82 and 2 038.71 mg L–1, respectively).  LR72-50% treatment significantly promoted the synthesis of aspartic acid, serine, arginine, alanine, aminobutyric acid and proline at both severity levels for grapes, the concentrations of all of these amino acids were increased relative to the control concentrations.  The LR72-50%, LR40-100% and LR72-100% treated wines had higher total amino acids concentrations and higher concentrations of some individual amino acids, such as arginine, alanine and serine, than did the control wines.  Of all the amino acids studied, glycine, tyrosine, cysteine, methionine and lysine were not significantly influenced by the timing or severity basal defoliation in grapes and wines.  The present study reveals the effects of the timing and severity of leaf removal on the amino acids profiles of grapes and wines.

Plant Protection

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Combined application of Trichoderma harzianum SH2303 and difenoconazole-propiconazolein controlling Southern corn leaf blight disease caused by Cochliobolus heterostrophus in maize WANG Shao-qing, MA Jia, WANG Meng, WANG Xin-hua, LI Ya-qian, CHEN Jie 2019, 18(9): 2063-2071.  DOI: 10.1016/S2095-3119(19)62603-1 Abstract ( )   PDF in ScienceDirect   Southern corn leaf blight (SCLB) disease caused by Cochliobolus heterostrophus is one of the major threats to corn production worldwide.  The synergistic application of low toxic chemical fungicide and biocontrol agents could improve biocontrol stability and efficiency against plant diseases, which ultimately reduce use of chemical fungicide.  Trichoderma spp., well-known biocontrol fungi have been used to control some foliar diseases.  However, few works have been reported on synergistic application of chemical fungicide and Trichoderma against foliar diseases.  This study was aimed to investigate the control effect on the synergistic application of Trichoderma harzianum SH2303 and difenoconazole-propiconazole (DP) against SCLB.  Results showed that the synergistic application of DP and SH2303 reduced the leaf spot area compared to the control.  The efficacy of synergistic application of DP+SH2303 against SCLB could last for 15–20 d in pot trial under the greenhouse condition.  Under the natural field condition, maize treated with DP+DP and DP+SH2303 showed 60% control, which was higher than that of SH2303+DP (45%) and SH2303+SH2303 (35%).  All these treatments induced the synthesis of defense-related enzymes (phenylalanine ammonia lyase (PAL), catalase (CAT), and superoxide dismutase (SOD)) and the defence-related gene expression of SA pathway (PR1).  Taken together the in-vitro leaf test and field trial, the control of SCLB by synergistic application of DP+SH2303 was similar to that of DP+DP.  Among synergistic application, the sequential application of DP+SH2303 showed better control than the sequential application of SH2303+DP.  It was concluded that the synergistic application of chemical fungicide (DP) and biocontrol agent (T. harzianum SH2303) could be used to reduce the chemical fungicide and to reduce the SCLB diseases in maize, which provided alternative approach to realize an eco-friendly controlling of the foliar disease.

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Evaluating effective Trichoderma isolates for biocontrol of Rhizoctonia solani causing root rot of Vigna unguiculata WANG Chao, ZHUANG Wen-ying 2019, 18(9): 2072-2079.  DOI: 10.1016/S2095-3119(19)62593-1 Abstract ( )   PDF in ScienceDirect   The highly diverse genus Trichoderma has provided many formulations that are alternatives to the chemical pesticides in agriculture.  The present study was undertaken to investigate the biocontrol potential of eight Trichoderma species, T. atrobrunneum, T. guizhouense, T. paratroviride, T. pyramidale, T. rufobrunneum, T. simmonsii, T. thermophilum and T. viridulum, against the phytopathogenic fungus Rhizoctonia solani.  Trichoderma isolates were first evaluated in vitro by dual culture tests for their antagonism, mycoparasitic ability and antifungal activity against R. solani.  Their growth promoting potential was further assessed in relation to phosphate solubilization, indole acetic acid and siderophore production.  Five of the isolates were selected and evaluated for their abilities to prompt plant growth and to control R. solani infecting Vigna unguiculata (cowpea) seedlings in vivo.  Two most effective isolates, T. guizhouense 9185 and T. simmonsii 8702, significantly (P<0.05) reduced the disease severity incidences (36.6 and 45.0%, respectively) and promoted plant growth, which have good prospects for application.

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Fermentation, formulation and evaluation of PGPR Bacillus subtilis isolate as a bioagent for reducing occurrence of peanut soil-borne diseases Abdel-Gayed M. Ahmad, Abo-Zaid G. Attia, Matar S. Mohamed, Hafez E. Elsayed 2019, 18(9): 2080-2092.  DOI: 10.1016/S2095-3119(19)62578-5 Abstract ( )   PDF in ScienceDirect   Four isolates of Bacillus subtilis coded, B4, B7, B8 and B10 were examined as biocontrol agents for their abilities and antagonistic effect on the in vitro growth of certain phytopathogenic fungi of peanut, Rhizoctonia solani and Sclerotium rolfsii.  Bacillus subtilis isolate B4 (GenBank accession no. EF150884) was the highly effective one for inhibiting the fungal mycelial growth.  Batch fermentation of B. subtilis isolate B4 was carried out and the maximum biomass achieved was 4.53 g L–1 at 11 h.  Bacillus subtilis isolate B4 was formulated and evaluated as a biofungicide to reduce peanut soil-borne diseases under greenhouse and field conditions at the side of Rizolex-T (fungicide) as standard.  Treatments by formulated plant growth-promoting rhizobacteria (PGPR) B. subtilis B4 and Rizolex-T in a soil infested with R. solani, S. rolfsii and mixture of them were more effective in decreasing percentage of damping-off, root and pod rot disease incidence (%) in greenhouse and open field environment during the two seasons 2015 and 2016.  Treatments by PGPR gave highly dry weight and number of healthy pods compared to control of fungi treatment which was nearby to dry weights of healthy pods achieved by treatments by Rizolex-T in a soil infested with S. rolfsii, R. solani and mixture of them.  Formulated PGPR B. subtilis B4 gave higher increasing of yield percentage than treatment by Rizolex-T in the two evaluated seasons 2015 and 2016.  It can conclude that the produced bioforumlated agent was more efficient as fungicide when compared with the other chemical synthesized fungicides, safe for human and the environment and economy.

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The synergistic advantage of combining chloropicrin or dazomet with fosthiazate nematicide to control root-knot nematode in cucumber production HUANG Bin, WANG Qian, GUO Mei-xia, FANG Wen-sheng, WANG Xiao-ning, WANG Qiu-xia, YAN Dong-dong, OUYANG Can-bin, LI Yuan, CAO Ao-cheng 2019, 18(9): 2093-2106.  DOI: 10.1016/S2095-3119(19)62565-7 Abstract ( )   PDF in ScienceDirect   The highly-damaging root-knot nematode (Meloidogyne spp., RKN) cannot be reliably controlled using only a nematicide such as fosthiazate because of increasing pest resistance.  In laboratory and greenhouse trials, we showed that chloropicrin (CP) or dazomet (DZ) synergized the efficacy of fosthiazate against RKN.  The combination significantly extended the degradation half-life of fosthiazate by an average of about 1.25 times.  CP or DZ with fosthiazate reduced the time for fosthiazate to penetrate the RKN cuticle compared to fosthiazate alone.  CP or DZ combined with low or medium rate of fosthiazate increased the total cucumber yield, compared to the use of each product alone.  A low-dose fosthiazate with DZ improved total yield more than a low dose fosthiazate with CP.  Extending the half-life of fosthiazate and reducing the time for fosthiazate or fumigant to penetrate the RKN cuticle were the two features that gave the fumigant-fosthiazate combination its synergistic advantage over these products used singularly.  This synergy provides the opportunity for farmers to use a low dose of fosthiazate which lowers the risk of RKN resistance.  Farmers could combine DZ at 30 g m–2 with fosthiazate at a low rate of 0.375 g m–2 to control RKN and adequately control two major soil-borne diseases in cucumber greenhouses.

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Transmission characteristics of Tomato chlorosis virus (ToCV) by Bemisia tabaci MED and its effects on host preference of vector whitefly WEI Ke-ke, LI Jie, DING Tian-bo, LIU Tong-xian, CHU Dong 2019, 18(9): 2107-2114.  DOI: 10.1016/S2095-3119(18)62080-5 Abstract ( )   PDF in ScienceDirect   The epidemiology of Tomato chlorosis virus (ToCV) in China is closely associated with its vector whitefly, Bemisia tabaci (Gennadius) MED.  However, the transmission characteristics of ToCV by B. tabaci MED remain poorly understood.  In this study, we analyzed: 1) the horizontal and vertical transmission of ToCV by B. tabaci MED whiteflies; 2) the acquisition of ToCV by male and female B. tabaci MED whiteflies after different feeding durations; 3) the transmission efficacy of viruliferous male and female B. tabaci MED whiteflies after different inoculation access periods (IAPs); 4) the retention of ToCV by viruliferous male and female B. tabaci MED whiteflies after a 48 h acquisition access period (AAP); and 5) the effects of ToCV on host choice of healthy or ToCV-infected tomato plant of viruliferous and non-viruliferous B. tabaci MED at different time points.  Our results showed that: 1) viruliferous males could not transfer ToCV to non-viruliferous females, and vice versa, viruliferous females could not pass on ToCV to non-viruliferous males.  ToCV could not be detected in the F1 generation adults; 2) ToCV could be detected within 4.0% of females or males after a 20 min AAP; 3) ToCV could be detected in 33.3% of tomato plants inoculated by 10 viruliferous males or females with IAPs of 20 or 30 min; 4) the maximum retention time in females was 7 and 5 days in males; and 5) non-viruliferous B. tabaci MED did not show a preference for ToCV-infected tomato plants or healthy tomato plants.  However, viruliferous B. tabaci MED whiteflies did prefer to settle on healthy tomato plants over ToCV-infected tomato plants.  These findings will be helpful to better understand the epidemiology of the recently emerged plant virus, ToCV, in tomato fields in China.

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Field effect of Cnaphalocrocis medinalis granulovirus (CnmeGV) on the pest of rice leaffolder XU Jian, LIU Qin, LI Chuan-ming, HAN Guang-jie 2019, 18(9): 2115-2122.  DOI: 10.1016/S2095-3119(18)62097-0 Abstract ( )   PDF in ScienceDirect   Rice leaffolder, Cnaphalocrocis medinalis (Guenée), has become a major pest throughout the rice cultivating areas of China and caused severe damage to rice production.  Cnaphalocrocis medinalis granulovirus (CnmeGV), a naturally occurring baculovirus, is revealed as a potential microbial agent for the pest control.  Field applications of CnmeGV were conducted against rice leaffolder larvae in rice paddies.  CnmeGV infected the larvae not only in the current generation but also in the successive generation, resulting in a sustained infection in the larva population for at least 48 days.  Under diferent concentrations of CnmeGV (7.5×1011 and 1.125×1012 occlusion body (OB) ha–1) at 30 days after spraying, larval population reduced up to 76.32% and rice leaf rolled rate kept in 15.42%.  Simultaneously, CnmeGV had no impact on arthropod predators of C. medinalis, with abundances ranging from 2.39 to 3.79 per ten hills.  These results revealed that CnmeGV is suitable as a bio-pesticide for rice leaffolder management in rice paddies.

Animal Science · Veterinary Medicine

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Effects of dietary graded levels of cinnamon essential oil and its combination with bamboo leaf flavonoid on immune function, antioxidative ability and intestinal microbiota of broilers YANG Yun-feng, ZHAO Lu-lu, SHAO Yu-xin, LIAO Xiu-dong, ZHANG Li-yang, LU Lin, LUO Xu-gang 2019, 18(9): 2123-2132.  DOI: 10.1016/S2095-3119(19)62566-9 Abstract ( )   PDF in ScienceDirect   Cinnamon essential oil (CEO) and its combination with bamboo leaf flavonoid (BLF) have been shown to exhibit an additive antibacterial effect in vitro, but their functions in broilers were not clear.  An experiment was conducted to investigate the effects of dietary graded levels of CEO and its combination with BLF on the growth performance, immune responses, antioxidative ability, and intestinal morphology and microbiota of broilers fed a corn-soybean meal basal diet.  A total of 576 1-d-old Arbor Acres commercial male broilers were randomly allotted to 9 treatments with 8 replicates of 8 birds each in a completely randomized design.  Birds were fed on a basal corn-soybean meal diet (control, without plant extracts and antibiotics), or the basal diet supplemented with 50 mg of aureomycin kg–1, 50, 100, 200, 400, or 800 mg  of CEO kg–1, a combination of 100 mg of CEO and 16.7 mg of BLF kg–1, or a combination of 200 mg of CEO kg–1 and 33.3 mg of BLF kg–1 for 42 d.  Dietary treatment affected (P<0.05) the serum immune globulin M (IgM) contents on d 42, liver malondialdehyde (MDA) contents on d 21, duodenal crypt depth on d 42, relative abundance of Lactobacillus in the cecal contents on d 21, and relative abundances of Escherichia coli and Bifidobacterium in the cecal contents on d 42, but had no effect (P>0.16) on all other measured indices.  The addition of 400 mg of CEO kg–1 or a combination of 200 mg CEO kg–1 and 33.3 mg BLF kg–1 increased (P<0.02) serum IgM contents on d 42.  Dietary supplementation with 100 or 200 mg CEO kg–1, or 50 mg aureomycin kg–1 decreased (P<0.003) liver MDA contents on d 21.  In addition, the supplement of 100 mg CEO kg–1 increased (P<0.002) the Lactobacillus relative abundance in caecum on d 21 and Bifidobacterium relative abundance in caecum on d 42, and decreased (P<0.0001) E. coli relative abundance in caecum on d 42.  The results indicated that dietary supplementation with CEO, an alternative to aureomycin, improved the immune status, antioxidantative ability and cecal microbiota of broilers, and dietary supplementation with the combinations of CEO and BLF did not exhibit further effects.  Dietary supplementation with 100 mg CEO kg–1 is beneficial for broilers fed a corn-soybean meal basal diet.

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Serologic and molecular survey for major viral pathogens in grazing hybrid wild boars in Northeast China GUO Huan-cheng, REN Zhao-wen, DING Mei-ming, XIAO Wan-jun, PENG Peng, HE Biao, FENG Ye, LIU Yan, LI Xing-yu, CAI Jian-qiu, ZHANG Bi-kai, LUO Qing-hua, TU Chang-chun 2019, 18(9): 2133-2140.  DOI: 10.1016/S2095-3119(19)62650-X Abstract ( )   PDF in ScienceDirect   Hybrid wild boar husbandry is an important component of livestock production in Northeast China.  However, the current disease situation of these animals is largely unknown due to a lack of disease surveillance.  The present study was conducted to determine the prevalence of several important viral diseases in the hybrid wild boar population of Northeast China.  Between September 2015 to December 2016, 169 blood and 61 tissue samples were collected from apparently healthy hybrid wild boars from farms in Jilin, Inner Mongolia and Heilongjiang provinces.  ELISA detected serum antibodies against classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), pseudorabies virus (PRV), porcine circovirus type 2 (PCV2) and Japanese encephalitis virus (JEV), but not against African swine fever virus (ASFV), with PCV2 having the highest seropositive rate (87.2–100% in different farms).  RT-PCR or PCR performed on the processed samples detected only PCV2, with 33.1% (56/169) of blood samples and 32.8% (20/61) of spleen samples being positive, respectively, indicating widespread PCV2 infection in hybrid wild boars.  Phylogenetic analysis of 15 PCV2 ORF2 sequences showed that they belong to genotypes PCV2a, PCV2b and PCV2d, with nucleotide and deduced amino acid homologies of 88.5–100% and 88.1–100%, respectively.

Agro-ecosystem & Environment

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Characterization of low-N responses in maize (Zea mays L.) cultivars with contrasting nitrogen use efficiency in the North China Plain LI Xiang-ling, GUO Li-guo, ZHOU Bao-yuan, TANG Xiang-ming, CHEN Cong-cong, ZHANG Lei, ZHANG Shao-yun, LI Chong-feng, XIAO Kai, DONG Wei-xin, YIN Bao-zhong, ZHANG Yue-chen 2019, 18(9): 2141-2152.  DOI: 10.1016/S2095-3119(19)62597-9 Abstract ( )   PDF in ScienceDirect   Over-use of N fertilizer in crop production has resulted in a series of environmental problems in the North China Plain (NCP).  Thus, improvement of nitrogen use efficiency (NUE) in summer maize has become an effective strategy for promoting sustainable agriculture in this region.  Using twenty maize cultivars, plant dry matter production, N absorption and accumulation, yield formation, and NUE in summer maize were investigated under three N levels in two growing seasons.  Based on their yield and yield components, these maize cultivars were categorized into four groups including efficient-efficient (EE) cultivars, high-nitrogen efficient (HNE) cultivars, low-nitrogen efficient (LNE) cultivars and nonefficient-nonefficient (NN) cultivars.  In both two seasons, the EE cultivars improved grain yield together with increased plant biomass, and enhanced accumulative amounts as well as higher average grain yields than the other cultivar groups under deficient-N conditions.  Significant correlations were observed between yield and kernel numbers (KN), dry matter (DM) amount and N accumulation at both post-silking and maturity stages.  DM and N accumulation at late growth stage (i.e., from silking to maturity) contributed largely to the enhanced yield capacity and improved NUE under N-deficient conditions.  Compared with the NN cultivars, the EE cultivars also showed increased N assimilation amount (NAA) and N remobilization content (NRC), and elevated N remobilization efficiency (NRE), NUE and nitrogen partial factor productivity (PFPN).  Our investigation has revealed N-associated physiological processes and may provide guidance for cultivation and breeding of high yield and NUE summer maize under limited N conditions in the NCP.

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Internal phosphate starvation signaling and external phosphate availability have no obvious effect on the accumulation of cadmium in rice WANG Xue-qing, RUAN Wen-yuan, YI Ke-ke 2019, 18(9): 2153-2161.  DOI: 10.1016/S2095-3119(18)62100-8 Abstract ( )   PDF in ScienceDirect   Phosphorus (P) is a limiting nutrient element for crop.  To obtain maximum crop yield, P fertilizer is often over-applied, which leads to accelerating exhaustion of phosphate resources and serious environmental problems.  Reducing the application of P fertilizer and enhancing the P utilization efficiency of crops are significant for the sustainable development of agriculture.  Cadmium (Cd) contamination in rice is another serious agricultural issue.  However, whether reducing the application of P fertilizer and enhancing the P utilization efficiency of crops will increase the risk of Cd accumulation in crops remains obscure.  In this study, we are aiming to elucidate the relationship between Cd and P in rice from physiological and genetic perspectives.  For this purpose, the wild type (WT) rice plants and phosphate (Pi)-starvation signaling repressed mutant phr2 were used to analyze the relationship between Cd and P.  Here, we found that Cd stress could promote P accumulation and induce Pi-starvation signaling in WT and phr2 shoots under Pi-sufficient condition in a PHOSPHATE STARVATION RESPONSE 2 (PHR2) independent manner.  Besides, the expression level of Cd transporter of OsNramp5 and the uptake speed of Cd2+ were not obviously changed under Pi-sufficient and Pi-deficient conditions.  Furthermore, our Cd determination results showed that the Cd concentrations in WT and phr2 were not obviously changed under Pi-sufficient and Pi-deficient conditions.  These results indicate that the external P availability and internal Pi-starvation signaling cannot obviously affect the accumulation of Cd in rice seedling.

Food Science

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Drying characteristics, functional properties and in vitro digestion of purple potato slices dried by different methods QIU Gan, JIANG Yong-li, DENG Yun 2019, 18(9): 2162-2172.  DOI: 10.1016/S2095-3119(19)62654-7 Abstract ( )   PDF in ScienceDirect   The drying characteristics, physico-chemical and functional properties, as well as starch digestibility, of purple potato slices dried using different methods (such as, vacuum freeze-drying, VFD; hot-air drying, HAD; air-impingement jet drying, AIJD; and far-infrared assisted heat-pump drying, FIHPD) were investigated.  Drying rate was the highest (3.0 g 100 g–1 min–1) using AIJD, followed by FIHPD and HAD, and the rate of VFD was the lowest one (0.3 g 100 g–1 min–1).  Drying data were fitted to 12 thin-layer drying models, with the Midilli model giving the best predictions.  Moreover, AIJD showed higher diffusivity (5.5×10–10 m2 s–1) and energy efficiency (55 J g–1) than any other drying method used in this study.  With reference to the samples dried by VFD, the starch granules of the samples obtained by HAD, FIHPD, and AIJD exhibited different extent of disruption, which significantly increased their water absorption capacity, swelling power, and in vitro digestibility, but decreased the peak viscosity.  The sample resulting from AIJD had the greatest water absorption capacity (7.9 g g–1) and solubility (21.6%), but the smallest syneresis rate (48%).  Good correlation coefficients (R2>0.98) implied that the pseudo-first order kinetic model adequately described the rate and extent of starch digestion of dried potato flours.  Samples from AIJD and FIHPD showed the highest digestibility percentages, reaching to 72.4 and 72.5%.  Based on the drying rate, specific energy consumption, functional properties and digestibility, AIJD appeared to be quite effective and suitable to be transferred on the industry scale.

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Inhibitory effect of tartary buckwheat seedling extracts and associated flavonoid compounds on the polyphenol oxidase activity in potatoes (Solanum tuberosum L.) LI Jun, WANG Hui, LU Yang, MAO Tang-fen, XIONG Jiang, HE Sheng-ling, LIU Hui 2019, 18(9): 2173-2182.  DOI: 10.1016/S2095-3119(19)62692-4 Abstract ( )   PDF in ScienceDirect   To improve the processing quality of potatoes, phosphate buffer extract (PBE), 50% ethanol (E50), and aqueous extract (AE) of tartary buckwheat seedlings were evaluated for their ability to inhibit the enzymatic browning of potatoes.  The results suggest that all extracts of tartary buckwheat seedlings exert significant inhibitory effects on the polyphenol oxidase (PPO) activity in potatoes.  The relative concentrations required for a 50% reduction in the PPO activity (IC50) were 0.21, 0.28 and 0.41 mg mL–1, for PBE, E50 and AE, respectively.  The strongest inhibitory activity was observed for PBE, followed by E50 and AE.  Four flavone compounds in the PBE of tartary buckwheat seedlings (i.e., rutin, kaempferol-3-O-rutinoside, quercetin, and kaempferol) were identified by high-performance liquid chromatography.  These compounds were subsequently evaluated for their roles in the inhibition of PPO from potatoes using a model system.  The results indicated that rutin exhibited the highest inhibition rate on the PPO of potato.  A synergistic inhibitory effect was observed by mixing rutin, kaempferol-3-O-rutinoside, quercetin, and proteins.  The inhibitory patterns of rutin, kaempferol-3-O-rutinoside, and quercetin on the enzyme were noncompetitive and reversible, with inhibitory constants of 0.12, 0.31, and 0.40 mg mL–1, respectively.  Flavonoids from tartary buckwheat seedlings may exhibit a common mechanism with phenolic compounds, involving the blockage of the reaction of oxygen with PPO leading to the inhibition of the enzymes involved in browning.  Based on these results, extracts of tartary buckwheat seedlings can be used as potent natural inhibitors.