All Cover Illustrations

    Volume 22, Issue 2, Feb. 2023

    The melon fly Zeugodacus cucurbitae (Coquillett) is a very destructive tephritid pest across the world. Maleness-on-the-Y (MoY) is a primary factor that regulates sex determination in Ceratitis capitata and is supposed to be conserved in tephritid fruit flies. To investigate whether MoY plays a role in male sex determination of Z. cucurbitae, we examined the expression pattern of ZcMoY during embryogenesis and transiently inhibited ZcMoY in early embryos by RNAi. The expression pattern and knockdown phenotypes of ZcMoY indicate that ZcMoY plays a key role in regulating sex determination of Z. cucurbitae males. Our findings will help the understanding of sex determination in Z. cucurbitae and facilitate the development of genetic sexing strains in its biological control. The photo that depicts the morphology of a Z. cucurbitae female adult is provided by Associate Professor Lin Xianwu from the School of Plant Protection, Hainan University, China. See pages 505–513 for details

    Volume 22, Issue 1, Jan. 2023

    Early defoliation is gradually becoming a major problem that poses a threat to the pear industry in southern China, which is caused by multiple factors including abiotic and biotic stress. Notably, the occurrence of early defoliation induces the out-of-season blooming, which subsequently has negative effects on pear tree vigor, fruit quality, and sustained high yield in the following year. To investigate the cultivars resistant to early defoliation, we performed the resistance and susceptibility evaluation of 155 pear accessions response to early defoliation, which provided the important information for both cultivation protection and future breeding in pear, and the transcriptome analysis provides new insights into potentially essential genes responding to early defoliation in pears for future molecular breeding. The photo is provided by the research team of Dr. Wu Jun from Nanjing Agricultural University, China. See pages 120–138 for details.

    Volume 21, Issue 12, Dec. 2022

    Crop production and livelihoods of smallholder farmers are often threatened by crop insect pests and diseases worsening the insecurity of food. The goal of this special focus is to share knowledge on integrated pest management of four major crop diseases and one insect pest. The innovative technologies presented in the reviews offer valuable guidance and reference for sustainable control of the devastating diseases and insect pests. The cover photo is a combination of the symptoms caused by rice blast disease, fusarium head blight, maize lethal necrosis disease, potato late blight, and desert locust, which were provided by the corresponding authors of the reviews included in this special focus. See pages 3417–3487 for more details.

    Volume 21, Issue 11, Nov. 2022

    China has the largest number of sheep in the world. In order to improve the efficiency of sheep production, a complete understanding of the early-life establishment of the gastrointestinal fungal community allows us to develop better management operations and manipulate the gut microbiota for lambs, as well as provide new insight and directions for future studies in this research area. The succession process of the fungal community from birth to 4 months of age can be divided into
    3 phases: colonization, transition, and a relatively stable period of maturation. Initially, the gastrointestinal fungal communities are heterogeneous, but they become more homogeneous with the lambs’ progress to maturity. The age-related genera Acremonium, Microascus, Valsonectria, Myrmecridium, Scopulariopsis, Myrothecium, Saccharomyces, and Stephanonectria were presented in both rumen and rectum, indicating that these genera may be important in the maturity process of the fungal community. The cover photo of sheep was provided by Prof. Zhang Yingjie from College of Animal Science and Technology, Hebei Agricultural University, China. See pages 3314–3328 for more details.

    Volume 21, Issue 10, Oct. 2022

    Foxtail millet (Setaria italica (L.) Beauv.) is a minor food crop of global importance and a new model for C4 plants. YABBY genes are plant-specific transcription factors (TFs) that function in plant growth and development. To investigate the functions of the YABBY genes in plants’ stress tolerance, we analyzed the YABBY genes in foxtail millet and investigated their functions on plant growth and responses to different stresses. The objective of this study was to analyze the YABBY genes and their functions in this species at the genome-wide level. We also characterized the function of one of the YABBY genes, SiDL, in Arabidopsis. The findings provided a scientific foundation for further analysis of YABBY genes in foxtail millet. The photo is provided by the research team of Dr. Guo Jie from Shanxi Agricultural University, China. See pages 2876–2887 for details.

    Volume 21, Issue 9, Sept. 2022

    Cassava (Manihot esculenta) is an important tropical crop for starch, biofuel production, and animal feed due to its starch-enriched root. Severe drought stresses affect cassava productivity and quality. In plants, it is known that long non-coding RNAs (lncRNAs) are involved in response to abiotic stresses by regulating gene expression. However, the function of cassava lncRNAs in drought response remains largely unknown. The present four-year study demonstrated that DROUGHT-INDUCED INTERGENIC lncRNA (DIR) play a pivotal role in regulating drought stress tolerance in cassava, which may be related to mRNA export and protein quality control pathways. Gain-of-function analysis revealed that DIR overexpression in transgenic cassava seedlings conferred tolerance to drought stress. RNA sequencing (RNA-seq) analysis indicated that a range of drought-responsive genes, such as TFs (NAC, WRKY and bHLH), were induced in DIR-overexpressing transgenic lines. Furthermore, we found that DIR interacted directly with proteins that regulate mRNAs or protein metabolisms in cassava cells to cope with drought stress. Taken together, this study greatly extends the repertoire of lncRNAs in plants, and may provide new insights into lncRNA functions conserved among tropical crops in response to drought stress. The cover photo shows the morphology of fieldgrown of cassava plant and the predicted secondary structure of DIR, which was provided by Prof. Ruan Mengbin and Prof. Li Shuxia from Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, China. See pages 2588–2602 for more details.

    Volume 21, Issue 8, Aug. 2022

    Conservation agriculture (CA) practice systems have been promoted as an effective approach to achieve sustainable agricultural. The present two-year study demonstrated that major rice pests and paddy weeds were effectively controlled by reduced tillage (RT) practice compared to the conventional tillage (CT) treatment, while no tillage (NT) treatment could aggravate the incidence of some weed species. In addition, the diversity of beneficial organisms, such as the pest predators Trichogramma japonicun Ashmead, increased remarkably where either RT or NT was applied, which highlighted the significance of a CA strategy for the promotion of biodiversity in the agroecosystem. More importantly, the rice yield gradually increased after the two-year RT practice, while there was no significant difference in NT. Taken together, this study indicates that the implementation of RT practices could benefit crop protection by enhancing paddy biodiversity and improving crop yield in southern China, which provides a solid basis and novel insights for the establishment of sustainable agro-ecosystems. The cover photo shows the biodiversity of organisms and crop yield differs under three tillage management practices (CT, RT and NT) applied in the present study, which was provided by Prof. Zhong Guohua and Dr. Liu Jie from College of Plant Protection, South China Agricultural University, China. See pages 2345–2356 for more details.

    Volume 21, Issue 7, Jul. 2022

    H5N1 and H5N8 viruses bearing the clade HA gene have been widely circulating in wild birds and are responsible for the loss of over 100 million domestic poultry in Europe, Asia, and North America since January 2020. To prevent domestic poultry from being infected with these exotic viruses, a novel trivalent vaccine with the seed viruses H5-Re13, H5-Re14, and H7-Re4 that carry the HA and NA genes of the newly detected H5N6 virus, H5N8 virus, and H7N9 virus, respectively, was developed in China. Animal studies proved that this novel H5/H7 trivalent vaccine is immunogenic and could provide solid protection against the H5N1, H5N6, H5N8, and H7N9 viruses that are currently circulating in nature. Given the sound protective efficacy of this vaccine and the wide circulation of different H5 and H7 viruses, it’s recommended that this new H5/H7 trivalent inactivated vaccine be used not only in China, but also in other countries where poultry are threatened by H5 and H7 viruses. The cover photo shows the solid protection of the vaccine against different viruses, which was provided by Prof. Chen Hualan from Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, China. See pages 2086–2094 for more details.

    Volume 21, Issue 6, Jun. 2022

    Strawberry (Fragaria×ananassa), known as ‘the queen of fruits’, is very popular with consumers due to its flavor and nutritional value.  WRKY transcription factors play a critical role in biotic and abiotic stress responses in plants.  Based on the cultivated strawberry ‘Camarosa’ genome, 222 FaWRKY genes were identified and analyzed.  Meanwhile, FaWRKY genes participate in regulating the growth and development of different tissues and fruit ripening stages.  In addition, FaWRKY expression profiles were also studied in the strawberry seedlings inoculated with Colletotrichum fructicola, a major pathogen of strawberry.  The photo shows the fruits of the new strawberry cultivar ‘Shenxin’, which was provided by Dr. Zou Xiaohua from Shanghai Academy of Agricultural Sciences, China. See pages 1658–1672 for more details. 

    Volume 21, Issue 5, May 2022

    Pea aphid (Acyrthosiphon pisum) is a destructive insect pest of multiple leguminous plants, it is widely used as a research model for investigating interactions between insects and their host plants. A highly conserved odorant receptor clade among different aphid species was identified by phylogenetic analysis. One of this clade member ApisOr23 in A. pisum had the highest expression level in the antennae compared to other tissues. Functional characterization of ApisOr23 using a heterologous Xenopus expression system revealed that ApisOr23 was broadly tuned to plant volatiles, in which trans-2-hexen-1-al, one of the main volatile organic compounds released from legume plants, activated the highest response of ApisOr23. The results suggest that the conserved Or23 clade in most aphid species might play an important role in host plant detection. The cover photo shows two pea aphids (A. pisum) colonize on the broad bean (Vicia faba) through detecting plant volatiles by antennae, which was provided by Dr. LIU Lei from Institute of Plant Protection, Chinese Academy of Agricultural Sciences. See pages 1414–1423 for details.

    Volume 21, Issue 4, Apr. 2022

    Rice (Oryza sativa L.) is one of the most important food crops in the world, providing nearly 60% of the dietary calories for more than 3 billion people. A major challenge in rice production is to achieve the dual goal of increasing grain yield and nitrogen (N) use efficiency (NUE). The adoption of N-efficient rice varieties (NEVs) is an important approach to achieve the dual goal. It is observed that, in comparison with N-inefficient rice varieties, NEVs produce both higher grain yield and higher NUE, due mainly to a larger sink size resulted from a larger panicle (more spikelets per panicle), higher N dry matter production efficiency (dry matter weight/N uptake) and higher harvest index. The NEVs also exhibit better leaf photosynthetic performance including higher specific leaf weight, greater leaf photosynthetic rate, and higher contents of ribulose-1,5-bisphosphate carboxylase/ oxygenase and chlorophyll in leaves. Furthermore, NEVs show a better canopy structure, which is reflected by a higher ratio of the extinction coefficient for effective leaf N to the light extinction coefficient. All these observations indicate that improved source and sink traits and coordinated source–sink relationship contribute to higher grain yield and higher NUE of NEVs. The cover photo shows the NEV with larger sink size and better leaf photosynthetic performance, which was provided by the Rice Cultivation and Physiology Innovation Team, College of Agriculture, Yangzhou University, China. See pages 947–963 for details

    Volume 21, Issue 3, Mar. 2022

    Ponkan (Citrus reticulata Blanco) is one of the most widely grown citrus species in China due to its elite palatability, strong flavor and good storability. The size and quality of Ponkan fresh fruit are two crucial factors determining its marketing and consumer preference. Various approaches have been employed to improve the fruit size and quality, including manual fruit thinning. Manual fruit thinning was found to increase the proportion of fruit with larger size and elevate the total soluble solids, leading to substantially improved fruit quality. Meanwhile, the fruits from the thinned trees exhibited higher mRNA abundance of sugar transporters, auxin and gibberellin biosynthesis or signaling genes. Therefore, manual fruit thinning could greatly improve fruit quality by promoting fruit expansion due to the increased auxin levels and expediting sugar accumulation through the up-regulation of sugar transporter genes. The cover photo shows the Ponkan fruits with favorable external appearance and internal fruit quality, which was provided by Prof. Liu Jihong from Huazhong Agricultural University, China. See pages 725–735 for more details.

    Volume 21, Issue 2, Jan. 2022

    China is currently undergoing a critical transformation from traditional to modern agriculture. The development of the corn industry urgently requires vital technologies such as mechanical grain harvesting, which can save labor and cost, reduce losses, and raise quality, thus known as the “last mile” of the whole mechanization process of corn production. However, foreign technology was difficult to apply directly in China’s main corn-producing areas, characterized by intricate climatic conditions, diverse planting patterns, and small-scale households. In recent years, corn cultivars suitable for mechanical grain harvesting have been developed, promoted, and gradually reached full-adoption. This has led to harvesting machinery improvements and other technological advances such as the creation of cultivar characteristics catered to regional climatic resources, innovation in cultivation management, and storage and drying facility upgrades. In different regions of China, the adoption of mechanical grain harvesting technology has significantly improved grain quality, and a series of local standards for this technology have been formulated and publicized. For example, “high-efficiency production technology for mechanical grain harvesting of corn” was listed by the Ministry of Agriculture and Rural Affairs as one of the “New Rural Technologies of Chinese Agriculture” in 2020. For the time being, the preliminary development of mechanical corn harvesting technology has been completed, and it is expected to enter a stage of rapid growth. In the coming time, mechanical harvesting, as presently done for wheat and rice, will become a standard practice for corn in China. The photo was provided by the Crop Cultivation and Physiology Innovation Team of the Chinese Academy of Agricultural Sciences.

    Volume 21, Issue 1, Jan. 2022

    The most recent breakthrough in agricultural biotechnology is the introduction of RNAi-mediated strategy to control insect pests, either by transgenic crops expressing insecticidal dsRNAs/siRNAs or RNA pesticides. There is a highly demand to develop a reliable risk evaluation method on the potential off-targets effect of this novel technique. The cover photos showed the larvae of the beet armyworm (Spodoptera exigua) (left), a widely distributed polyphagous pest of both food and economic crops worldwide and the management of this pest insect continues to rely on synthetic chemical insecticides nowadays. The non-target organism, the silkworm (Bombyx mori) (right), is a widely used species in the safety evaluation of agricultural techniques against insect pest. These pictures were provided by Mr. Xiong Kaifan from Huazhong Agricultural University, China and Dr. Li Muwang from Jiangsu University of Science and Technology, China. See pages 170–177 for details.

    Volume 20, Issue 12, Dec. 2021

    Bacterial panicle blight of rice (BPBR), also known as bacterial grain rot of rice, is a serious seed borne disease of rice caused by Burkholderia glumae. Because the optimal temperature range for the growth of B. glumae is relatively high (30–35°C), it is considered that this disease may occur more frequently with current global climate change. Horizontal gene transfer (HGT), also known as lateral gene, has been proved a major driving force in prokaryotic evolution. However, the molecular functions of these transferred genes in pathogenic bacteria especially plant pathogenic bacteria are still not fully investigated. In this study, the whole-genome in silico analysis was performed and found a syringopeptin synthetase (syp) homolog in B. glumae, which can cause bacterial panicle blight in rice, was predicted to be horizontally transferred from Pseudomonas ancestor with solid confidence by phylogenetic analysis. Inoculation of rice panicles with the syp mutant resulted in 60% lower disease index compared with the wild type (WT) parent strain, suggesting the requirement of syp for the full virulence of B. glumae. Chromatography analysis of exudates from B. glumae showed suppression of synthesis of metabolites analogous to syringopeptin in the mutants. All these data raise the possibility of HGT phenomenon in shaping the virulence and adaptation of B. glumae over evolutionary time. The photos are provided by the research team of Prof. Zhu Bo from Shanghai Jiao Tong University, China. See pages 3222–3229 for details.

    Volume 20, Issue 11, Nov. 2021

    Cotton is an important economic crop in China and plays a vital role in improving farmers’ income. In recent years, cotton planting areas have dropped rapidly in China because of high labor cost and low profit. Defoliation is an indispensable step in cotton production with mechanical harvesting, especially in the North China Plain (NCP) where mechanical harvesting is limited by a large proportion of green leaves and unopened bolls at harvest time due to insufficient thermal resources. The goal of this study was to quantify the optimal use of defoliation products while minimizing yield and quality loss in China. The findings would offer valuable guidance for the management of cotton production, promote cotton mechanical harvesting and reduce the labor cost of cotton production in China. The pictures were provided by Engineering Research Center of Plant Growth Regulator, Ministry of Education/College of Agronomy and Biotechnology, China Agricultural University, China. See pages 2892–2899 for details.