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2023 Vol. 22 No. 3 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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Arbuscular mycorrhizal fungi (AMF) help plants acquire phosphorus (P) from the soil. Cotton responds poorly to P-fertilizer application and lacks the ability to obtain P from sparingly soluble P sources, making it likely that cotton crucially depends on the AMF symbiosis. In this study, we addressed the role of mycorrhizal root traits and explored the interplay of root and mycorrhizal traits in enhancing P acquisition. We found that the more recent accessions had smaller root diameters, acquired less P, and produced less biomass at intermediate soil P levels, indicating an inadvertent varietal selection for thinner roots that provided less cortical space for AMF which then increased the need for a high P-fertilizer level. We conclude that selection for cotton should consider both morphological and mycorrhizal root traits when breeding for high-yielding cotton varieties. The photo depicts the carbon and P exchange between plants and AMF. The image was provided by MSc Ma Ruonan and Prof. Feng Gu from the College of Resources and Environmental Sciences, China Agricultural University, China. See pages 701–715 for details.


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Review

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CRISPR-based genetic control strategies for insect pests Ying YAN, Roswitha A. AUMANN, Irina HÄCKER, Marc F. SCHETELIG 2023, 22(3): 651-668.  DOI: 10.1016/j.jia.2022.11.003 Abstract ( )   PDF in ScienceDirect   Genetic control strategies such as the sterile insect technique have successfully fought insect pests worldwide.  The CRISPR (clustered regularly interspaced short palindromic repeats) technology, together with high-quality genomic resources obtained in more and more species, greatly facilitates the development of novel genetic control insect strains that can be used in area-wide and species-specific pest control programs.  Here, we review the research progress towards state-of-art CRISPR-based genetic control strategies, including gene drive, sex ratio distortion, CRISPR-engineered genetic sexing strains, and precision-guided sterile insect technique.  These strategies’ working mechanisms, potential resistance development mechanisms, and regulations are illustrated and discussed.  In addition, recent developments such as stacked and conditional systems are introduced.  We envision that the advances in genetic technology will continue to be one of the driving forces for developing the next generation of pest control strategies.

Crop Science

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OsDXR interacts with OsMORF1 to regulate chloroplast development and the RNA editing of chloroplast genes in rice CAO Peng-hui, WANG Di, GAO Su, LIU Xi, QIAO Zhong-ying, XIE Yu-lin, DONG Ming-hui, DU Tan-xiao, ZHANG Xian, ZHANG Rui, JI Jian-hui 2023, 22(3): 669-678.  DOI: 10.1016/j.jia.2022.08.005 Abstract ( )   PDF in ScienceDirect   Plant chlorophyll biosynthesis and chloroplast development are two complex processes that are regulated by exogenous and endogenous factors.  In this study, we identified OsDXR, a gene encoding a reductoisomerase that positively regulates chlorophyll biosynthesis and chloroplast development in rice.  OsDXR knock-out lines displayed the albino phenotype and could not complete the whole life cycle process.  OsDXR was highly expressed in rice leaves, and subcellular localization indicated that OsDXR is a chloroplast protein.  Many genes involved in chlorophyll biosynthesis and chloroplast development were differentially expressed in the OsDXR knock-out lines compared to the wild type.  Moreover, we found that the RNA editing efficiencies of ndhA-1019 and rpl2-1 were significantly reduced in the OsDXR knock-out lines.  Furthermore, OsDXR interacted with the RNA editing factor OsMORF1 in a yeast two-hybrid screen and bimolecular fluorescence complementation assay.  Finally, disruption of the plastidial 2-C-methyl-derythritol-4-phosphate pathway resulted in defects in chloroplast development and the RNA editing of chloroplast genes.

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Development of new aromatic rice lines with high eating and cooking qualities Kanokwan KAEWMUNGKUN, Keasinee TONGMARK, Sriprapai CHAKHONKAEN, Numphet SANGARWUT, Thiwawan WASINANON, Natjaree PANYAWUT, Khanittha DITTHAB, Kannika SIKAEWTUNG, QI Yong-bin, Sukanya DAPHA, Atikorn PANYA, Natthaporn PHONSATTA, Amorntip MUANGPROM 2023, 22(3): 679-690.  DOI: 10.1016/j.jia.2022.07.001 Abstract ( )   PDF in ScienceDirect   Rice is the staple food for about half of the world’s population.  Preferred by consumers, aromatic rice is a special type of rice with great commercial value.  Cooking and eating qualities and aroma are the major grain qualities favored by most consumers.  Currently, most of the available aromatic varieties have low yields and some undesirable agronomic traits.  Thus, there is an urgent need to develop better aromatic rice varieties.  This work aims to identify rice germplasm lines that have good grain quality and to develop new varieties with desirable traits.  Thirty-six out of 188 germplasm lines were found to have betaine aldehyde dehydrogenase 2 (badh2) controlling the aroma and were analyzed for their 2-acetyl-1-pyrroline (2AP) contents.  Then, 17 of those lines were found to have alleles for low amylose content and low gelatinization temperature, controlled by waxy and starch synthase IIa (SSIIa), respectively, suggesting that they are aromatic rice lines with high cooking and eating qualities.  A total of 158 F7 recombinant inbred lines (RILs) generated from five crosses of the selected germplasm lines were planted for phenotypic and yield observations, resulting in 27 F8 RILs selected for yield evaluation and genotyping.  Finally, four out of the seven F9 aromatic RILs showed high yield, high 2AP production, and low amylose content, in agreement with their genotypes.  The other three F9 RILs were aromatic rice lines with high amylose content and high yield.  Because consumer preferences for grain quality vary depending on regions and ethnic groups, the high-yielding aromatic RILs generated from this study can be used to increase the yield of Thai rice and to raise market value and farm profits.

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Changes in grain-filling characteristics of single-cross maize hybrids released in China from 1964 to 2014 GAO Xing, LI Yong-xiang, YANG Ming-tao, LI Chun-hui, SONG Yan-chun, WANG Tian-yu, LI Yu, SHI Yun-su 2023, 22(3): 691-700.  DOI: 10.1016/j.jia.2022.08.006 Abstract ( )   PDF in ScienceDirect   Grain filling is the physiological process for determining the obtainment of yield in cereal crops.  The grain-filling characteristics of 50 maize brand hybrids released from 1964 to 2014 in China were assayed across multiple environments.  We found that the grain-filling duration (54.46%) and rate (43.40%) at the effective grain-filling phase greatly contributed to the final performance parameter of 100-kernel weight (HKW).  Meanwhile, along with the significant increase in HKW, the accumulated growing degree days (GDDs) for the actual grain-filling period duration (AFPD) among the selected brand hybrids released from the 1960s to the 2010s in China had a decadal increase of 23.41°C d.  However, there was a decadal increase of only 19.76°C d for GDDs of the days from sowing to physiological maturity (DPM), which was also demonstrated by a continuous decrease in the ratio between the days from sowing to silking (DS) and DPM (i.e., from 53.24% in the 1960s to 49.78% in the 2010s).  In contrast, there were no significant changes in grain-filling rate along with the release years of the selected hybrids.  Moreover, the stability of grain-filling characteristics across environments also significantly increased along with the hybrid release years.  We also found that the exotic hybrids showed a longer grain-filling duration at the effective grain-filling phase and more stability of the grain-filling characteristics than those of the Chinese local hybrids.  According to the results of this study, it is expected that the relatively longer grain-filling duration, shorter DS, higher grain-filling rate, and steady grain-filling characteristics would contribute to the yield improvement of maize hybrids in the future.

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Breeding against mycorrhizal symbiosis: Modern cotton (Gossypium hirsutum L.) varieties perform more poorly than older varieties except at very high phosphorus supply levels WANG Xin-xin, ZHANG Min, SHENG Jian-dong, FENG Gu, Thomas W. KUYPER 2023, 22(3): 701-715.  DOI: 10.1016/j.jia.2022.08.004 Abstract ( )   PDF in ScienceDirect   Cotton (Gossypium hirsutum L.) is an important fiber cash crop, but its root traits related to phosphorus (P) acquisition, including mycorrhizal root traits, are poorly understood.  Eight cotton varieties bred in northwestern China that were released between 1950 and 2013 were grown in pots with or without one arbuscular mycorrhizal fungal (AMF) species (Funneliformis mosseae) at three P supply levels (0, 50 and 300 mg P as KH2PO4 kg–1).  Eleven root traits were measured and calculated after 7 wk of growth.  The more recent accessions had smaller root diameters, acquired less P and produced less biomass, indicating an (inadvertent) varietal selection for thinner roots that provided less cortical space for AMF, which then increased the need for a high P fertilizer level.  At the two lower P levels, the mycorrhizal plants acquired more P and produced more biomass than non-mycorrhizal plants (3.2 vs. 0.9 mg P per plant; 1.8 vs. 0.9 g biomass per plant at P0; 14.5 vs. 1.7 mg P per plant; and 4.7 vs. 1.6 g biomass per plant at P50).  At the highest P level, the mycorrhizal plants acquired more P than non-mycorrhizal plants (18.8 vs. 13.4 mg per P plant), but there was no difference in biomass (6.2 vs. 6.3 g per plant).  At the intermediate P level, root diameter was significantly positively correlated with shoot biomass, P concentration and the P content of mycorrhizal plants.  The results of our study support the importance of the outsourcing model of P acquisition in the root economics space framework.  Inadvertent varietal selection in the last decades, resulting in thinner roots and a lower benefit from AMF, has led to a lower productivity of cotton varieties at moderate P supply (i.e., when mycorrhizal, the average biomass of older varieties 5.0 g per plant vs. biomass of newer varieties 4.4 g per plant), indicating the need to rethink cotton breeding efforts in order to achieve high yields without very high P input.  One feasible way to solve the problem of inadvertent varietal selection for cotton is to be aware of the trade-offs between the root do-it-yourself strategy and the outsourcing towards AMF strategy, and to consider both morphological and mycorrhizal root traits when breeding cotton varieties.

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Effects of erect panicle genotype and environment interactions on rice yield and yield components WANG Yuan-zheng, Olusegun IDOWU, WANG Yun, HOMMA Koki, NAKAZAKI Tetsuya, ZHENG Wen-jing, XU Zheng-jin, SHIRAIWA Tatsuhiko 2023, 22(3): 716-726.  DOI: 10.1016/j.jia.2022.08.013 Abstract ( )   PDF in ScienceDirect   The dense and erect panicle (EP) genotype conferred by DEP1 has been widely used in the breeding of high-yield Chinese japonica rice varieties.  However, the breeding value of the EP genotype has rarely been determined at the plant population level.  Therefore, the effects of the interaction of EP genotype and the environment at different locations and times on rice yield and its various components were investigated in this study.  Two sets of near-isogenic lines (NILs) of EP and non-EP (NEP) genotypes with Liaojing 5 (LG5) and Akitakomachi (AKI) backgrounds were grown in the field in 2016 and 2017 in Shenyang, China, and Kyoto, Japan.  In 2018, these sets were grown only in Kyoto, Japan.  The average yields of the EP and NEP genotypes were 6.67 and 6.13 t ha−1 for the AKI background, and 6.66 and 6.58 t ha−1 for the LG5 background, respectively.  The EP genotype positively affected panicle number (PN) and grain number per square meter (GNPM), mostly resulting in a positive effect on harvest index (HI).  In contrast, the EP genotype exerted a negative effect on thousand-grain weight (KGW).  The ratio of the performance of the EP genotype relative to the NEP genotype in terms of yield and total biomass correlated positively with mean daily solar radiation during a 40-day period around heading.  These results indicate that the effectiveness of the EP genotype depends on the availability of solar radiation, and the effect of this genotype is consistently positive for sink formation, conditional in terms of source capacity, and positive in a high-radiation environment.

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Discrimination of individual seed viability by using the oxygen consumption technique and headspace-gas chromatography-ion mobility spectrometry TU Ke-ling, YIN Yu-lin, YANG Li-ming, WANG Jian-hua, SUN Qun 2023, 22(3): 727-737.  DOI: 10.1016/j.jia.2022.08.058 Abstract ( )   PDF in ScienceDirect   Identifying and selecting high-quality seeds is crucial for improving crop yield.  The purpose of this study was to improve the selection of crop seeds based on separating vital seeds from dead seeds, by predicting the potential germination ability of each seed, and thus improving seed quality.  The methods of oxygen consumption (Q) of seeds and the headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were evaluated for identifying the viability of individual seeds.  Firstly, the oxygen consumption technique showed clear differences among the values related to respiratory characteristics for seeds that were either vital or not, and the discrimination ability of final oxygen consumption (Q120) was achieved not only in sweet corn seeds but also in pepper and wheat seeds.  Besides, Qt was established as a new variable to shorten the measuring process in the Q2 (oxygen sensor) procedure, which was significantly related to the viability of individual seeds.  To minimize seed damage during measurement, the timing for viability evaluation was pinpointed at the 12, 6 and 9 h for pepper, sweet corn, and wheat seeds based on the new variables concerning oxygen consumption (i.e., Q12, Q6 and Q9, respectively).  The accuracies of viability prediction were 91.9, 97.7 and 96.2%, respectively.  Dead seeds were identified and hence discarded, leading to an enhancement in the quality of the seed lot as indicated by an increase in germination percentage, from 86.6, 90.9, and 53.8% to all at 100%.  We then used the HS-GC-IMS to determine the viability of individual sweet corn seeds, noting that corn seed has a heavier weight so the volatile gas components are more likely to be detected.  A total of 48 chromatographic peaks were identified, among which 38 target compounds were characterized, including alcohols, aldehydes, acids and esters.  However, there were no significant differences between the vital and dead seeds, due to the trace amount volatile composition differences among the individual seeds.  Furthermore, a PCA based on the signal intensities of the target volatile compounds obtained was found to lose its effectiveness, as it was unable to distinguish those two types of sweet corn seeds.  These strategies can provide a reference for the rapid detection of single seed viability.

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Millet/peanut intercropping at a moderate N rate increases crop productivity and N use efficiency, as well as economic benefits, under rain-fed conditions LIU Zhu, NAN Zhen-wu, LIN Song-ming, YU Hai-qiu, XIE Li-yong, MENG Wei-wei, ZHANG Zheng, WAN Shu-bo 2023, 22(3): 738-751.  DOI: 10.1016/j.jia.2022.08.078 Abstract ( )   PDF in ScienceDirect   Cereal and legume intercropping has been widely adopted to increase crop productivity in sustainable farming systems worldwide.  Among different intercropping combinations, millet and peanut intercropping can be adapted to most water-limited areas.  However, there are few studies on the differences in yield characteristics and nitrogen use efficiency between millet/peanut intercropping and monocultures under different nitrogen (N) application rates.  The objective of this study was to determine the yield advantages and economic benefits, as well as the appropriate N application rate, of millet/peanut intercropping.  A two-year field experiment was conducted with three cropping patterns (monoculture millet, monoculture peanut and millet/peanut intercropping) and four N rates (0, 75, 150 and 225 kg ha−1).  The results showed that the land equivalent ratio (LER) and net effect (NE) of the intercropping system reached their highest levels at the N input of 150 kg ha−1 in 2018 and 2019 (1.04 for LER, 0.347 Mg ha−1 for NE, averaged across two years).  Millet was the dominant crop in the intercropping system (aggressivity of millet and peanut (Amp)>0, competitive ratio of millet and peanut (CRmp)>1), and millet yields achieved their highest values at N inputs of 225 kg ha−1 for monoculture and 150 kg ha−1 for intercropping.  NUE reached its highest levels with N inputs of 150 kg ha−1 for all planting patterns over the two years.  Intercropping combined with an N input of 150 kg ha−1 achieved the highest net income of 2 791 USD ha−1, with a benefit-cost ratio of 1.56, averaged over the two years.  From the perspective of economics and agricultural sustainable development, millet/peanut intercropping at 150 kg N ha−1 seems to be a promising alternative to millet or peanut monoculture.

Horticulture

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StOFP20 regulates tuber shape and interacts with TONNEAU1 Recruiting Motif proteins in potato AI Ju, WANG Ye, YAN Ya-wen, LI Chen-xiao, LUO Wei, MA Ling, SHANG Yi, GAO Dong-li 2023, 22(3): 752-761.  DOI: 10.1016/j.jia.2022.08.069 Abstract ( )   PDF in ScienceDirect   The OVATE family proteins (OFPs) are plant-specific proteins that modulate diverse aspects of plant growth and development.  In tomato, OFP20 has been shown to interact with TONNEAU1 Recruiting Motif (TRM) proteins to regulate fruit shape.  In this study, we demonstrated that the mutation of StOFP20 caused a shift from round to oval shaped tubers in a diploid accession C151, supporting the role of StOFP20 in controlling tuber shape.  Its expression reached a maximum in the tuber initiation stage and then decreased as the tuber develops.  To help elucidate the mechanism of tuber shape regulation by StOFP20, 27 TONNEAU1 Recruiting Motif (TRM) proteins were identified and 23 of them were successfully amplified in C151.  A yeast two-hybrid assay identified three TRM proteins that interacted with StOFP20, which was confirmed by firefly luciferase complementation in tobacco leaves.  The OVATE domain was indispensable for the interactions, while the necessity of the M10 motif in TRM proteins varied among the interactions between StOFP20 and the three TRMs.  In summary, both StOFP20 and SlOFP20 directed interactions with TRM proteins, but the corresponding interactants were not completely consistent, implying that they exert regulatory roles through mechanisms that are only partially overlapping.

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Functional analysis of MdSUT2.1, a plasma membrane sucrose transporter from apple ZHANG Bo, FAN Wen-min, ZHU Zhen-zhen, WANG Ying, ZHAO Zheng-yang 2023, 22(3): 762-775.  DOI: 10.1016/j.jia.2022.09.012 Abstract ( )   PDF in ScienceDirect   Sugar content is a determinant of apple (Malus×domestica Borkh.) sweetness.  However, the molecular mechanism underlying sucrose accumulation in apple fruit remains elusive.  Herein, this study reported the role of the sucrose transporter MdSUT2.1 in the regulation of sucrose accumulation in apples.  The MdSUT2.1 gene encoded a protein with 612 amino acid residues that could be localized at the plasma membrane when expressed in tobacco leaf protoplasts.  MdSUT2.1 was highly expressed in fruit and was positively correlated with sucrose accumulation during apple fruit development.  Moreover, complementary growth assays in a yeast mutant validated the sucrose transport activity of MdSUT2.1.  MdSUT2.1 overexpression in apples and tomatoes resulted in significant increases in sucrose, fructose, and glucose contents compared to the wild type (WT).  Further analysis revealed that the expression levels of sugar metabolism- and transport-related genes SUSYs, NINVs, FRKs, HXKs, and TSTs increased in apples and tomatoes with MdSUT2.1 overexpression compared to WT.  Finally, unlike the tonoplast sugar transporters MdTST1 and MdTST2, the promoter of MdSUT2.1 was not induced by exogenous sugars.  These findings provide valuable insights into the molecular mechanism underlying sugar accumulation in apples.

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Identification and functional analysis of arabinogalactan protein expressed in pear pollen tubes JIAO Hui-jun, WANG Hong-wei, RAN Kun, DONG Xiao-chang, DONG Ran, WEI Shu-wei, WANG Shao-min 2023, 22(3): 776-789.  DOI: 10.1016/j.jia.2023.02.007 Abstract ( )   PDF in ScienceDirect   Arabinogalactan proteins (AGPs) are widely distributed in the plant kingdom and play a vital role during the process of plant sexual reproduction.  In this study, we performed a comprehensive identification of the PbrAGPs expressed in pear pollen and further explored their influences on pollen tube growth.  Among the 187 PbrAGPs that were found to be expressed in pear pollen tubes, 38 PbrAGPs were specifically expressed in pollen according to the RNA-seq data.  The PbrAGPs were divided into two groups of highly expressed and specifically expressed in pear pollen.  We further tested their expression patterns using RT-PCR and RT-qPCR.  Most of the PbrAGPs were expressed in multiple tissues and their expression levels were consistent with reads per kilobase per million map reads (RPKM) values during pollen tube growth, implying that PbrAGPs might be involved in the regulation of pear pollen tube growth.  We also constructed phylogenetic trees to identify the functional genes in pear pollen tube growth.  Therefore, 19 PbrAGPs (PbrAGP1 to PbrAGP19) were selected to test their influences on pollen tube growth.  Recombinant proteins of the 19 PbrAGP-His were purified and used to treat pear pollen, and 11 of the PbrAGP-His recombinant proteins could promote pear pollen tube growth.  Additionally, pollen tube growth was inhibited when the expression levels of PbrAGP1 and PbrAGP5 were knocked down using an antisense oligonucleotide assay.  PbrAGP1 and PbrAGP5 were localized in the plasma membrane and might not alter the distribution of pectin in the pollen tube.  In summary, this study identified the PbrAGPs expressed in pear pollen and lays the foundation for further exploring their functions in pollen tube growth.

Plant Protection

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A universal probe for simultaneous detection of six pospiviroids and natural infection of potato spindle tuber viroid (PSTVd) in tomato in China ZHANG Yu-hong, LI Zhi-xin, DU Ya-jie, LI Shi-fang, ZHANG Zhi-xiang 2023, 22(3): 790-798.  DOI: 10.1016/j.jia.2022.08.119 Abstract ( )   PDF in ScienceDirect   Several viroids in the genus Pospiviroid can infect tomato (Solanum lycopersicum) and cause severe diseases, posing a serious threat to tomato production.  For simultaneous detection of six tomato-infecting pospiviroids - columnea latent viroid (CLVd), pepper chat fruit viroid (PCFVd), potato spindle tuber viroid (PSTVd), tomato apical stunt viroid (TASVd), tomato chlorotic dwarf viroid (TCDVd), and tomato planta macho viroid (TPMVd), we developed a universal probe based on a highly conserved 61 nt long sequence shared among them.  Compared with their specific probes, the universal probe has a similar, though slightly reduced, detection sensitivity and has the advantages of simple and cost-effective preparation and simultaneous detection of the six pospiviroids.  In addition, the universal probe was used in dot-blot hybridization assays for a large-scale survey of viroid(s) in tomato plantings in China.  Only PSTVd was detected in a few greenhouse-planted tomato plants.  Sequence analysis revealed that these tomato PSTVd isolates may have been introduced from tomato seeds imported from abroad.

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A Meloidogyne incognita effector Minc03329 suppresses plant immunity and promotes parasitism ZHOU Jing-jing, ZHANG Xiao-ping, LIU Rui, LING Jian, LI Yan, YANG Yu-hong, XIE Bing-yan, ZHAO Jian-long, MAO Zhen-chuan 2023, 22(3): 799-811.  DOI: 10.1016/j.jia.2022.08.117 Abstract ( )   PDF in ScienceDirect   Meloidogyne incognita is a devastating plant-parasitic nematode.  Effectors play important roles during the stages of nematodes infection and parasitism, but their molecular functions remain largely unknown.  In this study, we characterized a new effector, Minc03329, which contains signal peptide for secretion and a C-type lectin domain.  The yeast signal sequence trap experiments indicated that the signal peptide of Minc03329 is functional.  In situ hybridization showed that Minc03329 was specifically expressed in the subventral esophageal gland.  Real-time qPCR confirmed that the expression level of Minc03329 transcript was significantly increased in pre-parasitic and parasitic second-stage juveniles (pre-J2s and par-J2s).  Tobacco rattle virus (TRV)-mediated gene silencing of Minc03329 in host plants largely reduced the pathogenicity of nematodes.  On the contrary, ectopic expression of Minc03329 in Arabidopsis thaliana significantly increased plant susceptibility to nematodes.  Transient expression of Minc03329 in Nicotiana benthamiana leaves suppressed the programmed cell death triggered by the pro-apoptotic protein BAX.  Moreover, the transcriptome analysis of Minc03329-transgenic Arabidopsis and wild type revealed that many defense-related genes were significantly down-regulated.  Interestingly, some different expressed genes were involved in the formation of nematode feeding sites.  These results revealed that Minc03329 is an important effector for M. incognita, suppressing host defense response and promoting pathogenicity.

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Halloween genes AhCYP307A2 and AhCYP314A1 modulate last instar larva–pupa–adult transition, ovarian development and oogenesis in Agasicles hygrophila (Coleoptera: Chrysomelidae) JIN Ji-su, LIU Yi-ran, ZHOU Zhong-shi, WAN Fang-hao, GUO Jian-ying 2023, 22(3): 812-824.  DOI: 10.1016/j.jia.2022.08.021 Abstract ( )   PDF in ScienceDirect   In insects, ecdysteroids are synthesized by genes of the Halloween family and play important roles in several key developmental events, including molting and metamorphosis.  However, the roles of these genes in Agasicles hygrophila are still largely unknown.  In this study, the expression patterns of the two Halloween genes AhCYP307A2 and AhCYP314A1 were determined by quantitative PCR (qPCR) at different developmental stages.  Moreover, the functions of these two genes were explored using RNA interference (RNAi), and ovarian development was observed by dissecting the ovaries of A. hygrophila females.  The qPCR results showed that AhCYP307A2 and AhCYP314A1 were highly expressed in last instar larvae and in adult females.  In addition, AhCYP307A2 was also highly expressed in eggs and pupae but was markedly lower than in third-instar larvae and females.  The RNAi results showed that the injection of dsAhCYP307A2 or dsAhCYP314A1 markedly inhibited their expression and the transcription levels of three related AhVgs.  Knockdown of AhCYP307A2 or AhCYP314A1 significantly inhibited larval molting, impaired last instar larva–pupa–adult transition, delayed ovarian development, and stopped egg production (i.e., no eggs were laid).  These results indicate that AhCYP307A2 and AhCYP314A1 play important regulatory roles in last instar larva–pupa–adult transition and reproduction in A. hygrophila.

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Chromosome-level genome assembly of Cylas formicarius provides insights into its adaptation and invasion mechanisms HUA Jin-feng, ZHANG Lei, HAN Yong-hua, GOU Xiao-wan, CHEN Tian-yuan, HUANG Yong-mei, LI Yan-qing, MA Dai-fu, LI Zong-yun 2023, 22(3): 825-843.  DOI: 10.1016/j.jia.2022.08.027 Abstract ( )   PDF in ScienceDirect   Cylas formicarius is one of the most important pests of sweet potato worldwide, causing considerable ecological and economic damage.  This study improved the effect of comprehensive management and understanding of genetic mechanisms by examining the functional genomics of C. formicarius.  Using Illumina and PacBio sequencing, this study obtained a chromosome-level genome assembly of adult weevils from lines inbred for 15 generations.  The high-quality assembly obtained was 338.84 Mb, with contig and scaffold N50 values of 14.97 and 34.23 Mb, respectively.  In total, 157.51 Mb of repeat sequences and 11 907 protein-coding genes were predicted.  A total of 337.06 Mb of genomic sequences was located on the 11 chromosomes, accounting for 99.03% of the total length of the associated chromosome.  Comparative genomic analysis showed that C. formicarius was sister to Dendroctonus ponderosae, and C. formicarius diverged from D. ponderosae approximately 138.89 million years ago (Mya).  Many important gene families expanded in the C. formicarius genome were involved in the detoxification of pesticides, tolerance to cold stress and chemosensory system.  To further study the role of odorant-binding proteins (OBPs) in olfactory recognition of C. formicarius, the binding assay results indicated that CforOBP4–6 had strong binding affinities for sex pheromones and other ligands.  The high-quality C. formicarius genome provides a valuable resource to reveal the molecular ecological basis, genetic mechanism, and evolutionary process of major agricultural pests; it also offers new ideas and new technologies for ecologically sustainable pest control.

Animal Science · Veterinary Medicine

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Effect of group size and regrouping on physiological stress and behavior of dairy calves LYU Jing, WANG Chao, ZHAO Xun-wu, MIAO Er-yu, WANG Zhi-peng, XU Yuan, BAI Xiu-juan, BAO Jun 2023, 22(3): 844-852.  DOI: 10.1016/j.jia.2022.08.073 Abstract ( )   PDF in ScienceDirect   Mixing or regrouping of calves from different pens is a common animal management practice on the farm, which frequently occurs after weaning and has a negative effect on calve welfare.  Social integration before regrouping may relieve stresses, but more evidences are needed to verify this hypothesis.  The present study aimed to investigate acute physiological and behavioral variations of individually- or group-housed calves after being introduced into a mixed group.  A total of 132 postnatal calves were randomly divided into groups of 1, 3, 6 and 12 animals (S, G3, G6, and G12; 6 replicates in each group) until 59 days of age.  At 60 days of age, every two replicates from different groups (S, G3, G6 and G12) were introduced in a larger pen which containing 44 of the aboved experimental calves.  Before and after regrouping, physiological parameters of stress, including heart rate (HR), saliva cortisol (S-CORT), saliva secretory immunoglobulin A (SIgA), interleukin-2 (IL-2), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) levels, and behavioral responses were recorded.  After regrouping, HR and S-CORT increased immediately (P<0.05), and higher (P<0.05) levels of such molecules were found in S calves compared to those in group-housed calves.  Levels of SIgA and IL-2 were decreased (P<0.05), and the lowest (P<0.05) IL-2 values were found in S calves compared to those in group-housed calves.  In addition, the introduced calves displayed a distinct behavior, including altered active and rest time, which was associated with negative emotions triggered by the novel surroundings.  Allogrooming, play, exploration behaviors and lying time were increased significantly (P<0.05) in group-housed calves than those in S calves.  Conversely, self-grooming, aggressive behaviors, standing and walking time were increased (P<0.05) in S calves than those in group-housed calves.  These findings suggest that individually-housed calves may be more susceptible to stressors arising from regrouping than group-housed calves, which consequently negatively affected behavioral and neuroendocrine responses.  Furthermore, moving calves with previous social experience may help mitigate regrouping stress.

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TIMP2 promotes intramuscular fat deposition by regulating the extracellular matrix in chicken CUI Huan-xian, LUO Na, GUO Li-ping, LIU Lu, XING Si-yuan, ZHAO Gui-ping, WEN Jie 2023, 22(3): 853-863.  DOI: 10.1016/j.jia.2022.08.071 Abstract ( )   PDF in ScienceDirect   The interaction between myocytes and intramuscular adipocytes is a hot scientific topic.  Using a co-culture system, this study aims to investigate the regulation of intramuscular fat deposition in chicken muscle tissue through the interaction between myocyte and adipocyte and identify important intermediary regulatory factors.  Our proteomics data showed that the protein expression of tissue inhibitor of metalloproteinases 2 (TIMP2) increased significantly in the culture medium of the co-culture system, and the content of lipid droplets was more in the co-culture intramuscular adipocytes.  In addition, TIMP2 was significantly upregulated (P<0.01) in muscle tissue of individuals with high intramuscular fat content.  Weighted gene co-expression network analysis revealed that TIMP2 was mainly involved in the extracellular matrix receptor interaction signaling pathway and its expression was significantly correlated with triglyceride, intramuscular fat, C14:0, C14:1, C16:0, C16:1, and C18:1n9C levels.  Additionally, TIMP2 was co-expressed with various representative genes related to lipid metabolism (such as ADIPOQ, SCD, ELOVL5, ELOVL7, and LPL), as well as certain genes involved in extracellular matrix receptor interaction (such as COL1A2, COL4A2, COL5A1, COL6A1, and COL6A3), which are also significantly upregulated (P<0.05 or P<0.01) in muscle tissue of individuals with high intramuscular fat content.  Our findings reveal that TIMP2 promotes intramuscular fat deposition in muscle tissue through the extracellular matrix receptor interaction signaling pathway.

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SCSMRD: A database for single-cell skeletal muscle regeneration FENG Xi-kang, XIE Chun-di, LI Yong-yao, WANG Zi-shuai, BAI Li-jing 2023, 22(3): 864-871.  DOI: 10.1016/j.jia.2022.08.108 Abstract ( )   PDF in ScienceDirect   Skeletal muscle regeneration is a complex process where various cell types and cytokines are involved.  Single-cell RNA-sequencing (scRNA-seq) provides the opportunity to deconvolute heterogeneous tissue into individual cells based on their transcriptomic profiles.  Recent scRNA-seq studies on mouse muscle regeneration have provided insights to understand the transcriptional dynamics that underpin muscle regeneration.  However, a database to investigate gene expression profiling during skeletal muscle regeneration at the single-cell level is lacking.  Here, we collected over 105 000 cells at 7 key regenerative time-points and non-injured muscles and developed a database, the Single-cell Skeletal Muscle Regeneration Database (SCSMRD).  SCSMRD allows users to search the dynamic expression profiles of genes of interest across different cell types during the skeletal muscle regeneration process.  It also provides a network to show the activity of regulons in different cell types at different time points.  Pesudotime analysis showed the state changes trajectory of muscle stem cells (MuSCs) during skeletal muscle regeneration.  This database is freely available at https://scsmrd.fengs-lab.com.

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Genome characterization of the Caprine arthritis-encephalitis virus in China: A retrospective genomic analysis of the earliest Chinese isolates WANG Deng-feng, YANG Xue-yun, WEI Yu-rong, LI Jian-jun, BOLATI Hongduzi, MENG Xiao-xiao, TUERXUN Gunuer, NUERDAN Nuerbaiheti, WU Jian-yong 2023, 22(3): 872-880.  DOI: 10.1016/j.jia.2022.08.110 Abstract ( )   PDF in ScienceDirect   Caprine arthritis-encephalitis virus (CAEV) is an under-studied virus infecting caprines and ovines worldwide.  Over the last four decades, CAEV has spread in China, obtaining genomic data on CAEV strains circulating in China is of importance for developing diagnostic methods and eradicating associated diseases.  However, there is limited information on the genome, including characterizations, and the probable origin.  This work aimed to characterize Chinese CAEV genomes and population structures.  Five CAEV strains isolated from infected dairy goats between 1989 and 1994 in Gansu, Guizhou, Shaanxi, Shandong and Sichuan provinces were cloned and sequenced.  The Chinese CAEV had a 58–93% genome similarities to strains outside of China, and they belonged to subgenotype B1.  The highest similarity levels (98.3–99.3%) were with two other Chinese strains, and they shared a 91.8–92.3% similarity with the strain Clements (GenBank accession no. NC_001463.1) from outside of China.  The Chinese CAEV strains isolated from different provinces over five years were still highly homologous and contained unique ancestral population components, indicating that these Chinese strains had a common origin that differed from other known strains.  Our results provide genomic data on circulating Chinese CAEV strains and will be useful for future epidemiological investigations and CAEV eradication programs.

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Phylogenetic and epidemiological characteristics of H9N2 avian influenza viruses in Shandong Province, China from 2019 to 2021 ZHAO Yi-ran, ZHAO Yu-zhong, LIU Si-dang, XIAO Yi-hong, LI Ning, LIU Kui-hao, MENG Fan-liang, ZHAO Jun, LIU Meng-da, LI Bao-quan 2023, 22(3): 881-896.  DOI: 10.1016/j.jia.2022.08.114 Abstract ( )   PDF in ScienceDirect   H9N2 avian influenza virus (AIV) has widely circulated in poultry worldwide and sporadic infections in humans and mammals.  During our surveillance of chicken from 2019 to 2021 in Shandong Province, China, we isolated 11 H9N2 AIVs.  Phylogenetic analyses showed that the eight gene segments of the 11 isolates were closely related to several sublineages of Eurasian lineage: BJ/94-like clades (HA and NA genes), G1-like clades (PB2 and M genes), and SH/F/98-like clades (PB1, PA, NP and NS genes).  The isolates showed mutation sites that preferentially bind to human-like receptors (HA) and mammalian fitness sites (PB2, PB1 and PA), as well as mutations in antigen and drug resistance sites.  Moreover, studies with mice revealed four isolates with varying levels of pathogenicity.  The average antibody titer of the H9N2 AIVs was 8.60 log2.  Based on our results, the epidemiological surveillance of H9N2 AIVs should be strengthened.

Agro-ecosystem & Environment

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Effect of fertigation frequency on soil nitrogen distribution and tomato yield under alternate partial root-zone drip irrigation FENG Xu-yu, PU Jing-xuan, LIU Hai-jun, WANG Dan, LIU Yu-hang, QIAO Shu-ting, LEI Tao, LIU Rong-hao 2023, 22(3): 897-907.  DOI: 10.1016/j.jia.2022.09.002 Abstract ( )   PDF in ScienceDirect   Alternate partial root-zone drip fertigation (ADF) is a combination of alternating irrigation and drip fertigation, with the potential to save water and increase nitrogen (N) fertilizer efficiency.  A 2-year greenhouse experiment was conducted to evaluate the effect of different fertigation frequencies on the distribution of soil moisture and nutrients and tomato yield under ADF.  The treatments included three ADF frequencies with intervals of 3 days (F3), 6 days (F6) and 12 days (F12), and conventional drip fertigation as a control (CK), which was fertilized once every 6 days.  For the ADF treatments, two drip tapes were placed 10 cm away on each side of the tomato row, and alternate drip irrigation was realized using a manual valve on the distribution tapes.  For the CK treatment, a drip tape was located close to the roots of the tomato plants.  The total N application rate of all treatments was 180 kg ha–1.  The total irrigation amounts applied to the CK treatment were 450.6 and 446.1 mm in 2019 and 2020, respectively; and the irrigation amounts applied to the ADF treatments were 60% of those of the CK treatment.   The F3 treatment resulted in water and N being distributed mainly in the 0–40-cm soil layer with less water and N being distributed in the 40–60-cm soil layer.  The F6 treatment led to 21.0 and 29.0% higher 2-year average concentration of mineral N in the 0–20 and 20–40-cm soil layer, respectively and a 23.0% lower N concentration in the 40–60-cm soil layer than in the CK treatment.  The 2-year average tomato yields of the F3, F6, F12, and CK treatments were 107.5, 102.6, 87.2, and 98.7 t ha–1, respectively.  The tomato yield of F3 was significantly higher (23.3%) than that in the F12 treatment, whereas there was no significant difference between the F3 and F6 treatment.  The F6 treatment resulted in yield similar to the CK treatment, indicating that ADF could maintain tomato yield with a 40% saving in water use.  Based on the distribution of water and N, and tomato yield, a fertigation frequency of 6 days under ADF should be considered as a water-saving strategy for greenhouse tomato production.

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Growth and nitrogen productivity of drip-irrigated winter wheat under different nitrogen fertigation strategies in the North China Plain Sunusi Amin ABUBAKAR, Abdoul Kader Mounkaila HAMANI, WANG Guang-shuai, LIU Hao, Faisal MEHMOOD, Abubakar Sadiq ABDULLAHI, GAO Yang, DUAN Ai-wang 2023, 22(3): 908-922.  DOI: 10.1016/j.jia.2022.08.107 Abstract ( )   PDF in ScienceDirect   Excessive application of nitrogen (N) fertilizer is the main cause of N loss and poor use efficiency in winter wheat (Triticum aestivum L.) production in the North China Plain (NCP).  Drip fertigation is considered to be an effective method for improving N use efficiency and reducing losses, while the performance of drip fertigation in winter wheat is limited by poor N scheduling.  A two-year field experiment was conducted to evaluate the growth, development and yield of drip-fertigated winter wheat under different split urea (46% N, 240 kg ha–1) applications.  The six treatments consisted of five fertigation N application scheduling programs and one slow-release fertilizer (SRF) application.  The five N scheduling treatments were N0–100 (0% at sowing and 100% at jointing/booting), N25–75 (25% at sowing and 75% at jointing and booting), N50–50 (50% at sowing and 50% at jointing/booting), N75–25 (75% at sowing and 25 at jointing/booting), and N100–0 (100% at sowing and 0% at jointing/booting).  The SRF (43% N, 240 kg ha–1) was only used as fertilizer at sowing.  Split N application significantly (P<0.05) affected wheat grain yield, yield components, aboveground biomass (ABM), water use efficiency (WUE) and nitrogen partial factor productivity (NPFP).  The N50–50 and SRF treatments respectively had the highest yield (8.84 and 8.85 t ha–1), ABM (20.67 and 20.83 t ha–1), WUE (2.28 and 2.17 kg m–3) and NPFP (36.82 and 36.88 kg kg–1).  This work provided substantial evidence that urea-N applied in equal splits between basal and topdressing doses compete economically with the highly expensive SRF for fertilization of winter wheat crops.  Although the single-dose SRF could reduce labor costs involved with the traditional method of manual spreading, the drip fertigation system used in this study with the N50–50 treatment provides an option for farmers to maintain wheat production in the NCP.

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Changes in the activities of key enzymes and the abundance of functional genes involved in nitrogen transformation in rice rhizosphere soil under different aerated conditions XU Chun-mei, XIAO De-shun, CHEN Song, CHU Guang, LIU Yuan-hui, ZHANG Xiu-fu, WANG Dan-ying 2023, 22(3): 923-934.  DOI: 10.1016/j.jia.2022.08.036 Abstract ( )   PDF in ScienceDirect   Soil microorganisms play important roles in nitrogen transformation.  The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in rhizosphere soil aerated using three different methods (continuous flooding (CF), continuous flooding and aeration (CFA), and alternate wetting and drying (AWD)).  The abundances of amoA ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), nirS, nirK, and nifH genes, and the activities of urease, protease, ammonia oxidase, nitrate reductase, and nitrite reductase were measured at the tillering (S1), heading (S2), and ripening (S3) stages.  We analyzed the relationships of the aforementioned microbial activity indices, in addition to soil microbial biomass carbon (MBC) and soil microbial biomass nitrogen (MBN), with the concentration of soil nitrate and ammonium nitrogen.  The abundance of nitrogen function genes and the activities of nitrogen invertase in rice rhizosphere soil were higher at S2 compared with S1 and S3 in all treatments.  AWD and CFA increased the abundance of amoA and nifH genes, and the activities of urease, protease, and ammonia oxidase, and decreased the abundance of nirS and nirK genes and the activities of nitrate reductase and nitrite reductase, with the effect of AWD being particularly strong.  During the entire growth period, the mean abundances of the AOA amoA, AOB amoA, and nifH genes were 2.9, 5.8, and 3.0 higher in the AWD treatment than in the CF treatment, respectively, and the activities of urease, protease, and ammonia oxidase were 1.1, 0.5, and 0.7 higher in the AWD treatment than in the CF treatment, respectively.  The abundances of the nirS and nirK genes, and the activities of nitrate reductase and nitrite reductase were 73.6, 84.8, 10.3 and 36.5% lower in the AWD treatment than in the CF treatment, respectively.  The abundances of the AOA amoA, AOB amoA, and nifH genes were significantly and positively correlated with the activities of urease, protease, and ammonia oxidase, and the abundances of the nirS and nirK genes were significantly positively correlated with the activities of nitrate reductase.  All the above indicators were positively correlated with soil MBC and MBN.  In sum, microbial activity related to nitrogen transformation in rice rhizosphere soil was highest at S2.  Aeration can effectively increase the activity of most nitrogen-converting microorganisms and MBN, and thus promote soil nitrogen transformation.

Food Science

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Melatonin treatment alleviates chilling injury in mango fruit 'Keitt' by modulating proline metabolism under chilling stress Mariama KEBBEH, DONG Jing-xian, HUAN Chen, SHEN Shu-ling, LIU Yan, ZHENG Xiao-lin 2023, 22(3): 935-944.  DOI: 10.1016/j.jia.2023.02.008 Abstract ( )   PDF in ScienceDirect   Mangoes often suffer from low temperature-induced chilling injury (CI) during postharvest cold storage.  Therefore, advanced techniques are crucial and in high demand to solve the chilling stress of mango fruit for a higher value.  This study addresses chilling stress modulation by investigating the effects of melatonin treatment on CI, proline metabolism, and related gene expressions of ‘Keitt’ mango during cold storage after dipped in 0 (control), 0.1 (MT1), and 0.2 mmol L–1 (MT2) melatonin solution for 30 min.  The results revealed that melatonin treatment in MT1 significantly reduced CI development and increased proline content in mango fruit during cold storage compared to the control.  These changes were along with increases in the activity of critical enzymes as well as the expression of encoding genes involved in proline biosynthesis, such as pyrroline-5-carboxylate synthetase (P5CS), pyrroline-5-carboxylate reductase (P5CR), ornithine D-aminotransferase (OAT), P5CS2, P5CR2, and OAT3.  Additionally, proline dehydrogenase (PDH) activity and the expression of the PDH3 gene associated with proline dehydrogenation were lower in MT1-treated mangoes than the controlled group.  Thus, melatonin treatment has regulated proline metabolism resulting in the accumulation of proline, subsequently contributing to enhancing the chilling tolerance of ‘Keitt’ mango fruit.

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Germinated brown rice relieves hyperlipidemia by alleviating gut microbiota dysbiosis REN Chuan-ying, ZHANG Shan, HONG Bin, GUAN Li-jun, HUANG Wen-gong, FENG Jun-ran, SHA Di-xin, YUAN Di, LI Bo, JI Ni-na, LIU Wei, LU Shu-wen 2023, 22(3): 945-957.  DOI: 10.1016/j.jia.2023.02.015 Abstract ( )   PDF in ScienceDirect   Hyperlipidemia is a frequent metabolic disorder that is closely associated with diet.  It is believed that brown rice, containing the outer bran layer and germ, is beneficial for the remission of hyperlipidemia.  This study established a rat model of hyperlipidemia by feeding a high-fat diet.  The hypolipidemic potential of germinated brown rice (Gbrown) and germinated black rice (a germinated black-pigmented brown rice, Gblack) were explored in the model rats, mainly in the aspects of blood lipids, lipases, apolipoproteins, and inflammation.  The gut microbiota in hyperlipidemic rats receiving diverse dietary interventions was determined by 16S rDNA sequencing.  The results showed that the intervention of Gbrown/Gblack alleviated the hyperlipidemia in rats, evidenced by decreased TC, TG, LDL-C, and apolipoprotein B, and increased HDL-C, HL, LPL, LCAT, and apolipoprotein A1.  Gbrown/Gblack also weakened the inflammation in hyperlipidemia rats, evidenced by decreased TNF-α, IL-6, and ET-1.  In addition, 16S rDNA sequencing revealed that the diet of Gbrown/Gblack elevated the abundance and diversity of gut microbiota in hyperlipidemia rats.  At the phylum level, Gbrown/Gblack decreased Firmicutes, increased Bacteroidetes, and decreased the F/B ratio in hyperlipidemia rats.  At the genus level, Gbrown/Gblack decreased Streptococcus and increased Ruminococcus and Allobaculum in hyperlipidemia rats.  Some differential microbial genera relating to lipid metabolism were also determined, such as the Lachnospira and Ruminococcus in the Gblack group, and the Phascolarctobacterium, Dorea, Turicibacter, and Escherichia-Shigella in the Gbrown group.  Notably, the beneficial effect of Gblack was stronger than Gbrown.  To sum up, the dietary interventions of Gbrown/Gblack contributed to the remission of hyperlipidemia by alleviating the dysbiosis of gut microbiota.